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Unified Diff: tests/MatrixTest.cpp

Issue 19569007: Add basic SVD support to SkMatrix. Allows you to pull out the x- and y-scale factors, sandwiched by… (Closed) Base URL: https://skia.googlecode.com/svn/trunk
Patch Set: Remove trailing white space; replace fabs() with SkScalarAbs() Created 7 years, 5 months ago
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Index: tests/MatrixTest.cpp
diff --git a/tests/MatrixTest.cpp b/tests/MatrixTest.cpp
index 5dface74d82d0e79f7389212ac650dba54035bbc..f57a964dc8315d946c3abfdf258f72e84a19114b 100644
--- a/tests/MatrixTest.cpp
+++ b/tests/MatrixTest.cpp
@@ -8,6 +8,7 @@
#include "Test.h"
#include "SkMath.h"
#include "SkMatrix.h"
+#include "SkMatrixUtils.h"
#include "SkRandom.h"
static bool nearly_equal_scalar(SkScalar a, SkScalar b) {
@@ -345,6 +346,252 @@ static void test_matrix_is_similarity(skiatest::Reporter* reporter) {
REPORTER_ASSERT(reporter, mat.isSimilarity());
}
+// For test_matrix_decomposition, below.
+static bool scalar_nearly_equal_relative(SkScalar a, SkScalar b,
+ SkScalar tolerance = SK_ScalarNearlyZero) {
+ // from Bruce Dawson
+ SkScalar diff = SkScalarAbs(a - b);
+ if (diff < tolerance) {
+ return true;
+ }
+
+ a = SkScalarAbs(a);
+ b = SkScalarAbs(b);
+ SkScalar largest = (b > a) ? b : a;
+
+ if (diff <= largest*tolerance) {
+ return true;
+ }
+
+ return false;
+}
+
+static void test_matrix_decomposition(skiatest::Reporter* reporter) {
+ SkMatrix mat;
+ SkScalar rotation0, scaleX, scaleY, rotation1;
+
+ const float kRotation0 = 15.5f;
+ const float kRotation1 = -50.f;
+ const float kScale0 = 5000.f;
+ const float kScale1 = 0.001f;
+
+ // identity
+ mat.reset();
+ REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation0));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, SK_Scalar1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, SK_Scalar1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
+ // make sure it doesn't crash if we pass in NULLs
+ REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, NULL, NULL, NULL, NULL));
+
+ // rotation only
+ mat.setRotate(kRotation0);
+ REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(rotation0, SkDegreesToRadians(kRotation0)));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, SK_Scalar1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, SK_Scalar1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
+
+ // uniform scale only
+ mat.setScale(kScale0, kScale0);
+ REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation0));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, kScale0));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, kScale0));
+ REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
+
+ // anisotropic scale only
+ mat.setScale(kScale1, kScale0);
+ REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation0));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, kScale1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, kScale0));
+ REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
+
+ // rotation then uniform scale
+ mat.setRotate(kRotation1);
+ mat.postScale(kScale0, kScale0);
+ REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(rotation0, SkDegreesToRadians(kRotation1)));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, kScale0));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, kScale0));
+ REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
+
+ // uniform scale then rotation
+ mat.setScale(kScale0, kScale0);
+ mat.postRotate(kRotation1);
+ REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(rotation0, SkDegreesToRadians(kRotation1)));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, kScale0));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, kScale0));
+ REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
+
+ // rotation then uniform scale+reflection
+ mat.setRotate(kRotation0);
+ mat.postScale(kScale1, -kScale1);
+ REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(rotation0, SkDegreesToRadians(kRotation0)));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, kScale1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, -kScale1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
+
+ // uniform scale+reflection, then rotate
+ mat.setScale(kScale0, -kScale0);
+ mat.postRotate(kRotation1);
+ REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(rotation0, SkDegreesToRadians(-kRotation1)));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, kScale0));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, -kScale0));
+ REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
+
+ // rotation then anisotropic scale
+ mat.setRotate(kRotation1);
+ mat.postScale(kScale1, kScale0);
+ REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(rotation0, SkDegreesToRadians(kRotation1)));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, kScale1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, kScale0));
+ REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
+
+ // anisotropic scale then rotation
+ mat.setScale(kScale1, kScale0);
+ mat.postRotate(kRotation0);
+ REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation0));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, kScale1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, kScale0));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(rotation1, SkDegreesToRadians(kRotation0)));
+
+ // rotation, uniform scale, then different rotation
+ mat.setRotate(kRotation1);
+ mat.postScale(kScale0, kScale0);
+ mat.postRotate(kRotation0);
+ REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(rotation0,
+ SkDegreesToRadians(kRotation0 + kRotation1)));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, kScale0));
+ REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, kScale0));
+ REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
+
+ // rotation, anisotropic scale, then different rotation
+ mat.setRotate(kRotation0);
+ mat.postScale(kScale1, kScale0);
+ mat.postRotate(kRotation1);
+ REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
+ // Because of the shear/skew we won't get the same results, so we need to multiply it out.
+ // Generating the matrices requires doing a radian-to-degree calculation, then degree-to-radian
+ // calculation (in setRotate()), which adds error, so this just computes the matrix elements
+ // directly.
