4 rubthru_targ_noalpha(i_img *im, i_img *src,
6 int src_minx, int src_miny,
7 int src_maxx, int src_maxy) {
11 int width = src_maxx - src_minx;
16 if (im->channels == 3 && (src->channels == 4 || src->channels == 2)) {
20 else if (im->channels == 1 && (src->channels == 4 || src->channels == 2)) {
25 i_copyto(im, src, src_minx, src_miny, src_maxx, src_maxy, tx, ty);
29 #code im->bits <= 8 && src->bits <= 8
31 IM_COLOR *src_line, *dest_line;
33 src_line = mymalloc(sizeof(IM_COLOR) * width);
34 dest_line = mymalloc(sizeof(IM_COLOR) * width);
37 for(y = src_miny; y < src_maxy; y++) {
38 IM_COLOR *srcp = src_line;
39 IM_COLOR *destp = dest_line;
41 IM_GLIN(src, src_minx, src_maxx, y, src_line);
42 IM_GLIN(im, tx, tx + width, tty, dest_line);
43 if (src->channels != want_channels)
44 IM_ADAPT_COLORS(want_channels, src->channels, src_line, width);
46 for(x = src_minx; x < src_maxx; x++) {
47 alpha = srcp->channel[alphachan];
48 for (ch = 0; ch < im->channels; ++ch) {
49 IM_WORK_T samp = (alpha * srcp->channel[ch]
50 + (IM_SAMPLE_MAX - alpha) * destp->channel[ch])/IM_SAMPLE_MAX;
51 destp->channel[ch] = IM_LIMIT(samp);
57 IM_PLIN(im, tx, tx + width, tty, dest_line);
68 rubthru_targ_alpha(i_img *im, i_img *src, int tx, int ty,
69 int src_minx, int src_miny,
70 int src_maxx, int src_maxy) {
76 int width = src_maxx - src_minx;
78 if (im->channels == 4 && (src->channels == 4 || src->channels == 2)) {
82 else if (im->channels == 2 && (src->channels == 4 || src->channels == 2)) {
87 i_copyto(im, src, src_minx, src_miny, src_maxx, src_maxy, tx, ty);
91 targ_alpha_chan = im->channels - 1;
93 #code im->bits <= 8 && src->bits <= 8
94 IM_WORK_T src_alpha, orig_alpha, dest_alpha, remains;
95 IM_COLOR *src_line, *dest_line;
97 src_line = mymalloc(sizeof(IM_COLOR) * width);
98 dest_line = mymalloc(sizeof(IM_COLOR) * width);
101 for(y = src_miny; y < src_maxy; y++) {
103 IM_COLOR *srcp = src_line;
104 IM_COLOR *destp = dest_line;
105 IM_GLIN(src, src_minx, src_maxx, y, src_line);
106 if (src->channels != want_channels)
107 IM_ADAPT_COLORS(want_channels, src->channels, src_line, width);
111 while (min_x < max_x && srcp->channel[alphachan] == 0) {
115 while (max_x > min_x && src_line[max_x-1].channel[alphachan] == 0) {
120 int work_left = tx + min_x - src_minx;
121 int work_width = max_x - min_x;
123 IM_GLIN(im, work_left, work_left + work_width, tty, dest_line);
125 for(x = src_minx; x < src_maxx; x++) {
126 src_alpha = srcp->channel[alphachan];
128 remains = IM_SAMPLE_MAX - src_alpha;
129 orig_alpha = destp->channel[targ_alpha_chan];
130 dest_alpha = src_alpha + (remains * orig_alpha) / IM_SAMPLE_MAX;
132 for (ch = 0; ch < im->channels-1; ++ch) {
134 ( src_alpha * srcp->channel[ch]
135 + remains * destp->channel[ch] * orig_alpha / IM_SAMPLE_MAX
137 destp->channel[ch] = IM_LIMIT(samp);
140 destp->channel[targ_alpha_chan] = dest_alpha;
146 IM_PLIN(im, work_left, work_left + work_width, tty, dest_line);
157 =item i_rubthru(im, src, tx, ty, src_minx, src_miny, src_maxx, src_maxy )
161 Takes the sub image I<src[src_minx, src_maxx)[src_miny, src_maxy)> and
162 overlays it at (I<tx>,I<ty>) on the image object.
164 The alpha channel of each pixel in I<src> is used to control how much
165 the existing colour in I<im> is replaced, if it is 255 then the colour
166 is completely replaced, if it is 0 then the original colour is left
173 i_rubthru(i_img *im, i_img *src, int tx, int ty, int src_minx, int src_miny,
174 int src_maxx, int src_maxy) {
191 if (src_maxx > src->xsize) {
192 src_maxx = src->xsize;
194 if (src_maxy > src->ysize) {
195 src_maxy = src->ysize;
197 if (tx >= im->xsize || ty >= im->ysize
198 || src_minx >= src_maxx || src_miny >= src_maxy) {
200 i_push_error(0, "rubthrough: nothing to do");
204 if (im->channels == 1 || im->channels == 3)
205 return rubthru_targ_noalpha(im, src, tx, ty, src_minx, src_miny,
208 return rubthru_targ_alpha(im, src, tx, ty, src_minx, src_miny,