[imager.git] / paste.im

#include "imager.h"

/*
=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 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));

#code im->bits == i_8_bits
  IM_COLOR *row = mymalloc(sizeof(IM_COLOR) * (x2-x1));
  tty = ty;
  for(y=y1; y<y2; y++) {
    ttx = tx;
    IM_GLIN(src, x1, x2, y, row);
    if (src->channels != im->channels)
      IM_ADAPT_COLORS(im->channels, src->channels, row, x2-x1);
    IM_PLIN(im, tx, tx+x2-x1, tty, row);
    tty++;
  }
  myfree(row);
#/code
}

#define color_to_grey(col) ((col)->rgb.r * 0.222  + (col)->rgb.g * 0.707 + (col)->rgb.b * 0.071)

#code
void
#ifdef IM_EIGHT_BIT
i_adapt_colors
#else
i_adapt_fcolors
#endif
(int out_channels, int in_channels, IM_COLOR *colors, 
	       size_t count) {
  if (out_channels == in_channels)
    return;
  if (count == 0)
    return;

  switch (out_channels) {
  case 1:
    {
      switch (in_channels) {
      case 2:
	/* apply alpha against a black background */
	while (count) {
	  colors->channel[0] = colors->channel[0] * colors->channel[1] / IM_SAMPLE_MAX;
	  ++colors;
	  --count;
	}
	return;

      case 3:
	/* convert to grey */
	while (count) {
	  colors->channel[0] = IM_ROUND(color_to_grey(colors));
	  ++colors;
	  --count;
	}
	return;
	    
      case 4:
	while (count) {
	  colors->channel[0] = IM_ROUND(color_to_grey(colors) * colors->channel[3] / IM_SAMPLE_MAX);
	  ++colors;
	  --count;
	}
	return;

      default:
	i_fatal(3, "i_adapt_colors: in_channels of %d invalid\n", in_channels);
	return; /* avoid warnings */
      }
    }

  case 2:
    {
      switch (in_channels) {
      case 1:
	while (count) {
	  colors->channel[1] = IM_SAMPLE_MAX;
	  ++colors;
	  --count;
	}
	return;

      case 3:
	while (count) {
	  colors->channel[0] = IM_ROUND(color_to_grey(colors));
	  colors->channel[1] = IM_SAMPLE_MAX;
	  ++colors;
	  --count;
	}
	return;

      case 4:
	while (count) {
	  colors->channel[0] = IM_ROUND(color_to_grey(colors));
	  colors->channel[1] = colors->channel[3];
	  ++colors;
	  --count;
	}
	return;

      default:
	i_fatal(3, "i_adapt_colors: in_channels of %d invalid\n", in_channels);
	return; /* avoid warnings */
      }
    }

  case 3:
    {
      switch (in_channels) {
      case 1:
	while (count) {
	  colors->channel[1] = colors->channel[2] = colors->channel[0];
	  ++colors;
	  --count;
	}
	return;

      case 2:
	while (count) {
	  int alpha = colors->channel[1];
	  colors->channel[0] = colors->channel[1] = colors->channel[2] =
	    IM_ROUND(colors->channel[0] * alpha / IM_SAMPLE_MAX);
	  ++colors;
	  --count;
	}
	return;

      case 4:
	while (count) {
	  int alpha = colors->channel[3];
	  colors->channel[0] = 
	    IM_ROUND(colors->channel[0] * alpha / IM_SAMPLE_MAX);
	  colors->channel[1] = 
	    IM_ROUND(colors->channel[1] * alpha / IM_SAMPLE_MAX);
	  colors->channel[2] = 
	    IM_ROUND(colors->channel[2] * alpha / IM_SAMPLE_MAX);
	  ++colors;
	  --count;
	}
	return;

      default:
	i_fatal(3, "i_adapt_colors: in_channels of %d invalid\n", in_channels);
	return; /* avoid warnings */
      }
    }

  case 4:
    {
      switch (in_channels) {
      case 1:
	while (count) {
	  colors->channel[1] = colors->channel[2] = colors->channel[0];
	  colors->channel[3] = IM_SAMPLE_MAX;
	  ++colors;
	  --count;
	}
	return;

