rmutil.c

/* $Id: rmutil.c,v 1.78 2006/06/28 23:07:55 rmagick Exp $ */
/*============================================================================\
|                Copyright (C) 2006 by Timothy P. Hunter
| Name:     rmutil.c
| Author:   Tim Hunter
| Purpose:  Utility functions for RMagick
\============================================================================*/

#include "rmagick.h"
#include <errno.h>

static const char *ComplianceType_name(ComplianceType *);
static const char *StyleType_name(StyleType);
static const char *StretchType_name(StretchType);
static void Color_Name_to_PixelPacket(PixelPacket *, VALUE);
static VALUE Enum_type_values(VALUE);
static VALUE Enum_type_inspect(VALUE);
static void handle_exception(ExceptionInfo *, Image *, ErrorRetention);

/*
    Extern:     magick_malloc, magick_free, magick_realloc
    Purpose:    ****Magick versions of standard memory routines.
    Notes:      use when managing memory that ****Magick may have
                allocated or may free.
                If malloc fails, it raises an exception
*/
void *magick_malloc(const size_t size)
{
    void *ptr;
#if defined(HAVE_ACQUIREMAGICKMEMORY)
    ptr = AcquireMagickMemory(size);
#else
    ptr = AcquireMemory(size);
#endif
    if (!ptr)
    {
        rb_raise(rb_eNoMemError, "not enough memory to continue");
    }

    return ptr;
}

void magick_free(void *ptr)
{
#if defined(HAVE_ACQUIREMAGICKMEMORY)
    RelinquishMagickMemory(ptr);
#else
    void *v = ptr;
    LiberateMemory(&v);
#endif
}

void *magick_realloc(void *ptr, const size_t size)
{
    void *v;
#if defined(HAVE_ACQUIREMAGICKMEMORY)
    v = ResizeMagickMemory(ptr, size);
#else
    v = ptr;
    ReacquireMemory(&v, size);
#endif
    if (!v)
    {
        rb_raise(rb_eNoMemError, "not enough memory to continue");
    }
    return v;
}

/*
    Extern:     magick_clone_string
    Purpose:    make a copy of a string in malloc'd memory
    Notes:      Any existing string pointed to by *new_str is freed.
                CloneString asserts if no memory. No need to check
                its return value.

*/
void magick_clone_string(char **new_str, const char *str)
{
    CloneString(new_str, str);
}



/*
    Extern:     rm_string_value_ptr(VALUE*)
    Purpose:    emulate Ruby 1.8's rb_string_value_ptr
    Notes:      This is essentially 1.8's rb_string_value_ptr
                with a few minor changes to make it work in 1.6.
                Always called via STRING_PTR
*/
#if !defined StringValuePtr
char *
rm_string_value_ptr(volatile VALUE *ptr)
{
    volatile VALUE s = *ptr;

    // If VALUE is not a string, call to_str on it
    if (TYPE(s) != T_STRING)
    {
       s = rb_str_to_str(s);
       *ptr = s;
    }
    // If ptr == NULL, allocate a 1 char array
    if (!RSTRING(s)->ptr)
    {
        RSTRING(s)->ptr = ALLOC_N(char, 1);
        (RSTRING(s)->ptr)[0] = 0;
        RSTRING(s)->orig = 0;
    }
    return RSTRING(s)->ptr;
}
#endif

/*
    Extern:     rm_string_value_ptr_len
    Purpose:    safe replacement for rb_str2cstr
    Returns:    stores string length in 2nd arg, returns ptr to C string
    Notes:      Uses rb/rm_string_value_ptr to ensure correct String
                argument.
                Always called via STRING_PTR_LEN
*/
char *rm_string_value_ptr_len(volatile VALUE *ptr, long *len)
{
    volatile VALUE v = *ptr;
    char *str;

    str = STRING_PTR(v);
    *ptr = v;
    *len = RSTRING(v)->len;
    return str;
}


/*
 *  Extern:     rm_strcasecmp(s1, s2)
 *  Purpose:    compare s1 and s2 ignoring case
 *  Returns:    same as strcmp(3)
*/
int
rm_strcasecmp(const char *s1, const char *s2)
{
    while (*s1 && *s2)
    {
        if (toupper(*s1) != toupper(*s2))
        {
            break;
        }
        s1 += 1;
        s2 += 1;
    }
    return (int)(*s1 - *s2);
}



/*
 *  Extern:     rm_check_ary_len(ary, len)
 *  Purpose:    raise exception if array too short
*/
void
rm_check_ary_len(VALUE ary, int len)
{
    if (RARRAY(ary)->len < len)
    {
        rb_raise(rb_eIndexError, "not enough elements in array - expecting %d, got %d",
                        len, RARRAY(ary)->len);
    }
}

/*
    Extern:     rm_check_frozen
    Purpose:    backport rb_check_frozen for 1.6.x releases
*/
void
rm_check_frozen(VALUE obj)
{
    if (OBJ_FROZEN(obj))
    {
        rb_error_frozen(rb_class2name(CLASS_OF(obj)));
    }
}


/*
    Extern:     rm_no_freeze(obj)
    Purpose:    overrides freeze in classes that can't be frozen.
*/
VALUE
rm_no_freeze(VALUE obj)
{
    rb_raise(rb_eTypeError, "can't freeze %s", rb_class2name(CLASS_OF(obj)));
}


/*
 *  Static:     arg_is_number
 *  Purpose:    Try to convert the argument to a double,
 *              raise an exception if fail.
*/
static VALUE
arg_is_number(VALUE arg)
{
    double d;
    d = NUM2DBL(arg);
    d = d;      // satisfy icc
    return arg;
}


/*
 *  Static:     rescue_not_str
 *  Purpose:    called when `rb_str_to_str' raised an exception below
*/
static VALUE
rescue_not_str(VALUE arg)
{
    rb_raise(rb_eTypeError, "argument must be a number or a string in the form 'NN%' (%s given)",
            rb_class2name(CLASS_OF(arg)));
}

/*
 *  Extern:     rm_percentage(obj)
 *  Purpose:    Return a double between 0.0 and 1.0, inclusive.
 *              If the argument is a number convert to a Float object,
 *              otherwise it's supposed to be a string in the form "NN%".
 *              Convert to a number and then to a Float.
*/
double
rm_percentage(VALUE arg)
{
    double pct;
    long pct_long;
    char *pct_str, *end;
    int not_num;

    // Try to convert the argument to a number. If failure, sets not_num to non-zero.
    rb_protect(arg_is_number, arg, &not_num);

    if (not_num)
    {
        arg = rb_rescue(rb_str_to_str, arg, rescue_not_str, arg);
        pct_str = STRING_PTR(arg);
        errno = 0;
        pct_long = strtol(pct_str, &end, 10);
        if (errno == ERANGE)
        {
            rb_raise(rb_eRangeError, "`%s' out of range", pct_str);
        }
        if (*end != '\0' && *end != '%')
        {
            rb_raise(rb_eArgError, "expected percentage, got `%s'", pct_str);
        }

        if (*end == '%' && pct_long != 0)
        {
            pct = ((double)pct_long) / 100.0;
        }
        else
        {
            pct = (double) pct_long;
        }
        if (pct < 0.0)
        {
            rb_raise(rb_eArgError, "percentages may not be negative (got `%s')", pct_str);
        }
    }
    else
    {
        pct = NUM2DBL(arg);
        if (pct < 0.0)
        {
            rb_raise(rb_eArgError, "percentages may not be negative (got `%g')", pct);
        }
    }

    return pct;
}


/*
    Static:     check_num2dbl
    Purpose:    return 0 if rb_num2dbl doesn't raise an exception
 */
static VALUE
check_num2dbl(VALUE obj)
{
    rb_num2dbl(obj);
    return INT2FIX(1);
}


/*
    Static:     rescue_not_dbl
    Purpose:    called if rb_num2dbl raises an exception
 */
static VALUE
rescue_not_dbl(VALUE ignored)
{
    return INT2FIX(0);
}


/*
    Extern:     rm_check_num2dbl
    Purpose:    Return 1 if the object can be converted to a double, 0 otherwise.
*/
int rm_check_num2dbl(VALUE obj)
{
    return FIX2INT(rb_rescue(check_num2dbl, obj, rescue_not_dbl, (VALUE)0));
}


/*
 *  Extern:     rm_str_to_pct
 *  Purpose:    Given a string in the form NN% return the corresponding double.
 *
*/
double rm_str_to_pct(VALUE str)
{
    long pct;
    char *pct_str, *end;

    str = rb_rescue(rb_str_to_str, str, rescue_not_str, str);
    pct_str = STRING_PTR(str);
    errno = 0;
    pct = strtol(pct_str, &end, 10);

    if (errno == ERANGE)
    {
        rb_raise(rb_eRangeError, "`%s' out of range", pct_str);
    }
    if (*end != '%')
    {
        rb_raise(rb_eArgError, "expected percentage, got `%s'", pct_str);
    }
    if (pct < 0L)
    {
        rb_raise(rb_eArgError, "percentages may not be negative (got `%s')", pct_str);
    }

    return pct / 100.0;
}


/*
 *  Extern:     rm_fuzz_to_dbl(obj)
 *  Purpose:    If the argument is a number, convert it to a double.
 *              Otherwise it's supposed to be a string in the form 'NN%'.
 *              Return a percentage of MaxRGB.
 *  Notes:      Called from Image#fuzz= and Info#fuzz=
*/
double
rm_fuzz_to_dbl(VALUE fuzz_arg)
{
    double fuzz;
    char *fuzz_str, *end;
    int not_num;

    // Try to convert the argument to a number. If failure, sets not_num to non-zero.
    rb_protect(arg_is_number, fuzz_arg, &not_num);

    if (not_num)
    {
        // Convert to string, issue error message if failure.
        fuzz_arg = rb_rescue(rb_str_to_str, fuzz_arg, rescue_not_str, fuzz_arg);
        fuzz_str = STRING_PTR(fuzz_arg);
        errno = 0;
        fuzz = strtod(fuzz_str, &end);
        if (errno == ERANGE)
        {
            rb_raise(rb_eRangeError, "`%s' out of range", fuzz_str);
        }
        if(*end == '%')
        {
            if (fuzz < 0.0)
            {
                rb_raise(rb_eArgError, "percentages may not be negative (got `%s')", fuzz_arg);
            }
            fuzz = (fuzz * MaxRGB) / 100.0;
        }
        else if(*end != '\0')
        {
            rb_raise(rb_eArgError, "expected percentage, got `%s'", fuzz_str);
        }
    }
    else
    {
        fuzz = NUM2DBL(fuzz_arg);
        if (fuzz < 0.0)
        {
            rb_raise(rb_eArgError, "fuzz may not be negative (got `%g')", fuzz_arg);
        }
    }

    return fuzz;
}


/*
    Extern:     ImageList_cur_image
    Purpose:    Sends the "cur_image" method to the object. If 'img'
                is an ImageList, then cur_image is self[@scene].
                If 'img' is an image, then cur_image is simply
                'self'.
    Returns:    the return value from "cur_image"
*/
VALUE
ImageList_cur_image(VALUE img)
{
    return rb_funcall(img, ID_cur_image, 0);
}

/*
    Method:     Magick::PrimaryInfo#to_s
    Purpose:    Create a string representation of a Magick::PrimaryInfo
*/
VALUE
PrimaryInfo_to_s(VALUE self)
{
    PrimaryInfo pi;
    char buff[100];

    PrimaryInfo_to_PrimaryInfo(&pi, self);
    sprintf(buff, "x=%g, y=%g, z=%g", pi.x, pi.y, pi.z);
    return rb_str_new2(buff);
}

/*
    Method:     Magick::Chromaticity#to_s
    Purpose:    Create a string representation of a Magick::Chromaticity
*/
VALUE
ChromaticityInfo_to_s(VALUE self)
{
    ChromaticityInfo ci;
    char buff[200];

    ChromaticityInfo_to_ChromaticityInfo(&ci, self);
    sprintf(buff, "red_primary=(x=%g,y=%g) "
                  "green_primary=(x=%g,y=%g) "
                  "blue_primary=(x=%g,y=%g) "
                  "white_point=(x=%g,y=%g) ",
                  ci.red_primary.x, ci.red_primary.y,
                  ci.green_primary.x, ci.green_primary.y,
                  ci.blue_primary.x, ci.blue_primary.y,
                  ci.white_point.x, ci.white_point.y);
    return rb_str_new2(buff);
}

/*
    Method:     Magick::Pixel#to_s
    Purpose:    Create a string representation of a Magick::Pixel
*/
VALUE
Pixel_to_s(VALUE self)
{
    Pixel *pixel;
    char buff[100];

    Data_Get_Struct(self, Pixel, pixel);
    sprintf(buff, "red=%d, green=%d, blue=%d, opacity=%d"
          , pixel->red, pixel->green, pixel->blue, pixel->opacity);
    return rb_str_new2(buff);
}

/*
    Method:     Magick::Pixel.from_color(string)
    Purpose:    Construct an Magick::Pixel corresponding to the given color name.
    Notes:      the "inverse" is Image *#to_color, b/c the conversion of a pixel
                to a color name requires both a color depth and if the opacity
                value has meaning (i.e. whether image->matte == True or not).

