Add base types for path ops
Paths contain lines, quads, and cubics, which are
collectively curves.
To work with path intersections, intermediary curves
are constructed. For now, those intermediates use
doubles to guarantee sufficient precision.
The DVector, DPoint, DLine, DQuad, and DCubic
structs encapsulate these intermediate curves.
The DRect and DTriangle structs are created to
describe intersectable areas of interest.
The Bounds struct inherits from SkRect to create
a SkScalar-based rectangle that intersects shared
edges.
This also includes common math equalities and
debugging that the remainder of path ops builds on,
as well as a temporary top-level interface in
include/pathops/SkPathOps.h.
Review URL: https://codereview.chromium.org/12827020
git-svn-id: http://skia.googlecode.com/svn/trunk@8551 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/pathops/SkPathOpsCubic.h b/src/pathops/SkPathOpsCubic.h
new file mode 100644
index 0000000..48280fd
--- /dev/null
+++ b/src/pathops/SkPathOpsCubic.h
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkPathOpsCubic_DEFINED
+#define SkPathOpsCubic_DEFINED
+
+#include "SkPathOpsPoint.h"
+#include "SkTDArray.h"
+
+struct SkDCubicPair {
+ const SkDCubic& first() const { return (const SkDCubic&) pts[0]; }
+ const SkDCubic& second() const { return (const SkDCubic&) pts[3]; }
+ SkDPoint pts[7];
+};
+
+struct SkDCubic {
+ SkDPoint fPts[4];
+
+ void set(const SkPoint pts[4]) {
+ fPts[0] = pts[0];
+ fPts[1] = pts[1];
+ fPts[2] = pts[2];
+ fPts[3] = pts[3];
+ }
+
+ static const int gPrecisionUnit;
+
+ const SkDPoint& operator[](int n) const { SkASSERT(n >= 0 && n < 4); return fPts[n]; }
+ SkDPoint& operator[](int n) { SkASSERT(n >= 0 && n < 4); return fPts[n]; }
+
+ double calcPrecision() const;
+ SkDCubicPair chopAt(double t) const;
+ bool clockwise() const;
+ static void Coefficients(const double* cubic, double* A, double* B, double* C, double* D);
+ bool controlsContainedByEnds() const;
+ SkDVector dxdyAtT(double t) const;
+ bool endsAreExtremaInXOrY() const;
+ static int FindExtrema(double a, double b, double c, double d, double tValue[2]);
+ int findInflections(double tValues[]) const;
+ int findMaxCurvature(double tValues[]) const;
+ bool isLinear(int startIndex, int endIndex) const;
+ bool monotonicInY() const;
+ static int RootsReal(double A, double B, double C, double D, double t[3]);
+ static int RootsValidT(const double A, const double B, const double C, double D, double s[3]);
+ bool serpentine() const;
+ SkDCubic subDivide(double t1, double t2) const;
+ static SkDCubic SubDivide(const SkPoint a[4], double t1, double t2) {
+ SkDCubic cubic;
+ cubic.set(a);
+ return cubic.subDivide(t1, t2);
+ }
+ void subDivide(const SkDPoint& a, const SkDPoint& d, double t1, double t2, SkDPoint p[2]) const;
+
+ static void SubDivide(const SkPoint pts[4], const SkDPoint& a, const SkDPoint& d, double t1,
+ double t2, SkDPoint p[2]) {
+ SkDCubic cubic;
+ cubic.set(pts);
+ cubic.subDivide(a, d, t1, t2, p);
+ }
+
+ SkDPoint top(double startT, double endT) const;
+ void toQuadraticTs(double precision, SkTDArray<double>* ts) const;
+ SkDQuad toQuad() const;
+ SkDPoint xyAtT(double t) const;
+};
+
+#endif