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image.c
2271 lines (1816 loc) · 49.5 KB
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image.c
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#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_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
*/
#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 */
static void fake(void) { ceil(1); }
static int i_ppix_d(i_img *im, int x, int y, const i_color *val);
static int i_gpix_d(i_img *im, int x, int y, i_color *val);
static int i_glin_d(i_img *im, int l, int r, int y, i_color *vals);
static int i_plin_d(i_img *im, int l, int r, int y, const i_color *vals);
static int i_ppixf_d(i_img *im, int x, int y, const i_fcolor *val);
static int i_gpixf_d(i_img *im, int x, int y, i_fcolor *val);
static int i_glinf_d(i_img *im, int l, int r, int y, i_fcolor *vals);
static int i_plinf_d(i_img *im, int l, int r, int y, const i_fcolor *vals);
static int i_gsamp_d(i_img *im, int l, int r, int y, i_sample_t *samps, const int *chans, int chan_count);
static int i_gsampf_d(i_img *im, int l, int r, int y, i_fsample_t *samps, const int *chans, int chan_count);
/*static int i_psamp_d(i_img *im, int l, int r, int y, i_sample_t *samps, int *chans, int chan_count);
static int i_psampf_d(i_img *im, int l, int r, int y, i_fsample_t *samps, int *chans, int chan_count);*/
/*
=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;
mm_log((1,"ICL_new_internal(r %d,g %d,b %d,a %d)\n", r, g, b, a));
if ( (cl=mymalloc(sizeof(i_color))) == NULL) i_fatal(2,"malloc() error\n");
cl->rgba.r = r;
cl->rgba.g = g;
cl->rgba.b = b;
cl->rgba.a = a;
mm_log((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) {
mm_log((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)
i_fatal(2,"malloc() error\n");
cl->rgba.r=r;
cl->rgba.g=g;
cl->rgba.b=b;
cl->rgba.a=a;
mm_log((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) {
mm_log((1,"i_color_info(cl* %p)\n",cl));
mm_log((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) {
mm_log((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;
mm_log((1,"i_fcolor_new(r %g,g %g,b %g,a %g)\n", r, g, b, a));
if ( (cl=mymalloc(sizeof(i_fcolor))) == NULL) i_fatal(2,"malloc() error\n");
cl->rgba.r = r;
cl->rgba.g = g;
cl->rgba.b = b;
cl->rgba.a = a;
mm_log((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 IIM_base_8bit_direct (static)
A static i_img object used to initialize direct 8-bit per sample images.
=cut
*/
static i_img IIM_base_8bit_direct =
{
0, /* channels set */
0, 0, 0, /* xsize, ysize, bytes */
~0U, /* ch_mask */
i_8_bits, /* bits */
i_direct_type, /* type */
0, /* virtual */
NULL, /* idata */
{ 0, 0, NULL }, /* tags */
NULL, /* ext_data */
i_ppix_d, /* i_f_ppix */
i_ppixf_d, /* i_f_ppixf */
i_plin_d, /* i_f_plin */
i_plinf_d, /* i_f_plinf */
i_gpix_d, /* i_f_gpix */
i_gpixf_d, /* i_f_gpixf */
i_glin_d, /* i_f_glin */
i_glinf_d, /* i_f_glinf */
i_gsamp_d, /* i_f_gsamp */
i_gsampf_d, /* i_f_gsampf */
NULL, /* i_f_gpal */
NULL, /* i_f_ppal */
NULL, /* i_f_addcolors */
NULL, /* i_f_getcolors */
NULL, /* i_f_colorcount */
NULL, /* i_f_maxcolors */
NULL, /* i_f_findcolor */
NULL, /* i_f_setcolors */
NULL, /* i_f_destroy */
};
/*static void set_8bit_direct(i_img *im) {
im->i_f_ppix = i_ppix_d;
im->i_f_ppixf = i_ppixf_d;
im->i_f_plin = i_plin_d;
im->i_f_plinf = i_plinf_d;
im->i_f_gpix = i_gpix_d;
im->i_f_gpixf = i_gpixf_d;
im->i_f_glin = i_glin_d;
im->i_f_glinf = i_glinf_d;
im->i_f_gpal = NULL;
im->i_f_ppal = NULL;
im->i_f_addcolor = NULL;
im->i_f_getcolor = NULL;
im->i_f_colorcount = NULL;
im->i_f_findcolor = NULL;
}*/
/*
=item IIM_new(x, y, ch)
=item i_img_8_new(x, y, ch)
=category Image creation
Creates a new image object I<x> pixels wide, and I<y> pixels high with
I<ch> channels.
