work in progress
in the middle of switching to sortless version
git-svn-id: http://skia.googlecode.com/svn/trunk@3768 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/experimental/Intersection/QuadraticBounds.cpp b/experimental/Intersection/QuadraticBounds.cpp
new file mode 100644
index 0000000..11591b3
--- /dev/null
+++ b/experimental/Intersection/QuadraticBounds.cpp
@@ -0,0 +1,46 @@
+#include "DataTypes.h"
+#include "Extrema.h"
+
+static int isBoundedByEndPoints(double a, double b, double c)
+{
+ return (a <= b && b <= c) || (a >= b && b >= c);
+}
+
+double leftMostT(const Quadratic& quad, double startT, double endT) {
+ double leftT;
+ if (findExtrema(quad[0].x, quad[1].x, quad[2].x, &leftT)
+ && startT <= leftT && leftT <= endT) {
+ return leftT;
+ }
+ _Point startPt;
+ xy_at_t(quad, startT, startPt.x, startPt.y);
+ _Point endPt;
+ xy_at_t(quad, endT, endPt.x, endPt.y);
+ return startPt.x <= endPt.x ? startT : endT;
+}
+
+void _Rect::setBounds(const Quadratic& quad) {
+ set(quad[0]);
+ add(quad[2]);
+ double tValues[2];
+ int roots = 0;
+ if (!isBoundedByEndPoints(quad[0].x, quad[1].x, quad[2].x)) {
+ roots = findExtrema(quad[0].x, quad[1].x, quad[2].x, tValues);
+ }
+ if (!isBoundedByEndPoints(quad[0].y, quad[1].y, quad[2].y)) {
+ roots += findExtrema(quad[0].y, quad[1].y, quad[2].y,
+ &tValues[roots]);
+ }
+ for (int x = 0; x < roots; ++x) {
+ _Point result;
+ xy_at_t(quad, tValues[x], result.x, result.y);
+ add(result);
+ }
+}
+
+void _Rect::setRawBounds(const Quadratic& quad) {
+ set(quad[0]);
+ for (int x = 1; x < 3; ++x) {
+ add(quad[x]);
+ }
+}