Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(186)

Issues Search
    My Issues | Starred     Open | Closed | All

Unified Diff: src/core/SkPath.cpp

Issue 48783002: perpendicular round rects; fuzzy convexity (Closed) Base URL: https://skia.googlecode.com/svn/trunk
Patch Set: fix conflict Created 7 years, 1 month ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View side-by-side diff with in-line comments
Download patch
« no previous file with comments | « src/core/SkGeometry.cpp ('k') | no next file » | no next file with comments »
Expand Comments ('e') | Collapse Comments ('c') | Show Comments Hide Comments ('s')
Index: src/core/SkPath.cpp
diff --git a/src/core/SkPath.cpp b/src/core/SkPath.cpp
index 94dd6518afbec24535f24ed5f219abc404429684..60cfe0373c08628573cf5be16ff829f428e7cd0f 100644
--- a/src/core/SkPath.cpp
+++ b/src/core/SkPath.cpp
@@ -1083,23 +1083,21 @@ void SkPath::addRoundRect(const SkRect& rect, SkScalar rx, SkScalar ry,
} else if (skip_vert) {
ry = halfH;
}
-
#ifdef SK_IGNORE_QUAD_RR_CORNERS_OPT
SkScalar sx = SkScalarMul(rx, CUBIC_ARC_FACTOR);
SkScalar sy = SkScalarMul(ry, CUBIC_ARC_FACTOR);
this->incReserve(17);
#else
- // Please see SkBuildQuadArc for more information but, we need to pull
- // the off-curve quadratic points in a little bit to make the round
- // rects convex.
- static const SkScalar kOffCurveEpsilon = 0.0001f;
-
- SkScalar midPtX = rx * SK_ScalarRoot2Over2;
- SkScalar midPtY = ry * SK_ScalarRoot2Over2;
+// The mid point of the quadratic arc approximation is half way between the two
+// control points. The float epsilon adjustment moves the on curve point out by
+// two bits, distributing the convex test error between the round rect approximation
+// and the convex cross product sign equality test.
+ SkScalar midPtX = rx * (SK_Scalar1 + SK_ScalarTanPIOver8 + FLT_EPSILON * 4) / 2;
+ SkScalar midPtY = ry * (SK_Scalar1 + SK_ScalarTanPIOver8 + FLT_EPSILON * 4) / 2;
- SkScalar offPtX = rx * SK_ScalarTanPIOver8 - kOffCurveEpsilon;
- SkScalar offPtY = ry * SK_ScalarTanPIOver8 - kOffCurveEpsilon;
+ SkScalar offPtX = rx * SK_ScalarTanPIOver8;
+ SkScalar offPtY = ry * SK_ScalarTanPIOver8;
this->incReserve(21);
#endif
@@ -1113,9 +1111,9 @@ void SkPath::addRoundRect(const SkRect& rect, SkScalar rx, SkScalar ry,
rect.fLeft, rect.fTop + ry - sy,
rect.fLeft, rect.fTop + ry); // top-left
#else
- this->quadTo(rect.fLeft + rx - offPtX, rect.fTop + kOffCurveEpsilon,
+ this->quadTo(rect.fLeft + rx - offPtX, rect.fTop,
rect.fLeft + rx - midPtX, rect.fTop + ry - midPtY);
- this->quadTo(rect.fLeft + kOffCurveEpsilon, rect.fTop + ry - offPtY,
+ this->quadTo(rect.fLeft, rect.fTop + ry - offPtY,
rect.fLeft, rect.fTop + ry);
#endif
if (!skip_vert) {
@@ -1126,9 +1124,9 @@ void SkPath::addRoundRect(const SkRect& rect, SkScalar rx, SkScalar ry,
rect.fLeft + rx - sx, rect.fBottom,
rect.fLeft + rx, rect.fBottom); // bot-left
#else
