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image.c
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image.c
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#define IMAGER_NO_CONTEXT
#include "imager.h"
#include "imageri.h"
/*
=head1 NAME
image.c - implements most of the basic functions of Imager and much of the rest
=head1 SYNOPSIS
i_img *i;
i_color *c;
c = i_color_new(red, green, blue, alpha);
ICL_DESTROY(c);
i = i_img_8_new();
i_img_destroy(i);
// and much more
=head1 DESCRIPTION
image.c implements the basic functions to create and destroy image and
color objects for Imager.
=head1 FUNCTION REFERENCE
Some of these functions are internal.
=over
=cut
*/
im_context_t (*im_get_context)(void) = NULL;
#define XAXIS 0
#define YAXIS 1
#define XYAXIS 2
#define minmax(a,b,i) ( ((a>=i)?a: ( (b<=i)?b:i )) )
/* Hack around an obscure linker bug on solaris - probably due to builtin gcc thingies */
void i_linker_bug_fake(void) { ceil(1); }
/*
=item im_img_alloc(aIMCTX)
X<im_img_alloc API>X<i_img_alloc API>
=category Image Implementation
=synopsis i_img *im = im_img_alloc(aIMCTX);
=synopsis i_img *im = i_img_alloc();
Allocates a new i_img structure.
When implementing a new image type perform the following steps in your
image object creation function:
=over
=item 1.
allocate the image with i_img_alloc().
=item 2.
initialize any function pointers or other data as needed, you can
overwrite the whole block if you need to.
=item 3.
initialize Imager's internal data by calling i_img_init() on the image
object.
=back
=cut
*/
i_img *
im_img_alloc(pIMCTX) {
return mymalloc(sizeof(i_img));
}
/*
=item im_img_init(aIMCTX, image)
X<im_img_init API>X<i_img_init API>
=category Image Implementation
=synopsis im_img_init(aIMCTX, im);
=synopsis i_img_init(im);
Imager internal initialization of images.
See L</im_img_alloc(aIMCTX)> for more information.
=cut
*/
void
im_img_init(pIMCTX, i_img *img) {
img->im_data = NULL;
img->context = aIMCTX;
im_context_refinc(aIMCTX, "img_init");
}
/*
=item ICL_new_internal(r, g, b, a)
Return a new color object with values passed to it.
r - red component (range: 0 - 255)
g - green component (range: 0 - 255)
b - blue component (range: 0 - 255)
a - alpha component (range: 0 - 255)
=cut
*/
i_color *
ICL_new_internal(unsigned char r,unsigned char g,unsigned char b,unsigned char a) {
i_color *cl = NULL;
dIMCTX;
im_log((aIMCTX,1,"ICL_new_internal(r %d,g %d,b %d,a %d)\n", r, g, b, a));
if ( (cl=mymalloc(sizeof(i_color))) == NULL) im_fatal(aIMCTX, 2,"malloc() error\n");
cl->rgba.r = r;
cl->rgba.g = g;
cl->rgba.b = b;
cl->rgba.a = a;
im_log((aIMCTX,1,"(%p) <- ICL_new_internal\n",cl));
return cl;
}
/*
=item ICL_set_internal(cl, r, g, b, a)
Overwrite a color with new values.
cl - pointer to color object
r - red component (range: 0 - 255)
g - green component (range: 0 - 255)
b - blue component (range: 0 - 255)
a - alpha component (range: 0 - 255)
=cut
*/
i_color *
ICL_set_internal(i_color *cl,unsigned char r,unsigned char g,unsigned char b,unsigned char a) {
dIMCTX;
im_log((aIMCTX,1,"ICL_set_internal(cl* %p,r %d,g %d,b %d,a %d)\n",cl,r,g,b,a));
if (cl == NULL)
if ( (cl=mymalloc(sizeof(i_color))) == NULL)
im_fatal(aIMCTX, 2,"malloc() error\n");
cl->rgba.r=r;
cl->rgba.g=g;
cl->rgba.b=b;
cl->rgba.a=a;
im_log((aIMCTX,1,"(%p) <- ICL_set_internal\n",cl));
return cl;
}
/*
=item ICL_add(dst, src, ch)
Add src to dst inplace - dst is modified.