                Also see Magick::Pixel#to_color, below.
*/
VALUE
Pixel_from_color(VALUE class, VALUE name)
{
    PixelPacket pp;
    ExceptionInfo exception;
    MagickBooleanType okay;

    class = class;      // defeat "never referenced" message from icc

    GetExceptionInfo(&exception);
    okay = QueryColorDatabase(STRING_PTR(name), &pp, &exception);
    CHECK_EXCEPTION()
    DestroyExceptionInfo(&exception);

    if (!okay)
    {
        rb_raise(rb_eArgError, "invalid color name: %s", STRING_PTR(name));
    }

    return Pixel_from_PixelPacket(&pp);
}

/*
    Method:     Magick::Pixel#to_color(compliance=Magick::???Compliance,
                                      matte=False
                                      depth=QuantumDepth)
    Purpose:    return the color name corresponding to the pixel values
    Notes:      the conversion respects the value of the 'opacity' field
                in the Pixel.
*/
VALUE
Pixel_to_color(int argc, VALUE *argv, VALUE self)
{
    Info *info;
    Image *image;
    Pixel *pixel;
    char name[MaxTextExtent];
    ExceptionInfo exception;
    ComplianceType compliance = AllCompliance;
    unsigned int matte = False;
    unsigned int depth = QuantumDepth;

    switch (argc)
    {
        case 3:
            depth = NUM2UINT(argv[2]);

            // Ensure depth is appropriate for the way xMagick was compiled.
            switch (depth)
            {
                case 8:
#if QuantumDepth == 16 || QuantumDepth == 32
                case 16:
#endif
#if QuantumDepth == 32
                case 32:
#endif
                    break;
                default:
                    rb_raise(rb_eArgError, "invalid depth (%d)", depth);
                    break;
            }
       case 2:
            matte = RTEST(argv[1]);
        case 1:
            VALUE_TO_ENUM(argv[0], compliance, ComplianceType);
        case 0:
            break;
        default:
            rb_raise(rb_eArgError, "wrong number of arguments (%d for 0 to 2)", argc);
    }

    Data_Get_Struct(self, Pixel, pixel);

    info = CloneImageInfo(NULL);
    image = AllocateImage(info);
    image->depth = depth;
    image->matte = matte;
    DestroyImageInfo(info);
    GetExceptionInfo(&exception);
    (void) QueryColorname(image, pixel, compliance, name, &exception);
    DestroyImage(image);
    CHECK_EXCEPTION()
    DestroyExceptionInfo(&exception);

    // Always return a string, even if it's ""
    return rb_str_new2(name);
}

/*
    Method:     Pixel#to_HSL
    Purpose:    Converts an RGB pixel to the array
                [hue, saturation, luminosity].
*/
VALUE
Pixel_to_HSL(VALUE self)
{
    Pixel *pixel;
    double hue, saturation, luminosity;
    volatile VALUE hsl;

    Data_Get_Struct(self, Pixel, pixel);
    TransformHSL(pixel->red, pixel->green, pixel->blue,
                 &hue, &saturation, &luminosity);

    hsl = rb_ary_new3(3, rb_float_new(hue), rb_float_new(saturation),
                      rb_float_new(luminosity));

    return hsl;
}

/*
    Method:     Pixel.from_HSL
    Purpose:    Constructs an RGB pixel from the array
                [hue, saturation, luminosity].
*/
VALUE
Pixel_from_HSL(VALUE class, VALUE hsl)
{
    PixelPacket rgb = {0};
    double hue, saturation, luminosity;

    class = class;      // defeat "never referenced" message from icc

    hsl = rb_Array(hsl);    // Ensure array
    if (RARRAY(hsl)->len < 3)
    {
        rb_raise(rb_eArgError, "array argument must have at least 3 elements");
    }

    hue        = NUM2DBL(rb_ary_entry(hsl, 0));
    saturation = NUM2DBL(rb_ary_entry(hsl, 1));
    luminosity = NUM2DBL(rb_ary_entry(hsl, 2));

    HSLTransform(hue, saturation, luminosity,
                 &rgb.red, &rgb.green, &rgb.blue);
    return Pixel_from_PixelPacket(&rgb);
}

/*
    Method:     Pixel#eql?
    Purpose:    For use with Hash
*/
VALUE
Pixel_eql_q(VALUE self, VALUE other)
{
    return NUM2INT(Pixel_spaceship(self, other)) == 0 ? Qtrue : Qfalse;
}

/*
    Method:  Pixel#fcmp(other[, fuzz[, colorspace]])
    Purpose: Compare pixel values for equality
*/
VALUE
Pixel_fcmp(int argc, VALUE *argv, VALUE self)
{
#if defined(HAVE_FUZZYCOLORCOMPARE)
    Image *image;
    Info *info;
#endif

    Pixel *this, *that;
    ColorspaceType colorspace = RGBColorspace;
    double fuzz = 0.0;
    unsigned int equal;

    switch (argc)
    {
        case 3:
            VALUE_TO_ENUM(argv[2], colorspace, ColorspaceType);
        case 2:
            fuzz = NUM2DBL(argv[1]);
        case 1:
            // Allow 1 argument
            break;
        default:
            rb_raise(rb_eArgError, "wrong number of arguments (%d for 1 to 3)", argc);
            break;
    }

    Data_Get_Struct(self, Pixel, this);
    Data_Get_Struct(argv[0], Pixel, that);

#if defined(HAVE_FUZZYCOLORCOMPARE) || defined(HAVE_ISCOLORSIMILAR)
    // The FuzzyColorCompare function expects to get the
    // colorspace and fuzz parameters from an Image structure.

    info = CloneImageInfo(NULL);
    if (!info)
    {
        rb_raise(rb_eNoMemError, "not enough memory to continue");
    }

    image = AllocateImage(info);
    if (!image)
    {
        rb_raise(rb_eNoMemError, "not enough memory to continue");
    }
    DestroyImageInfo(info);

    image->colorspace = colorspace;
    image->fuzz = fuzz;

#if defined(HAVE_ISCOLORSIMILAR)
    equal = IsColorSimilar(image, this, that);
#else
    equal = FuzzyColorCompare(image, this, that);
#endif
    DestroyImage(image);

#else
    equal = FuzzyColorMatch(this, that, fuzz);
#endif

    return equal ? Qtrue : Qfalse;
}


/*
    Method:     Pixel#hash
    Notes:      INT2FIX left-shifts 1 bit. Sacrifice 1 bit
                from the opacity attribute to the FIXNUM_FLAG.
*/
VALUE
Pixel_hash(VALUE self)
{
    Pixel *pixel;
    unsigned int hash;

    Data_Get_Struct(self, Pixel, pixel);

    hash  = ScaleQuantumToChar(pixel->red)   << 24;
    hash += ScaleQuantumToChar(pixel->green) << 16;
    hash += ScaleQuantumToChar(pixel->blue)  << 8;
    hash += ScaleQuantumToChar(pixel->opacity);
    hash >>= 1;

    return INT2FIX(hash);

}

/*
    Method:  Pixel#intensity
    Purpose: Return the "intensity" of a pixel
*/
VALUE
Pixel_intensity(VALUE self)
{
    Pixel *pixel;
    unsigned long intensity;

    Data_Get_Struct(self, Pixel, pixel);

    intensity = (unsigned long)
                (0.299*pixel->red) + (0.587*pixel->green) + (0.114*pixel->blue);

    return ULONG2NUM(intensity);
}


/*
    Methods:    Pixel RGBA attribute accessors
    Purpose:    Get/set Pixel attributes
    Note:       Pixel is Observable. Setters call changed, notify_observers
    Note:       Setters return their argument values for backward compatibility
                to when Pixel was a Struct class.
*/

DEF_ATTR_READER(Pixel, red, int)
DEF_ATTR_READER(Pixel, green, int)
DEF_ATTR_READER(Pixel, blue, int)
DEF_ATTR_READER(Pixel, opacity, int)
DEF_PIXEL_CHANNEL_WRITER(red)
DEF_PIXEL_CHANNEL_WRITER(green)
DEF_PIXEL_CHANNEL_WRITER(blue)
DEF_PIXEL_CHANNEL_WRITER(opacity)


/*
    Methods:    Pixel CMYK attribute accessors
    Purpose:    Get/set Pixel attributes
    Note:       Pixel is Observable. Setters call changed, notify_observers
    Note:       Setters return their argument values for backward compatibility
                to when Pixel was a Struct class.
*/
DEF_PIXEL_CMYK_CHANNEL_ACCESSOR(cyan, red)
DEF_PIXEL_CMYK_CHANNEL_ACCESSOR(magenta, green)
DEF_PIXEL_CMYK_CHANNEL_ACCESSOR(yellow, blue)
DEF_PIXEL_CMYK_CHANNEL_ACCESSOR(black, opacity)



/*
    Method:     Pixel#<=>
    Purpose:    Support Comparable mixin
*/
VALUE Pixel_spaceship(VALUE self, VALUE other)
{
    Pixel *this, *that;

    Data_Get_Struct(self, Pixel, this);
    Data_Get_Struct(other, Pixel, that);

    if (this->red != that->red)
    {
        return INT2NUM((this->red - that->red)/abs(this->red - that->red));
    }
    else if(this->green != that->green)
    {
        return INT2NUM((this->green - that->green)/abs(this->green - that->green));
    }
    else if(this->blue != that->blue)
    {
        return INT2NUM((this->blue - that->blue)/abs(this->blue - that->blue));
    }
    else if(this->opacity != that->opacity)
    {
        return INT2NUM((this->opacity - that->opacity)/abs(this->opacity - that->opacity));
    }

    // Values are equal, check class.

    return rb_funcall(CLASS_OF(self), rb_intern("<=>"), 1, CLASS_OF(other));

}


/*
    Static:     destroy_Pixel
    Purpose:    Free the storage associated with a Pixel object
*/
static void
destroy_Pixel(Pixel *pixel)
{
    xfree(pixel);
}


#if defined(HAVE_RB_DEFINE_ALLOC_FUNC)
/*
    Extern:     Pixel_alloc
    Purpose:    Allocate a Pixel object
*/
VALUE
Pixel_alloc(VALUE class)
{
    Pixel *pixel;

    pixel = ALLOC(Pixel);
    memset(pixel, '\0', sizeof(Pixel));
    return Data_Wrap_Struct(class, NULL, destroy_Pixel, pixel);
}

#else

/*
    Method:     Pixel.new
    Purpose:    Construct a new Pixel object
*/
VALUE
Pixel_new(int argc, VALUE *argv, VALUE class)
{
    Pixel *pixel;
    volatile VALUE pixel_obj;

    pixel = ALLOC(Pixel);
    memset(pixel, '\0', sizeof(Pixel));
    pixel_obj = Data_Wrap_Struct(class, NULL, destroy_Pixel, pixel);

    rb_obj_call_init(pixel_obj, argc, argv);
    return pixel_obj;
}
#endif


/*
    Method:     Pixel#initialize(red=0,green=0,blue=0,opacity=0)
    Notes:      For backward compatibility, arguments may be nil.
*/
VALUE
Pixel_initialize(int argc, VALUE *argv, VALUE self)
{
    Pixel *pixel;