      case 2:
	while (count) {
	  colors->channel[3] = colors->channel[1];
	  colors->channel[1] = colors->channel[2] = colors->channel[0];
	  ++colors;
	  --count;
	}
	return;

      case 3:
	while (count) {
	  colors->channel[3] = IM_SAMPLE_MAX;
	  ++colors;
	  --count;
	}
	return;

      default:
	i_fatal(3, "i_adapt_colors: in_channels of %d invalid\n", in_channels);
	return; /* avoid warnings */
      }
    }

  default:
    i_fatal(3, "i_adapt_colors: out_channels of %d invalid\n", out_channels);
    return; /* avoid warnings */
  }
}

void
#ifdef IM_EIGHT_BIT
i_adapt_colors_bg
#else
i_adapt_fcolors_bg
#endif
(int out_channels, int in_channels, IM_COLOR *colors, 
	       size_t count, IM_COLOR const *bg) {
  if (out_channels == in_channels)
    return;
  if (count == 0)
    return;

  switch (out_channels) {
  case 2:
  case 4:
    IM_ADAPT_COLORS(out_channels, in_channels, colors, count);
    return;

  case 1:
    switch (in_channels) {
    case 3:
      IM_ADAPT_COLORS(out_channels, in_channels, colors, count);
      return;

    case 2:
      {
	/* apply alpha against our given background */
	IM_WORK_T grey_bg = IM_ROUND(color_to_grey(bg));
	while (count) {
	  colors->channel[0] = 
	    (colors->channel[0] * colors->channel[1] +
	     grey_bg * (IM_SAMPLE_MAX - colors->channel[1])) / IM_SAMPLE_MAX;
	  ++colors;
	  --count;
	}
      }
      break;

    case 4:
      {
	IM_WORK_T grey_bg = IM_ROUND(color_to_grey(bg));
	while (count) {
	  IM_WORK_T src_grey = IM_ROUND(color_to_grey(colors));
	  colors->channel[0] =
	    (src_grey * colors->channel[3]
	     + grey_bg * (IM_SAMPLE_MAX - colors->channel[3])) / IM_SAMPLE_MAX;
	  ++colors;
	  --count;
	}
      }
      break;
    }
    break;
      
  case 3:
    switch (in_channels) {
    case 1:
      IM_ADAPT_COLORS(out_channels, in_channels, colors, count);
      return;

    case 2:
      {
	while (count) {
	  int ch;
	  IM_WORK_T src_grey = colors->channel[0];
	  IM_WORK_T src_alpha = colors->channel[1];
	  for (ch = 0; ch < 3; ++ch) {
	    colors->channel[ch] =
	      (src_grey * src_alpha
	       + bg->channel[ch] * (IM_SAMPLE_MAX - src_alpha)) 
	      / IM_SAMPLE_MAX;
	  }
	  ++colors;
	  --count;
	}
      }
      break;

    case 4:
      {
	while (count) {
	  int ch;
	  IM_WORK_T src_alpha = colors->channel[3];
	  for (ch = 0; ch < 3; ++ch) {
	    colors->channel[ch] =
	      (colors->channel[ch] * src_alpha
	       + bg->channel[ch] * (IM_SAMPLE_MAX - src_alpha)) 
	      / IM_SAMPLE_MAX;
	  }
	  ++colors;
	  --count;
	}
      }
      break;
    }
    break;
  }
}

/*
=item i_gsamp_bg(im, l, r, y, samples, out_channels, bg)

=item i_gsampf_bg(im, l, r, y, samples, out_channels, bg)

This is similar to i_adapt_colors_bg() except it can only strip an
alpha channel.  It cannot be used to convert a source RGB image to
greyscale.

The samples parameter MUST include enough space for all samples of the
source image.