dst - pointer to destination color object
src - pointer to color object that is added
ch - number of channels
=cut
*/
void
ICL_add(i_color *dst,i_color *src,int ch) {
int tmp,i;
for(i=0;i<ch;i++) {
tmp=dst->channel[i]+src->channel[i];
dst->channel[i]= tmp>255 ? 255:tmp;
}
}
/*
=item ICL_info(cl)
Dump color information to log - strictly for debugging.
cl - pointer to color object
=cut
*/
void
ICL_info(i_color const *cl) {
dIMCTX;
im_log((aIMCTX, 1,"i_color_info(cl* %p)\n",cl));
im_log((aIMCTX, 1,"i_color_info: (%d,%d,%d,%d)\n",cl->rgba.r,cl->rgba.g,cl->rgba.b,cl->rgba.a));
}
/*
=item ICL_DESTROY
Destroy ancillary data for Color object.
cl - pointer to color object
=cut
*/
void
ICL_DESTROY(i_color *cl) {
dIMCTX;
im_log((aIMCTX, 1,"ICL_DESTROY(cl* %p)\n",cl));
myfree(cl);
}
/*
=item i_fcolor_new(double r, double g, double b, double a)
=cut
*/
i_fcolor *i_fcolor_new(double r, double g, double b, double a) {
i_fcolor *cl = NULL;
dIMCTX;
im_log((aIMCTX, 1,"i_fcolor_new(r %g,g %g,b %g,a %g)\n", r, g, b, a));
if ( (cl=mymalloc(sizeof(i_fcolor))) == NULL) im_fatal(aIMCTX, 2,"malloc() error\n");
cl->rgba.r = r;
cl->rgba.g = g;
cl->rgba.b = b;
cl->rgba.a = a;
im_log((aIMCTX, 1,"(%p) <- i_fcolor_new\n",cl));
return cl;
}
/*
=item i_fcolor_destroy(i_fcolor *cl)
=cut
*/
void i_fcolor_destroy(i_fcolor *cl) {
myfree(cl);
}
/*
=item i_img_exorcise(im)
Free image data.
im - Image pointer
=cut
*/
void
i_img_exorcise(i_img *im) {
dIMCTXim(im);
im_log((aIMCTX,1,"i_img_exorcise(im* %p)\n",im));
i_tags_destroy(&im->tags);
if (im->i_f_destroy)
(im->i_f_destroy)(im);
if (im->idata != NULL) { myfree(im->idata); }
im->idata = NULL;
im->xsize = 0;
im->ysize = 0;
im->channels = 0;
im->ext_data=NULL;
}
/*
=item i_img_destroy(C<img>)
=order 90
=category Image creation/destruction
=synopsis i_img_destroy(img)
Destroy an image object
=cut
*/
void
i_img_destroy(i_img *im) {
dIMCTXim(im);
im_log((aIMCTX, 1,"i_img_destroy(im %p)\n",im));
i_img_exorcise(im);
if (im) { myfree(im); }
im_context_refdec(aIMCTX, "img_destroy");
}
/*
=item i_img_info(im, info)
=category Image
Return image information
im - Image pointer
info - pointer to array to return data
info is an array of 4 integers with the following values:
info[0] - width
info[1] - height
info[2] - channels
info[3] - channel mask
=cut
*/
void
i_img_info(i_img *im, i_img_dim *info) {
dIMCTXim(im);
im_log((aIMCTX,1,"i_img_info(im %p)\n",im));
if (im != NULL) {
im_log((aIMCTX,1,"i_img_info: xsize=%" i_DF " ysize=%" i_DF " channels=%d "
"mask=%ud\n",
i_DFc(im->xsize), i_DFc(im->ysize), im->channels,im->ch_mask));
im_log((aIMCTX,1,"i_img_info: idata=%p\n",im->idata));
info[0] = im->xsize;
info[1] = im->ysize;
info[2] = im->channels;
info[3] = im->ch_mask;
} else {
info[0] = 0;
info[1] = 0;
info[2] = 0;
info[3] = 0;
}
}
/*
=item i_img_setmask(C<im>, C<ch_mask>)
=category Image Information
=synopsis // only channel 0 writable
=synopsis i_img_setmask(img, 0x01);
Set the image channel mask for C<im> to C<ch_mask>.
