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