=cut
*/
int
#ifdef IM_EIGHT_BIT
i_gsamp_bg
#else
i_gsampf_bg
#endif
(i_img *im, int l, int r, int y, IM_SAMPLE_T *samples, 
 int out_channels, IM_COLOR const *bg) {
  if (out_channels == im->channels)
    return IM_GSAMP(im, l, r, y, samples, NULL, im->channels);
  
  switch (out_channels) {
  case 1:
    switch (im->channels) {
    case 2:
      {
	int x;
	IM_SAMPLE_T *inp = samples, *outp = samples;
	IM_WORK_T grey_bg = IM_ROUND(color_to_grey(bg));
	int count;

	count = IM_GSAMP(im, l, r, y, samples, NULL, im->channels);
	if (!count)
	  return 0;
	
	for (x = l; x < r; ++x) {
	  *outp++ = ( inp[0] * inp[1] +
		      grey_bg * (IM_SAMPLE_MAX - inp[1])) / IM_SAMPLE_MAX;
	  inp += 2;
	}

	return count;
      }
      break;

    default:
      i_fatal(0, "i_gsamp_bg() can only remove alpha channels");
      break;
    }
    break;
  case 3:
    switch (im->channels) {
    case 1:
      {
	int channels[3] = { 0, 0, 0 };
	return IM_GSAMP(im, l, r, y, samples, channels, out_channels);
      }
    case 2:
      {
	int x, ch;
	IM_SAMPLE_T *inp = samples, *outp = samples;
	int count;
	int channels[4] = { 0, 0, 0, 1 };

	count = IM_GSAMP(im, l, r, y, samples, channels, im->channels);
	if (!count)
	  return 0;
	
	for (x = l; x < r; ++x) {
	  IM_WORK_T alpha = inp[3];
	  for (ch = 0; ch < 3; ++ch) {
	    *outp++ = ( *inp++ * alpha +
			bg->channel[ch] * (IM_SAMPLE_MAX - alpha)) / IM_SAMPLE_MAX;
	  }
	  ++inp;
	}

	return count;
      }

    case 4:
      {
	int x, ch;
	IM_SAMPLE_T *inp = samples, *outp = samples;
	int count;

	count = IM_GSAMP(im, l, r, y, samples, NULL, im->channels);
	if (!count)
	  return 0;
	
	for (x = l; x < r; ++x) {
	  IM_WORK_T alpha = inp[3];
	  for (ch = 0; ch < 3; ++ch) {
	    *outp++ = ( *inp++ * alpha +
			bg->channel[ch] * (IM_SAMPLE_MAX - alpha)) / IM_SAMPLE_MAX;
	  }
	  ++inp;
	}

	return count;
      }
      break;
    default:
      i_fatal(0, "i_gsamp_bg() can only remove alpha channels");
      break;
    }
    break;