- this->quadTo(rect.fLeft + kOffCurveEpsilon, rect.fBottom - ry + offPtY,
+ this->quadTo(rect.fLeft, rect.fBottom - ry + offPtY,
rect.fLeft + rx - midPtX, rect.fBottom - ry + midPtY);
- this->quadTo(rect.fLeft + rx - offPtX, rect.fBottom - kOffCurveEpsilon,
+ this->quadTo(rect.fLeft + rx - offPtX, rect.fBottom,
rect.fLeft + rx, rect.fBottom);
#endif
if (!skip_hori) {
@@ -1139,9 +1137,9 @@ void SkPath::addRoundRect(const SkRect& rect, SkScalar rx, SkScalar ry,
rect.fRight, rect.fBottom - ry + sy,
rect.fRight, rect.fBottom - ry); // bot-right
#else
- this->quadTo(rect.fRight - rx + offPtX, rect.fBottom - kOffCurveEpsilon,
+ this->quadTo(rect.fRight - rx + offPtX, rect.fBottom,
rect.fRight - rx + midPtX, rect.fBottom - ry + midPtY);
- this->quadTo(rect.fRight - kOffCurveEpsilon, rect.fBottom - ry + offPtY,
+ this->quadTo(rect.fRight, rect.fBottom - ry + offPtY,
rect.fRight, rect.fBottom - ry);
#endif
if (!skip_vert) {
@@ -1152,9 +1150,9 @@ void SkPath::addRoundRect(const SkRect& rect, SkScalar rx, SkScalar ry,
rect.fRight - rx + sx, rect.fTop,
rect.fRight - rx, rect.fTop); // top-right
#else
- this->quadTo(rect.fRight - kOffCurveEpsilon, rect.fTop + ry - offPtY,
+ this->quadTo(rect.fRight, rect.fTop + ry - offPtY,
rect.fRight - rx + midPtX, rect.fTop + ry - midPtY);
- this->quadTo(rect.fRight - rx + offPtX, rect.fTop + kOffCurveEpsilon,
+ this->quadTo(rect.fRight - rx + offPtX, rect.fTop,
rect.fRight - rx, rect.fTop);
#endif
} else {
@@ -1163,9 +1161,9 @@ void SkPath::addRoundRect(const SkRect& rect, SkScalar rx, SkScalar ry,
rect.fRight, rect.fTop + ry - sy,
rect.fRight, rect.fTop + ry); // top-right
#else
- this->quadTo(rect.fRight - rx + offPtX, rect.fTop + kOffCurveEpsilon,
+ this->quadTo(rect.fRight - rx + offPtX, rect.fTop,
rect.fRight - rx + midPtX, rect.fTop + ry - midPtY);
- this->quadTo(rect.fRight - kOffCurveEpsilon, rect.fTop + ry - offPtY,
+ this->quadTo(rect.fRight, rect.fTop + ry - offPtY,
rect.fRight, rect.fTop + ry);
#endif
if (!skip_vert) {
@@ -1176,9 +1174,9 @@ void SkPath::addRoundRect(const SkRect& rect, SkScalar rx, SkScalar ry,
rect.fRight - rx + sx, rect.fBottom,
rect.fRight - rx, rect.fBottom); // bot-right
#else
- this->quadTo(rect.fRight - kOffCurveEpsilon, rect.fBottom - ry + offPtY,
+ this->quadTo(rect.fRight, rect.fBottom - ry + offPtY,
rect.fRight - rx + midPtX, rect.fBottom - ry + midPtY);
- this->quadTo(rect.fRight - rx + offPtX, rect.fBottom - kOffCurveEpsilon,
+ this->quadTo(rect.fRight - rx + offPtX, rect.fBottom,
rect.fRight - rx, rect.fBottom);
#endif
if (!skip_hori) {
@@ -1189,9 +1187,9 @@ void SkPath::addRoundRect(const SkRect& rect, SkScalar rx, SkScalar ry,
rect.fLeft, rect.fBottom - ry + sy,
rect.fLeft, rect.fBottom - ry); // bot-left
#else
- this->quadTo(rect.fLeft + rx - offPtX, rect.fBottom - kOffCurveEpsilon,
+ this->quadTo(rect.fLeft + rx - offPtX, rect.fBottom,
rect.fLeft + rx - midPtX, rect.fBottom - ry + midPtY);