    Data_Get_Struct(self, Pixel, pixel);

    switch(argc)
    {
        case 4:
            if (argv[3] != Qnil)
            {
                pixel->opacity = (Quantum) NUM2UINT(argv[3]);
            }
        case 3:
            if (argv[2] != Qnil)
            {
                pixel->blue = (Quantum) NUM2UINT(argv[2]);
            }
        case 2:
            if (argv[1] != Qnil)
            {
                pixel->green = (Quantum) NUM2UINT(argv[1]);
            }
        case 1:
            if (argv[0] != Qnil)
            {
                pixel->red = (Quantum) NUM2UINT(argv[0]);
            }
        case 0:
            break;
        default:
            rb_raise(rb_eArgError, "wrong number of arguments (%d for 0 to 4)", argc);
    }

    return self;
}


/*
    Method: Pixel#===
    Purpose:    "Case equal" operator for Pixel
*/

VALUE Pixel_case_eq(VALUE self, VALUE other)
{
    Pixel *this, *that;

    if (CLASS_OF(self) == CLASS_OF(other))
    {
        Data_Get_Struct(self, Pixel, this);
        Data_Get_Struct(other, Pixel, that);
        return (this->red == that->red
            && this->blue == that->blue
            && this->green == that->green
            && this->opacity == that->opacity) ? Qtrue : Qfalse;
    }

    return Qfalse;
}


VALUE
Pixel_dup(VALUE self)
{
    Pixel *pixel;
    volatile VALUE dup;

    pixel = ALLOC(Pixel);
    memset(pixel, '\0', sizeof(Pixel));
    dup = Data_Wrap_Struct(CLASS_OF(self), NULL, destroy_Pixel, pixel);
    if (rb_obj_tainted(self))
    {
        rb_obj_taint(dup);
    }
    return rb_funcall(dup, ID_initialize_copy, 1, self);
}


/*
    Method:     Pixel#clone
    Notes:      see dup, init_copy
*/
VALUE
Pixel_clone(VALUE self)
{
    volatile VALUE clone;

    clone = Pixel_dup(self);
    if (OBJ_FROZEN(self))
    {
        rb_obj_freeze(clone);
    }

    return clone;
}


/*
    Method:     Pixel#initialize_copy
    Purpose:    initialize clone, dup methods
*/
VALUE Pixel_init_copy(VALUE self, VALUE orig)
{
    Pixel *copy, *original;

    Data_Get_Struct(orig, Pixel, original);
    Data_Get_Struct(self, Pixel, copy);

    *copy = *original;

    return self;
}



/*
    Method:     Magick::Rectangle#to_s
    Purpose:    Create a string representation of a Magick::Rectangle
*/
VALUE
RectangleInfo_to_s(VALUE self)
{
    RectangleInfo rect;
    char buff[100];

    Rectangle_to_RectangleInfo(&rect, self);
    sprintf(buff, "width=%lu, height=%lu, x=%ld, y=%ld"
          , rect.width, rect.height, rect.x, rect.y);
    return rb_str_new2(buff);
}

/*
    Method:     Magick::SegmentInfo#to_s
    Purpose:    Create a string representation of a Magick::Segment
*/
VALUE
SegmentInfo_to_s(VALUE self)
{
    SegmentInfo segment;
    char buff[100];

    Segment_to_SegmentInfo(&segment, self);
    sprintf(buff, "x1=%g, y1=%g, x2=%g, y2=%g"
          , segment.x1, segment.y1, segment.x2, segment.y2);
    return rb_str_new2(buff);
}

/*
    Extern:     PixelPacket_to_Color_Name
    Purpose:    Map the color intensity to a named color
    Returns:    the named color as a String
    Notes:      See below for the equivalent function that accepts an Info
                structure instead of an Image.
*/
VALUE
PixelPacket_to_Color_Name(Image *image, PixelPacket *color)
{
    char name[MaxTextExtent];
    ExceptionInfo exception;

    GetExceptionInfo(&exception);

    (void) QueryColorname(image, color, X11Compliance, name, &exception);
    CHECK_EXCEPTION()
    DestroyExceptionInfo(&exception);

    return rb_str_new2(name);
}

/*
    Extern:     PixelPacket_to_Color_Name_Info
    Purpose:    Map the color intensity to a named color
    Returns:    the named color as a String
    Notes:      Accepts an Info structure instead of an Image (see above).
                Simply create an Image from the Info, call QueryColorname,
                and then destroy the Image.
                If the Info structure is NULL, creates a new one.

                Note that the default depth is always used, and the matte
                value is set to False, which means "don't use the alpha channel".
*/
VALUE
PixelPacket_to_Color_Name_Info(Info *info, PixelPacket *color)
{
    Image *image;
    Info *my_info;
    volatile VALUE color_name;

    my_info = info ? info : CloneImageInfo(NULL);

    image = AllocateImage(info);
    image->matte = False;
    color_name = PixelPacket_to_Color_Name(image, color);
    DestroyImage(image);
    if (!info)
    {
        DestroyImageInfo(my_info);
    }

    return color_name;
}

/*
    Static:     Color_Name_to_PixelPacket
    Purpose:    Convert a color name to a PixelPacket
    Raises:     ArgumentError
*/
static void
Color_Name_to_PixelPacket(PixelPacket *color, VALUE name_arg)
{
    MagickBooleanType okay;
    char *name;
    ExceptionInfo exception;

    GetExceptionInfo(&exception);
    name = STRING_PTR(name_arg);
    okay = QueryColorDatabase(name, color, &exception);
    DestroyExceptionInfo(&exception);
    if (!okay)
    {
        rb_raise(rb_eArgError, "invalid color name %s", name);
    }
}

/*
    Extern:     AffineMatrix_to_AffineMatrix
    Purpose:    Convert a Magick::AffineMatrix object to a AffineMatrix structure.
    Notes:      If not initialized, the defaults are [sx,rx,ry,sy,tx,ty] = [1,0,0,1,0,0]
*/
void
AffineMatrix_to_AffineMatrix(AffineMatrix *am, VALUE st)
{
    volatile VALUE values, v;

    if (CLASS_OF(st) != Class_AffineMatrix)
    {
        rb_raise(rb_eTypeError, "type mismatch: %s given",
                 rb_class2name(CLASS_OF(st)));
    }
    values = rb_funcall(st, ID_values, 0);
    v = rb_ary_entry(values, 0);
    am->sx = v == Qnil ? 1.0 : NUM2DBL(v);
    v = rb_ary_entry(values, 1);
    am->rx = v == Qnil ? 0.0 : NUM2DBL(v);
    v = rb_ary_entry(values, 2);
    am->ry = v == Qnil ? 0.0 : NUM2DBL(v);
    v = rb_ary_entry(values, 3);
    am->sy = v == Qnil ? 1.0 : NUM2DBL(v);
    v = rb_ary_entry(values, 4);
    am->tx = v == Qnil ? 0.0 : NUM2DBL(v);
    v = rb_ary_entry(values, 4);
    am->ty = v == Qnil ? 0.0 : NUM2DBL(v);
}


/*
    Extern:     ClassType_new
    Purpose:    Construct a ClassType enum object for the specified value
*/
VALUE
ClassType_new(ClassType cls)
{
    const char *name;

    switch(cls)
    {
        default:
        case UndefinedClass:
            name = "UndefineClass";
            break;
        case DirectClass:
            name = "DirectClass";
            break;
        case PseudoClass:
            name = "PseudoClass";
            break;
    }

    return rm_enum_new(Class_ClassType, ID2SYM(rb_intern(name)), INT2FIX(cls));
}


/*
    Extern:     ColorspaceType_new
    Purpose:    construct a ColorspaceType enum object for the specified value
*/
VALUE
ColorspaceType_new(ColorspaceType cs)
{
    const char *name;

#if defined(HAVE_REC601YCBCRCOLORSPACE)
    // GM 1.2  defines this symbol to be equal to YCbCrColorspace,  so we
    // can't use it as a case label.  GM wants the string version of this
    // enumerator to be Rec601YCbCrColorspace (see ColorspaceTypeToString
    // in colorspace.c) so that's what we return for both versions of the
    // enumerator.
    if (cs == Rec601YCbCrColorspace)
    {
        return rm_enum_new(Class_ColorspaceType
            , ID2SYM(rb_intern("Rec601YCbCrColorspace")), INT2FIX(cs));
    }
#endif

    switch(cs)
    {
        default:
        case UndefinedColorspace:
            name = "UndefinedColorspace";
            break;
        case RGBColorspace:
            name = "RGBColorspace";
            break;
        case GRAYColorspace:
            name = "GRAYColorspace";
            break;
        case TransparentColorspace:
            name = "TransparentColorspace";
            break;
        case OHTAColorspace:
            name = "OHTAColorspace";
            break;
        case XYZColorspace:
            name = "XYZColorspace";
            break;
        case YCbCrColorspace:
            name = "YCbCrColorspace";
            break;
        case YCCColorspace:
            name = "YCCColorspace";
            break;
        case YIQColorspace:
            name = "YIQColorspace";
            break;
        case YPbPrColorspace:
            name = "YPbPrColorspace";
            break;
        case YUVColorspace:
            name = "YUVColorspace";
            break;
        case CMYKColorspace:
            name = "CMYKColorspace";
            break;
        case sRGBColorspace:
            name = "sRGBColorspace";
            break;
        case HSLColorspace:
            name = "HSLColorspace";
            break;
        case HWBColorspace:
            name = "HWBColorspace";
            break;
#if defined(HAVE_HSBCOLORSPACE)
        case HSBColorspace:
            name = "HSBColorspace";
            break;
#endif
#if defined(HAVE_LABCOLORSPACE)
        case LABColorspace:
            name = "LABColorspace";
            break;
#endif
#if defined(HAVE_CINEONLOGRGBCOLORSPACE)
        case CineonLogRGBColorspace:
            name = "CineonLogRGBColorspace";
            break;
#endif
#if defined(HAVE_REC601LUMACOLORSPACE)
        case Rec601LumaColorspace:
            name = "Rec601LumaColorspace";
            break;
#endif
#if defined(HAVE_REC709LUMACOLORSPACE)
        case Rec709LumaColorspace:
            name = "Rec709LumaColorspace";
            break;
#endif
#if defined(HAVE_REC709YCBCRCOLORSPACE)
        case Rec709YCbCrColorspace:
            name = "Rec709YCbCrColorspace";
            break;
#endif
#if defined(HAVE_LOGCOLORSPACE)
        case LogColorspace:
            name = "LogColorspace";
            break;
#endif
    }

    return rm_enum_new(Class_ColorspaceType, ID2SYM(rb_intern(name)), INT2FIX(cs));

}

/*
 *  Static:     ComplianceType_new
    Purpose:    construct a ComplianceType enum object for the specified value
*/
static VALUE
ComplianceType_new(ComplianceType compliance)
{
    const char *name;

    // Turn off undefined bits
    compliance &= (SVGCompliance|X11Compliance|XPMCompliance);
    name = ComplianceType_name(&compliance);
    return rm_enum_new(Class_ComplianceType, ID2SYM(rb_intern(name)), INT2FIX(compliance));
}


/*
    Static:     CompositeOperator_new
    Purpose:    return the name of a CompositeOperator enum as a string
*/
static const char *
CompositeOperator_name(CompositeOperator op)
{
    switch (op)
    {
        default:
        ENUM_TO_NAME(UndefinedCompositeOp)
        ENUM_TO_NAME(NoCompositeOp)
        ENUM_TO_NAME(AddCompositeOp)
        ENUM_TO_NAME(AtopCompositeOp)
        ENUM_TO_NAME(BumpmapCompositeOp)
        ENUM_TO_NAME(ClearCompositeOp)
#if defined(HAVE_COLORDODGECOMPOSITEOP)
        ENUM_TO_NAME(ColorBurnCompositeOp)
        ENUM_TO_NAME(BlendCompositeOp)
        ENUM_TO_NAME(ColorDodgeCompositeOp)
        ENUM_TO_NAME(ExclusionCompositeOp)
        ENUM_TO_NAME(HardLightCompositeOp)
        ENUM_TO_NAME(SoftLightCompositeOp)
#endif
        ENUM_TO_NAME(ColorizeCompositeOp)
        ENUM_TO_NAME(CopyBlueCompositeOp)
        ENUM_TO_NAME(CopyCompositeOp)
#if defined(HAVE_COPYCYANCOMPOSITEOP)   // CYMK added 5.5.7
        ENUM_TO_NAME(CopyCyanCompositeOp)
        ENUM_TO_NAME(CopyMagentaCompositeOp)
        ENUM_TO_NAME(CopyYellowCompositeOp)
        ENUM_TO_NAME(CopyBlackCompositeOp)
#endif
        ENUM_TO_NAME(CopyGreenCompositeOp)
        ENUM_TO_NAME(CopyOpacityCompositeOp)
        ENUM_TO_NAME(CopyRedCompositeOp)
        ENUM_TO_NAME(DarkenCompositeOp)
#if defined(HAVE_DSTCOMPOSITEOP)
        ENUM_TO_NAME(DstAtopCompositeOp)
        ENUM_TO_NAME(DstCompositeOp)
        ENUM_TO_NAME(DstInCompositeOp)
        ENUM_TO_NAME(DstOutCompositeOp)
        ENUM_TO_NAME(DstOverCompositeOp)
#endif
        ENUM_TO_NAME(DifferenceCompositeOp)
        ENUM_TO_NAME(DisplaceCompositeOp)
        ENUM_TO_NAME(DissolveCompositeOp)
        ENUM_TO_NAME(HueCompositeOp)
        ENUM_TO_NAME(InCompositeOp)
        ENUM_TO_NAME(LightenCompositeOp)
        ENUM_TO_NAME(LuminizeCompositeOp)
        ENUM_TO_NAME(MinusCompositeOp)
        ENUM_TO_NAME(ModulateCompositeOp)
        ENUM_TO_NAME(MultiplyCompositeOp)
        ENUM_TO_NAME(OutCompositeOp)
        ENUM_TO_NAME(OverCompositeOp)
        ENUM_TO_NAME(OverlayCompositeOp)
        ENUM_TO_NAME(PlusCompositeOp)
#if defined(HAVE_REPLACECOMPOSITEOP)    // Added 5.5.8
        ENUM_TO_NAME(ReplaceCompositeOp)
#endif
        ENUM_TO_NAME(SaturateCompositeOp)
        ENUM_TO_NAME(ScreenCompositeOp)
#if defined(HAVE_DSTCOMPOSITEOP)
        ENUM_TO_NAME(SrcAtopCompositeOp)
        ENUM_TO_NAME(SrcCompositeOp)
        ENUM_TO_NAME(SrcInCompositeOp)
        ENUM_TO_NAME(SrcOutCompositeOp)
        ENUM_TO_NAME(SrcOverCompositeOp)
#endif
        ENUM_TO_NAME(SubtractCompositeOp)
        ENUM_TO_NAME(ThresholdCompositeOp)
        ENUM_TO_NAME(XorCompositeOp)
    }
}