The image channel mask gives some control over which channels can be
written to in the image.
=cut
*/
void
i_img_setmask(i_img *im,int ch_mask) { im->ch_mask=ch_mask; }
/*
=item i_img_getmask(C<im>)
=category Image Information
=synopsis int mask = i_img_getmask(img);
Get the image channel mask for C<im>.
=cut
*/
int
i_img_getmask(i_img *im) { return im->ch_mask; }
/*
=item i_img_getchannels(C<im>)
=category Image Information
=synopsis int channels = i_img_getchannels(img);
Get the number of channels in C<im>.
=cut
*/
int
i_img_getchannels(i_img *im) { return im->channels; }
/*
=item i_img_get_width(C<im>)
=category Image Information
=synopsis i_img_dim width = i_img_get_width(im);
Returns the width in pixels of the image.
=cut
*/
i_img_dim
i_img_get_width(i_img *im) {
return im->xsize;
}
/*
=item i_img_get_height(C<im>)
=category Image Information
=synopsis i_img_dim height = i_img_get_height(im);
Returns the height in pixels of the image.
=cut
*/
i_img_dim
i_img_get_height(i_img *im) {
return im->ysize;
}
/*
=item i_copyto_trans(C<im>, C<src>, C<x1>, C<y1>, C<x2>, C<y2>, C<tx>, C<ty>, C<trans>)
=category Image
(C<x1>,C<y1>) (C<x2>,C<y2>) specifies the region to copy (in the
source coordinates) (C<tx>,C<ty>) specifies the upper left corner for
the target image. pass NULL in C<trans> for non transparent i_colors.
=cut
*/
void
i_copyto_trans(i_img *im,i_img *src,i_img_dim x1,i_img_dim y1,i_img_dim x2,i_img_dim y2,i_img_dim tx,i_img_dim ty,const i_color *trans) {
i_color pv;
i_img_dim x,y,t,ttx,tty,tt;
int ch;
dIMCTXim(im);
im_log((aIMCTX, 1,"i_copyto_trans(im* %p,src %p, p1(" i_DFp "), p2(" i_DFp "), "
"to(" i_DFp "), trans* %p)\n",
im, src, i_DFcp(x1, y1), i_DFcp(x2, y2), i_DFcp(tx, ty), trans));
if (x2<x1) { t=x1; x1=x2; x2=t; }
if (y2<y1) { t=y1; y1=y2; y2=t; }
ttx=tx;
for(x=x1;x<x2;x++)
{
tty=ty;
for(y=y1;y<y2;y++)
{
i_gpix(src,x,y,&pv);
if ( trans != NULL)
{
tt=0;
for(ch=0;ch<im->channels;ch++) if (trans->channel[ch]!=pv.channel[ch]) tt++;
if (tt) i_ppix(im,ttx,tty,&pv);
} else i_ppix(im,ttx,tty,&pv);
tty++;
}
ttx++;
}
}
/*
=item i_copy(source)
=category Image
Creates a new image that is a copy of the image C<source>.
Tags are not copied, only the image data.