  default:
    i_fatal(0, "i_gsamp_bg() can only remove alpha channels");
  }

  return 0;
}

#/code
Commit	Line	Data
9b1ec2b8 TC	1	#include "imager.h"
	2
	3	/*
	4	=item i_copyto(dest, src, x1, y1, x2, y2, tx, ty)
	5
	6	=category Image
	7
	8	Copies image data from the area (x1,y1)-[x2,y2] in the source image to
	9	a rectangle the same size with it's top-left corner at (tx,ty) in the
	10	destination image.
	11
	12	If x1 > x2 or y1 > y2 then the corresponding co-ordinates are swapped.
	13
	14	=cut
	15	*/
	16
	17	void
	18	i_copyto(i_img im, i_img src, int x1, int y1, int x2, int y2, int tx, int ty) {
a827f5b4	19	int y, t, ttx, tty;
9b1ec2b8 TC	20
	21	if (x2<x1) { t=x1; x1=x2; x2=t; }
	22	if (y2<y1) { t=y1; y1=y2; y2=t; }
	23	if (tx < 0) {
	24	/* adjust everything equally */
	25	x1 += -tx;
	26	x2 += -tx;
	27	tx = 0;
	28	}
	29	if (ty < 0) {
	30	y1 += -ty;
	31	y2 += -ty;
	32	ty = 0;
	33	}
	34	if (x1 >= src->xsize \|\| y1 >= src->ysize)
	35	return; /* nothing to do */
	36	if (x2 > src->xsize)
	37	x2 = src->xsize;
	38	if (y2 > src->ysize)
	39	y2 = src->ysize;
	40	if (x1 == x2 \|\| y1 == y2)
	41	return; /* nothing to do */
	42
	43	mm_log((1,"i_copyto(im* %p, src %p, x1 %d, y1 %d, x2 %d, y2 %d, tx %d, ty %d)\n",
	44	im, src, x1, y1, x2, y2, tx, ty));
	45
	46	#code im->bits == i_8_bits
	47	IM_COLOR row = mymalloc(sizeof(IM_COLOR) (x2-x1));
	48	tty = ty;
	49	for(y=y1; y<y2; y++) {
	50	ttx = tx;
	51	IM_GLIN(src, x1, x2, y, row);
	52	if (src->channels != im->channels)
	53	IM_ADAPT_COLORS(im->channels, src->channels, row, x2-x1);
	54	IM_PLIN(im, tx, tx+x2-x1, tty, row);
	55	tty++;
	56	}
	57	myfree(row);
	58	#/code
	59	}
	60
	61	#define color_to_grey(col) ((col)->rgb.r * 0.222 + (col)->rgb.g * 0.707 + (col)->rgb.b * 0.071)
	62
	63	#code
	64	void
	65	#ifdef IM_EIGHT_BIT
	66	i_adapt_colors
	67	#else
	68	i_adapt_fcolors
	69	#endif
	70	(int out_channels, int in_channels, IM_COLOR *colors,
	71	size_t count) {
9b1ec2b8 TC	72	if (out_channels == in_channels)
	73	return;
	74	if (count == 0)
	75	return;
	76
	77	switch (out_channels) {
	78	case 1:
	79	{
	80	switch (in_channels) {
	81	case 2:
	82	/* apply alpha against a black background */
	83	while (count) {
	84	colors->channel[0] = colors->channel[0] * colors->channel[1] / IM_SAMPLE_MAX;
	85	++colors;
	86	--count;
	87	}
	88	return;
	89
	90	case 3:
	91	/* convert to grey */
	92	while (count) {
	93	colors->channel[0] = IM_ROUND(color_to_grey(colors));
	94	++colors;
	95	--count;
	96	}
	97	return;
	98
	99	case 4:
	100	while (count) {
	101	colors->channel[0] = IM_ROUND(color_to_grey(colors) * colors->channel[3] / IM_SAMPLE_MAX);
	102	++colors;
	103	--count;
	104	}
	105	return;
	106
	107	default:
	108	i_fatal(3, "i_adapt_colors: in_channels of %d invalid\n", in_channels);
	109	return; /* avoid warnings */
	110	}
	111	}
	112
	113	case 2:
	114	{
	115	switch (in_channels) {
	116	case 1:
	117	while (count) {
	118	colors->channel[1] = IM_SAMPLE_MAX;
	119	++colors;
	120	--count;
	121	}
	122	return;
	123
	124	case 3:
	125	while (count) {
	126	colors->channel[0] = IM_ROUND(color_to_grey(colors));
	127	colors->channel[1] = IM_SAMPLE_MAX;
	128	++colors;
	129	--count;
	130	}
	131	return;
	132
	133	case 4:
	134	while (count) {
	135	colors->channel[0] = IM_ROUND(color_to_grey(colors));
136	colors->channel[1] = colors->channel[3];
137	++colors;
138	--count;
139	}
140	return;
141
142	default:
