libtthimage/Lib/alpha.c

/*
		alpha.c
		-------
	Various transparency operations, aka "alpha channel ops"

			--------------------------------------
			Et c,a va me forcer a installer libpng
			--------------------------------------
			    15May01: on attend toujours libPNG
			    07Dec01: pfeue, libPNG toujours pas la...
			    03Fev14: ... please wait more ...
			    04Oct22: on the way, stay tuned.
*/

#include  <stdio.h>
#include  <string.h>
#include  <stdlib.h>
#include  "../tthimage.h"

/*::------------------------------------------------------------------::*/
int
Image_RGBA_over_RGB(Image_Desc *rgba, Image_Desc *src, Image_Desc *dst)
{
int	x, y;
int	rs, gs, bs, rm, gm, bm, am, r, g, b;
int	foo;

if (rgba->type != IMAGE_RGBA)
	{
	fprintf(stderr, "RGBA over RGB: image is not RGBA (%d)\n", rgba->type);
	return IMAGE_BAD_TYPE;
	}
if ( (foo=Image_compare_desc(rgba, src)) )
	{
	fprintf(stderr, "RGBA over RGB: err on sources: %s\n",
						Image_err2str(foo));
	return foo;
	}

#if DEBUG_LEVEL
fprintf(stderr, "RGBA/RGB types: %d %d %d\n", rgba->type, src->type, dst->type);
#endif

for (y=0; y<src->height; y++)
	{
	for (x=0; x<src->width; x++)
		{
		rs = (src->Rpix[y])[x];
		gs = (src->Gpix[y])[x];
		bs = (src->Bpix[y])[x];
		Image_getRGBA(rgba, x, y, &rm, &gm, &bm, &am);

		r = ((rs*(255-am)) + (rm*am)) / 256;
		g = ((gs*(255-am)) + (gm*am)) / 256;
		b = ((bs*(255-am)) + (bm*am)) / 256;

		Image_plotRGB(dst, x, y, r, g, b);
		}
	}

return FUNC_IS_BETA;
}
/*::------------------------------------------------------------------::*/
/*
 *		this function do some dirty things with the internals
 *		of the library. And you got here a 'secret' prototype.
 */
int Image_alloc_pixels(unsigned char ***pix, int w, int h);
/*
 *		Ahem. You, if you use this prototype, you are going
 *		to be a big laM3r. Don't do it. You have be warned.
 */
int
Image_add_alpha_channel(Image_Desc *img, int value)
{
uint8_t	**tmp_ptr;
int	foo;

#if DEBUG_LEVEL
fprintf(stderr, "Add Alpha Channel v=%d to Img %p\n", value, img);
#endif

if (img == NULL)
	{
	fprintf(stderr, "Add Alpha Channel: ZarWa, 'img' is NULL\n");
	return NULL_DESCRIPTOR;
	}

if (img->Apix != NULL)
	{
	fprintf(stderr, "Image %p already has an alpha channel\n", img);
	return VERY_STRANGE;
	}

if (img->type != IMAGE_RGB)
	{
	fprintf(stderr, "Image %p is not RGB.\n", img);
	return VERY_STRANGE;
	}

foo = Image_alloc_pixels(&tmp_ptr, img->width, img->height);
#if DEBUG_LEVEL
fprintf(stderr, "creation channel alpha foo=%d ptr=%p\n", foo, tmp_ptr);
#endif

/*	Yo, le plan memoire est disponible, on y poke la 'value'	*/
for (foo=0; foo<img->height; foo++) {
	memset(tmp_ptr[foo], value, img->width);
	}

/*	and now, we update the image descriptor	*/
img->type	= IMAGE_RGBA;
img->nb_planes	= 4;
img->Apix	= tmp_ptr;
img->modified   = 1;

#if DEBUG_LEVEL
Image_dump_descriptor(img, "apres creation canal Alpha");
#endif

return OLL_KORRECT;
}
/*::------------------------------------------------------------------::*/
int
Image_kill_alpha_channel(Image_Desc *img)
{
int		line;