Returns: i_img *
=cut
*/
i_img *
i_copy(i_img *src) {
i_img_dim y, y1, x1;
dIMCTXim(src);
i_img *im = i_sametype(src, src->xsize, src->ysize);
im_log((aIMCTX,1,"i_copy(src %p)\n", src));
if (!im)
return NULL;
x1 = src->xsize;
y1 = src->ysize;
if (src->type == i_direct_type) {
if (src->bits == i_8_bits) {
i_color *pv;
pv = mymalloc(sizeof(i_color) * x1);
for (y = 0; y < y1; ++y) {
i_glin(src, 0, x1, y, pv);
i_plin(im, 0, x1, y, pv);
}
myfree(pv);
}
else {
i_fcolor *pv;
pv = mymalloc(sizeof(i_fcolor) * x1);
for (y = 0; y < y1; ++y) {
i_glinf(src, 0, x1, y, pv);
i_plinf(im, 0, x1, y, pv);
}
myfree(pv);
}
}
else {
i_palidx *vals;
vals = mymalloc(sizeof(i_palidx) * x1);
for (y = 0; y < y1; ++y) {
i_gpal(src, 0, x1, y, vals);
i_ppal(im, 0, x1, y, vals);
}
myfree(vals);
}
return im;
}
/*
http://en.wikipedia.org/wiki/Lanczos_resampling
*/
static
float
Lanczos(float x) {
float PIx, PIx2;
PIx = PI * x;
PIx2 = PIx / 2.0;
if ((x >= 2.0) || (x <= -2.0)) return (0.0);
else if (x == 0.0) return (1.0);
else return(sin(PIx) / PIx * sin(PIx2) / PIx2);
}
/*
=item i_scaleaxis(im, value, axis)
Returns a new image object which is I<im> scaled by I<value> along
wither the x-axis (I<axis> == 0) or the y-axis (I<axis> == 1).
=cut
*/
i_img*
i_scaleaxis(i_img *im, double Value, int Axis) {
i_img_dim hsize, vsize, i, j, k, l, lMax, iEnd, jEnd;
i_img_dim LanczosWidthFactor;
float *l0, *l1;
double OldLocation;
i_img_dim T;
double t;
float F, PictureValue[MAXCHANNELS];
short psave;
i_color val,val1,val2;
i_img *new_img;
int has_alpha = i_img_has_alpha(im);
int color_chans = i_img_color_channels(im);
dIMCTXim(im);
i_clear_error();
im_log((aIMCTX, 1,"i_scaleaxis(im %p,Value %.2f,Axis %d)\n",im,Value,Axis));
if (Axis == XAXIS) {
hsize = (i_img_dim)(0.5 + im->xsize * Value);
if (hsize < 1) {
hsize = 1;
Value = 1.0 / im->xsize;
}
vsize = im->ysize;
jEnd = hsize;
iEnd = vsize;
} else {
hsize = im->xsize;
vsize = (i_img_dim)(0.5 + im->ysize * Value);
if (vsize < 1) {
vsize = 1;
Value = 1.0 / im->ysize;
}
jEnd = vsize;
iEnd = hsize;
}
new_img = i_img_8_new(hsize, vsize, im->channels);
if (!new_img) {
i_push_error(0, "cannot create output image");
return NULL;
}
/* 1.4 is a magic number, setting it to 2 will cause rather blurred images */
LanczosWidthFactor = (Value >= 1) ? 1 : (i_img_dim) (1.4/Value);
lMax = LanczosWidthFactor << 1;
l0 = mymalloc(lMax * sizeof(float));
l1 = mymalloc(lMax * sizeof(float));
for (j=0; j<jEnd; j++) {
OldLocation = ((double) j) / Value;
T = (i_img_dim) (OldLocation);
F = OldLocation - T;
for (l = 0; l<lMax; l++) {
l0[lMax-l-1] = Lanczos(((float) (lMax-l-1) + F) / (float) LanczosWidthFactor);
l1[l] = Lanczos(((float) (l+1) - F) / (float) LanczosWidthFactor);
}
/* Make sure filter is normalized */
t = 0.0;
for(l=0; l<lMax; l++) {
t+=l0[l];
t+=l1[l];
}
t /= (double)LanczosWidthFactor;
for(l=0; l<lMax; l++) {
l0[l] /= t;
l1[l] /= t;
}
if (Axis == XAXIS) {
for (i=0; i<iEnd; i++) {
