AuroraMiddleware/skia2
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

chop hairlines against 32K bounds, since that is our limit (currently)

Browse Source 
for a fixedpoint implementation.



git-svn-id: http://skia.googlecode.com/svn/trunk@3713 2bbb7eff-a529-9590-31e7-b0007b416f81
This commit is contained in:
reed@google.com 2012-04-17 20:43:47 +00:00
parent 8aa66b6f76
commit 99b300ed9d
1 changed files with 25 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
src/core/SkScan_Antihair.cpp
View File

@ -230,6 +230,11 @@ static int any_bad_ints(int a, int b, int c, int d) {
}
#endif
static bool canConvertFDot6ToFixed(SkFDot6 x) {
const int maxDot6 = SK_MaxS32 >> (16 - 6);
return SkAbs32(x) <= maxDot6;
}
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)
@ -239,6 +244,13 @@ static void do_anti_hairline(SkFDot6 x0, SkFDot6 y0, SkFDot6 x1, SkFDot6 y1,
return;
}
// The caller must clip the line to [-32767.0 ... 32767.0] ahead of time
// (in dot6 format)
SkASSERT(canConvertFDot6ToFixed(x0));
SkASSERT(canConvertFDot6ToFixed(y0));
SkASSERT(canConvertFDot6ToFixed(x1));
SkASSERT(canConvertFDot6ToFixed(y1));
if (SkAbs32(x1 - x0) > SkIntToFDot6(511) || SkAbs32(y1 - y0) > SkIntToFDot6(511)) {
/* instead of (x0 + x1) >> 1, we shift each separately. This is less
precise, but avoids overflowing the intermediate result if the
@ -428,6 +440,19 @@ void SkScan::AntiHairLineRgn(const SkPoint& pt0, const SkPoint& pt1,
SkPoint pts[2] = { pt0, pt1 };
#ifdef SK_SCALAR_IS_FLOAT
// We have to pre-clip the line to fit in a SkFixed, so we just chop
// the line. TODO find a way to actually draw beyond that range.
{
SkRect fixedBounds;
const SkScalar max = SkIntToScalar(32767);
fixedBounds.set(-max, -max, max, max);
if (!SkLineClipper::IntersectLine(pts, fixedBounds, pts)) {
return;
}
}
#endif
if (clip) {
SkRect clipBounds;
clipBounds.set(clip->getBounds());