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/SkPathOpsQuad.h b/src/pathops/SkPathOpsQuad.h
new file mode 100644
index 0000000..d5ca0c7
--- /dev/null
+++ b/src/pathops/SkPathOpsQuad.h
@@ -0,0 +1,62 @@
+/*
+ * 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 SkPathOpsQuad_DEFINED
+#define SkPathOpsQuad_DEFINED
+
+#include "SkPathOpsPoint.h"
+
+struct SkDQuadPair {
+ const SkDQuad& first() const { return (const SkDQuad&) pts[0]; }
+ const SkDQuad& second() const { return (const SkDQuad&) pts[2]; }
+ SkDPoint pts[5];
+};
+
+struct SkDQuad {
+ SkDPoint fPts[3];
+
+ void set(const SkPoint pts[3]) {
+ fPts[0] = pts[0];
+ fPts[1] = pts[1];
+ fPts[2] = pts[2];
+ }
+
+ const SkDPoint& operator[](int n) const { SkASSERT(n >= 0 && n < 3); return fPts[n]; }
+ SkDPoint& operator[](int n) { SkASSERT(n >= 0 && n < 3); return fPts[n]; }
+
+ static int AddValidTs(double s[], int realRoots, double* t);
+ SkDQuadPair chopAt(double t) const;
+ SkDVector dxdyAtT(double t) const;
+ static int FindExtrema(double a, double b, double c, double tValue[1]);
+ bool isLinear(int startIndex, int endIndex) const;
+ bool monotonicInY() const;
+ double nearestT(const SkDPoint&) const;
+ bool pointInHull(const SkDPoint&) const;
+ static int RootsReal(double A, double B, double C, double t[2]);
+ static int RootsValidT(const double A, const double B, const double C, double s[2]);
+ static void SetABC(const double* quad, double* a, double* b, double* c);
+ SkDQuad subDivide(double t1, double t2) const;
+ static SkDQuad SubDivide(const SkPoint a[3], double t1, double t2) {
+ SkDQuad quad;
+ quad.set(a);
+ return quad.subDivide(t1, t2);
+ }
+ SkDPoint subDivide(const SkDPoint& a, const SkDPoint& c, double t1, double t2) const;
+ static SkDPoint SubDivide(const SkPoint pts[3], const SkDPoint& a, const SkDPoint& c,
+ double t1, double t2) {
+ SkDQuad quad;
+ quad.set(pts);
+ return quad.subDivide(a, c, t1, t2);
+ }
+ SkDCubic toCubic() const;
+ SkDPoint top(double startT, double endT) const;
+ SkDPoint xyAtT(double t) const;
+private:
+// static double Tangent(const double* quadratic, double t); // uncalled
+};
+
+#endif