for (k=0; k<im->channels; k++) PictureValue[k] = 0.0;
for (l=0; l<lMax; l++) {
i_img_dim mx = T-lMax+l+1;
i_img_dim Mx = T+l+1;
mx = (mx < 0) ? 0 : mx;
Mx = (Mx >= im->xsize) ? im->xsize-1 : Mx;
i_gpix(im, Mx, i, &val1);
i_gpix(im, mx, i, &val2);
if (has_alpha) {
i_sample_t alpha1 = val1.channel[color_chans];
i_sample_t alpha2 = val2.channel[color_chans];
for (k=0; k < color_chans; k++) {
PictureValue[k] += l1[l] * val1.channel[k] * alpha1 / 255;
PictureValue[k] += l0[lMax-l-1] * val2.channel[k] * alpha2 / 255;
}
PictureValue[color_chans] += l1[l] * val1.channel[color_chans];
PictureValue[color_chans] += l0[lMax-l-1] * val2.channel[color_chans];
}
else {
for (k=0; k<im->channels; k++) {
PictureValue[k] += l1[l] * val1.channel[k];
PictureValue[k] += l0[lMax-l-1] * val2.channel[k];
}
}
}
if (has_alpha) {
float fa = PictureValue[color_chans] / LanczosWidthFactor;
int alpha = minmax(0, 255, fa+0.5);
if (alpha) {
for (k = 0; k < color_chans; ++k) {
psave = (short)(0.5+(PictureValue[k] / LanczosWidthFactor * 255 / fa));
val.channel[k]=minmax(0,255,psave);
}
val.channel[color_chans] = alpha;
}
else {
/* zero alpha, so the pixel has no color */
for (k = 0; k < im->channels; ++k)
val.channel[k] = 0;
}
}
else {
for(k=0;k<im->channels;k++) {
psave = (short)(0.5+(PictureValue[k] / LanczosWidthFactor));
val.channel[k]=minmax(0,255,psave);
}
}
i_ppix(new_img, j, i, &val);
}
} else {
for (i=0; i<iEnd; i++) {
for (k=0; k<im->channels; k++) PictureValue[k] = 0.0;
for (l=0; l < lMax; l++) {
i_img_dim mx = T-lMax+l+1;
i_img_dim Mx = T+l+1;
mx = (mx < 0) ? 0 : mx;
Mx = (Mx >= im->ysize) ? im->ysize-1 : Mx;
i_gpix(im, i, Mx, &val1);
i_gpix(im, i, mx, &val2);
if (has_alpha) {
i_sample_t alpha1 = val1.channel[color_chans];
i_sample_t alpha2 = val2.channel[color_chans];
for (k=0; k < color_chans; k++) {
PictureValue[k] += l1[l] * val1.channel[k] * alpha1 / 255;
PictureValue[k] += l0[lMax-l-1] * val2.channel[k] * alpha2 / 255;
}
PictureValue[color_chans] += l1[l] * val1.channel[color_chans];
PictureValue[color_chans] += l0[lMax-l-1] * val2.channel[color_chans];
}
else {
for (k=0; k<im->channels; k++) {
PictureValue[k] += l1[l] * val1.channel[k];
PictureValue[k] += l0[lMax-l-1] * val2.channel[k];
}
}
}
if (has_alpha) {
float fa = PictureValue[color_chans] / LanczosWidthFactor;
int alpha = minmax(0, 255, fa+0.5);
if (alpha) {
for (k = 0; k < color_chans; ++k) {
psave = (short)(0.5+(PictureValue[k] / LanczosWidthFactor * 255 / fa));
val.channel[k]=minmax(0,255,psave);
}
val.channel[color_chans] = alpha;
}
else {
for (k = 0; k < im->channels; ++k)
val.channel[k] = 0;
}
}
else {
for(k=0;k<im->channels;k++) {
psave = (short)(0.5+(PictureValue[k] / LanczosWidthFactor));
val.channel[k]=minmax(0,255,psave);
}
}
i_ppix(new_img, i, j, &val);
}
}
}
myfree(l0);
myfree(l1);
im_log((aIMCTX, 1,"(%p) <- i_scaleaxis\n", new_img));
return new_img;
}
/*
=item i_scale_nn(im, scx, scy)
Scale by using nearest neighbor
Both axes scaled at the same time since
