diff options
| -rw-r--r-- | samplecode/SamplePath.cpp | 28 | ||||
| -rw-r--r-- | src/core/SkGeometry.cpp | 35 |
2 files changed, 58 insertions, 5 deletions
diff --git a/samplecode/SamplePath.cpp b/samplecode/SamplePath.cpp index b39e65c6f5..e63c513064 100644 --- a/samplecode/SamplePath.cpp +++ b/samplecode/SamplePath.cpp @@ -14,14 +14,38 @@ #include "SkTime.h" #include "SkTypeface.h" +#include "SkGeometry.h" + +// http://code.google.com/p/skia/issues/detail?id=32 +static void test_cubic() { + SkPoint src[4] = { + { 556.25000, 523.03003 }, + { 556.23999, 522.96002 }, + { 556.21997, 522.89001 }, + { 556.21997, 522.82001 } + }; + SkPoint dst[11]; + dst[10].set(42, -42); // one past the end, that we don't clobber these + SkScalar tval[] = { 0.33333334f, 0.99999994f }; + + SkChopCubicAt(src, dst, tval, 2); + +#if 0 + for (int i = 0; i < 11; i++) { + SkDebugf("--- %d [%g %g]\n", i, dst[i].fX, dst[i].fY); + } +#endif +} + class PathView : public SkView { public: int fDStroke, fStroke, fMinStroke, fMaxStroke; SkPath fPath[6]; bool fShowHairline; - PathView() - { + PathView() { + test_cubic(); + fShowHairline = false; fDStroke = 1; diff --git a/src/core/SkGeometry.cpp b/src/core/SkGeometry.cpp index 229c3d8999..2775543919 100644 --- a/src/core/SkGeometry.cpp +++ b/src/core/SkGeometry.cpp @@ -505,6 +505,29 @@ void SkChopCubicAt(const SkPoint src[4], SkPoint dst[7], SkScalar t) interp_cubic_coords(&src[0].fY, &dst[0].fY, t); } +/* http://code.google.com/p/skia/issues/detail?id=32 + + This test code would fail when we didn't check the return result of + valid_unit_divide in SkChopCubicAt(... tValues[], int roots). The reason is + that after the first chop, the parameters to valid_unit_divide are equal + (thanks to finite float precision and rounding in the subtracts). Thus + even though the 2nd tValue looks < 1.0, after we renormalize it, we end + up with 1.0, hence the need to check and just return the last cubic as + a degenerate clump of 4 points in the sampe place. + + static void test_cubic() { + SkPoint src[4] = { + { 556.25000, 523.03003 }, + { 556.23999, 522.96002 }, + { 556.21997, 522.89001 }, + { 556.21997, 522.82001 } + }; + SkPoint dst[10]; + SkScalar tval[] = { 0.33333334f, 0.99999994f }; + SkChopCubicAt(src, dst, tval, 2); + } + */ + void SkChopCubicAt(const SkPoint src[4], SkPoint dst[], const SkScalar tValues[], int roots) { #ifdef SK_DEBUG @@ -533,12 +556,18 @@ void SkChopCubicAt(const SkPoint src[4], SkPoint dst[], const SkScalar tValues[] if (i == roots - 1) break; - SkDEBUGCODE(int valid =) valid_unit_divide(tValues[i+1] - tValues[i], SK_Scalar1 - tValues[i], &t); - SkASSERT(valid); - dst += 3; + // have src point to the remaining cubic (after the chop) memcpy(tmp, dst, 4 * sizeof(SkPoint)); src = tmp; + + // watch out in case the renormalized t isn't in range + if (!valid_unit_divide(tValues[i+1] - tValues[i], + SK_Scalar1 - tValues[i], &t)) { + // if we can't, just create a degenerate cubic + dst[4] = dst[5] = dst[6] = src[3]; + break; + } } } } |