diff options
Diffstat (limited to 'src/core')
| -rw-r--r-- | src/core/SkScan_Antihair.cpp | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/src/core/SkScan_Antihair.cpp b/src/core/SkScan_Antihair.cpp index 932f29ffc4..bf1b81f158 100644 --- a/src/core/SkScan_Antihair.cpp +++ b/src/core/SkScan_Antihair.cpp @@ -348,6 +348,25 @@ static bool canConvertFDot6ToFixed(SkFDot6 x) { return SkAbs32(x) <= maxDot6; } +/* + * We want the fractional part of ordinate, but we want multiples of 64 to + * return 64, not 0, so we can't just say (ordinate & 63). + * We basically want to compute those bits, and if they're 0, return 64. + * We can do that w/o a branch with an extra sub and add. + */ +static int contribution_64(SkFDot6 ordinate) { +#if 0 + int result = ordinate & 63; + if (0 == result) { + result = 64; + } +#else + int result = ((ordinate - 1) & 63) + 1; +#endif + SkASSERT(result > 0 && result <= 64); + return result; +} + static void do_anti_hairline(SkFDot6 x0, SkFDot6 y0, SkFDot6 x1, SkFDot6 y1, const SkIRect* clip, SkBlitter* blitter) { // check for integer NaN (0x80000000) which we can't handle (can't negate it) @@ -409,6 +428,7 @@ static void do_anti_hairline(SkFDot6 x0, SkFDot6 y0, SkFDot6 x1, SkFDot6 y1, SkASSERT(istop > istart); if (istop - istart == 1) { + // we are within a single pixel scaleStart = x1 - x0; SkASSERT(scaleStart >= 0 && scaleStart <= 64); scaleStop = 0; @@ -425,6 +445,11 @@ static void do_anti_hairline(SkFDot6 x0, SkFDot6 y0, SkFDot6 x1, SkFDot6 y1, fstart += slope * (clip->fLeft - istart); istart = clip->fLeft; scaleStart = 64; + if (istop - istart == 1) { + // we are within a single pixel + scaleStart = contribution_64(x1); + scaleStop = 0; + } } if (istop > clip->fRight) { istop = clip->fRight; @@ -479,6 +504,7 @@ static void do_anti_hairline(SkFDot6 x0, SkFDot6 y0, SkFDot6 x1, SkFDot6 y1, SkASSERT(istop > istart); if (istop - istart == 1) { + // we are within a single pixel scaleStart = y1 - y0; SkASSERT(scaleStart >= 0 && scaleStart <= 64); scaleStop = 0; @@ -495,6 +521,11 @@ static void do_anti_hairline(SkFDot6 x0, SkFDot6 y0, SkFDot6 x1, SkFDot6 y1, fstart += slope * (clip->fTop - istart); istart = clip->fTop; scaleStart = 64; + if (istop - istart == 1) { + // we are within a single pixel + scaleStart = contribution_64(y1); + scaleStop = 0; + } } if (istop > clip->fBottom) { istop = clip->fBottom; @@ -536,6 +567,13 @@ static void do_anti_hairline(SkFDot6 x0, SkFDot6 y0, SkFDot6 x1, SkFDot6 y1, SkASSERT(hairBlitter); hairBlitter->setup(blitter); +#ifdef SK_DEBUG + if (scaleStart > 0 && scaleStop > 0) { + // be sure we don't draw twice in the same pixel + SkASSERT(istart < istop - 1); + } +#endif + fstart = hairBlitter->drawCap(istart, fstart, slope, scaleStart); istart += 1; int fullSpans = istop - istart - (scaleStop > 0); |