nothing is gained by doing it in two steps
=cut
*/
i_img*
i_scale_nn(i_img *im, double scx, double scy) {
i_img_dim nxsize,nysize,nx,ny;
i_img *new_img;
i_color val;
dIMCTXim(im);
im_log((aIMCTX, 1,"i_scale_nn(im %p,scx %.2f,scy %.2f)\n",im,scx,scy));
nxsize = (i_img_dim) ((double) im->xsize * scx);
if (nxsize < 1) {
nxsize = 1;
scx = 1.0 / im->xsize;
}
nysize = (i_img_dim) ((double) im->ysize * scy);
if (nysize < 1) {
nysize = 1;
scy = 1.0 / im->ysize;
}
im_assert(scx != 0 && scy != 0);
new_img=i_img_empty_ch(NULL,nxsize,nysize,im->channels);
for(ny=0;ny<nysize;ny++) for(nx=0;nx<nxsize;nx++) {
i_gpix(im,((double)nx)/scx,((double)ny)/scy,&val);
i_ppix(new_img,nx,ny,&val);
}
im_log((aIMCTX, 1,"(%p) <- i_scale_nn\n",new_img));
return new_img;
}
/*
=item i_sametype(C<im>, C<xsize>, C<ysize>)
=category Image creation/destruction
=synopsis i_img *img = i_sametype(src, width, height);
Returns an image of the same type (sample size, channels, paletted/direct).
For paletted images the palette is copied from the source.
=cut
*/
i_img *
i_sametype(i_img *src, i_img_dim xsize, i_img_dim ysize) {
dIMCTXim(src);
if (src->type == i_direct_type) {
if (src->bits == 8) {
return i_img_empty_ch(NULL, xsize, ysize, src->channels);
}
else if (src->bits == i_16_bits) {
return i_img_16_new(xsize, ysize, src->channels);
}
else if (src->bits == i_double_bits) {
return i_img_double_new(xsize, ysize, src->channels);
}
else {
i_push_error(0, "Unknown image bits");
return NULL;
}
}
else {
i_color col;
int i;
i_img *targ = i_img_pal_new(xsize, ysize, src->channels, i_maxcolors(src));
for (i = 0; i < i_colorcount(src); ++i) {
i_getcolors(src, i, &col, 1);
i_addcolors(targ, &col, 1);
}
return targ;
}
}
/*
=item i_sametype_chans(C<im>, C<xsize>, C<ysize>, C<channels>)
=category Image creation/destruction
=synopsis i_img *img = i_sametype_chans(src, width, height, channels);
Returns an image of the same type (sample size).
For paletted images the equivalent direct type is returned.
=cut
*/
i_img *
i_sametype_chans(i_img *src, i_img_dim xsize, i_img_dim ysize, int channels) {
dIMCTXim(src);
if (src->bits == 8) {
return i_img_empty_ch(NULL, xsize, ysize, channels);
}
else if (src->bits == i_16_bits) {
return i_img_16_new(xsize, ysize, channels);
}
else if (src->bits == i_double_bits) {
return i_img_double_new(xsize, ysize, channels);
}
else {
i_push_error(0, "Unknown image bits");
return NULL;
}
}
/*
=item i_transform(im, opx, opxl, opy, opyl, parm, parmlen)
Spatially transforms I<im> returning a new image.
opx for a length of opxl and opy for a length of opy are arrays of
operators that modify the x and y positions to retreive the pixel data from.
parm and parmlen define extra parameters that the operators may use.
Note that this function is largely superseded by the more flexible
L<transform.c/i_transform2>.
Returns the new image.
The operators for this function are defined in L<stackmach.c>.
