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Diffstat (limited to 'experimental/Intersection/TestUtilities.cpp')
-rw-r--r-- | experimental/Intersection/TestUtilities.cpp | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/experimental/Intersection/TestUtilities.cpp b/experimental/Intersection/TestUtilities.cpp new file mode 100644 index 0000000000..5e3c18e186 --- /dev/null +++ b/experimental/Intersection/TestUtilities.cpp @@ -0,0 +1,69 @@ +#include "CubicIntersection.h" +#include "TestUtilities.h" + +void quad_to_cubic(const Quadratic& quad, Cubic& cubic) { + cubic[0] = quad[0]; + cubic[1].x = quad[0].x / 3 + quad[1].x * 2 / 3; + cubic[1].y = quad[0].y / 3 + quad[1].y * 2 / 3; + cubic[2].x = quad[2].x / 3 + quad[1].x * 2 / 3; + cubic[2].y = quad[2].y / 3 + quad[1].y * 2 / 3; + cubic[3] = quad[2]; +} + +static bool tiny(const Cubic& cubic) { + int index, minX, maxX, minY, maxY; + minX = maxX = minY = maxY = 0; + for (index = 1; index < 4; ++index) { + if (cubic[minX].x > cubic[index].x) { + minX = index; + } + if (cubic[minY].y > cubic[index].y) { + minY = index; + } + if (cubic[maxX].x < cubic[index].x) { + maxX = index; + } + if (cubic[maxY].y < cubic[index].y) { + maxY = index; + } + } + return approximately_equal(cubic[maxX].x, cubic[minX].x) + && approximately_equal(cubic[maxY].y, cubic[minY].y); +} + +void find_tight_bounds(const Cubic& cubic, _Rect& bounds) { + CubicPair cubicPair; + chop_at(cubic, cubicPair, 0.5); + if (!tiny(cubicPair.first()) && !controls_inside(cubicPair.first())) { + find_tight_bounds(cubicPair.first(), bounds); + } else { + bounds.add(cubicPair.first()[0]); + bounds.add(cubicPair.first()[3]); + } + if (!tiny(cubicPair.second()) && !controls_inside(cubicPair.second())) { + find_tight_bounds(cubicPair.second(), bounds); + } else { + bounds.add(cubicPair.second()[0]); + bounds.add(cubicPair.second()[3]); + } +} + +bool controls_inside(const Cubic& cubic) { + return + ((cubic[0].x <= cubic[1].x && cubic[0].x <= cubic[2].x && cubic[1].x <= cubic[3].x && cubic[2].x <= cubic[3].x) + || (cubic[0].x >= cubic[1].x && cubic[0].x >= cubic[2].x && cubic[1].x >= cubic[3].x && cubic[2].x >= cubic[3].x)) + && ((cubic[0].y <= cubic[1].y && cubic[0].y <= cubic[2].y && cubic[1].y <= cubic[3].y && cubic[2].y <= cubic[3].y) + || (cubic[0].y >= cubic[1].y && cubic[0].y >= cubic[2].y && cubic[1].y >= cubic[3].y && cubic[2].x >= cubic[3].y)); +} + +void xy_at_t(const Cubic& cubic, double t, double& x, double& y) { + double one_t = 1 - t; + double one_t2 = one_t * one_t; + double a = one_t2 * one_t; + double b = 3 * one_t2 * t; + double t2 = t * t; + double c = 3 * one_t * t2; + double d = t2 * t; + x = a * cubic[0].x + b * cubic[1].x + c * cubic[2].x + d * cubic[3].x; + y = a * cubic[0].y + b * cubic[1].y + c * cubic[2].y + d * cubic[3].y; +} |