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| author | Robin Watts <robin.watts@artifex.com> | 2017-08-09 18:10:37 +0100 |
|---|---|---|
| committer | Robin Watts <robin.watts@artifex.com> | 2017-10-24 15:16:36 +0100 |
| commit | f2e0ab5afee63d9f446f37201291010e68282cc4 (patch) | |
| tree | 64c8092a02ee898db2ce19452c912d9806e390d3 /source/fitz/draw-paint.c | |
| parent | edcac9b62fd9034f3901c2b23467be9632c07b99 (diff) | |
| download | mupdf-f2e0ab5afee63d9f446f37201291010e68282cc4.tar.xz | |
Fix fz_paint_pixmap alpha blending.
We were failing to allow for the fact that the source pixmap
is premultiplied, meaning we were squaring the alpha each
time.
Diffstat (limited to 'source/fitz/draw-paint.c')
| -rw-r--r-- | source/fitz/draw-paint.c | 38 |
1 files changed, 22 insertions, 16 deletions
diff --git a/source/fitz/draw-paint.c b/source/fitz/draw-paint.c index 0a58fd58..5735f615 100644 --- a/source/fitz/draw-paint.c +++ b/source/fitz/draw-paint.c @@ -1357,11 +1357,12 @@ template_span_1_with_alpha_general(byte * restrict dp, int da, const byte * rest do { int masa = (sa ? FZ_COMBINE(sp[1], alpha) : alpha); - *dp = FZ_BLEND(*sp, *dp, masa); + int t = FZ_EXPAND(255-masa); + *dp = FZ_COMBINE(*sp, alpha) + FZ_COMBINE(*dp, t); dp++; sp++; if (da) { - *dp = FZ_BLEND((sa ? *sp : 255), *dp, masa); + *dp = masa + FZ_COMBINE(*dp, t); dp++; } if (sa) @@ -1378,15 +1379,16 @@ template_span_3_with_alpha_general(byte * restrict dp, int da, const byte * rest do { int masa = (sa ? FZ_COMBINE(sp[3], alpha) : alpha); - *dp = FZ_BLEND(*sp, *dp, masa); + int t = FZ_EXPAND(255-masa); + *dp = FZ_COMBINE(*sp, alpha) + FZ_COMBINE(*dp, t); sp++; dp++; - *dp = FZ_BLEND(*sp, *dp, masa); + *dp = FZ_COMBINE(*sp, alpha) + FZ_COMBINE(*dp, t); sp++; dp++; - *dp = FZ_BLEND(*sp, *dp, masa); + *dp = FZ_COMBINE(*sp, alpha) + FZ_COMBINE(*dp, t); sp++; dp++; if (da) { - *dp = FZ_BLEND((sa ? *sp : 255), *dp, masa); + *dp = masa + FZ_COMBINE(*dp, t); dp++; } if (sa) @@ -1403,17 +1405,18 @@ template_span_4_with_alpha_general(byte * restrict dp, int da, const byte * rest do { int masa = (sa ? FZ_COMBINE(sp[4], alpha) : alpha); - *dp = FZ_BLEND(*sp, *dp, masa); + int t = FZ_EXPAND(255-masa); + *dp = FZ_COMBINE(*sp, alpha) + FZ_COMBINE(*dp, t); sp++; dp++; - *dp = FZ_BLEND(*sp, *dp, masa); + *dp = FZ_COMBINE(*sp, alpha) + FZ_COMBINE(*dp, t); sp++; dp++; - *dp = FZ_BLEND(*sp, *dp, masa); + *dp = FZ_COMBINE(*sp, alpha) + FZ_COMBINE(*dp, t); sp++; dp++; - *dp = FZ_BLEND(*sp, *dp, masa); + *dp = FZ_COMBINE(*sp, alpha) + FZ_COMBINE(*dp, t); sp++; dp++; if (da) { - *dp = FZ_BLEND((sa ? *sp : 255), *dp, masa); + *dp = masa + FZ_COMBINE(*dp, t); dp++; } if (sa) @@ -1431,15 +1434,16 @@ template_span_N_with_alpha_general(byte * restrict dp, int da, const byte * rest do { int masa = (sa ? FZ_COMBINE(sp[n1], alpha) : alpha); + int t = FZ_EXPAND(255-masa); int k; for (k = 0; k < n1; k++) { - *dp = FZ_BLEND(*sp, *dp, masa); + *dp = FZ_COMBINE(*sp, alpha) + FZ_COMBINE(*dp, t); sp++; dp++; } if (da) { - *dp = FZ_BLEND((sa ? *sp : 255), *dp, masa); + *dp = masa + FZ_COMBINE(*dp, t); dp++; } if (sa) @@ -1456,17 +1460,18 @@ template_span_N_with_alpha_general_op(byte * restrict dp, int da, const byte * r do { int masa = (sa ? FZ_COMBINE(sp[n1], alpha) : alpha); + int t = FZ_EXPAND(255-masa); int k; for (k = 0; k < n1; k++) { if (fz_overprint_component(eop, k)) - *dp = FZ_BLEND(*sp, *dp, masa); + *dp = FZ_COMBINE(*sp, alpha) + FZ_COMBINE(*dp, t); sp++; dp++; } if (da) { - *dp = FZ_BLEND((sa ? *sp : 255), *dp, masa); + *dp = masa + FZ_COMBINE(*dp, t); dp++; } if (sa) @@ -1731,7 +1736,8 @@ paint_span_0_da_sa_alpha(byte * restrict dp, int da, const byte * restrict sp, i do { int masa = FZ_COMBINE(sp[0], alpha); - *dp = FZ_BLEND(*sp, *dp, masa); + int t = FZ_EXPAND(255-masa); + *dp = masa + FZ_COMBINE(*dp, t); dp++; sp++; } |