#if DEBUG_LEVEL
Image_dump_descriptor(img, "Killing Alpha Channel");
#endif

if (img->type != IMAGE_RGBA) {
#if DEBUG_LEVEL
	fprintf(stderr, "Kill Alpha Channel: bad type %d\n", img->type);
#endif
	return VERY_STRANGE;
	}

if (img->nb_planes != 4) {
	fprintf(stderr, "Kill Alpha Channel: bad planes number %d\n",
						img->nb_planes);
	return VERY_STRANGE;
	}

if (img->Apix == NULL) {
	fprintf(stderr, "Kill Alpha Channel: _no_ alpha channel in %p\n", img);
	return NO_ALPHA_CHANNEL;
	}

for (line=0; line<img->height; line++)
	if (img->Apix[line] != NULL)     free(img->Apix[line]);

free(img->Apix);	img->Apix = NULL;
img->nb_planes	= 3;
img->type = IMAGE_RGB;
img->modified   = 1;

return OLL_KORRECT;
}
/*::------------------------------------------------------------------::*/
int
Image_map_alpha_on_img(Image_Desc *img)
{
register int pix;
int	x, y;

if (img->Apix == NULL)
	{
	fprintf(stderr, "%s : %p have no alpha channel.\n", __func__, img);
	return FULL_NUCKED;
	}

if (img->type != IMAGE_RGBA)
	{
	fprintf(stderr, "%s : %p is not an RGBA image.\n", __func__, img);
	return FULL_NUCKED;
	}

for (y=0; y<img->height; y++)
	{
	for (x=0; x<img->width; x++)
		{
		pix = (img->Rpix[y])[x] * (img->Apix[y])[x];
		(img->Rpix[y])[x] = pix / 256;

		pix = (img->Gpix[y])[x] * (img->Apix[y])[x];
		(img->Gpix[y])[x] = pix / 256;

		pix = (img->Bpix[y])[x] * (img->Apix[y])[x];
		(img->Bpix[y])[x] = pix / 256;
		}
	}

return OLL_KORRECT;
}
/*::------------------------------------------------------------------::*/
/*
 *	given two levels by RGB component, this func build an alpha
 *	binary mask where pixels in the 3 RGB intervals have the v1
 *	alpha value, and all others have the v2 alpha value.
 */
int
Image_alpha_op_0(Image_Desc *src, Image_Desc *dst, int v1, int v2,
		    int rb, int rt, int gb, int gt, int bb, int bt,
		    int param)
{
int	x, y, foo, r, g, b;
int	c1, c2;

/*
	XXX NO SAFETY CONTROLS ?
*/
if (dst->Apix == NULL)
	{
	fprintf(stderr, "Alpha op 0: dst %p have no alpha channel.\n", dst);
	return FULL_NUCKED;
	}
if (0 != param)
	{
	fprintf(stderr, "%s: parameter must be 0\n", __func__);
	}

c1 = c2 = 0;
for (y=0; y<src->height; y++)
	{
	for (x=0; x<src->width; x++)
		{
		foo = Image_getRGB(src, x, y, &r, &g, &b);

		if (	(r > rb && r < rt) ||
			(g > gb && g < gt) ||
			(b > bb && b < bt)	)
			{
			dst->Apix[y][x] = v1;
			c1++;
			}
		else
			{
			dst->Apix[y][x] = v2;
			c2++;
			}
		}
	}

#if DEBUG_LEVEL
fprintf(stderr, "Alpha op 0:  c1=%d   c2=%d\n", c1, c2);
#endif

return FUNC_IS_BETA;
}
/*::------------------------------------------------------------------::*/
/*
 *	New: 16 Oct 2001.
 */
int Image_copy_component_to_alpha(Image_Desc *img, char component)
{
int	x, y;

if (img->type != IMAGE_RGBA)
	{
	fprintf(stderr, "Alpha copy comp: %p is not an RGBA image.\n", img);
	return NO_ALPHA_CHANNEL;
	}

if (img->Apix == NULL)
	{
	fprintf(stderr, "Alpha copy comp: %p have no alpha channel.\n", img);
	return NO_ALPHA_CHANNEL;
	}

#if DEBUG_LEVEL
fprintf(stderr, "moving component '%c' to alpha channel of %p\n", 
				component, 		img);
#endif

for (y=0; y<img->height; y++) {
    for (x=0; x<img->width; x++) {
	switch (component)
	    	{
    		case 'r': case 'R':
    			img->Apix[y][x] = img->Rpix[y][x];	break;
	    	case 'g': case 'G':
    			img->Apix[y][x] = img->Gpix[y][x];	break;
	    	case 'b': case 'B':
    			img->Apix[y][x] = img->Bpix[y][x];	break;
	    	}
	}
    }
return FUNC_IS_ALPHA;
}
/*::------------------------------------------------------------------::*/
/*
 *			   bon, et maintenant, qu'est-ce qu'on invente ?
 *							ben 'alpha2.c' !
 */
/*::------------------------------------------------------------------::*/