+ SkScalar c0;
+ SkScalar s0 = SkScalarSinCos(rotation0, &c0);
+ SkScalar c1;
+ SkScalar s1 = SkScalarSinCos(rotation1, &c1);
+ // We do a relative check here because large scale factors cause problems with an absolute check
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleX],
+ scaleX*c0*c1 - scaleY*s0*s1));
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewX],
+ -scaleX*s0*c1 - scaleY*c0*s1));
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewY],
+ scaleX*c0*s1 + scaleY*s0*c1));
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleY],
+ -scaleX*s0*s1 + scaleY*c0*c1));
+
+ // try some random matrices
+ SkMWCRandom rand;
+ for (int m = 0; m < 1000; ++m) {
+ SkScalar rot0 = rand.nextRangeF(-SK_ScalarPI, SK_ScalarPI);
+ SkScalar sx = rand.nextRangeF(-3000.f, 3000.f);
+ SkScalar sy = rand.nextRangeF(-3000.f, 3000.f);
+ SkScalar rot1 = rand.nextRangeF(-SK_ScalarPI, SK_ScalarPI);
+ mat.setRotate(rot0);
+ mat.postScale(sx, sy);
+ mat.postRotate(rot1);
+
+ if (SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1)) {
+ SkScalar c0;
+ SkScalar s0 = SkScalarSinCos(rotation0, &c0);
+ SkScalar c1;
+ SkScalar s1 = SkScalarSinCos(rotation1, &c1);
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleX],
+ scaleX*c0*c1 - scaleY*s0*s1));
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewX],
+ -scaleX*s0*c1 - scaleY*c0*s1));
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewY],
+ scaleX*c0*s1 + scaleY*s0*c1));
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleY],
+ -scaleX*s0*s1 + scaleY*c0*c1));
+ } else {
+ // if the matrix is degenerate, the basis vectors should be near-parallel or near-zero
+ SkScalar perpdot = mat[SkMatrix::kMScaleX]*mat[SkMatrix::kMScaleY] -
+ mat[SkMatrix::kMSkewX]*mat[SkMatrix::kMSkewY];
+ REPORTER_ASSERT(reporter, SkScalarNearlyZero(perpdot));
+ }
+ }
+
+ // translation shouldn't affect this
+ mat.postTranslate(-1000.f, 1000.f);
+ REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
+ s0 = SkScalarSinCos(rotation0, &c0);
+ s1 = SkScalarSinCos(rotation1, &c1);
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleX],
+ scaleX*c0*c1 - scaleY*s0*s1));
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewX],
+ -scaleX*s0*c1 - scaleY*c0*s1));
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewY],
+ scaleX*c0*s1 + scaleY*s0*c1));
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleY],
+ -scaleX*s0*s1 + scaleY*c0*c1));
+
+ // perspective shouldn't affect this
+ mat[SkMatrix::kMPersp0] = 12.0;
+ mat[SkMatrix::kMPersp1] = 4.0;
+ mat[SkMatrix::kMPersp2] = 1872.0;
+ REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
+ s0 = SkScalarSinCos(rotation0, &c0);
+ s1 = SkScalarSinCos(rotation1, &c1);
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleX],
+ scaleX*c0*c1 - scaleY*s0*s1));
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewX],
+ -scaleX*s0*c1 - scaleY*c0*s1));
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewY],
+ scaleX*c0*s1 + scaleY*s0*c1));
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleY],
+ -scaleX*s0*s1 + scaleY*c0*c1));
+
+ // rotation, anisotropic scale + reflection, then different rotation
+ mat.setRotate(kRotation0);
+ mat.postScale(-kScale1, kScale0);
+ mat.postRotate(kRotation1);
+ REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
+ s0 = SkScalarSinCos(rotation0, &c0);
+ s1 = SkScalarSinCos(rotation1, &c1);
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleX],
+ scaleX*c0*c1 - scaleY*s0*s1));
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewX],
+ -scaleX*s0*c1 - scaleY*c0*s1));
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewY],
+ scaleX*c0*s1 + scaleY*s0*c1));
+ REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleY],
+ -scaleX*s0*s1 + scaleY*c0*c1));
+
+ // degenerate matrices
+ // mostly zero entries
+ mat.reset();
+ mat[SkMatrix::kMScaleX] = 0.f;
+ REPORTER_ASSERT(reporter, !SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
+ mat.reset();
+ mat[SkMatrix::kMScaleY] = 0.f;
+ REPORTER_ASSERT(reporter, !SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
+ mat.reset();
+ // linearly dependent entries
+ mat[SkMatrix::kMScaleX] = 1.f;
+ mat[SkMatrix::kMSkewX] = 2.f;
+ mat[SkMatrix::kMSkewY] = 4.f;
+ mat[SkMatrix::kMScaleY] = 8.f;
+ REPORTER_ASSERT(reporter, !SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
+}
+
static void TestMatrix(skiatest::Reporter* reporter) {
SkMatrix mat, inverse, iden1, iden2;
@@ -465,6 +712,7 @@ static void TestMatrix(skiatest::Reporter* reporter) {
test_matrix_max_stretch(reporter);
test_matrix_is_similarity(reporter);
test_matrix_recttorect(reporter);
+ test_matrix_decomposition(reporter);
}
#include "TestClassDef.h"
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