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Add color blending to GDISP

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inmarket 2013-08-01 14:52:28 +10:00
parent 2d27673f0f
commit 9d2b0b667b
2 changed files with 34 additions and 0 deletions
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13
include/gdisp/gdisp.h
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@ -800,6 +800,19 @@ void gdispDrawBox(coord_t x, coord_t y, coord_t cx, coord_t cy, color_t color);
void gdispFillRoundedBox(coord_t x, coord_t y, coord_t cx, coord_t cy, coord_t radius, color_t color);
#endif
/**
* @brief Blend 2 colors according to the alpha
* @return The combined color
*
* @param[in] fg The foreground color
* @param[in] bg The background color
* @param[in] alpha The alpha value (0-255). 0 is all background, 255 is all foreground.
*
* @api
*/
color_t gdispBlendColor(color_t fg, color_t bg, uint8_t alpha);
/* Support routine for packed pixel formats */
#if !defined(gdispPackPixels) || defined(__DOXYGEN__)
/**

21
src/gdisp/gdisp.c
View file

@ -990,6 +990,27 @@ void gdispDrawBox(coord_t x, coord_t y, coord_t cx, coord_t cy, color_t color) {
}
#endif
color_t gdispBlendColor(color_t fg, color_t bg, uint8_t alpha)
{
uint16_t fg_ratio = alpha + 1;
uint16_t bg_ratio = 256 - alpha;
uint16_t r, g, b;
r = RED_OF(fg) * fg_ratio;
g = GREEN_OF(fg) * fg_ratio;
b = BLUE_OF(fg) * fg_ratio;
r += RED_OF(bg) * bg_ratio;
g += GREEN_OF(bg) * bg_ratio;
b += BLUE_OF(bg) * bg_ratio;
r /= 256;
g /= 256;
b /= 256;
return RGB2COLOR(r, g, b);
}
#if (!defined(gdispPackPixels) && !defined(GDISP_PIXELFORMAT_CUSTOM))
void gdispPackPixels(pixel_t *buf, coord_t cx, coord_t x, coord_t y, color_t color) {
/* No mutex required as we only read static data */