commit adf9990cb56ca389f37f02ac637496083b3c3cfc
author reed <reed@google.com> Thu Mar 19 16:10:54 2015 -0700
committer Commit bot <commit-bot@chromium.org> Thu Mar 19 16:10:54 2015 -0700
tree 9836e2845d7cc22b84d5f035d868610925b38f1d
parent d800d878caae5d25b275d488a1b5ae8c24cea492

add SkMatrix::decomposeScale

BUG=skia:

Review URL: https://codereview.chromium.org/1006173005

tests/MatrixTest.cpp

diff --git a/tests/MatrixTest.cpp b/tests/MatrixTest.cpp
index 7875d9e..95d33ac 100644
--- a/tests/MatrixTest.cpp
+++ b/tests/MatrixTest.cpp
@@ -771,6 +771,34 @@
 
 }
 
+static bool check_decompScale(const SkMatrix& matrix) {
+    SkSize scale;
+    SkMatrix remaining;
+
+    if (!matrix.decomposeScale(&scale, &remaining)) {
+        return false;
+    }
+    if (scale.width() <= 0 || scale.height() <= 0) {
+        return false;
+    }
+    remaining.preScale(scale.width(), scale.height());
+    return nearly_equal(matrix, remaining);
+}
+
+static void test_decompScale(skiatest::Reporter* reporter) {
+    SkMatrix m;
+
+    m.reset();
+    REPORTER_ASSERT(reporter, check_decompScale(m));
+    m.setScale(2, 3);
+    REPORTER_ASSERT(reporter, check_decompScale(m));
+    m.setRotate(35, 0, 0);
+    REPORTER_ASSERT(reporter, check_decompScale(m));
+
+    m.setScale(1, 0);
+    REPORTER_ASSERT(reporter, !check_decompScale(m));
+}
+
 DEF_TEST(Matrix, reporter) {
     SkMatrix    mat, inverse, iden1, iden2;
 
@@ -889,6 +917,8 @@
     test_matrix_decomposition(reporter);
     test_matrix_homogeneous(reporter);
     test_set9(reporter);
+
+    test_decompScale(reporter);
 }
 
 DEF_TEST(Matrix_Concat, r) {