143	i_fatal(3, "i_adapt_colors: in_channels of %d invalid\n", in_channels);
144	return; /* avoid warnings */
145	}
146	}
147
148	case 3:
149	{
150	switch (in_channels) {
151	case 1:
152	while (count) {
153	colors->channel[1] = colors->channel[2] = colors->channel[0];
154	++colors;
155	--count;
156	}
157	return;
158
159	case 2:
160	while (count) {
161	int alpha = colors->channel[1];
162	colors->channel[0] = colors->channel[1] = colors->channel[2] =
163	IM_ROUND(colors->channel[0] * alpha / IM_SAMPLE_MAX);
164	++colors;
165	--count;
166	}
167	return;
168
169	case 4:
170	while (count) {
171	int alpha = colors->channel[3];
172	colors->channel[0] =
173	IM_ROUND(colors->channel[0] * alpha / IM_SAMPLE_MAX);
174	colors->channel[1] =
175	IM_ROUND(colors->channel[1] * alpha / IM_SAMPLE_MAX);
176	colors->channel[2] =
177	IM_ROUND(colors->channel[2] * alpha / IM_SAMPLE_MAX);
178	++colors;
179	--count;
180	}
181	return;
182
183	default:
184	i_fatal(3, "i_adapt_colors: in_channels of %d invalid\n", in_channels);
185	return; /* avoid warnings */
186	}
187	}
188
189	case 4:
190	{
191	switch (in_channels) {
192	case 1:
193	while (count) {
194	colors->channel[1] = colors->channel[2] = colors->channel[0];
195	colors->channel[3] = IM_SAMPLE_MAX;
196	++colors;
197	--count;
198	}
199	return;
200
201	case 2:
202	while (count) {
203	colors->channel[3] = colors->channel[1];
204	colors->channel[1] = colors->channel[2] = colors->channel[0];
205	++colors;
206	--count;
207	}
208	return;
209
210	case 3:
211	while (count) {
212	colors->channel[3] = IM_SAMPLE_MAX;
213	++colors;
214	--count;
215	}
216	return;
217
218	default:
219	i_fatal(3, "i_adapt_colors: in_channels of %d invalid\n", in_channels);
220	return; /* avoid warnings */
221	}
222	}
223
224	default:
225	i_fatal(3, "i_adapt_colors: out_channels of %d invalid\n", out_channels);
226	return; /* avoid warnings */
227	}
228	}
229
6e4af7d4 TC	230	void
	231	#ifdef IM_EIGHT_BIT
	232	i_adapt_colors_bg
	233	#else
	234	i_adapt_fcolors_bg
	235	#endif
	236	(int out_channels, int in_channels, IM_COLOR *colors,
	237	size_t count, IM_COLOR const *bg) {
	238	if (out_channels == in_channels)
	239	return;
	240	if (count == 0)
	241	return;
	242
	243	switch (out_channels) {
	244	case 2:
	245	case 4:
	246	IM_ADAPT_COLORS(out_channels, in_channels, colors, count);
	247	return;
	248
	249	case 1:
	250	switch (in_channels) {
	251	case 3:
	252	IM_ADAPT_COLORS(out_channels, in_channels, colors, count);
	253	return;
	254
	255	case 2:
	256	{
	257	/* apply alpha against our given background */
	258	IM_WORK_T grey_bg = IM_ROUND(color_to_grey(bg));
	259	while (count) {
	260	colors->channel[0] =
	261	(colors->channel[0] * colors->channel[1] +
	262	grey_bg * (IM_SAMPLE_MAX - colors->channel[1])) / IM_SAMPLE_MAX;
	263	++colors;
	264	--count;
	265	}
	266	}
	267	break;
	268
	269	case 4:
	270	{
	271	IM_WORK_T grey_bg = IM_ROUND(color_to_grey(bg));
	272	while (count) {
	273	IM_WORK_T src_grey = IM_ROUND(color_to_grey(colors));
	274	colors->channel[0] =
	275	(src_grey * colors->channel[3]
	276	+ grey_bg * (IM_SAMPLE_MAX - colors->channel[3])) / IM_SAMPLE_MAX;
	277	++colors;
	278	--count;
	279	}
	280	}
	281	break;
	282	}
	283	break;
	284
	285	case 3:
	286	switch (in_channels) {
	287	case 1:
	288	IM_ADAPT_COLORS(out_channels, in_channels, colors, count);
	289	return;
	290
	291	case 2:
	292	{
	293	while (count) {
294	int ch;
295	IM_WORK_T src_grey = colors->channel[0];
