KittyPatch/kitty
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Avoid calculation when over px is transparent

Browse Source
This commit is contained in:
Kovid Goyal 2021-02-04 14:26:10 +05:30
parent 0f18fedf13
commit 2650c7dd9e
No known key found for this signature in database
GPG Key ID: 06BC317B515ACE7C
1 changed files with 7 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
kitty/graphics.c
View File

@ -861,12 +861,14 @@ blend_on_opaque(uint8_t *under_px, const uint8_t *over_px) {
static inline void static inline void
alpha_blend(uint8_t *dest_px, const uint8_t *src_px) { alpha_blend(uint8_t *dest_px, const uint8_t *src_px) {
if (src_px[3]) {
const float dest_a = (float)dest_px[3] / 255.f, src_a = (float)src_px[3] / 255.f; const float dest_a = (float)dest_px[3] / 255.f, src_a = (float)src_px[3] / 255.f;
const float alpha = src_a + dest_a * (1.f - src_a); const float alpha = src_a + dest_a * (1.f - src_a);
dest_px[3] = (uint8_t)(255 * alpha); dest_px[3] = (uint8_t)(255 * alpha);
if (!dest_px[3]) { dest_px[0] = 0; dest_px[1] = 0; dest_px[2] = 0; return; } if (!dest_px[3]) { dest_px[0] = 0; dest_px[1] = 0; dest_px[2] = 0; return; }
for (unsigned i = 0; i < 3; i++) dest_px[i] = (uint8_t)((src_px[i] * src_a + dest_px[i] * dest_a * (1.f - src_a))/alpha); for (unsigned i = 0; i < 3; i++) dest_px[i] = (uint8_t)((src_px[i] * src_a + dest_px[i] * dest_a * (1.f - src_a))/alpha);
} }
}
typedef struct { typedef struct {
bool needs_blending; bool needs_blending;