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