296	IM_WORK_T src_alpha = colors->channel[1];
297	for (ch = 0; ch < 3; ++ch) {
298	colors->channel[ch] =
299	(src_grey * src_alpha
300	+ bg->channel[ch] * (IM_SAMPLE_MAX - src_alpha))
301	/ IM_SAMPLE_MAX;
302	}
303	++colors;
304	--count;
305	}
306	}
307	break;
308
309	case 4:
310	{
311	while (count) {
312	int ch;
313	IM_WORK_T src_alpha = colors->channel[3];
314	for (ch = 0; ch < 3; ++ch) {
315	colors->channel[ch] =
316	(colors->channel[ch] * src_alpha
317	+ bg->channel[ch] * (IM_SAMPLE_MAX - src_alpha))
318	/ IM_SAMPLE_MAX;
319	}
320	++colors;
321	--count;
322	}
323	}
324	break;
325	}
326	break;
327	}
2a31a4b4 TC	328	}
	329
	330	/*
	331	=item i_gsamp_bg(im, l, r, y, samples, out_channels, bg)
	332
	333	=item i_gsampf_bg(im, l, r, y, samples, out_channels, bg)
	334
	335	This is similar to i_adapt_colors_bg() except it can only strip an
	336	alpha channel. It cannot be used to convert a source RGB image to
	337	greyscale.
	338
	339	The samples parameter MUST include enough space for all samples of the
	340	source image.
	341
	342	=cut
	343	*/
	344	int
	345	#ifdef IM_EIGHT_BIT
	346	i_gsamp_bg
	347	#else
	348	i_gsampf_bg
	349	#endif
	350	(i_img im, int l, int r, int y, IM_SAMPLE_T samples,
	351	int out_channels, IM_COLOR const *bg) {
	352	if (out_channels == im->channels)
	353	return IM_GSAMP(im, l, r, y, samples, NULL, im->channels);
	354
	355	switch (out_channels) {
	356	case 1:
	357	switch (im->channels) {
	358	case 2:
	359	{
	360	int x;
	361	IM_SAMPLE_T inp = samples, outp = samples;
	362	IM_WORK_T grey_bg = IM_ROUND(color_to_grey(bg));
	363	int count;
	364
	365	count = IM_GSAMP(im, l, r, y, samples, NULL, im->channels);
	366	if (!count)
	367	return 0;
	368
	369	for (x = l; x < r; ++x) {
	370	outp++ = ( inp[0] inp[1] +
	371	grey_bg * (IM_SAMPLE_MAX - inp[1])) / IM_SAMPLE_MAX;
	372	inp += 2;
	373	}
	374
	375	return count;
	376	}
	377	break;
	378
	379	default:
	380	i_fatal(0, "i_gsamp_bg() can only remove alpha channels");
	381	break;
	382	}
	383	break;
	384	case 3:
	385	switch (im->channels) {
	386	case 1:
	387	{
	388	int channels[3] = { 0, 0, 0 };
	389	return IM_GSAMP(im, l, r, y, samples, channels, out_channels);
	390	}
	391	case 2:
392	{
393	int x, ch;
394	IM_SAMPLE_T inp = samples, outp = samples;
395	int count;
396	int channels[4] = { 0, 0, 0, 1 };
397
398	count = IM_GSAMP(im, l, r, y, samples, channels, im->channels);
399	if (!count)
400	return 0;
401
402	for (x = l; x < r; ++x) {
403	IM_WORK_T alpha = inp[3];
404	for (ch = 0; ch < 3; ++ch) {
405	outp++ = ( inp++ * alpha +
406	bg->channel[ch] * (IM_SAMPLE_MAX - alpha)) / IM_SAMPLE_MAX;
407	}
408	++inp;
409	}
410
411	return count;
412	}
413
414	case 4:
415	{
416	int x, ch;
417	IM_SAMPLE_T inp = samples, outp = samples;
418	int count;
419
420	count = IM_GSAMP(im, l, r, y, samples, NULL, im->channels);
421	if (!count)
422	return 0;
423
424	for (x = l; x < r; ++x) {
425	IM_WORK_T alpha = inp[3];
426	for (ch = 0; ch < 3; ++ch) {
427	outp++ = ( inp++ * alpha +
428	bg->channel[ch] * (IM_SAMPLE_MAX - alpha)) / IM_SAMPLE_MAX;
429	}
430	++inp;
431	}
432
433	return count;
434	}
435	break;
436	default:
437	i_fatal(0, "i_gsamp_bg() can only remove alpha channels");
438	break;
439	}
440	break;
441
442	default:
443	i_fatal(0, "i_gsamp_bg() can only remove alpha channels");
444	}
6e4af7d4	445
2a31a4b4	446	return 0;
6e4af7d4 TC	447	}
6e4af7d4 TC	448
9b1ec2b8 TC	449	#/code
9b1ec2b8 TC	450