/*
   External:    CompositeOperator_new
   Purpose:     Construct a CompositeOperator enum object for the specified value
*/
VALUE
CompositeOperator_new(CompositeOperator op)
{
    const char *name;

    name = CompositeOperator_name(op);
    return rm_enum_new(Class_CompositeOperator, ID2SYM(rb_intern(name)), INT2FIX(op));
}


/*
    Static:     CompressionType_name
    Purpose:    Return the name of a CompressionType enum as a string
*/
static const char *
CompressionType_name(CompressionType ct)
{
    switch (ct)
    {
        default:
        ENUM_TO_NAME(UndefinedCompression)
        ENUM_TO_NAME(NoCompression)
        ENUM_TO_NAME(BZipCompression)
        ENUM_TO_NAME(FaxCompression)
        ENUM_TO_NAME(Group4Compression)
        ENUM_TO_NAME(JPEGCompression)
        ENUM_TO_NAME(LosslessJPEGCompression)
        ENUM_TO_NAME(LZWCompression)
        ENUM_TO_NAME(RLECompression)
        ENUM_TO_NAME(ZipCompression)
    }
}


/*
 * External:    CompressionType_new
   Purpose:     Construct a CompressionType enum object for the specified value
*/
VALUE
CompressionType_new(CompressionType ct)
{
    const char *name;

    name = CompressionType_name(ct);
    return rm_enum_new(Class_CompressionType, ID2SYM(rb_intern(name)), INT2FIX(ct));
}


/*
    Static:     DisposeType_name
    Purpose:    Return the name of a DisposeType enum as a string
*/
static const char *
DisposeType_name(DisposeType type)
{
    switch(type)
    {
        default:
        ENUM_TO_NAME(UndefinedDispose)
        ENUM_TO_NAME(BackgroundDispose)
        ENUM_TO_NAME(NoneDispose)
        ENUM_TO_NAME(PreviousDispose)
    }
}


/*
    External:   DisposeType.new
    Purpose:    Construct a DisposeType enum object for the specified value..new
*/
VALUE
DisposeType_new(DisposeType type)
{
    const char *name;

    name = DisposeType_name(type);
    return rm_enum_new(Class_DisposeType, ID2SYM(rb_intern(name)), INT2FIX(type));
}


/*
    Static:     FilterTypes_name
    Purpose:    Return the name of a FilterTypes enum as a string
*/
static const char *
FilterTypes_name(FilterTypes type)
{
    switch(type)
    {
        default:
        ENUM_TO_NAME(UndefinedFilter)
        ENUM_TO_NAME(PointFilter)
        ENUM_TO_NAME(BoxFilter)
        ENUM_TO_NAME(TriangleFilter)
        ENUM_TO_NAME(HermiteFilter)
        ENUM_TO_NAME(HanningFilter)
        ENUM_TO_NAME(HammingFilter)
        ENUM_TO_NAME(BlackmanFilter)
        ENUM_TO_NAME(GaussianFilter)
        ENUM_TO_NAME(QuadraticFilter)
        ENUM_TO_NAME(CubicFilter)
        ENUM_TO_NAME(CatromFilter)
        ENUM_TO_NAME(MitchellFilter)
        ENUM_TO_NAME(LanczosFilter)
        ENUM_TO_NAME(BesselFilter)
        ENUM_TO_NAME(SincFilter)
    }
}


/*
    External:  FilterTypes.new
    Purpose: Construct an FilterTypes enum object for the specified value
*/
VALUE
FilterTypes_new(FilterTypes type)
{
    const char *name;

    name = FilterTypes_name(type);
    return rm_enum_new(Class_FilterTypes, ID2SYM(rb_intern(name)), INT2FIX(type));
}



/*
    Static:     EndianType_name
    Purpose:    Return the name of a EndianType enum as a string
*/
static const char *
EndianType_name(EndianType type)
{
    switch(type)
    {
        default:
        ENUM_TO_NAME(UndefinedEndian)
        ENUM_TO_NAME(LSBEndian)
        ENUM_TO_NAME(MSBEndian)
    }
}

/*
    External:   EndianType.new
    Purpose:    Construct an EndianType enum object
*/
VALUE
EndianType_new(EndianType type)
{
    const char *name;

    name = EndianType_name(type);
    return rm_enum_new(Class_EndianType, ID2SYM(rb_intern(name)), INT2FIX(type));
}



/*
    Static:     ImageType_name
    Purpose:    Return the name of a ImageType enum as a string
*/
static char *
ImageType_name(ImageType type)
{    switch(type)
    {
        default:
        ENUM_TO_NAME(UndefinedType)
        ENUM_TO_NAME(BilevelType)
        ENUM_TO_NAME(GrayscaleType)
        ENUM_TO_NAME(GrayscaleMatteType)
        ENUM_TO_NAME(PaletteType)
        ENUM_TO_NAME(PaletteMatteType)
        ENUM_TO_NAME(TrueColorType)
        ENUM_TO_NAME(TrueColorMatteType)
        ENUM_TO_NAME(ColorSeparationType)
        ENUM_TO_NAME(ColorSeparationMatteType)
        ENUM_TO_NAME(OptimizeType)
    }

}


/*
    External:   ImageType.new
    Purpose:    Construct an ImageType enum object for the specified value
*/
VALUE
ImageType_new(ImageType type)
{
    const char *name;

    name = ImageType_name(type);
    return rm_enum_new(Class_ImageType, ID2SYM(rb_intern(name)), INT2FIX(type));
}


/*
    Static:     InterlaceType_name
    Purpose:    Return the name of a InterlaceType enum as a string
*/
static const char *
InterlaceType_name(InterlaceType interlace)
{
    switch(interlace)
    {
        default:
        ENUM_TO_NAME(UndefinedInterlace)
        ENUM_TO_NAME(NoInterlace)
        ENUM_TO_NAME(LineInterlace)
        ENUM_TO_NAME(PlaneInterlace)
        ENUM_TO_NAME(PartitionInterlace)
    }
}


/*
    External:   InterlaceType_new
    Purpose:    Construct an InterlaceType enum object for the specified value.
*/
VALUE
InterlaceType_new(InterlaceType interlace)
{
    const char *name;

    name = InterlaceType_name(interlace);
    return rm_enum_new(Class_InterlaceType, ID2SYM(rb_intern(name)), INT2FIX(interlace));
}


/*
    External:   MagickLayerMethod_new
    Purpose:    Construct an MagickLayerMethod enum object for the specified value.
*/
#if defined(HAVE_COMPAREIMAGELAYERS)
static const char *
MagickLayerMethod_name(MagickLayerMethod method)
{
    switch(method)
    {
        default:
        ENUM_TO_NAME(UndefinedLayer)
        ENUM_TO_NAME(CompareAnyLayer)
        ENUM_TO_NAME(CompareClearLayer)
        ENUM_TO_NAME(CompareOverlayLayer)
        ENUM_TO_NAME(OptimizeLayer)
        ENUM_TO_NAME(OptimizePlusLayer)
#if defined(HAVE_COALESCELAYER)
        ENUM_TO_NAME(CoalesceLayer)
        ENUM_TO_NAME(DisposeLayer)
#endif
    }
}

VALUE
MagickLayerMethod_new(MagickLayerMethod method)
{
    const char *name;

    name = MagickLayerMethod_name(method);
    return rm_enum_new(Class_MagickLayerMethod, ID2SYM(rb_intern(name)), INT2FIX(method));
}
#endif


/*
    Static:     RenderingIntent_name
    Purpose:    Return the name of a RenderingIntent enum as a string
*/
static const char *
RenderingIntent_name(RenderingIntent intent)
{
    switch(intent)
    {
        default:
        ENUM_TO_NAME(UndefinedIntent)
        ENUM_TO_NAME(SaturationIntent)
        ENUM_TO_NAME(PerceptualIntent)
        ENUM_TO_NAME(AbsoluteIntent)
        ENUM_TO_NAME(RelativeIntent)
    }

}



/*
    External:   RenderingIntent_new
    Purpose:    Construct an RenderingIntent enum object for the specified value.
*/
VALUE
RenderingIntent_new(RenderingIntent intent)
{
    const char *name;

    name = RenderingIntent_name(intent);
    return rm_enum_new(Class_RenderingIntent, ID2SYM(rb_intern(name)), INT2FIX(intent));
}


/*
    Static:     ResolutionType_name
    Purpose:    Return the name of a ResolutionType enum as a string
*/
static const char *
ResolutionType_name(ResolutionType type)
{
    switch(type)
    {
        default:
        ENUM_TO_NAME(UndefinedResolution)
        ENUM_TO_NAME(PixelsPerInchResolution)
        ENUM_TO_NAME(PixelsPerCentimeterResolution)
    }

}


/*
    External:   ResolutionType_new
    Purpose:    Construct an ResolutionType enum object for the specified value.
*/
VALUE
ResolutionType_new(ResolutionType type)
{
    const char *name;

    name = ResolutionType_name(type);
    return rm_enum_new(Class_ResolutionType, ID2SYM(rb_intern(name)), INT2FIX(type));
}



#if defined(HAVE_IMAGE_ORIENTATION)
/*
    Static:     OrientationType_name
    Purpose:    Return the name of a OrientationType enum as a string
*/
static const char *
OrientationType_name(OrientationType type)
{
    switch(type)
    {
        default:
        ENUM_TO_NAME(UndefinedOrientation)
        ENUM_TO_NAME(TopLeftOrientation)
        ENUM_TO_NAME(TopRightOrientation)
        ENUM_TO_NAME(BottomRightOrientation)
        ENUM_TO_NAME(BottomLeftOrientation)
        ENUM_TO_NAME(LeftTopOrientation)
        ENUM_TO_NAME(RightTopOrientation)
        ENUM_TO_NAME(RightBottomOrientation)
        ENUM_TO_NAME(LeftBottomOrientation)
    }
}


/*
    External:   OrientationType_new
    Purpose:    Construct an OrientationType enum object for the specified value.
*/
VALUE
OrientationType_new(OrientationType type)
{
    const char *name;

    name = OrientationType_name(type);
    return rm_enum_new(Class_OrientationType, ID2SYM(rb_intern(name)), INT2FIX(type));
}
#endif


/*
    External:   Color_from_ColorInfo
    Purpose:    Convert a ColorInfo structure to a Magick::Color
*/
VALUE
Color_from_ColorInfo(const ColorInfo *ci)
{
    ComplianceType compliance_type;
    volatile VALUE name;
    volatile VALUE compliance;
    volatile VALUE color;

    name       = rb_str_new2(ci->name);

    compliance_type = ci->compliance;
    compliance = ComplianceType_new(compliance_type);
    color      = Pixel_from_PixelPacket((PixelPacket *)(&(ci->color)));

    return rb_funcall(Class_Color, ID_new, 3
                    , name, compliance, color);
}