=cut
*/
i_img *
IIM_new(int x,int y,int ch) {
i_img *im;
mm_log((1,"IIM_new(x %d,y %d,ch %d)\n",x,y,ch));
im=i_img_empty_ch(NULL,x,y,ch);
mm_log((1,"(%p) <- IIM_new\n",im));
return im;
}
void
IIM_DESTROY(i_img *im) {
mm_log((1,"IIM_DESTROY(im* %p)\n",im));
i_img_destroy(im);
/* myfree(cl); */
}
/*
=item i_img_new()
Create new image reference - notice that this isn't an object yet and
this should be fixed asap.
=cut
*/
i_img *
i_img_new() {
i_img *im;
mm_log((1,"i_img_struct()\n"));
if ( (im=mymalloc(sizeof(i_img))) == NULL)
i_fatal(2,"malloc() error\n");
*im = IIM_base_8bit_direct;
im->xsize=0;
im->ysize=0;
im->channels=3;
im->ch_mask=MAXINT;
im->bytes=0;
im->idata=NULL;
mm_log((1,"(%p) <- i_img_struct\n",im));
return im;
}
/*
=item i_img_empty(im, x, y)
Re-new image reference (assumes 3 channels)
im - Image pointer
x - xsize of destination image
y - ysize of destination image
**FIXME** what happens if a live image is passed in here?
Should this just call i_img_empty_ch()?
=cut
*/
i_img *
i_img_empty(i_img *im,int x,int y) {
mm_log((1,"i_img_empty(*im %p, x %d, y %d)\n",im, x, y));
return i_img_empty_ch(im, x, y, 3);
}
/*
=item i_img_empty_ch(im, x, y, ch)
Re-new image reference
im - Image pointer
x - xsize of destination image
y - ysize of destination image
ch - number of channels
=cut
*/
i_img *
i_img_empty_ch(i_img *im,int x,int y,int ch) {
int bytes;
mm_log((1,"i_img_empty_ch(*im %p, x %d, y %d, ch %d)\n", im, x, y, ch));
if (x < 1 || y < 1) {
i_push_error(0, "Image sizes must be positive");
return NULL;
}
if (ch < 1 || ch > MAXCHANNELS) {
i_push_errorf(0, "channels must be between 1 and %d", MAXCHANNELS);
return NULL;
}
/* check this multiplication doesn't overflow */
bytes = x*y*ch;
if (bytes / y / ch != x) {
i_push_errorf(0, "integer overflow calculating image allocation");
return NULL;
}
if (im == NULL)
if ( (im=mymalloc(sizeof(i_img))) == NULL)
i_fatal(2,"malloc() error\n");
memcpy(im, &IIM_base_8bit_direct, sizeof(i_img));
i_tags_new(&im->tags);
im->xsize = x;
im->ysize = y;
im->channels = ch;
im->ch_mask = MAXINT;
im->bytes=bytes;
if ( (im->idata=mymalloc(im->bytes)) == NULL)
i_fatal(2,"malloc() error\n");
memset(im->idata,0,(size_t)im->bytes);
im->ext_data = NULL;
mm_log((1,"(%p) <- i_img_empty_ch\n",im));
return im;
}
/*
=item i_img_exorcise(im)
Free image data.
im - Image pointer
=cut
*/
void
i_img_exorcise(i_img *im) {
mm_log((1,"i_img_exorcise(im* 0x%x)\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->i_f_ppix=i_ppix_d;
im->i_f_gpix=i_gpix_d;
im->i_f_plin=i_plin_d;
im->i_f_glin=i_glin_d;
im->ext_data=NULL;
}
/*
=item i_img_destroy(im)
=category Image
Destroy image and free data via exorcise.
