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#include "imager.h"
static int
rubthru_targ_noalpha(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 alphachan;
int ch;
int width = src_maxx - src_minx;
int want_channels;
i_clear_error();
if (im->channels == 3 && (src->channels == 4 || src->channels == 2)) {
want_channels = 4;
alphachan = 3;
}
else if (im->channels == 1 && (src->channels == 4 || src->channels == 2)) {
want_channels = 2;
alphachan = 1;
}
else {
i_copyto(im, src, src_minx, src_miny, src_maxx, src_maxy, tx, ty);
return 1;
}
#code im->bits <= 8 && src->bits <= 8
IM_WORK_T alpha;
IM_COLOR *src_line, *dest_line;
src_line = mymalloc(sizeof(IM_COLOR) * width);
dest_line = mymalloc(sizeof(IM_COLOR) * width);
tty = ty;
for(y = src_miny; y < src_maxy; y++) {
IM_COLOR *srcp = src_line;
IM_COLOR *destp = dest_line;
ttx = tx;
IM_GLIN(src, src_minx, src_maxx, y, src_line);
IM_GLIN(im, tx, tx + width, tty, dest_line);
if (src->channels != want_channels)
IM_ADAPT_COLORS(want_channels, src->channels, src_line, width);
for(x = src_minx; x < src_maxx; x++) {
alpha = srcp->channel[alphachan];
for (ch = 0; ch < im->channels; ++ch) {
IM_WORK_T samp = (alpha * srcp->channel[ch]
+ (IM_SAMPLE_MAX - alpha) * destp->channel[ch])/IM_SAMPLE_MAX;
destp->channel[ch] = IM_LIMIT(samp);
}
++srcp;
++destp;
}
IM_PLIN(im, tx, tx + width, tty, dest_line);
tty++;
}
myfree(src_line);
myfree(dest_line);
#/code
return 1;
}
static int
rubthru_targ_alpha(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 want_channels;
int alphachan;
int ch;
int targ_alpha_chan;
int width = src_maxx - src_minx;
if (im->channels == 4 && (src->channels == 4 || src->channels == 2)) {
alphachan = 3;
want_channels = 4;
}
else if (im->channels == 2 && (src->channels == 4 || src->channels == 2)) {
alphachan = 1;
want_channels = 2;
}
else {
i_copyto(im, src, src_minx, src_miny, src_maxx, src_maxy, tx, ty);
return 1;
}
targ_alpha_chan = im->channels - 1;
#code im->bits <= 8 && src->bits <= 8
IM_WORK_T src_alpha, orig_alpha, dest_alpha, remains;
IM_COLOR *src_line, *dest_line;
src_line = mymalloc(sizeof(IM_COLOR) * width);
dest_line = mymalloc(sizeof(IM_COLOR) * width);
tty = ty;
for(y = src_miny; y < src_maxy; y++) {
int min_x, max_x;
IM_COLOR *srcp = src_line;
IM_COLOR *destp = dest_line;
IM_GLIN(src, src_minx, src_maxx, y, src_line);
if (src->channels != want_channels)
IM_ADAPT_COLORS(want_channels, src->channels, src_line, width);
min_x = src_minx;
max_x = src_maxx;
while (min_x < max_x && srcp->channel[alphachan] == 0) {
++min_x;
++srcp;
}
while (max_x > min_x && src_line[max_x-1].channel[alphachan] == 0) {
--max_x;
}
if (max_x > min_x) {
int work_left = tx + min_x - src_minx;
int work_width = max_x - min_x;
ttx = work_left;
IM_GLIN(im, work_left, work_left + work_width, tty, dest_line);
for(x = min_x; x < max_x; x++) {
src_alpha = srcp->channel[alphachan];
if (src_alpha) {
remains = IM_SAMPLE_MAX - src_alpha;
orig_alpha = destp->channel[targ_alpha_chan];
dest_alpha = src_alpha + (remains * orig_alpha) / IM_SAMPLE_MAX;
for (ch = 0; ch < im->channels-1; ++ch) {
IM_WORK_T samp =
( src_alpha * srcp->channel[ch]
+ remains * destp->channel[ch] * orig_alpha / IM_SAMPLE_MAX
) / dest_alpha;
destp->channel[ch] = IM_LIMIT(samp);
}
/* dest's alpha */
destp->channel[targ_alpha_chan] = dest_alpha;
}
++srcp;
++destp;
ttx++;
}
IM_PLIN(im, work_left, work_left + work_width, tty, dest_line);
}
tty++;
}
myfree(dest_line);
myfree(src_line);
#/code
return 1;
}
/*
=item i_rubthru(C<im>, C<src>, C<tx>, C<ty>, C<src_minx>, C<src_miny>, C<src_maxx>, C<src_maxy>)
=category Image
Takes the sub image C<src>[C<src_minx>, C<src_maxx>)[C<src_miny>, C<src_maxy>)> and
overlays it at (C<tx>,C<ty>) on the image object.
The alpha channel of each pixel in C<src> is used to control how much
the existing color in C<im> is replaced, if it is 255 then the color
is completely replaced, if it is 0 then the original color 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) {
if (src_minx < 0) {
tx -= src_minx;
src_minx = 0;
}
if (src_miny < 0) {
ty -= src_miny;
src_miny = 0;
}
if (tx < 0) {
src_minx -= tx;
tx = 0;
}
if (ty < 0) {
src_miny -= ty;
ty = 0;
}
if (src_maxx > src->xsize) {
src_maxx = src->xsize;
}
if (src_maxy > src->ysize) {
src_maxy = src->ysize;
}
if (tx >= im->xsize || ty >= im->ysize
|| src_minx >= src_maxx || src_miny >= src_maxy) {
i_clear_error();
/* just do nothing, attempting to rubthrough outside the target isn't
worth being an error */
return 1;
}
if (im->channels == 1 || im->channels == 3)
return rubthru_targ_noalpha(im, src, tx, ty, src_minx, src_miny,
src_maxx, src_maxy);
else
return rubthru_targ_alpha(im, src, tx, ty, src_minx, src_miny,
src_maxx, src_maxy);
}
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