/*
    External:   Color_to_ColorInfo
    Purpose:    Convert a Magick::Color to a ColorInfo structure
*/
void
Color_to_ColorInfo(ColorInfo *ci, VALUE st)
{
    Pixel *pixel;
    volatile VALUE members, m;

    if (CLASS_OF(st) != Class_Color)
    {
        rb_raise(rb_eTypeError, "type mismatch: %s given",
                 rb_class2name(CLASS_OF(st)));
    }

    memset(ci, '\0', sizeof(ColorInfo));

    members = rb_funcall(st, ID_values, 0);

    m = rb_ary_entry(members, 0);
    if (m != Qnil)
    {
        CloneString((char **)&(ci->name), STRING_PTR(m));
    }
    m = rb_ary_entry(members, 1);
    if (m != Qnil)
    {
        VALUE_TO_ENUM(m, ci->compliance, ComplianceType);
    }
    m = rb_ary_entry(members, 2);
    if (m != Qnil)
    {
        Data_Get_Struct(m, Pixel, pixel);
        ci->color = *pixel;
    }
}

/*
    Static:     destroy_ColorInfo
    Purpose:    free the storage allocated by Color_to_ColorInfo, above.
*/
static void
destroy_ColorInfo(ColorInfo *ci)
{
    magick_free((void*)ci->name);
    ci->name = NULL;
}

/*
    Method:     Color#to_s
    Purpose:    Return a string representation of a Magick::Color object
*/
VALUE
Color_to_s(VALUE self)
{
    ColorInfo ci;
    char buff[1024];

    Color_to_ColorInfo(&ci, self);
    sprintf(buff, "name=%s, compliance=%s, "
                  "color.red=%d, color.green=%d, color.blue=%d, color.opacity=%d ",
                  ci.name,
                  ComplianceType_name(&ci.compliance),
                  ci.color.red, ci.color.green, ci.color.blue, ci.color.opacity);

    destroy_ColorInfo(&ci);
    return rb_str_new2(buff);
}

/*
    Extern:     Pixel_from_PixelPacket
    Purpose:    Create a Magick::Pixel object from a PixelPacket structure.
    Notes:      bypasses normal Pixel.new, Pixel#initialize methods
*/
VALUE
Pixel_from_PixelPacket(PixelPacket *pp)
{
    Pixel *pixel;

    pixel = ALLOC(Pixel);
    *pixel = *pp;
    return Data_Wrap_Struct(Class_Pixel, NULL, destroy_Pixel, pixel);
}


/*
 *  Static:     color_arg_rescue
 *  Purpose:    raise ArgumentError if the color name cannot be converted
 *              to a string via rb_str_to_str.
*/
static VALUE
color_arg_rescue(VALUE arg)
{
    rb_raise(rb_eTypeError, "argument must be color name or pixel (%s given)",
            rb_class2name(CLASS_OF(arg)));
}

/*
    Extern:     Color_to_PixelPacket
    Purpose:    Convert either a String color name or
                a Magick::Pixel to a PixelPacket
*/
void
Color_to_PixelPacket(PixelPacket *pp, VALUE color)
{
    Pixel *pixel;

    // Allow color name or Pixel
    if (CLASS_OF(color) == Class_Pixel)
    {
        Data_Get_Struct(color, Pixel, pixel);
        *pp = *pixel;
    }
    else
    {
        // require 'to_str' here instead of just 'to_s'.
        color = rb_rescue(rb_str_to_str, color, color_arg_rescue, color);
        Color_Name_to_PixelPacket(pp, color);
    }
}

/*
    Extern:     PrimaryInfo_from_PrimaryInfo(pp)
    Purpose:    Create a Magick::PrimaryInfo object from a PrimaryInfo structure.
*/
VALUE
PrimaryInfo_from_PrimaryInfo(PrimaryInfo *p)
{
    return rb_funcall(Class_Primary, ID_new, 3
                    , INT2FIX(p->x), INT2FIX(p->y), INT2FIX(p->z));
}

/*
    Extern:     PrimaryInfo_to_PrimaryInfo
    Purpose:    Convert a Magick::PrimaryInfo object to a PrimaryInfo structure
*/
void
PrimaryInfo_to_PrimaryInfo(PrimaryInfo *pi, VALUE sp)
{
    volatile VALUE members, m;

    if (CLASS_OF(sp) != Class_Primary)
    {
        rb_raise(rb_eTypeError, "type mismatch: %s given",
                 rb_class2name(CLASS_OF(sp)));
    }
    members = rb_funcall(sp, ID_values, 0);
    m = rb_ary_entry(members, 0);
    pi->x = m == Qnil ? 0 : FIX2INT(m);
    m = rb_ary_entry(members, 1);
    pi->y = m == Qnil ? 0 : FIX2INT(m);
    m = rb_ary_entry(members, 2);
    pi->z = m == Qnil ? 0 : FIX2INT(m);
}

/*
    Extern:     PointInfo_to_Point(pp)
    Purpose:    Create a Magick::Point object from a PointInfo structure.
*/
VALUE
PointInfo_to_Point(PointInfo *p)
{
    return rb_funcall(Class_Point, ID_new, 2
                    , INT2FIX(p->x), INT2FIX(p->y));
}

/*
    Extern:     Point_to_PointInfo
    Purpose:    Convert a Magick::Point object to a PointInfo structure
*/
void
Point_to_PointInfo(PointInfo *pi, VALUE sp)
{
    volatile VALUE members, m;

    if (CLASS_OF(sp) != Class_Point)
    {
        rb_raise(rb_eTypeError, "type mismatch: %s given",
                 rb_class2name(CLASS_OF(sp)));
    }
    members = rb_funcall(sp, ID_values, 0);
    m = rb_ary_entry(members, 0);
    pi->x = m == Qnil ? 0 : FIX2INT(m);
    m = rb_ary_entry(members, 1);
    pi->y = m == Qnil ? 0 : FIX2INT(m);
}



/*
    Extern:     ChromaticityInfo_new(pp)
    Purpose:    Create a Magick::ChromaticityInfo object from a
                ChromaticityInfo structure.
*/
VALUE
ChromaticityInfo_new(ChromaticityInfo *ci)
{
    volatile VALUE red_primary;
    volatile VALUE green_primary;
    volatile VALUE blue_primary;
    volatile VALUE white_point;

    red_primary   = PrimaryInfo_from_PrimaryInfo(&ci->red_primary);
    green_primary = PrimaryInfo_from_PrimaryInfo(&ci->green_primary);
    blue_primary  = PrimaryInfo_from_PrimaryInfo(&ci->blue_primary);
    white_point   = PrimaryInfo_from_PrimaryInfo(&ci->white_point);

    return rb_funcall(Class_Chromaticity, ID_new, 4
                    , red_primary, green_primary, blue_primary, white_point);
}

/*
    Extern:     ChromaticityInfo_to_ChromaticityInfo
    Purpose:    Extract the elements from a Magick::ChromaticityInfo
                and store in a ChromaticityInfo structure.
*/
void
ChromaticityInfo_to_ChromaticityInfo(ChromaticityInfo *ci, VALUE chrom)
{
    volatile VALUE chrom_members;
    volatile VALUE red_primary, green_primary, blue_primary, white_point;
    volatile VALUE entry_members, x, y;
    ID values_id;

    if (CLASS_OF(chrom) != Class_Chromaticity)
    {
        rb_raise(rb_eTypeError, "type mismatch: %s given",
                 rb_class2name(CLASS_OF(chrom)));
    }
    values_id = ID_values;

    // Get the struct members in an array
    chrom_members = rb_funcall(chrom, values_id, 0);
    red_primary   = rb_ary_entry(chrom_members, 0);
    green_primary = rb_ary_entry(chrom_members, 1);
    blue_primary  = rb_ary_entry(chrom_members, 2);
    white_point = rb_ary_entry(chrom_members, 3);

    // Get the red_primary PrimaryInfo members in an array
    entry_members = rb_funcall(red_primary, values_id, 0);
    x = rb_ary_entry(entry_members, 0);         // red_primary.x
    ci->red_primary.x = x == Qnil ? 0.0 : NUM2DBL(x);
    y = rb_ary_entry(entry_members, 1);         // red_primary.y
    ci->red_primary.y = y == Qnil ? 0.0 : NUM2DBL(y);
    ci->red_primary.z = 0.0;

    // Get the green_primary PrimaryInfo members in an array
    entry_members = rb_funcall(green_primary, values_id, 0);
    x = rb_ary_entry(entry_members, 0);         // green_primary.x
    ci->green_primary.x = x == Qnil ? 0.0 : NUM2DBL(x);
    y = rb_ary_entry(entry_members, 1);         // green_primary.y
    ci->green_primary.y = y == Qnil ? 0.0 : NUM2DBL(y);
    ci->green_primary.z = 0.0;

    // Get the blue_primary PrimaryInfo members in an array
    entry_members = rb_funcall(blue_primary, values_id, 0);
    x = rb_ary_entry(entry_members, 0);         // blue_primary.x
    ci->blue_primary.x = x == Qnil ? 0.0 : NUM2DBL(x);
    y = rb_ary_entry(entry_members, 1);         // blue_primary.y
    ci->blue_primary.y = y == Qnil ? 0.0 : NUM2DBL(y);
    ci->blue_primary.z = 0.0;

    // Get the white_point PrimaryInfo members in an array
    entry_members = rb_funcall(white_point, values_id, 0);
    x = rb_ary_entry(entry_members, 0);         // white_point.x
    ci->white_point.x = x == Qnil ? 0.0 : NUM2DBL(x);
    y = rb_ary_entry(entry_members, 1);         // white_point.y
    ci->white_point.y = y == Qnil ? 0.0 : NUM2DBL(y);
    ci->white_point.z = 0.0;
}

/*
    External:   Rectangle_from_RectangleInfo
    Purpose:    Convert a RectangleInfo structure to a Magick::Rectangle
*/
VALUE
Rectangle_from_RectangleInfo(RectangleInfo *rect)
{
    volatile VALUE width;
    volatile VALUE height;
    volatile VALUE x, y;

    width  = UINT2NUM(rect->width);
    height = UINT2NUM(rect->height);
    x      = INT2NUM(rect->x);
    y      = INT2NUM(rect->y);
    return rb_funcall(Class_Rectangle, ID_new, 4
                    , width, height, x, y);
}

/*
    External:   Rectangle_to_RectangleInfo
    Purpose:    Convert a Magick::Rectangle to a RectangleInfo structure.
*/
void
Rectangle_to_RectangleInfo(RectangleInfo *rect, VALUE sr)
{
    volatile VALUE members, m;

    if (CLASS_OF(sr) != Class_Rectangle)
    {
        rb_raise(rb_eTypeError, "type mismatch: %s given",
                 rb_class2name(CLASS_OF(sr)));
    }
    members = rb_funcall(sr, ID_values, 0);
    m = rb_ary_entry(members, 0);
    rect->width  = m == Qnil ? 0 : NUM2ULONG(m);
    m = rb_ary_entry(members, 1);
    rect->height = m == Qnil ? 0 : NUM2ULONG(m);
    m = rb_ary_entry(members, 2);
    rect->x      = m == Qnil ? 0 : NUM2LONG (m);
    m = rb_ary_entry(members, 3);
    rect->y      = m == Qnil ? 0 : NUM2LONG (m);
}

/*
    External:   Segment_from_SegmentInfo
    Purpose:    Convert a SegmentInfo structure to a Magick::Segment
*/
VALUE
Segment_from_SegmentInfo(SegmentInfo *segment)
{
    volatile VALUE x1, y1, x2, y2;

    x1 = rb_float_new(segment->x1);
    y1 = rb_float_new(segment->y1);
    x2 = rb_float_new(segment->x2);
    y2 = rb_float_new(segment->y2);
    return rb_funcall(Class_Segment, ID_new, 4, x1, y1, x2, y2);
}

