skia2/tests/GrPathUtilsTest.cpp
Chris Dalton f1aa6fc424 Fix GrPathUtils::convertLineToCubic
Change-Id: Ie096c9f0629102c5c6b2ca9ddfb8e5e2c31218f7
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/333145
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
2020-11-10 02:47:57 +00:00

92 lines
4.1 KiB
C++

/*
* Copyright 2020 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "include/utils/SkRandom.h"
#include "src/core/SkGeometry.h"
#include "src/gpu/geometry/GrPathUtils.h"
#include "tests/Test.h"
static bool is_linear(SkPoint p0, SkPoint p1, SkPoint p2) {
return SkScalarNearlyZero((p0 - p1).cross(p2 - p1));
}
static bool is_linear(const SkPoint p[4]) {
return is_linear(p[0],p[1],p[2]) && is_linear(p[0],p[2],p[3]) && is_linear(p[1],p[2],p[3]);
}
DEF_TEST(GrPathUtils_findCubicConvex180Chops, r) {
// Test all combinations of corners from the square [0,0,1,1]. This gives us all kinds of
// special cases for cusps, lines, loops, and inflections.
for (int i = 0; i < (1 << 8); ++i) {
SkPoint p[4] = {SkPoint::Make((i>>0)&1, (i>>1)&1),
SkPoint::Make((i>>2)&1, (i>>3)&1),
SkPoint::Make((i>>4)&1, (i>>5)&1),
SkPoint::Make((i>>6)&1, (i>>7)&1)};
float inflectT[2], convex180T[2];
if (int inflectN = SkFindCubicInflections(p, inflectT)) {
// The curve has inflections. findCubicConvex180Chops should return the inflection
// points.
int convex180N = GrPathUtils::findCubicConvex180Chops(p, convex180T);
REPORTER_ASSERT(r, inflectN == convex180N);
for (int i = 0; i < convex180N; ++i) {
REPORTER_ASSERT(r, SkScalarNearlyEqual(inflectT[i], convex180T[i]));
}
} else {
float totalRotation = SkMeasureNonInflectCubicRotation(p);
int convex180N = GrPathUtils::findCubicConvex180Chops(p, convex180T);
SkPoint chops[10];
SkChopCubicAt(p, chops, convex180T, convex180N);
float radsSum = 0;
for (int i = 0; i <= convex180N; ++i) {
float rads = SkMeasureNonInflectCubicRotation(chops + i*3);
SkASSERT(rads < SK_ScalarPI + SK_ScalarNearlyZero);
radsSum += rads;
}
if (totalRotation < SK_ScalarPI - SK_ScalarNearlyZero) {
// The curve should never chop if rotation is <180 degrees.
REPORTER_ASSERT(r, convex180N == 0);
} else if (!is_linear(p)) {
REPORTER_ASSERT(r, SkScalarNearlyEqual(radsSum, totalRotation));
if (totalRotation > SK_ScalarPI + SK_ScalarNearlyZero) {
REPORTER_ASSERT(r, convex180N == 1);
// This works because cusps take the "inflection" path above, so we don't get
// non-lilnear curves that lose rotation when chopped.
REPORTER_ASSERT(r, SkScalarNearlyEqual(
SkMeasureNonInflectCubicRotation(chops), SK_ScalarPI));
REPORTER_ASSERT(r, SkScalarNearlyEqual(
SkMeasureNonInflectCubicRotation(chops + 3), totalRotation - SK_ScalarPI));
}
}
}
}
// Now test an exact quadratic.
SkPoint quad[4] = {{0,0}, {2,2}, {4,2}, {6,0}};
float T[2];
REPORTER_ASSERT(r, GrPathUtils::findCubicConvex180Chops(quad, T) == 0);
}
DEF_TEST(GrPathUtils_convertToCubic, r) {
SkPoint cubic[4];
GrPathUtils::convertLineToCubic({0,0}, {3,6}, cubic);
REPORTER_ASSERT(r, cubic[0] == SkPoint::Make(0,0));
REPORTER_ASSERT(r, SkScalarNearlyEqual(cubic[1].fX, 1));
REPORTER_ASSERT(r, SkScalarNearlyEqual(cubic[1].fY, 2));
REPORTER_ASSERT(r, SkScalarNearlyEqual(cubic[2].fX, 2));
REPORTER_ASSERT(r, SkScalarNearlyEqual(cubic[2].fY, 4));
REPORTER_ASSERT(r, cubic[3] == SkPoint::Make(3,6));
SkPoint quad[3] = {{0,0}, {3,3}, {6,0}};
GrPathUtils::convertQuadToCubic(quad, cubic);
REPORTER_ASSERT(r, cubic[0] == SkPoint::Make(0,0));
REPORTER_ASSERT(r, SkScalarNearlyEqual(cubic[1].fX, 2));
REPORTER_ASSERT(r, SkScalarNearlyEqual(cubic[1].fY, 2));
REPORTER_ASSERT(r, SkScalarNearlyEqual(cubic[2].fX, 4));
REPORTER_ASSERT(r, SkScalarNearlyEqual(cubic[2].fY, 2));
REPORTER_ASSERT(r, cubic[3] == SkPoint::Make(6,0));
}