SkCanvas::adjustToTopLayer()

tests/CanvasTest.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /*  Description:
  *      This test defines a series of elementatry test steps that perform
  *      a single or a small group of canvas API calls. Each test step is
  *      used in several test cases that verify that different types of SkCanvas
  *      flavors and derivatives pass it and yield consistent behavior. The
  *      test cases analyse results that are queryable through the API. They do
  *      not look at rendering results.
  *
  *  Adding test stepss:
  *      The general pattern for creating a new test step is to write a test
  *      function of the form:
  *
  *          static void MyTestStepFunction(SkCanvas* canvas,
+ *                                         const TestData& d,
  *                                         skiatest::Reporter* reporter,
  *                                         CanvasTestStep* testStep)
  *          {
  *              canvas->someCanvasAPImethod();
  *              (...)
  *              REPORTER_ASSERT_MESSAGE(reporter, (...), \
  *                  testStep->assertMessage());
  *          }
  *
  *      The definition of the test step function should be followed by an
@@ skipping 460 matching lines @@
     canvas->translate(SkIntToScalar(2), SkIntToScalar(1));
     canvas->save();
     canvas->scale(SkIntToScalar(3), SkIntToScalar(3));
     canvas->drawRect(d.fRect,d.fPaint);
     canvas->flush();
     canvas->restore();
     canvas->restore();
 }
 TEST_STEP(NestedSaveRestoreWithFlush, NestedSaveRestoreWithFlushTestStep);
 
+static void DescribeTopLayerTestStep(SkCanvas* canvas,
+                                     const TestData& d,
+                                     skiatest::Reporter* reporter,
+                                     CanvasTestStep* testStep) {
+    SkMatrix m;
+    SkIRect r;
+    // NOTE: adjustToTopLayer() does *not* reduce the clip size, even if the canvas
+    // is smaller than 10x10!
+
+    canvas->temporary_internal_describeTopLayer(&m, &r);
+    REPORTER_ASSERT_MESSAGE(reporter, m.isIdentity(), testStep->assertMessage());
+    REPORTER_ASSERT_MESSAGE(reporter, r == SkIRect::MakeXYWH(0, 0, 2, 2),
+                            testStep->assertMessage());
+
+    // Putting a full-canvas layer on it should make no change to the results.
+    SkRect layerBounds = SkRect::MakeXYWH(0.f, 0.f, 10.f, 10.f);
+    canvas->saveLayer(layerBounds, nullptr);
+    canvas->temporary_internal_describeTopLayer(&m, &r);
+    REPORTER_ASSERT_MESSAGE(reporter, m.isIdentity(), testStep->assertMessage());
+    REPORTER_ASSERT_MESSAGE(reporter, r == SkIRect::MakeXYWH(0, 0, 2, 2),
+                            testStep->assertMessage());
+    canvas->restore();
+
+    // Adding a translated layer translates the results.
+    // Default canvas is only 2x2, so can't offset our layer by very much at all;
+    // saveLayer() aborts if the bounds don't intersect.
+    layerBounds = SkRect::MakeXYWH(1.f, 1.f, 6.f, 6.f);
+    canvas->saveLayer(layerBounds, nullptr);
+    canvas->temporary_internal_describeTopLayer(&m, &r);
+    REPORTER_ASSERT_MESSAGE(reporter, m == SkMatrix::MakeTrans(-1.f, -1.f),
+                            testStep->assertMessage());
+    REPORTER_ASSERT_MESSAGE(reporter, r == SkIRect::MakeXYWH(0, 0, 1, 1),
+                            testStep->assertMessage());
+    canvas->restore();
+
+}
+TEST_STEP(DescribeTopLayer, DescribeTopLayerTestStep);
+
+
 class CanvasTestingAccess {
 public:
     static bool SameState(const SkCanvas* canvas1, const SkCanvas* canvas2) {
         SkCanvas::LayerIter layerIter1(const_cast<SkCanvas*>(canvas1), false);
         SkCanvas::LayerIter layerIter2(const_cast<SkCanvas*>(canvas2), false);
         while (!layerIter1.done() && !layerIter2.done()) {
             if (layerIter1.matrix() != layerIter2.matrix()) {
                 return false;    
             }
             if (layerIter1.clip() != layerIter2.clip()) {
@@ skipping 255 matching lines @@
     REPORTER_ASSERT(reporter, canvas.getTotalMatrix() == filterCanvas.getTotalMatrix());
     REPORTER_ASSERT(reporter, canvas.getClipBounds(&clip1) == filterCanvas.getClipBounds(&clip2));
     REPORTER_ASSERT(reporter, clip1 == clip2);
 
     filterCanvas.clipRect(SkRect::MakeXYWH(30.5f, 30.7f, 100, 100));
     filterCanvas.scale(0.75f, 0.5f);
     REPORTER_ASSERT(reporter, canvas.getTotalMatrix() == filterCanvas.getTotalMatrix());
     REPORTER_ASSERT(reporter, canvas.getClipBounds(&clip1) == filterCanvas.getClipBounds(&clip2));
     REPORTER_ASSERT(reporter, clip1 == clip2);
 }