/*
    External:   Segment_to_SegmentInfo
    Purpose:    Convert a Magick::Segment to a SegmentInfo structure.
*/
void
Segment_to_SegmentInfo(SegmentInfo *segment, VALUE s)
{
    volatile VALUE members, m;

    if (CLASS_OF(s) != Class_Segment)
    {
        rb_raise(rb_eTypeError, "type mismatch: %s given",
                 rb_class2name(CLASS_OF(s)));
    }

    members = rb_funcall(s, ID_values, 0);
    m = rb_ary_entry(members, 0);
    segment->x1 = m == Qnil ? 0.0 : NUM2DBL(m);
    m = rb_ary_entry(members, 1);
    segment->y1 = m == Qnil ? 0.0 : NUM2DBL(m);
    m = rb_ary_entry(members, 2);
    segment->x2 = m == Qnil ? 0.0 : NUM2DBL(m);
    m = rb_ary_entry(members, 3);
    segment->y2 = m == Qnil ? 0.0 : NUM2DBL(m);
}

/*
    Static:     StretchType_new
    Purpose:    Construct a StretchType enum for a specified StretchType value
*/
static VALUE
StretchType_new(StretchType stretch)
{
    const char *name;

    name = StretchType_name(stretch);
    return rm_enum_new(Class_StretchType, ID2SYM(rb_intern(name)), INT2FIX(stretch));
}


/*
    Static:     StyleType_new
    Purpose:    Construct a StyleType enum for a specified StyleType value
*/
static VALUE
StyleType_new(StyleType style)
{
    const char *name;

    name = StyleType_name(style);
    return rm_enum_new(Class_StyleType, ID2SYM(rb_intern(name)), INT2FIX(style));
}

/*
    External:   Font_from_TypeInfo
    Purpose:    Convert a TypeInfo structure to a Magick::Font
*/
VALUE
Font_from_TypeInfo(TypeInfo *ti)
{
    volatile VALUE name, description, family;
    volatile VALUE style, stretch, weight;
    volatile VALUE encoding, foundry, format;

    name        = rb_str_new2(ti->name);
    family      = rb_str_new2(ti->family);
    style       = StyleType_new(ti->style);
    stretch     = StretchType_new(ti->stretch);
    weight      = INT2NUM(ti->weight);
    description = ti->description ? rb_str_new2(ti->description) : Qnil;
    encoding    = ti->encoding    ? rb_str_new2(ti->encoding) : Qnil;
    foundry     = ti->foundry     ? rb_str_new2(ti->foundry)  : Qnil;
    format      = ti->format      ? rb_str_new2(ti->format)   : Qnil;

    return rb_funcall(Class_Font, ID_new, 9
                    , name, description, family, style
                    , stretch, weight, encoding, foundry, format);
}

/*
    External:   Font_to_TypeInfo
    Purpose:    Convert a Magick::Font to a TypeInfo structure
*/
void
Font_to_TypeInfo(TypeInfo *ti, VALUE st)
{
    volatile VALUE members, m;

    if (CLASS_OF(st) != Class_Font)
    {
        rb_raise(rb_eTypeError, "type mismatch: %s given",
                 rb_class2name(CLASS_OF(st)));
    }

    memset(ti, '\0', sizeof(TypeInfo));

    members = rb_funcall(st, ID_values, 0);
    m = rb_ary_entry(members, 0);
    if (m != Qnil)
    {
        CloneString((char **)&(ti->name), STRING_PTR(m));
    }
    m = rb_ary_entry(members, 1);
    if (m != Qnil)
    {
        CloneString((char **)&(ti->description), STRING_PTR(m));
    }
    m = rb_ary_entry(members, 2);
    if (m != Qnil)
    {
        CloneString((char **)&(ti->family), STRING_PTR(m));
    }
    m = rb_ary_entry(members, 3); ti->style   = m == Qnil ? 0 : FIX2INT(m);
    m = rb_ary_entry(members, 4); ti->stretch = m == Qnil ? 0 : FIX2INT(m);
    m = rb_ary_entry(members, 5); ti->weight  = m == Qnil ? 0 : FIX2INT(m);

    m = rb_ary_entry(members, 6);
    if (m != Qnil)
        CloneString((char **)&(ti->encoding), STRING_PTR(m));
    m = rb_ary_entry(members, 7);
    if (m != Qnil)
        CloneString((char **)&(ti->foundry), STRING_PTR(m));
    m = rb_ary_entry(members, 8);
    if (m != Qnil)
        CloneString((char **)&(ti->format), STRING_PTR(m));
}


/*
    Static:     destroy_TypeInfo
    Purpose:    free the storage allocated by Font_to_TypeInfo, above.
*/
static void
destroy_TypeInfo(TypeInfo *ti)
{
    magick_free((void*)ti->name);
    ti->name = NULL;
    magick_free((void*)ti->description);
    ti->description = NULL;
    magick_free((void*)ti->family);
    ti->family = NULL;
    magick_free((void*)ti->encoding);
    ti->encoding = NULL;
    magick_free((void*)ti->foundry);
    ti->foundry = NULL;
    magick_free((void*)ti->format);
    ti->format = NULL;
}

/*
    External:   Font_to_s
    Purpose:    implement the Font#to_s method
*/
VALUE
Font_to_s(VALUE self)
{
    TypeInfo ti;
    char weight[20];
    char buff[1024];

    Font_to_TypeInfo(&ti, self);

    switch (ti.weight)
    {
        case 400:
            strcpy(weight, "NormalWeight");
            break;
        case 700:
            strcpy(weight, "BoldWeight");
            break;
        default:
            sprintf(weight, "%lu", ti.weight);
            break;
    }

    sprintf(buff, "name=%s, description=%s, "
                  "family=%s, style=%s, stretch=%s, weight=%s, "
                  "encoding=%s, foundry=%s, format=%s",
                  ti.name,
                  ti.description,
                  ti.family,
                  StyleType_name(ti.style),
                  StretchType_name(ti.stretch),
                  weight,
                  ti.encoding ? ti.encoding : "",
                  ti.foundry ? ti.foundry : "",
                  ti.format ? ti.format : "");

    destroy_TypeInfo(&ti);
    return rb_str_new2(buff);

}

/*
    External:   TypeMetric_from_TypeMetric
    Purpose:    Convert a TypeMetric structure to a Magick::TypeMetric
*/
VALUE
TypeMetric_from_TypeMetric(TypeMetric *tm)
{
    volatile VALUE pixels_per_em;
    volatile VALUE ascent, descent;
    volatile VALUE width, height, max_advance;
    volatile VALUE bounds, underline_position, underline_thickness;

    pixels_per_em       = PointInfo_to_Point(&tm->pixels_per_em);
    ascent              = rb_float_new(tm->ascent);
    descent             = rb_float_new(tm->descent);
    width               = rb_float_new(tm->width);
    height              = rb_float_new(tm->height);
    max_advance         = rb_float_new(tm->max_advance);
    bounds              = Segment_from_SegmentInfo(&tm->bounds);
    underline_position  = rb_float_new(tm->underline_position);
    underline_thickness = rb_float_new(tm->underline_position);

    return rb_funcall(Class_TypeMetric, ID_new, 9
                    , pixels_per_em, ascent, descent, width
                    , height, max_advance, bounds
                    , underline_position, underline_thickness);
}

/*
    External:   TypeMetric_to_TypeMetric
    Purpose:    Convert a Magick::TypeMetric to a TypeMetric structure.
*/
void
TypeMetric_to_TypeMetric(TypeMetric *tm, VALUE st)
{
    volatile VALUE members, m;
    volatile VALUE pixels_per_em;

    if (CLASS_OF(st) != Class_TypeMetric)
    {
        rb_raise(rb_eTypeError, "type mismatch: %s given",
                 rb_class2name(CLASS_OF(st)));
    }
    members = rb_funcall(st, ID_values, 0);

    pixels_per_em   = rb_ary_entry(members, 0);
    Point_to_PointInfo(&tm->pixels_per_em, pixels_per_em);

    m = rb_ary_entry(members, 1);
    tm->ascent      = m == Qnil ? 0.0 : NUM2DBL(m);
    m = rb_ary_entry(members, 2);
    tm->descent     = m == Qnil ? 0.0 : NUM2DBL(m);
    m = rb_ary_entry(members, 3);
    tm->width       = m == Qnil ? 0.0 : NUM2DBL(m);
    m = rb_ary_entry(members, 4);
    tm->height      = m == Qnil ? 0.0 : NUM2DBL(m);
    m = rb_ary_entry(members, 5);
    tm->max_advance = m == Qnil ? 0.0 : NUM2DBL(m);

    m = rb_ary_entry(members, 6);
    Segment_to_SegmentInfo(&tm->bounds, m);

    m = rb_ary_entry(members, 7);
    tm->underline_position  = m == Qnil ? 0.0 : NUM2DBL(m);
    m = rb_ary_entry(members, 8);
    tm->underline_thickness = m == Qnil ? 0.0 : NUM2DBL(m);
}

/*
    Method:     Magick::TypeMetric#to_s
    Purpose:    Create a string representation of a Magick::TypeMetric
*/
VALUE
TypeMetric_to_s(VALUE self)
{
    TypeMetric tm;
    char buff[200];

    TypeMetric_to_TypeMetric(&tm, self);
    sprintf(buff, "pixels_per_em=(x=%g,y=%g) "
                  "ascent=%g descent=%g width=%g height=%g max_advance=%g "
                  "bounds.x1=%g bounds.y1=%g bounds.x2=%g bounds.y2=%g "
                  "underline_position=%g underline_thickness=%g",
                  tm.pixels_per_em.x, tm.pixels_per_em.y,
                  tm.ascent, tm.descent, tm.width, tm.height, tm.max_advance,
                  tm.bounds.x1, tm.bounds.y1, tm.bounds.x2, tm.bounds.y2,
                  tm.underline_position, tm.underline_thickness);
    return rb_str_new2(buff);
}



/*
    Static:     VirtualPixelMethod_name
    Purpose:    Return the string representation of a VirtualPixelMethod value
*/
static const char *
VirtualPixelMethod_name(VirtualPixelMethod method)
{
    switch (method)
    {
        default:
        ENUM_TO_NAME(UndefinedVirtualPixelMethod)
        ENUM_TO_NAME(EdgeVirtualPixelMethod)
        ENUM_TO_NAME(MirrorVirtualPixelMethod)
        ENUM_TO_NAME(TileVirtualPixelMethod)
#if defined(HAVE_TRANSPARENTVIRTUALPIXELMETHOD)
        ENUM_TO_NAME(TransparentVirtualPixelMethod)
        ENUM_TO_NAME(BackgroundVirtualPixelMethod)
#endif
    }
}


/*
    Static:     VirtualPixelMethod_new
    Purpose:    Construct a VirtualPixelMethod enum for a specified VirtualPixelMethod value
*/
VALUE
VirtualPixelMethod_new(VirtualPixelMethod style)
{
    const char *name;

    name = VirtualPixelMethod_name(style);
    return rm_enum_new(Class_VirtualPixelMethod, ID2SYM(rb_intern(name)), INT2FIX(style));
}


/*
 *  Extern:     rm_define_enum_type
 *  Purpose:    set up a subclass of Enum
*/
VALUE rm_define_enum_type(char *tag)
{
    VALUE class;

    class = rb_define_class_under(Module_Magick, tag, Class_Enum);\

    rb_define_singleton_method(class, "values", Enum_type_values, 0);
    rb_define_method(class, "initialize", Enum_type_initialize, 2);
    RUBY16(rb_enable_super(class, "initialize");)
    rb_define_method(class, "inspect", Enum_type_inspect, 0);
    return class;
}


#if defined(HAVE_RB_DEFINE_ALLOC_FUNC)
/*
    Extern:  rm_enum_new (1.8)
    Purpose: Construct a new Enum subclass instance
*/
VALUE rm_enum_new(VALUE class, VALUE sym, VALUE val)
{
    VALUE argv[2];

    argv[0] = sym;
    argv[1] = val;
    return rb_class_new_instance(2, argv, class);
}

/*
    Extern:  Enum_alloc (1.8)
    Purpose: Enum class alloc function
*/
VALUE Enum_alloc(VALUE class)
{
   MagickEnum *magick_enum;
   volatile VALUE enumr;

   enumr = Data_Make_Struct(class, MagickEnum, NULL, NULL, magick_enum);
   OBJ_FREEZE(enumr);
   return enumr;
}


#else
/*
    Extern:  rm_enum_new (1.6)
    Purpose: Construct a new Enum subclass instance
*/
VALUE rm_enum_new(VALUE class, VALUE sym, VALUE val)
{
    return Enum_new(class, sym, val);
}