im - Image pointer
=cut
*/
void
i_img_destroy(i_img *im) {
mm_log((1,"i_img_destroy(im %p)\n",im));
i_img_exorcise(im);
if (im) { myfree(im); }
}
/*
=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,int *info) {
mm_log((1,"i_img_info(im 0x%x)\n",im));
if (im != NULL) {
mm_log((1,"i_img_info: xsize=%d ysize=%d channels=%d mask=%ud\n",im->xsize,im->ysize,im->channels,im->ch_mask));
mm_log((1,"i_img_info: idata=0x%d\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(im, ch_mask)
Set the image channel mask for I<im> to I<ch_mask>.
=cut
*/
void
i_img_setmask(i_img *im,int ch_mask) { im->ch_mask=ch_mask; }
/*
=item i_img_getmask(im)
Get the image channel mask for I<im>.
=cut
*/
int
i_img_getmask(i_img *im) { return im->ch_mask; }
/*
=item i_img_getchannels(im)
Get the number of channels in I<im>.
=cut
*/
int
i_img_getchannels(i_img *im) { return im->channels; }
/*
=item i_copyto_trans(im, src, x1, y1, x2, y2, tx, ty, trans)
=category Image
(x1,y1) (x2,y2) specifies the region to copy (in the source coordinates)
(tx,ty) specifies the upper left corner for the target image.
pass NULL in trans for non transparent i_colors.
=cut
*/
void
i_copyto_trans(i_img *im,i_img *src,int x1,int y1,int x2,int y2,int tx,int ty,const i_color *trans) {
i_color pv;
int x,y,t,ttx,tty,tt,ch;
mm_log((1,"i_copyto_trans(im* %p,src 0x%x, x1 %d, y1 %d, x2 %d, y2 %d, tx %d, ty %d, trans* 0x%x)\n",
im, src, x1, y1, x2, y2, 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_copyto(dest, src, x1, y1, x2, y2, tx, ty)
=category Image
Copies image data from the area (x1,y1)-[x2,y2] in the source image to
a rectangle the same size with it's top-left corner at (tx,ty) in the
destination image.
If x1 > x2 or y1 > y2 then the corresponding co-ordinates are swapped.
=cut
*/
void
i_copyto(i_img *im, i_img *src, int x1, int y1, int x2, int y2, int tx, int ty) {
int x, y, t, ttx, tty;
if (x2<x1) { t=x1; x1=x2; x2=t; }
if (y2<y1) { t=y1; y1=y2; y2=t; }
if (tx < 0) {
/* adjust everything equally */
x1 += -tx;
x2 += -tx;
tx = 0;
}
if (ty < 0) {
y1 += -ty;
y2 += -ty;
ty = 0;
}
if (x1 >= src->xsize || y1 >= src->ysize)
return; /* nothing to do */
if (x2 > src->xsize)
x2 = src->xsize;
if (y2 > src->ysize)
y2 = src->ysize;
if (x1 == x2 || y1 == y2)
return; /* nothing to do */
mm_log((1,"i_copyto(im* %p, src %p, x1 %d, y1 %d, x2 %d, y2 %d, tx %d, ty %d)\n",
im, src, x1, y1, x2, y2, tx, ty));
if (im->bits == i_8_bits) {
i_color *row = mymalloc(sizeof(i_color) * (x2-x1));
tty = ty;
for(y=y1; y<y2; y++) {
ttx = tx;
i_glin(src, x1, x2, y, row);
i_plin(im, tx, tx+x2-x1, tty, row);
tty++;
}
myfree(row);
}
else {
i_fcolor pv;
tty = ty;
for(y=y1; y<y2; y++) {
ttx = tx;
for(x=x1; x<x2; x++) {
i_gpixf(src, x, y, &pv);
i_ppixf(im, ttx, tty, &pv);
ttx++;
}
tty++;
}
}
}
/*
=item i_copy(src)
=category Image
Creates a new image that is a copy of src.
