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authorLee Salzman <lsalzman@mozilla.com>2018-05-25 15:43:12 -0400
committerwolfbeast <mcwerewolf@gmail.com>2018-06-07 06:18:58 +0200
commite810c8a5c0b116d7214c786186f0478a7f70ff64 (patch)
treefbb86fde6e1faa81bf642f12bdbafe4b6dfc073f /gfx
parentcd96ca11cd5beefb13820ab076439d2051ffe1fb (diff)
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Bug 1462682 - Skia path bounds rounding fix. r=rhunt, a=RyanVM
Diffstat (limited to 'gfx')
-rw-r--r--gfx/skia/skia/src/core/SkScan_Path.cpp22
1 files changed, 8 insertions, 14 deletions
diff --git a/gfx/skia/skia/src/core/SkScan_Path.cpp b/gfx/skia/skia/src/core/SkScan_Path.cpp
index 5b80492cf..d15d2d54b 100644
--- a/gfx/skia/skia/src/core/SkScan_Path.cpp
+++ b/gfx/skia/skia/src/core/SkScan_Path.cpp
@@ -591,16 +591,10 @@ static bool clip_to_limit(const SkRegion& orig, SkRegion* reduced) {
return true;
}
-/**
- * Variants of SkScalarRoundToInt, identical to SkDScalarRoundToInt except when the input fraction
- * is 0.5. When SK_RASTERIZE_EVEN_ROUNDING is enabled, we must bias the result before rounding to
- * account for potential FDot6 rounding edge-cases.
- */
-#ifdef SK_RASTERIZE_EVEN_ROUNDING
-static const double kRoundBias = 0.5 / SK_FDot6One;
-#else
-static const double kRoundBias = 0.0;
-#endif
+// Bias used for conservative rounding of float rects to int rects, to nudge the irects a little
+// larger, so we don't "think" a path's bounds are inside a clip, when (due to numeric drift in
+// the scan-converter) we might walk beyond the predicted limits.
+static const double kConservativeRoundBias = 0.5 + 1.5 / SK_FDot6One;
/**
* Round the value down. This is used to round the top and left of a rectangle,
@@ -608,8 +602,8 @@ static const double kRoundBias = 0.0;
*/
static inline int round_down_to_int(SkScalar x) {
double xx = x;
- xx -= 0.5 + kRoundBias;
- return (int)ceil(xx);
+ xx -= kConservativeRoundBias;
+ return pin_double_to_int(ceil(xx));
}
/**
@@ -618,8 +612,8 @@ static inline int round_down_to_int(SkScalar x) {
*/
static inline int round_up_to_int(SkScalar x) {
double xx = x;
- xx += 0.5 + kRoundBias;
- return (int)floor(xx);
+ xx += kConservativeRoundBias;
+ return pin_double_to_int(floor(xx));
}
/**