- this->quadTo(rect.fLeft + kOffCurveEpsilon, rect.fBottom - ry + offPtY,
+ this->quadTo(rect.fLeft, rect.fBottom - ry + offPtY,
rect.fLeft, rect.fBottom - ry);
#endif
if (!skip_vert) {
@@ -1202,9 +1200,9 @@ void SkPath::addRoundRect(const SkRect& rect, SkScalar rx, SkScalar ry,
rect.fLeft + rx - sx, rect.fTop,
rect.fLeft + rx, rect.fTop); // top-left
#else
- this->quadTo(rect.fLeft + kOffCurveEpsilon, rect.fTop + ry - offPtY,
+ this->quadTo(rect.fLeft, rect.fTop + ry - offPtY,
rect.fLeft + rx - midPtX, rect.fTop + ry - midPtY);
- this->quadTo(rect.fLeft + rx - offPtX, rect.fTop + kOffCurveEpsilon,
+ this->quadTo(rect.fLeft + rx - offPtX, rect.fTop,
rect.fLeft + rx, rect.fTop);
#endif
if (!skip_hori) {
@@ -2263,8 +2261,20 @@ void SkPath::validate() const {
static int sign(SkScalar x) { return x < 0; }
#define kValueNeverReturnedBySign 2
-static int CrossProductSign(const SkVector& a, const SkVector& b) {
- return SkScalarSignAsInt(SkPoint::CrossProduct(a, b));
+static bool AlmostEqual(SkScalar compA, SkScalar compB) {
scroggo 2013/11/01 16:04:10 Is this deliberately different from SkScalarNearly
+ // The error epsilon was empirically derived; worse case round rects
+ // with a mid point outset by 2x float epsilon in tests had an error
+ // of 12.
+ const int epsilon = 16;
+ if (!SkScalarIsFinite(compA) || !SkScalarIsFinite(compB)) {
+ return false;
+ }
+ if (sk_float_abs(compA) <= FLT_EPSILON && sk_float_abs(compB) <= FLT_EPSILON) {
+ return true;
+ }
+ int aBits = SkFloatAs2sCompliment(compA);
+ int bBits = SkFloatAs2sCompliment(compB);
+ return aBits < bBits + epsilon && bBits < aBits + epsilon;
}
// only valid for a single contour
@@ -2275,6 +2285,7 @@ struct Convexicator {
, fDirection(SkPath::kUnknown_Direction) {
fSign = 0;
// warnings
+ fLastPt.set(0, 0);
fCurrPt.set(0, 0);
fVec0.set(0, 0);
fVec1.set(0, 0);
@@ -2300,6 +2311,7 @@ struct Convexicator {
} else {
SkVector vec = pt - fCurrPt;
if (vec.fX || vec.fY) {
+ fLastPt = fCurrPt;
fCurrPt = pt;
if (++fPtCount == 2) {
fFirstVec = fVec1 = vec;
@@ -2333,7 +2345,11 @@ private:
SkASSERT(vec.fX || vec.fY);
fVec0 = fVec1;
fVec1 = vec;
- int sign = CrossProductSign(fVec0, fVec1);
+ SkScalar cross = SkPoint::CrossProduct(fVec0, fVec1);
+ SkScalar smallest = SkTMin(fCurrPt.fX, SkTMin(fCurrPt.fY, SkTMin(fLastPt.fX, fLastPt.fY)));
+ SkScalar largest = SkTMax(fCurrPt.fX, SkTMax(fCurrPt.fY, SkTMax(fLastPt.fX, fLastPt.fY)));
+ largest = SkTMax(largest, -smallest);
+ int sign = AlmostEqual(largest, largest + cross) ? 0 : SkScalarSignAsInt(cross);
if (0 == fSign) {
fSign = sign;
if (1 == sign) {
@@ -2349,6 +2365,7 @@ private:
}
}
+ SkPoint fLastPt;
SkPoint fCurrPt;
SkVector fVec0, fVec1, fFirstVec;
int fPtCount; // non-degenerate points
« no previous file with comments | « src/core/SkGeometry.cpp ('k') | no next file » | no next file with comments »

Powered by Google App Engine
This is Rietveld 408576698