1/*
2 * Copyright 2012 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#include "CubicUtilities.h"
9#include "CurveIntersection.h"
10#include "TestUtilities.h"
11
12void quad_to_cubic(const Quadratic& quad, Cubic& cubic) {
13    cubic[0] = quad[0];
14    cubic[1].x = quad[0].x / 3 + quad[1].x * 2 / 3;
15    cubic[1].y = quad[0].y / 3 + quad[1].y * 2 / 3;
16    cubic[2].x = quad[2].x / 3 + quad[1].x * 2 / 3;
17    cubic[2].y = quad[2].y / 3 + quad[1].y * 2 / 3;
18    cubic[3] = quad[2];
19}
20
21static bool tiny(const Cubic& cubic) {
22    int index, minX, maxX, minY, maxY;
23    minX = maxX = minY = maxY = 0;
24    for (index = 1; index < 4; ++index) {
25        if (cubic[minX].x > cubic[index].x) {
26            minX = index;
27        }
28        if (cubic[minY].y > cubic[index].y) {
29            minY = index;
30        }
31        if (cubic[maxX].x < cubic[index].x) {
32            maxX = index;
33        }
34        if (cubic[maxY].y < cubic[index].y) {
35            maxY = index;
36        }
37    }
38    return     approximately_equal(cubic[maxX].x, cubic[minX].x)
39            && approximately_equal(cubic[maxY].y, cubic[minY].y);
40}
41
42void find_tight_bounds(const Cubic& cubic, _Rect& bounds) {
43    CubicPair cubicPair;
44    chop_at(cubic, cubicPair, 0.5);
45    if (!tiny(cubicPair.first()) && !controls_inside(cubicPair.first())) {
46        find_tight_bounds(cubicPair.first(), bounds);
47    } else {
48        bounds.add(cubicPair.first()[0]);
49        bounds.add(cubicPair.first()[3]);
50    }
51    if (!tiny(cubicPair.second()) && !controls_inside(cubicPair.second())) {
52        find_tight_bounds(cubicPair.second(), bounds);
53    } else {
54        bounds.add(cubicPair.second()[0]);
55        bounds.add(cubicPair.second()[3]);
56    }
57}
58
59bool controls_inside(const Cubic& cubic) {
60    return
61        ((cubic[0].x <= cubic[1].x && cubic[0].x <= cubic[2].x && cubic[1].x <= cubic[3].x && cubic[2].x <= cubic[3].x)
62     ||  (cubic[0].x >= cubic[1].x && cubic[0].x >= cubic[2].x && cubic[1].x >= cubic[3].x && cubic[2].x >= cubic[3].x))
63     && ((cubic[0].y <= cubic[1].y && cubic[0].y <= cubic[2].y && cubic[1].y <= cubic[3].y && cubic[2].y <= cubic[3].y)
64     ||  (cubic[0].y >= cubic[1].y && cubic[0].y >= cubic[2].y && cubic[1].y >= cubic[3].y && cubic[2].x >= cubic[3].y));
65}
66