shape ops work in progress
mostly working on cubic/cubic intersect
git-svn-id: http://skia.googlecode.com/svn/trunk@7266 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/experimental/Intersection/CubicUtilities.cpp b/experimental/Intersection/CubicUtilities.cpp
index 958cabb..36aa9e8 100644
--- a/experimental/Intersection/CubicUtilities.cpp
+++ b/experimental/Intersection/CubicUtilities.cpp
@@ -7,6 +7,14 @@
#include "CubicUtilities.h"
#include "QuadraticUtilities.h"
+double calcPrecision(const Cubic& cubic) {
+ _Rect dRect;
+ dRect.setBounds(cubic);
+ double width = dRect.right - dRect.left;
+ double height = dRect.bottom - dRect.top;
+ return (width > height ? width : height) / 256;
+}
+
void coefficients(const double* cubic, double& A, double& B, double& C, double& D) {
A = cubic[6]; // d
B = cubic[4] * 3; // 3*c
@@ -93,15 +101,6 @@
return (b - a) * one_t * one_t + 2 * (c - b) * t * one_t + (d - c) * t * t;
}
-// same as derivativeAtT
-// which is more accurate? which is faster?
-double derivativeAtT_2(const double* cubic, double t) {
- double a = cubic[2] - cubic[0];
- double b = cubic[4] - 2 * cubic[2] + cubic[0];
- double c = cubic[6] + 3 * (cubic[2] - cubic[4]) - cubic[0];
- return c * c * t * t + 2 * b * t + a;
-}
-
void dxdy_at_t(const Cubic& cubic, double t, double& dx, double& dy) {
if (&dx) {
dx = derivativeAtT(&cubic[0].x, t);
@@ -111,6 +110,17 @@
}
}
+int find_cubic_inflections(const Cubic& src, double tValues[])
+{
+ double Ax = src[1].x - src[0].x;
+ double Ay = src[1].y - src[0].y;
+ double Bx = src[2].x - 2 * src[1].x + src[0].x;
+ double By = src[2].y - 2 * src[1].y + src[0].y;
+ double Cx = src[3].x + 3 * (src[1].x - src[2].x) - src[0].x;
+ double Cy = src[3].y + 3 * (src[1].y - src[2].y) - src[0].y;
+ return quadraticRoots(Bx * Cy - By * Cx, (Ax * Cy - Ay * Cx) / 2, Ax * By - Ay * Bx, tValues);
+}
+
bool rotate(const Cubic& cubic, int zero, int index, Cubic& rotPath) {
double dy = cubic[index].y - cubic[zero].y;
double dx = cubic[index].x - cubic[zero].x;