Tags are not copied, only the image data.
Returns: i_img *
=cut
*/
i_img *
i_copy(i_img *src) {
int y, y1, x1;
i_img *im = i_sametype(src, src->xsize, src->ysize);
mm_log((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_color temp;
int index;
int count;
i_palidx *vals;
/* paletted image */
i_img_pal_new_low(im, x1, y1, src->channels, i_maxcolors(src));
/* copy across the palette */
count = i_colorcount(src);
for (index = 0; index < count; ++index) {
i_getcolors(src, index, &temp, 1);
i_addcolors(im, &temp, 1);
}
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;
}
/*
=item i_rubthru(im, src, tx, ty, src_minx, src_miny, src_maxx, src_maxy )
=category Image
Takes the sub image I<src[src_minx, src_maxx)[src_miny, src_maxy)> and
overlays it at (I<tx>,I<ty>) on the image object.
The alpha channel of each pixel in I<src> is used to control how much
the existing colour in I<im> is replaced, if it is 255 then the colour
is completely replaced, if it is 0 then the original colour is left
unmodified.
=cut
*/
int
i_rubthru(i_img *im, i_img *src, int tx, int ty, int src_minx, int src_miny,
int src_maxx, int src_maxy) {
int x, y, ttx, tty;
int chancount;
int chans[3];
int alphachan;
int ch;
mm_log((1,"i_rubthru(im %p, src %p, tx %d, ty %d, src_minx %d, "
"src_miny %d, src_maxx %d, src_maxy %d)\n",
im, src, tx, ty, src_minx, src_miny, src_maxx, src_maxy));
i_clear_error();
if (im->channels == 3 && src->channels == 4) {
chancount = 3;
chans[0] = 0; chans[1] = 1; chans[2] = 2;
alphachan = 3;
}
else if (im->channels == 3 && src->channels == 2) {
chancount = 3;
chans[0] = chans[1] = chans[2] = 0;
alphachan = 1;
}
else if (im->channels == 1 && src->channels == 2) {
chancount = 1;
chans[0] = 0;
alphachan = 1;
}
else {
i_push_error(0, "rubthru can only work where (dest, src) channels are (3,4), (3,2) or (1,2)");
return 0;
}
if (im->bits <= 8) {
/* if you change this code, please make sure the else branch is
changed in a similar fashion - TC */
int alpha;
i_color pv, orig, dest;
tty = ty;
for(y = src_miny; y < src_maxy; y++) {
ttx = tx;
for(x = src_minx; x < src_maxx; x++) {
i_gpix(src, x, y, &pv);
i_gpix(im, ttx, tty, &orig);
alpha = pv.channel[alphachan];
for (ch = 0; ch < chancount; ++ch) {
dest.channel[ch] = (alpha * pv.channel[chans[ch]]
+ (255 - alpha) * orig.channel[ch])/255;
}
i_ppix(im, ttx, tty, &dest);
ttx++;
}
tty++;
}
}
else {
double alpha;
i_fcolor pv, orig, dest;
tty = ty;
for(y = src_miny; y < src_maxy; y++) {
ttx = tx;
for(x = src_minx; x < src_maxx; x++) {
i_gpixf(src, x, y, &pv);
i_gpixf(im, ttx, tty, &orig);
alpha = pv.channel[alphachan];
for (ch = 0; ch < chancount; ++ch) {
dest.channel[ch] = alpha * pv.channel[chans[ch]]
+ (1 - alpha) * orig.channel[ch];
}
i_ppixf(im, ttx, tty, &dest);
ttx++;
}
tty++;
}
}
return 1;
}
/*
=item i_flipxy(im, axis)
Flips the image inplace around the axis specified.