/*
    Method:  Enum.new
    Purpose: Construct a new Enum object
    Notes:   `class' can be an Enum subclass
*/
VALUE Enum_new(VALUE class, VALUE sym, VALUE val)
{
    volatile VALUE new_enum;
    volatile VALUE argv[2];
    MagickEnum *magick_enum;

    new_enum = Data_Make_Struct(class, MagickEnum, NULL, NULL, magick_enum);
    argv[0] = sym;
    argv[1] = val;

    rb_obj_call_init(new_enum, 2, argv);
    OBJ_FREEZE(new_enum);
    return new_enum;
}

#endif

/*
    Method:  Enum#initialize
    Purpose: Initialize a new Enum instance
*/
VALUE Enum_initialize(VALUE self, VALUE sym, VALUE val)
{
   MagickEnum *magick_enum;

   Data_Get_Struct(self, MagickEnum, magick_enum);
   magick_enum->id = rb_to_id(sym); /* convert symbol to ID */
   magick_enum->val = NUM2INT(val);

   return self;
}


/*
    Method:  Enum#to_s
    Purpose: Return the name of an enum
*/
VALUE Enum_to_s(VALUE self)
{
   MagickEnum *magick_enum;

   Data_Get_Struct(self, MagickEnum, magick_enum);
   return rb_str_new2(rb_id2name(magick_enum->id));
}


/*
    Method:  Enum#to_i
    Purpose: Return the value of an enum
*/
VALUE Enum_to_i(VALUE self)
{
   MagickEnum *magick_enum;

   Data_Get_Struct(self, MagickEnum, magick_enum);
   return INT2NUM(magick_enum->val);
}


/*
    Method:  Enum#<=>
    Purpose: Support Comparable module in Enum
    Returns: -1, 0, 1, or nil
    Notes:   Enums must be instances of the same class to be equal.
*/
VALUE Enum_spaceship(VALUE self, VALUE other)
{
    MagickEnum *this, *that;

    Data_Get_Struct(self, MagickEnum, this);
    Data_Get_Struct(other, MagickEnum, that);

    if (this->val > that->val)
    {
        return INT2FIX(1);
    }
    else if (this->val < that->val)
    {
        return INT2FIX(-1);
    }

    // Values are equal, check class.

    return rb_funcall(CLASS_OF(self), ID_spaceship, 1, CLASS_OF(other));
}


/*
    Method:  Enum#===
    Purpose: "Case equal" operator for Enum
    Returns: true or false
    Notes:   Yes, I know "case equal" is a misnomer.
*/
VALUE Enum_case_eq(VALUE self, VALUE other)
{
    MagickEnum *this, *that;

    if (CLASS_OF(self) == CLASS_OF(other))
    {
        Data_Get_Struct(self, MagickEnum, this);
        Data_Get_Struct(other, MagickEnum, that);
        return this->val == that->val ? Qtrue : Qfalse;
    }

    return Qfalse;
}


/*
 *  Method:     xxx#initialize
 *  Purpose:    initialize method for all Enum subclasses
*/
VALUE Enum_type_initialize(VALUE self, VALUE sym, VALUE val)
{
    volatile VALUE super_argv[2];
    volatile VALUE enumerators;

    super_argv[0] = sym;
    super_argv[1] = val;
    rb_call_super(2, (VALUE *)super_argv);

    if (rb_cvar_defined(CLASS_OF(self), ID_enumerators) != Qtrue)
    {
        RUBY18(rb_cvar_set(CLASS_OF(self), ID_enumerators, rb_ary_new(), 0));
        RUBY16(rb_cvar_set(CLASS_OF(self), ID_enumerators, rb_ary_new()));
    }

    enumerators = rb_cvar_get(CLASS_OF(self), ID_enumerators);
    rb_ary_push(enumerators, self);

    return self;
}


/*
 *  Method:     xxx#inspect
 *  Purpose:    Enum subclass #inspect
*/
static VALUE Enum_type_inspect(VALUE self)
{
    char str[100];
    MagickEnum *magick_enum;

    Data_Get_Struct(self, MagickEnum, magick_enum);
    sprintf(str, "%.32s=%d", rb_id2name(magick_enum->id), magick_enum->val);

    return rb_str_new2(str);
}


/*
 *  Method:     xxx.values
 *  Purpose:    Behaves like #each if a block is present, otherwise like #to_a.
 *  Notes:      defined for each Enum subclass
*/
static VALUE Enum_type_values(VALUE class)
{
    volatile VALUE enumerators, copy;
    volatile VALUE rv;
    int x;

    enumerators = rb_cvar_get(class, ID_enumerators);

    if (rb_block_given_p())
    {
        for (x = 0; x < RARRAY(enumerators)->len; x++)
        {
            rb_yield(rb_ary_entry(enumerators, x));
        }
        rv = class;
    }
    else
    {
        copy = rb_ary_new2(RARRAY(enumerators)->len);
        for (x = 0; x < RARRAY(enumerators)->len; x++)
        {
            rb_ary_push(copy, rb_ary_entry(enumerators, x));
        }
        OBJ_FREEZE(copy);
        rv = copy;
    }

    return rv;
}


/*
    Static:     ComplianceType_name
    Purpose:    Return the string representation of a ComplianceType value
    Notes:      xMagick will OR multiple compliance types so we have to
                arbitrarily pick one name. Set the compliance argument
                to the selected value.
*/
static const char *
ComplianceType_name(ComplianceType *c)
{
    if ((*c & (SVGCompliance|X11Compliance|XPMCompliance))
        == (SVGCompliance|X11Compliance|XPMCompliance))
    {
        return "AllCompliance";
    }
    else if (*c & SVGCompliance)
    {
        *c = SVGCompliance;
        return "SVGCompliance";
    }
    else if (*c & X11Compliance)
    {
        *c = X11Compliance;
        return "X11Compliance";
    }
    else if (*c & XPMCompliance)
    {
        *c = XPMCompliance;
        return "XPMCompliance";
    }
    else if (*c == NoCompliance)
    {
        *c = NoCompliance;
        return "NoCompliance";
    }
    else
    {
        *c = UndefinedCompliance;
        return "UndefinedCompliance";
    }
}


#if defined(HAVE_GETIMAGESTATISTICS)
/*
    Extern:     Statistics_new(stats)
    Purpose:    Create a Magick::Statistics object from an
                ImageStatistics structure.
*/
VALUE
Statistics_new(ImageStatistics *stats)
{
    volatile VALUE red, green, blue, opacity;
    volatile VALUE min, max, mean, stddev, var;

    min = rb_float_new(stats->red.minimum);
    max = rb_float_new(stats->red.maximum);
    mean = rb_float_new(stats->red.mean);
    stddev = rb_float_new(stats->red.standard_deviation);
    var = rb_float_new(stats->red.variance);
    red = rb_funcall(Class_StatisticsChannel, ID_new, 5, max, min, mean, stddev, var);

    min = rb_float_new(stats->green.minimum);
    max = rb_float_new(stats->green.maximum);
    mean = rb_float_new(stats->green.mean);
    stddev = rb_float_new(stats->green.standard_deviation);
    var = rb_float_new(stats->green.variance);
    green = rb_funcall(Class_StatisticsChannel, ID_new, 5, max, min, mean, stddev, var);

    min = rb_float_new(stats->blue.minimum);
    max = rb_float_new(stats->blue.maximum);
    mean = rb_float_new(stats->blue.mean);
    stddev = rb_float_new(stats->blue.standard_deviation);
    var = rb_float_new(stats->blue.variance);
    blue = rb_funcall(Class_StatisticsChannel, ID_new, 5, max, min, mean, stddev, var);

    min = rb_float_new(stats->opacity.minimum);
    max = rb_float_new(stats->opacity.maximum);
    mean = rb_float_new(stats->opacity.mean);
    stddev = rb_float_new(stats->opacity.standard_deviation);
    var = rb_float_new(stats->opacity.variance);
    opacity = rb_funcall(Class_StatisticsChannel, ID_new, 5, max, min, mean, stddev, var);

    return rb_funcall(Class_Statistics, ID_new, 4, red, green, blue, opacity);

}
#endif  // HAVE_GETIMAGESTATISTICS

/*
    Extern:     StorageType_name
    Purpose:    Return the string representation of a StorageType value
*/
const char *
StorageType_name(StorageType type)
{
    switch (type)
    {
        ENUM_TO_NAME(CharPixel)
        ENUM_TO_NAME(DoublePixel)
        ENUM_TO_NAME(FloatPixel)
        ENUM_TO_NAME(IntegerPixel)
        ENUM_TO_NAME(LongPixel)
#if defined(HAVE_QUANTUMPIXEL)
        ENUM_TO_NAME(QuantumPixel)
#endif
        ENUM_TO_NAME(ShortPixel)
        default:
#if defined(HAVE_UNDEFINEDGRAVITY)      // UndefinedGravity & UndefinedPixel were both introduced in IM 6.0.0
        ENUM_TO_NAME(UndefinedPixel)
#else
        return "UndefinedPixel";
#endif
    }
}

/*
    Static:     StretchType_name
    Purpose:    Return the string representation of a StretchType value
*/
static const char *
StretchType_name(StretchType stretch)
{
    switch (stretch)
    {
        ENUM_TO_NAME(NormalStretch)
        ENUM_TO_NAME(UltraCondensedStretch)
        ENUM_TO_NAME(ExtraCondensedStretch)
        ENUM_TO_NAME(CondensedStretch)
        ENUM_TO_NAME(SemiCondensedStretch)
        ENUM_TO_NAME(SemiExpandedStretch)
        ENUM_TO_NAME(ExpandedStretch)
        ENUM_TO_NAME(ExtraExpandedStretch)
        ENUM_TO_NAME(UltraExpandedStretch)
        ENUM_TO_NAME(AnyStretch)
        default:
#if defined(HAVE_UNDEFINEDGRAVITY)      // UndefinedGravity & UndefinedStretch were both introduced in IM 6.0.0
        ENUM_TO_NAME(UndefinedStretch)
#else
        return "UndefinedStretch";
#endif
    }
}


/*
    Static:     StyleType_name
    Purpose:    Return the string representation of a StyleType value
*/
static const char *
StyleType_name(StyleType style)
{
    switch (style)
    {
        ENUM_TO_NAME(NormalStyle)
        ENUM_TO_NAME(ItalicStyle)
        ENUM_TO_NAME(ObliqueStyle)
        ENUM_TO_NAME(AnyStyle)
        default:
#if defined(HAVE_UNDEFINEDGRAVITY)      // UndefinedGravity & UndefinedStyle were both introduced in IM 6.0.0
        ENUM_TO_NAME(UndefinedStyle)
#else
        return "UndefinedStyle";
#endif
    }
}


/*
    External:   write_temp_image
    Purpose:    Write a temporary copy of the image to the IM registry
    Returns:    the "filename" of the registered image
    Notes:      The `tmpnam' argument must point to an char array
                of size MaxTextExtent.
*/
void
rm_write_temp_image(Image *image, char *tmpnam)
{
    long registry_id;

    registry_id = SetMagickRegistry(ImageRegistryType, image, sizeof(Image), &image->exception);
    if (registry_id < 0)
    {
        rb_raise(rb_eRuntimeError, "SetMagickRegistry failed.");
    }
    rm_check_image_exception(image, RetainOnError);

    sprintf(tmpnam, "mpri:%ld", registry_id);
}

/*
    External:   delete_temp_image
    Purpose:    Delete the temporary image from the registry
    Returns:    void
*/

void
rm_delete_temp_image(char *tmpnam)
{
    long registry_id = -1;

    sscanf(tmpnam, "mpri:%ld", &registry_id);
    if (registry_id >= 0)
    {
        (void) DeleteMagickRegistry(registry_id);
    }
}

/*
    External:   rm_not_implemented
    Purpose:    raise NotImplementedError
    Notes:      Called when a xMagick API is not available.
                Replaces Ruby's rb_notimplement function.
    Notes:      The MagickPackageName macro is not available
                until 5.5.7. Use MAGICKNAME instead.
*/
void
rm_not_implemented(void)
{

    rb_raise(rb_eNotImpError, "the `%s' method is not supported by "
                              Q(MAGICKNAME) " " MagickLibVersionText
                              , rb_id2name(rb_frame_last_func()));
}

/*
    Static:     raise_error(msg, loc)
    Purpose:    create a new ImageMagickError object and raise an exception
    Notes:      does not return
                This funky technique allows me to safely add additional
                information to the ImageMagickError object in both 1.6.8 and
                1.8.0. See www.ruby_talk.org/36408.
*/
static void
raise_error(const char *msg, const char *loc)
{
    volatile VALUE exc, mesg, extra;

    mesg = rb_str_new2(msg);
    extra = loc ? rb_str_new2(loc) : Qnil;

    exc = rb_funcall(Class_ImageMagickError, ID_new, 2, mesg, extra);
    rb_funcall(rb_cObject, rb_intern("raise"), 1, exc);
}


