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/*
* Copyright 2012 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "CurveIntersection.h"
#include "CurveUtilities.h"
#include "Extrema.h"
static int isBoundedByEndPoints(double a, double b, double c, double d)
{
return between(a, b, d) && between(a, c, d);
}
double leftMostT(const Cubic& cubic, double startT, double endT) {
double leftTs[2];
_Point pt[2];
int results = findExtrema(cubic[0].x, cubic[1].x, cubic[2].x, cubic[3].x, leftTs);
int best = -1;
for (int index = 0; index < results; ++index) {
if (startT > leftTs[index] || leftTs[index] > endT) {
continue;
}
if (best < 0) {
best = index;
continue;
}
xy_at_t(cubic, leftTs[0], pt[0].x, pt[0].y);
xy_at_t(cubic, leftTs[1], pt[1].x, pt[1].y);
if (pt[0].x > pt[1].x) {
best = 1;
}
}
if (best >= 0) {
return leftTs[best];
}
xy_at_t(cubic, startT, pt[0].x, pt[0].y);
xy_at_t(cubic, endT, pt[1].x, pt[1].y);
return pt[0].x <= pt[1].x ? startT : endT;
}
void _Rect::setBounds(const Cubic& cubic) {
set(cubic[0]);
add(cubic[3]);
double tValues[4];
int roots = 0;
if (!isBoundedByEndPoints(cubic[0].x, cubic[1].x, cubic[2].x, cubic[3].x)) {
roots = findExtrema(cubic[0].x, cubic[1].x, cubic[2].x, cubic[3].x, tValues);
}
if (!isBoundedByEndPoints(cubic[0].y, cubic[1].y, cubic[2].y, cubic[3].y)) {
roots += findExtrema(cubic[0].y, cubic[1].y, cubic[2].y, cubic[3].y, &tValues[roots]);
}
for (int x = 0; x < roots; ++x) {
_Point result;
xy_at_t(cubic, tValues[x], result.x, result.y);
add(result);
}
}
void _Rect::setRawBounds(const Cubic& cubic) {
set(cubic[0]);
for (int x = 1; x < 4; ++x) {
add(cubic[x]);
}
}
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