work in progress for shape operations
A experimental/Intersection
A experimental/Intersection/Intersections.h
A experimental/Intersection/DataTypes.cpp
A experimental/Intersection/QuadraticReduceOrder.cpp
A experimental/Intersection/IntersectionUtilities.cpp
A experimental/Intersection/CubicIntersection_Tests.h
A experimental/Intersection/LineParameteters_Test.cpp
A experimental/Intersection/ReduceOrder.cpp
A experimental/Intersection/QuadraticIntersection.cpp
A experimental/Intersection/Extrema.h
A experimental/Intersection/CubicIntersection_TestData.h
A experimental/Intersection/QuadraticParameterization_Test.cpp
A experimental/Intersection/TestUtilities.cpp
A experimental/Intersection/CubicRoots.cpp
A experimental/Intersection/QuadraticParameterization.cpp
A experimental/Intersection/QuadraticSubDivide.cpp
A experimental/Intersection/LineIntersection_Test.cpp
A experimental/Intersection/LineIntersection.cpp
A experimental/Intersection/CubicParameterizationCode.cpp
A experimental/Intersection/LineParameters.h
A experimental/Intersection/CubicIntersection.h
A experimental/Intersection/CubeRoot.cpp
A experimental/Intersection/SkAntiEdge.h
A experimental/Intersection/ConvexHull_Test.cpp
A experimental/Intersection/CubicBezierClip_Test.cpp
A experimental/Intersection/CubicIntersection_Tests.cpp
A experimental/Intersection/CubicBezierClip.cpp
A experimental/Intersection/CubicIntersectionT.cpp
A experimental/Intersection/Inline_Tests.cpp
A experimental/Intersection/ReduceOrder_Test.cpp
A experimental/Intersection/QuadraticIntersection_TestData.h
A experimental/Intersection/DataTypes.h
A experimental/Intersection/Extrema.cpp
A experimental/Intersection/EdgeApp.cpp
A experimental/Intersection/CubicIntersection_TestData.cpp
A experimental/Intersection/IntersectionUtilities.h
A experimental/Intersection/CubicReduceOrder.cpp
A experimental/Intersection/CubicCoincidence.cpp
A experimental/Intersection/CubicIntersection_Test.cpp
A experimental/Intersection/CubicIntersection.cpp
A experimental/Intersection/QuadraticUtilities.h
A experimental/Intersection/SkAntiEdge.cpp
A experimental/Intersection/TestUtilities.h
A experimental/Intersection/CubicParameterization_Test.cpp
A experimental/Intersection/LineIntersection.h
A experimental/Intersection/CubicSubDivide.cpp
A experimental/Intersection/CubicParameterization.cpp
A experimental/Intersection/QuadraticBezierClip_Test.cpp
A experimental/Intersection/QuadraticBezierClip.cpp
A experimental/Intersection/BezierClip_Test.cpp
A experimental/Intersection/ConvexHull.cpp
A experimental/Intersection/BezierClip.cpp
A experimental/Intersection/QuadraticIntersection_TestData.cpp
git-svn-id: http://skia.googlecode.com/svn/trunk@3005 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/experimental/Intersection/CubicBezierClip.cpp b/experimental/Intersection/CubicBezierClip.cpp
new file mode 100644
index 0000000..1b5c60c
--- /dev/null
+++ b/experimental/Intersection/CubicBezierClip.cpp
@@ -0,0 +1,83 @@
+#include "CubicIntersection.h"
+#include "LineParameters.h"
+#include <algorithm> // used for std::swap
+
+// return false if unable to clip (e.g., unable to create implicit line)
+// caller should subdivide, or create degenerate if the values are too small
+bool bezier_clip(const Cubic& cubic1, const Cubic& cubic2, double& minT, double& maxT) {
+ minT = 1;
+ maxT = 0;
+ // determine normalized implicit line equation for pt[0] to pt[3]
+ // of the form ax + by + c = 0, where a*a + b*b == 1
+
+ // find the implicit line equation parameters
+ LineParameters endLine;
+ endLine.cubicEndPoints(cubic1);
+ if (!endLine.normalize()) {
+ printf("line cannot be normalized: need more code here\n");
+ return false;
+ }
+
+ double distance[2];
+ endLine.controlPtDistance(cubic1, distance);
+
+ // find fat line
+ double top = distance[0];
+ double bottom = distance[1];
+ if (top > bottom) {
+ std::swap(top, bottom);
+ }
+ if (top * bottom >= 0) {
+ const double scale = 3/4.0; // http://cagd.cs.byu.edu/~tom/papers/bezclip.pdf (13)
+ if (top < 0) {
+ top *= scale;
+ bottom = 0;
+ } else {
+ top = 0;
+ bottom *= scale;
+ }
+ } else {
+ const double scale = 4/9.0; // http://cagd.cs.byu.edu/~tom/papers/bezclip.pdf (15)
+ top *= scale;
+ bottom *= scale;
+ }
+
+ // compute intersecting candidate distance
+ Cubic distance2y; // points with X of (0, 1/3, 2/3, 1)
+ endLine.cubicDistanceY(cubic2, distance2y);
+
+ int flags = 0;
+ if (approximately_lesser(distance2y[0].y, top)) {
+ flags |= kFindTopMin;
+ } else if (approximately_greater(distance2y[0].y, bottom)) {
+ flags |= kFindBottomMin;
+ } else {
+ minT = 0;
+ }
+
+ if (approximately_lesser(distance2y[3].y, top)) {
+ flags |= kFindTopMax;
+ } else if (approximately_greater(distance2y[3].y, bottom)) {
+ flags |= kFindBottomMax;
+ } else {
+ maxT = 1;
+ }
+ // Find the intersection of distance convex hull and fat line.
+ char to_0[2];
+ char to_3[2];
+ bool do_1_2_edge = convex_x_hull(distance2y, to_0, to_3);
+ x_at(distance2y[0], distance2y[to_0[0]], top, bottom, flags, minT, maxT);
+ if (to_0[0] != to_0[1]) {
+ x_at(distance2y[0], distance2y[to_0[1]], top, bottom, flags, minT, maxT);
+ }
+ x_at(distance2y[to_3[0]], distance2y[3], top, bottom, flags, minT, maxT);
+ if (to_3[0] != to_3[1]) {
+ x_at(distance2y[to_3[1]], distance2y[3], top, bottom, flags, minT, maxT);
+ }
+ if (do_1_2_edge) {
+ x_at(distance2y[1], distance2y[2], top, bottom, flags, minT, maxT);
+ }
+
+ return minT < maxT; // returns false if distance shows no intersection
+}
+