/*
    Method:     ImageMagickError#initialize(msg, loc)
    Purpose:    initialize a new ImageMagickError object - store
                the "loc" string in the @magick_location instance variable
*/
VALUE
ImageMagickError_initialize(int argc, VALUE *argv, VALUE self)
{
    volatile VALUE super_argv[1] = {(VALUE)0};
    int super_argc = 0;
    volatile VALUE extra = Qnil;

    switch(argc)
    {
        case 2:
            extra = argv[1];
        case 1:
            super_argv[0] = argv[0];
            super_argc = 1;
        case 0:
            break;
        default:
            rb_raise(rb_eArgError, "wrong number of arguments (%d for 0 to 2)", argc);
    }

    rb_call_super(super_argc, (VALUE *)super_argv);
    rb_iv_set(self, "@"MAGICK_LOC, extra);


    return self;
}

/*
 *  Extern:     get_geometry
 *  Purpose:    Get the values from a Geometry object and return
 *              them in C variables.
*/
void
rm_get_geometry(
    VALUE geom,
    long *x,
    long *y,
    unsigned long *width,
    unsigned long *height,
    int *flag)
{
    VALUE v;

    v = rb_funcall(geom, ID_x, 0);
    *x = NUM2LONG(v);
    v = rb_funcall(geom, ID_y, 0);
    *y = NUM2LONG(v);
    v = rb_funcall(geom, ID_width, 0);
    *width = NUM2ULONG(v);
    v = rb_funcall(geom, ID_height, 0);
    *height = NUM2ULONG(v);

    // Getting the flag field is a bit more difficult since it's
    // supposed to be an instance of the GeometryValue Enum class. We
    // may not know the VALUE for the GeometryValue class, and we
    // need to check that the flag field is an instance of that class.
    if (flag)
    {
        MagickEnum *magick_enum;

        v = rb_funcall(geom, ID_flag, 0);
        if (!Class_GeometryValue)
        {
            Class_GeometryValue = rb_const_get(Module_Magick, ID_GeometryValue);
        }
        if (CLASS_OF(v) != Class_GeometryValue)
        {
            rb_raise(rb_eTypeError, "wrong enumeration type - expected %s, got %s"
                        , rb_class2name(Class_GeometryValue),rb_class2name(CLASS_OF(v)));
        }
        Data_Get_Struct(v, MagickEnum, magick_enum);
        *flag = magick_enum->val;
    }

}


/*
 *  Extern:     rm_clone_image
 *  Purpose:    clone an image, handle errors
 */
Image *rm_clone_image(Image *image)
{
    Image *clone;
    ExceptionInfo exception;

    GetExceptionInfo(&exception);
    clone = CloneImage(image, 0, 0, True, &exception);
    if (!clone)
    {
        rb_raise(rb_eNoMemError, "not enough memory to continue");
    }
    rm_check_exception(&exception, clone, DestroyOnError);
    DestroyExceptionInfo(&exception);

    return clone;
}


/*
    Extern:     rm_progress_monitor
    Purpose:    SetImage(Info)ProgressMonitor exit
    Notes:      ImageMagick's "tag" argument is unused. We pass along the method name instead.
*/
#if defined(HAVE_SETIMAGEPROGRESSMONITOR)
MagickBooleanType rm_progress_monitor(
    const char *tag,
    const MagickOffsetType of,
    const MagickSizeType sp,
    void *client_data)
{
    volatile VALUE rval;
    volatile VALUE method, offset, span;

#if defined(HAVE_LONG_LONG)     // defined in Ruby's defines.h
    offset = rb_ll2inum(of);
    span = rb_ull2inum(sp);
#else
    offset = rb_int2big((long)of);
    span = rb_uint2big((unsigned long)sp);
#endif

    method = rb_str_new2(rb_id2name(rb_frame_last_func()));

    rval = rb_funcall((VALUE)client_data, ID_call, 3, method, offset, span);

    return RTEST(rval) ? MagickTrue : MagickFalse;
}
#endif


/*
    Extern:     rm_split
    Purpose:    Remove the ImageMagick links between images in an scene
                sequence.
    Notes:      The images remain grouped via the ImageList
*/
void
rm_split(Image *image)
{

    if (!image)
    {
        rb_bug("RMagick FATAL: unseq called with NULL argument.");
    }
    while (image)
    {
        (void) RemoveFirstImageFromList(&image);
    }
}



/*
 *  Static:     copy_exception
 *              clear_exception
 *  Purpose:    Define alternative implementations of ImageMagick's
 *              InheritException and ClearMagickException.
 *  Notes:      InheritException is ALWAYS defined in ImageMagick and
 *              NEVER defined in GraphicsMagick. ClearMagickException
 *              is defined in ImageMagick 6.2.6 and later and NEVER
 *              defined in GraphicsMagick.
 *
 *              The purpose of InheritException is to copy the exception
 *              information from a "related" exception to a destination
 *              exception if the related exception is more severe than the
 *              destination exception.
 *
 *              The purpose of ClearException is to reset the ExceptionInfo
 *              structure to its initial format.
 */

#if defined(HAVE_INHERITEXCEPTION)

    // This is ImageMagick - InheritException is always defined
    static void copy_exception(ExceptionInfo *exception, ExceptionInfo *relative)
    {
        InheritException(exception, relative);
    }

    // ImageMagick < 6.2.6 had a different kind of ExceptionInfo struct
    // and doesn't define ClearMagickException.
    #if defined(HAVE_CLEARMAGICKEXCEPTION)
        static void clear_exception(ExceptionInfo *exception)
        {
           ClearMagickException(exception);
        }
    #else

        static void clear_exception(ExceptionInfo *exception)
        {
            DestroyExceptionInfo(exception);
            GetExceptionInfo(exception);
        }

    #endif


#else   // !defined(HAVE_INHERITEXCEPTION)

    // This is GraphicsMagick. Very old versions don't support the
    // module, function, and line fields in the ExceptionInfo struct.

    static void copy_exception(ExceptionInfo *exception, ExceptionInfo *relative)
    {
        assert(exception != NULL);
        assert(exception->signature == MagickSignature);
        assert(relative != NULL);

        if (relative->severity < exception->severity)
        {
          return;
        }

        DestroyExceptionInfo(exception);
        GetExceptionInfo(exception);

        exception->severity = relative->severity;
        if (relative->reason)
        {
          magick_clone_string(&exception->reason, relative->reason);
        }

        if (relative->description)
        {
          magick_clone_string(&exception->description, relative->description);
        }


        #if defined(HAVE_EXCEPTIONINFO_MODULE)
            if (relative->module)
            {
              magick_clone_string(&exception->module, relative->module);
            }
            if (relative->function)
            {
              magick_clone_string(&exception->function, relative->function);
            }

            exception->line = relative->line;
        #endif
    }


    static void clear_exception(ExceptionInfo *exception)
    {
        DestroyExceptionInfo(exception);
        GetExceptionInfo(exception);
    }

#endif


/*
    Extern:     rm_check_image_exception
    Purpose:    If an ExceptionInfo struct in a list of images indicates a warning,
                issue a warning message. If an ExceptionInfo struct indicates an
                error, raise an exception and optionally destroy the images.
 */
void
rm_check_image_exception(Image *imglist, ErrorRetention retention)
{
    ExceptionInfo exception;
    Image *badboy = NULL;
    Image *image;

    if (imglist == NULL)
    {
        return;
    }

    GetExceptionInfo(&exception);

    // Find the image with the highest severity
    image = GetFirstImageInList(imglist);
    while (image)
    {
        if (image->exception.severity != UndefinedException)
        {
            if (!badboy || image->exception.severity > badboy->exception.severity)
            {
                badboy = image;
                copy_exception(&exception, &badboy->exception);
            }

            clear_exception(&image->exception);
        }
        image = GetNextImageInList(image);
    }

    if (badboy)
    {
        rm_check_exception(&exception, imglist, retention);
    }

    DestroyExceptionInfo(&exception);
}


/*
 *  Extern:     rm_check_exception
 *  Purpose:    Call handle_exception if there is an exception to handle.
 */
void
rm_check_exception(ExceptionInfo *exception, Image *imglist, ErrorRetention retention)
{
    if (exception->severity == UndefinedException)
    {
        return;
    }

    handle_exception(exception, imglist, retention);
}


/*
 *  Static:     handle_exception
 *  Purpose:    called when rm_check_exception determines that we need
 *              to either issue a warning message or raise an exception.
 *              This function allocates a bunch of stack so we don't call
 *              it unless we have to.
*/
static void
handle_exception(ExceptionInfo *exception, Image *imglist, ErrorRetention retention)
{

    char reason[500];
    char desc[500];
    char msg[sizeof(reason)+sizeof(desc)+20];

#if defined(HAVE_EXCEPTIONINFO_MODULE)
    char module[200], function[200];
    char extra[sizeof(module)+sizeof(function)+20];
    unsigned long line;
#endif


    memset(msg, 0, sizeof(msg));


    // Handle simple warning
    if (exception->severity < ErrorException)
    {
#if defined(HAVE_SNPRINTF)
        snprintf(msg, sizeof(msg)-1, "RMagick: %s%s%s",
#else
        sprintf(msg, "RMagick: %.500s%s%.500s",
#endif
            GetLocaleExceptionMessage(exception->severity, exception->reason),
            exception->description ? ": " : "",
            exception->description ? GetLocaleExceptionMessage(exception->severity, exception->description) : "");
        msg[sizeof(msg)-1] = '\0';
        rb_warning(msg);

        // Caller deletes ExceptionInfo...

        return;
    }

    // Raise an exception. We're not coming back...


    // Newly-created images should be destroyed, images that are part
    // of image objects should be retained but split.
    if (imglist)
    {
        if (retention == DestroyOnError)
        {
            (void) DestroyImageList(imglist);
            imglist = NULL;
        }
        else
        {
            rm_split(imglist);
        }
    }


    // Clone the ExceptionInfo with all arguments on the stack.
    memset(reason, 0, sizeof(reason));
    memset(desc, 0, sizeof(desc));

    if (exception->reason)
    {
        strncpy(reason, exception->reason, sizeof(reason)-1);
        reason[sizeof(reason)-1] = '\0';
    }
    if (exception->description)
    {
        strncpy(desc, exception->description, sizeof(desc)-1);
        desc[sizeof(desc)-1] = '\0';
    }


#if defined(HAVE_SNPRINTF)
    snprintf(msg, sizeof(msg)-1, "%s%s%s",
        GetLocaleExceptionMessage(exception->severity, reason),
        desc[0] ? ": " : "",
        desc[0] ? GetLocaleExceptionMessage(exception->severity, desc) : "");
#else
    sprintf(msg, "%.*s%s%.*s",
        sizeof(reason)-1, GetLocaleExceptionMessage(exception->severity, reason),
        desc[0] ? ": " : "",
        sizeof(desc)-1, desc[0] ? GetLocaleExceptionMessage(exception->severity, desc) : "");
#endif

    msg[sizeof(msg)-1] = '\0';


#if defined(HAVE_EXCEPTIONINFO_MODULE)

    memset(module, 0, sizeof(module));
    memset(function, 0, sizeof(function));
    memset(extra, 0, sizeof(extra));

    if (exception->module)
    {
        strncpy(module, exception->module, sizeof(module)-1);
        module[sizeof(module)-1] = '\0';
    }
    if (exception->function)
    {
        strncpy(function, exception->function, sizeof(function)-1);
        function[sizeof(function)-1] = '\0';
    }
    line = exception->line;

#if defined(HAVE_SNPRINTF)
     snprintf(extra, sizeof(extra)-1, "%s at %s:%lu", function, module, line);
#else
     sprintf(extra, "%.*s at %.*s:%lu", sizeof(function), function, sizeof(module), module, line);
#endif

     extra[sizeof(extra)-1] = '\0';

     DestroyExceptionInfo(exception);
     raise_error(msg, extra);

#else
     DestroyExceptionInfo(exception);
     raise_error(msg, NULL);
#endif

}


/*
 *  Extern:     rm_ensure_result
 *  Purpose:    RMagick expected a result. If it got NULL instead raise an exception.
 */
void rm_ensure_result(Image *image)
{
    if (!image)
    {
        rb_raise(rb_eRuntimeError, MagickPackageName " library function failed to return a result.");
    }
}