Use pre-multiplied alpha for cairo rendering

Signed-off-by: Julien Danjou <julien@danjou.info>
This commit is contained in:
Julien Danjou 2008-03-24 10:26:35 +01:00
parent 822fe535e3
commit 8b411eb15d
1 changed files with 14 additions and 15 deletions

View File

@ -578,7 +578,8 @@ void draw_image_from_argb_data(DrawCtx *ctx, int x, int y, int w, int h,
cairo_t *cr; cairo_t *cr;
cairo_surface_t *source; cairo_surface_t *source;
source = cairo_image_surface_create_for_data(data, CAIRO_FORMAT_ARGB32, w, h, 0); source = cairo_image_surface_create_for_data(data, CAIRO_FORMAT_ARGB32, w, h,
cairo_format_stride_for_width(CAIRO_FORMAT_ARGB32, w));
cr = cairo_create(ctx->surface); cr = cairo_create(ctx->surface);
if(wanted_h > 0 && h > 0) if(wanted_h > 0 && h > 0)
{ {
@ -645,9 +646,10 @@ draw_imlib_load_strerror(Imlib_Load_Error e)
void void
draw_image(DrawCtx *ctx, int x, int y, int wanted_h, const char *filename) draw_image(DrawCtx *ctx, int x, int y, int wanted_h, const char *filename)
{ {
int w, h, size; int w, h, size, i;
DATA32 *data; DATA32 *data;
unsigned char *dataimg; double alpha;
unsigned char *dataimg, *rdataimg;
Imlib_Image image; Imlib_Image image;
Imlib_Load_Error e = IMLIB_LOAD_ERROR_NONE; Imlib_Load_Error e = IMLIB_LOAD_ERROR_NONE;
@ -662,25 +664,22 @@ draw_image(DrawCtx *ctx, int x, int y, int wanted_h, const char *filename)
data = imlib_image_get_data_for_reading_only(); data = imlib_image_get_data_for_reading_only();
dataimg = p_new(unsigned char, size * 4); rdataimg = dataimg = p_new(unsigned char, size * 4);
memcpy(dataimg, data, size * 4);
#if 0
/* Alternate method */
for(i = 0; i < size; i++, dataimg += 4) for(i = 0; i < size; i++, dataimg += 4)
{ {
dataimg[3] = (data[i] >> 24) & 0xff; /* A */ dataimg[3] = (data[i] >> 24) & 0xff; /* A */
dataimg[2] = (data[i] >> 16) & 0xff; /* R */ /* cairo wants pre-multiplied alpha */
dataimg[1] = (data[i] >> 8) & 0xff; /* G */ alpha = dataimg[3] / 255.0;
dataimg[0] = data[i] & 0xff; /* B */ dataimg[2] = ((data[i] >> 16) & 0xff) * alpha; /* R */
dataimg[1] = ((data[i] >> 8) & 0xff) * alpha; /* G */
dataimg[0] = (data[i] & 0xff) * alpha; /* B */
} }
#endif
draw_image_from_argb_data(ctx, x, y, w, h, wanted_h, dataimg); draw_image_from_argb_data(ctx, x, y, w, h, wanted_h, rdataimg);
imlib_free_image(); imlib_free_image();
p_delete(&dataimg); p_delete(&rdataimg);
} }
/** Get an image size /** Get an image size