Turn on concave analytic AA
This will allow Skia trybots to exercise analytic AA. But there's still
a guard flag in Chromium that prevents layout tests failure.
Additionally, we
1. fixed nagative shift problem
2. relax the ASSERT when slope is too large: If slope is large, the accuracy of the slope is limited due
to conversion to SkFDot6 and division. Hence we have to relax the constraint.
3. handle the special case where dx != 0 while slope == 0 because of very large dy and limited precision.
BUG=skia:
Change-Id: Ice70164f3f396f0db3896bedc7b96fbd613078dc
Reviewed-on: https://skia-review.googlesource.com/7120
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Yuqian Li <liyuqian@google.com>
diff --git a/src/core/SkAnalyticEdge.cpp b/src/core/SkAnalyticEdge.cpp
index 199fc4e..213262f 100644
--- a/src/core/SkAnalyticEdge.cpp
+++ b/src/core/SkAnalyticEdge.cpp
@@ -39,7 +39,11 @@
fY = y0;
fUpperY = y0;
fLowerY = y1;
+#ifdef SK_SUPPORT_LEGACY_AAA
fDY = (absSlope | dx) == 0
+#else
+ fDY = (dx == 0 || slope == 0)
+#endif
? SK_MaxS32
: absSlope < kInverseTableSize
? QuickFDot6Inverse::Lookup(absSlope)
@@ -113,7 +117,7 @@
#ifndef SK_SUPPORT_LEGACY_AAA
SkASSERT(slope == SK_MaxS32 ||
SkAbs32(fSnappedX + SkFixedMul(slope, newSnappedY - fSnappedY) - newSnappedX)
- < SK_FixedHalf);
+ < SkFixedMul(SK_Fixed1 >> 4, SkTMax(SK_Fixed1, SkAbs32(slope))));
#endif
dx += fQEdge.fQDDx;
dy += fQEdge.fQDDy;
diff --git a/src/core/SkAnalyticEdge.h b/src/core/SkAnalyticEdge.h
index 1ed25f3..c70772d 100644
--- a/src/core/SkAnalyticEdge.h
+++ b/src/core/SkAnalyticEdge.h
@@ -10,11 +10,6 @@
#include "SkEdge.h"
-// Use this to check that we successfully guard the change against Chromium layout tests
-#ifndef SK_SUPPORT_LEGACY_AAA
-# define SK_SUPPORT_LEGACY_AAA
-#endif
-
struct SkAnalyticEdge {
// Similar to SkEdge, the conic edges will be converted to quadratic edges
enum Type {
@@ -166,7 +161,6 @@
SkFDot6 dy = SkFixedToFDot6(y1 - y0);
SkFDot6 dx = SkFixedToFDot6(x1 - x0);
SkFixed slope = dy ? QuickSkFDot6Div(dx, dy) : SK_MaxS32;
- SkASSERT(dx == 0 || slope != 0);
SkFixed absSlope = SkAbs32(slope);
#endif
@@ -179,9 +173,9 @@
#ifdef SK_SUPPORT_LEGACY_AAA
fDY = x1 != x0 ? SkAbs32(SkFixedDiv(y1 - y0, x1 - x0)) : SK_MaxS32;
#else
- fDY = dx == 0 ? SK_MaxS32 : absSlope < kInverseTableSize
- ? QuickFDot6Inverse::Lookup(absSlope)
- : SkAbs32(QuickSkFDot6Div(dy, dx));
+ fDY = dx == 0 || slope == 0 ? SK_MaxS32 : absSlope < kInverseTableSize
+ ? QuickFDot6Inverse::Lookup(absSlope)
+ : SkAbs32(QuickSkFDot6Div(dy, dx));
#endif
fCurveCount = 0;
fWinding = SkToS8(winding);
diff --git a/src/core/SkScan.h b/src/core/SkScan.h
index d0c10fa..c995542 100644
--- a/src/core/SkScan.h
+++ b/src/core/SkScan.h
@@ -23,11 +23,6 @@
*/
typedef SkIRect SkXRect;
-// Use this to check that we successfully guard the change against Chromium layout tests
-#ifndef SK_SUPPORT_LEGACY_AAA
-# define SK_SUPPORT_LEGACY_AAA
-#endif
-
extern std::atomic<bool> gSkUseAnalyticAA;
extern std::atomic<bool> gSkForceAnalyticAA;
diff --git a/src/core/SkScan_AAAPath.cpp b/src/core/SkScan_AAAPath.cpp
index 1263228..af45f00 100644
--- a/src/core/SkScan_AAAPath.cpp
+++ b/src/core/SkScan_AAAPath.cpp
@@ -736,14 +736,14 @@
int uL = SkFixedFloorToInt(ul);
int lL = SkFixedCeilToInt(ll);
if (uL + 2 == lL) { // We only need to compute two triangles, accelerate this special case
- SkFixed first = (uL << 16) + SK_Fixed1 - ul;
+ SkFixed first = SkIntToFixed(uL) + SK_Fixed1 - ul;
SkFixed second = ll - ul - first;
SkAlpha a1 = fullAlpha - partialTriangleToAlpha(first, lDY);
SkAlpha a2 = partialTriangleToAlpha(second, lDY);
alphas[0] = alphas[0] > a1 ? alphas[0] - a1 : 0;
alphas[1] = alphas[1] > a2 ? alphas[1] - a2 : 0;
} else {
- computeAlphaBelowLine(tempAlphas + uL - L, ul - (uL << 16), ll - (uL << 16),
+ computeAlphaBelowLine(tempAlphas + uL - L, ul - SkIntToFixed(uL), ll - SkIntToFixed(uL),
lDY, fullAlpha);
for (int i = uL; i < lL; ++i) {
if (alphas[i - L] > tempAlphas[i - L]) {
@@ -757,14 +757,14 @@
int uR = SkFixedFloorToInt(ur);
int lR = SkFixedCeilToInt(lr);
if (uR + 2 == lR) { // We only need to compute two triangles, accelerate this special case
- SkFixed first = (uR << 16) + SK_Fixed1 - ur;
+ SkFixed first = SkIntToFixed(uR) + SK_Fixed1 - ur;
SkFixed second = lr - ur - first;
SkAlpha a1 = partialTriangleToAlpha(first, rDY);
SkAlpha a2 = fullAlpha - partialTriangleToAlpha(second, rDY);
alphas[len-2] = alphas[len-2] > a1 ? alphas[len-2] - a1 : 0;
alphas[len-1] = alphas[len-1] > a2 ? alphas[len-1] - a2 : 0;
} else {
- computeAlphaAboveLine(tempAlphas + uR - L, ur - (uR << 16), lr - (uR << 16),
+ computeAlphaAboveLine(tempAlphas + uR - L, ur - SkIntToFixed(uR), lr - SkIntToFixed(uR),
rDY, fullAlpha);
for (int i = uR; i < lR; ++i) {
if (alphas[i - L] > tempAlphas[i - L]) {
@@ -1605,7 +1605,9 @@
leftEnds, false, blitter, maskRow, isUsingMask, noRealBlitter,
leftClip, rightClip, yShift);
} else {
- blit_trapezoid_row(blitter, y >> 16, left, rightClip, leftE->fX, rightClip,
+ blit_trapezoid_row(blitter, y >> 16,
+ SkTMax(leftClip, left), rightClip,
+ SkTMax(leftClip, leftE->fX), rightClip,
leftDY, 0, fullAlpha, maskRow, isUsingMask,
noRealBlitter ||
(fullAlpha == 0xFF && edges_too_close(leftE->fPrev, leftE, nextY)),