Returns 0 if parameters are invalid.
im - Image pointer
axis - 0 = x, 1 = y, 2 = both
=cut
*/
undef_int
i_flipxy(i_img *im, int direction) {
int x, x2, y, y2, xm, ym;
int xs = im->xsize;
int ys = im->ysize;
mm_log((1, "i_flipxy(im %p, direction %d)\n", im, direction ));
if (!im) return 0;
switch (direction) {
case XAXIS: /* Horizontal flip */
xm = xs/2;
ym = ys;
for(y=0; y<ym; y++) {
x2 = xs-1;
for(x=0; x<xm; x++) {
i_color val1, val2;
i_gpix(im, x, y, &val1);
i_gpix(im, x2, y, &val2);
i_ppix(im, x, y, &val2);
i_ppix(im, x2, y, &val1);
x2--;
}
}
break;
case YAXIS: /* Vertical flip */
xm = xs;
ym = ys/2;
y2 = ys-1;
for(y=0; y<ym; y++) {
for(x=0; x<xm; x++) {
i_color val1, val2;
i_gpix(im, x, y, &val1);
i_gpix(im, x, y2, &val2);
i_ppix(im, x, y, &val2);
i_ppix(im, x, y2, &val1);
}
y2--;
}
break;
case XYAXIS: /* Horizontal and Vertical flip */
xm = xs/2;
ym = ys/2;
y2 = ys-1;
for(y=0; y<ym; y++) {
x2 = xs-1;
for(x=0; x<xm; x++) {
i_color val1, val2;
i_gpix(im, x, y, &val1);
i_gpix(im, x2, y2, &val2);
i_ppix(im, x, y, &val2);
i_ppix(im, x2, y2, &val1);
i_gpix(im, x2, y, &val1);
i_gpix(im, x, y2, &val2);
i_ppix(im, x2, y, &val2);
i_ppix(im, x, y2, &val1);
x2--;
}
y2--;
}
if (xm*2 != xs) { /* odd number of column */
mm_log((1, "i_flipxy: odd number of columns\n"));
x = xm;
y2 = ys-1;
for(y=0; y<ym; y++) {
i_color val1, val2;
i_gpix(im, x, y, &val1);
i_gpix(im, x, y2, &val2);
i_ppix(im, x, y, &val2);
i_ppix(im, x, y2, &val1);
y2--;
}
}
if (ym*2 != ys) { /* odd number of rows */
mm_log((1, "i_flipxy: odd number of rows\n"));
y = ym;
x2 = xs-1;
for(x=0; x<xm; x++) {
i_color val1, val2;
i_gpix(im, x, y, &val1);
i_gpix(im, x2, y, &val2);
i_ppix(im, x, y, &val2);
i_ppix(im, x2, y, &val1);
x2--;
}
}
break;
default:
mm_log((1, "i_flipxy: direction is invalid\n" ));
return 0;
}
return 1;
}
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, float Value, int Axis) {
int hsize, vsize, i, j, k, l, lMax, iEnd, jEnd;
int LanczosWidthFactor;
float *l0, *l1, OldLocation;
int T;
float t;
float F, PictureValue[MAXCHANNELS];
short psave;
i_color val,val1,val2;
i_img *new_img;
mm_log((1,"i_scaleaxis(im %p,Value %.2f,Axis %d)\n",im,Value,Axis));
if (Axis == XAXIS) {
hsize = (int)(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 = (int)(0.5 + im->ysize * Value);
if (vsize < 1) {
vsize = 1;
Value = 1.0 / im->ysize;
}
jEnd = vsize;
iEnd = hsize;
}
new_img = i_img_empty_ch(NULL, hsize, vsize, im->channels);
/* 1.4 is a magic number, setting it to 2 will cause rather blurred images */
LanczosWidthFactor = (Value >= 1) ? 1 : (int) (1.4/Value);
lMax = LanczosWidthFactor << 1;
l0 = mymalloc(lMax * sizeof(float));
l1 = mymalloc(lMax * sizeof(float));
for (j=0; j<jEnd; j++) {
OldLocation = ((float) j) / Value;
T = (int) (OldLocation);
F = OldLocation - (float) 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 /= (float)LanczosWidthFactor;
for(l=0; l<lMax; l++) {
l0[l] /= t;
l1[l] /= t;