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| author | Robin Watts <Robin.Watts@artifex.com> | 2011-08-01 22:01:46 +0100 |
|---|---|---|
| committer | Robin Watts <Robin.Watts@artifex.com> | 2011-08-01 22:27:34 +0100 |
| commit | 332b2aed1f1f17bdcafdffe2b9f773e00d7e6a0d (patch) | |
| tree | 9e62ea9b93625e3a9af3997b29a12ea2df553741 /draw/draw_blend.c | |
| parent | d451b09f75625a1b902c14afdede5242ad66713a (diff) | |
| download | mupdf-332b2aed1f1f17bdcafdffe2b9f773e00d7e6a0d.tar.xz | |
Fix bug 692377: Incorrect rendering of blending groups.
A combination of constant alpha and non-zero blending modes resulted
in incorrect rendering.
Various fixes seem to have made it work:
* Allow for non-full alpha when blending non-isolated groups back.
* Clamp blended pixels to allow for overflow.
* Allow for alpha in the shape blending.
Diffstat (limited to 'draw/draw_blend.c')
| -rw-r--r-- | draw/draw_blend.c | 21 |
1 files changed, 11 insertions, 10 deletions
diff --git a/draw/draw_blend.c b/draw/draw_blend.c index 0634f944..20ad8a28 100644 --- a/draw/draw_blend.c +++ b/draw/draw_blend.c @@ -330,14 +330,14 @@ fz_blend_nonseparable(byte * restrict bp, byte * restrict sp, int w, int blendmo } } -void -fz_blend_separable_isolated(byte * restrict bp, byte * restrict sp, int n, int w, int blendmode, byte * restrict hp) +static void +fz_blend_separable_nonisolated(byte * restrict bp, byte * restrict sp, int n, int w, int blendmode, byte * restrict hp, int alpha) { int k; int n1 = n - 1; while (w--) { - int ha = *hp++; /* ha = shape_alpha */ + int ha = fz_mul255(*hp++, alpha); /* ha = shape_alpha */ /* If ha == 0 then leave everything unchanged */ if (ha != 0) { @@ -374,8 +374,9 @@ fz_blend_separable_isolated(byte * restrict bp, byte * restrict sp, int n, int w case FZ_BLEND_DIFFERENCE: rc = fz_difference_byte(bc, sc); break; case FZ_BLEND_EXCLUSION: rc = fz_exclusion_byte(bc, sc); break; } - rc = fz_mul255(255 - ha, bc) + fz_mul255(255 - ba, sc) + fz_mul255(baha, rc); + if (rc < 0) rc = 0; + if (rc > 255) rc = 255; bp[k] = fz_mul255(rc, ra); } } @@ -385,12 +386,12 @@ fz_blend_separable_isolated(byte * restrict bp, byte * restrict sp, int n, int w } } -void -fz_blend_nonseparable_isolated(byte * restrict bp, byte * restrict sp, int w, int blendmode, byte * restrict hp) +static void +fz_blend_nonseparable_nonisolated(byte * restrict bp, byte * restrict sp, int w, int blendmode, byte * restrict hp, int alpha) { while (w--) { - int ha = *hp++; + int ha = fz_mul255(*hp++, alpha); if (ha != 0) { int sa = sp[3]; @@ -455,7 +456,7 @@ fz_blend_pixmap(fz_pixmap *dst, fz_pixmap *src, int alpha, int blendmode, int is int x, y, w, h, n; /* TODO: fix this hack! */ - if (alpha < 255) + if (isolated && alpha < 255) { sp = src->samples; n = src->w * src->h * src->n; @@ -487,9 +488,9 @@ fz_blend_pixmap(fz_pixmap *dst, fz_pixmap *src, int alpha, int blendmode, int is while (h--) { if (n == 4 && blendmode >= FZ_BLEND_HUE) - fz_blend_nonseparable_isolated(dp, sp, w, blendmode, hp); + fz_blend_nonseparable_nonisolated(dp, sp, w, blendmode, hp, alpha); else - fz_blend_separable_isolated(dp, sp, n, w, blendmode, hp); + fz_blend_separable_nonisolated(dp, sp, n, w, blendmode, hp, alpha); sp += src->w * n; dp += dst->w * n; hp += shape->w; |