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/LineIntersection.cpp b/experimental/Intersection/LineIntersection.cpp
index ab23c44..5308a26 100644
--- a/experimental/Intersection/LineIntersection.cpp
+++ b/experimental/Intersection/LineIntersection.cpp
@@ -9,12 +9,28 @@
#include "LineIntersection.h"
#include <algorithm> // used for std::swap
+/* Determine the intersection point of two lines. This assumes the lines are not parallel,
+ and that that the lines are infinite.
+ From http://en.wikipedia.org/wiki/Line-line_intersection
+ */
+void lineIntersect(const _Line& a, const _Line& b, _Point& p) {
+ double axLen = a[1].x - a[0].x;
+ double ayLen = a[1].y - a[0].y;
+ double bxLen = b[1].x - b[0].x;
+ double byLen = b[1].y - b[0].y;
+ double denom = byLen * axLen - ayLen * bxLen;
+ assert(denom);
+ double term1 = a[1].x * a[0].y - a[1].y * a[0].x;
+ double term2 = b[1].x * b[0].y - b[1].y * b[0].x;
+ p.x = (term1 * bxLen - axLen * term2) / denom;
+ p.y = (term1 * byLen - ayLen * term2) / denom;
+}
/*
Determine the intersection point of two line segments
Return FALSE if the lines don't intersect
from: http://paulbourke.net/geometry/lineline2d/
-*/
+ */
int intersect(const _Line& a, const _Line& b, double aRange[2], double bRange[2]) {
double axLen = a[1].x - a[0].x;
@@ -27,7 +43,7 @@
byLen * axLen == ayLen * bxLen
byLen * axLen - ayLen * bxLen == 0 ( == denom )
*/
- double denom = byLen * axLen - ayLen * bxLen;
+ double denom = byLen * axLen - ayLen * bxLen;
if (approximately_zero(denom)) {
/* See if the axis intercepts match:
ay - ax * ayLen / axLen == by - bx * ayLen / axLen