=cut
*/
i_img*
i_transform(i_img *im, int *opx,int opxl,int *opy,int opyl,double parm[],int parmlen) {
double rx,ry;
i_img_dim nxsize,nysize,nx,ny;
i_img *new_img;
i_color val;
dIMCTXim(im);
im_log((aIMCTX, 1,"i_transform(im %p, opx %p, opxl %d, opy %p, opyl %d, parm %p, parmlen %d)\n",im,opx,opxl,opy,opyl,parm,parmlen));
nxsize = im->xsize;
nysize = im->ysize ;
new_img=i_img_empty_ch(NULL,nxsize,nysize,im->channels);
/* fprintf(stderr,"parm[2]=%f\n",parm[2]); */
for(ny=0;ny<nysize;ny++) for(nx=0;nx<nxsize;nx++) {
/* parm[parmlen-2]=(double)nx;
parm[parmlen-1]=(double)ny; */
parm[0]=(double)nx;
parm[1]=(double)ny;
/* fprintf(stderr,"(%d,%d) ->",nx,ny); */
rx=i_op_run(opx,opxl,parm,parmlen);
ry=i_op_run(opy,opyl,parm,parmlen);
/* fprintf(stderr,"(%f,%f)\n",rx,ry); */
i_gpix(im,rx,ry,&val);
i_ppix(new_img,nx,ny,&val);
}
im_log((aIMCTX, 1,"(%p) <- i_transform\n",new_img));
return new_img;
}
/*
=item i_img_diff(im1, im2)
Calculates the sum of the squares of the differences between
correspoding channels in two images.
If the images are not the same size then only the common area is
compared, hence even if images are different sizes this function
can return zero.
=cut
*/
float
i_img_diff(i_img *im1,i_img *im2) {
i_img_dim x, y, xb, yb;
int ch, chb;
float tdiff;
i_color val1,val2;
dIMCTXim(im1);
im_log((aIMCTX, 1,"i_img_diff(im1 %p,im2 %p)\n",im1,im2));
xb=(im1->xsize<im2->xsize)?im1->xsize:im2->xsize;
yb=(im1->ysize<im2->ysize)?im1->ysize:im2->ysize;
chb=(im1->channels<im2->channels)?im1->channels:im2->channels;
im_log((aIMCTX, 1,"i_img_diff: b=(" i_DFp ") chb=%d\n",
i_DFcp(xb,yb), chb));
tdiff=0;
for(y=0;y<yb;y++) for(x=0;x<xb;x++) {
i_gpix(im1,x,y,&val1);
i_gpix(im2,x,y,&val2);
for(ch=0;ch<chb;ch++) tdiff+=(val1.channel[ch]-val2.channel[ch])*(val1.channel[ch]-val2.channel[ch]);
}
im_log((aIMCTX, 1,"i_img_diff <- (%.2f)\n",tdiff));
return tdiff;
}
/*
=item i_img_diffd(im1, im2)
Calculates the sum of the squares of the differences between
correspoding channels in two images.
If the images are not the same size then only the common area is
compared, hence even if images are different sizes this function
can return zero.
This is like i_img_diff() but looks at floating point samples instead.
=cut
*/
double
i_img_diffd(i_img *im1,i_img *im2) {
i_img_dim x, y, xb, yb;
int ch, chb;
double tdiff;
i_fcolor val1,val2;
dIMCTXim(im1);
im_log((aIMCTX, 1,"i_img_diffd(im1 %p,im2 %p)\n",im1,im2));
xb=(im1->xsize<im2->xsize)?im1->xsize:im2->xsize;
yb=(im1->ysize<im2->ysize)?im1->ysize:im2->ysize;
chb=(im1->channels<im2->channels)?im1->channels:im2->channels;
im_log((aIMCTX, 1,"i_img_diffd: b(" i_DFp ") chb=%d\n",
i_DFcp(xb, yb), chb));
tdiff=0;
for(y=0;y<yb;y++) for(x=0;x<xb;x++) {
i_gpixf(im1,x,y,&val1);
i_gpixf(im2,x,y,&val2);
for(ch=0;ch<chb;ch++) {
double sdiff = val1.channel[ch]-val2.channel[ch];
tdiff += sdiff * sdiff;
}
}