Added OrientedBitmapDrawable class

drawee/src/main/java/com/facebook/drawee/drawable/OrientedBitmapDrawable.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+package com.facebook.drawee.drawable;
+
+import android.content.res.Resources;
+import android.graphics.Bitmap;
+import android.graphics.Canvas;
+import android.graphics.Matrix;
+import android.graphics.Rect;
+import android.graphics.drawable.BitmapDrawable;
+
+import com.facebook.common.internal.Preconditions;
+import com.facebook.common.internal.VisibleForTesting;
+
+/**
+ * Drawable that automatically rotates the underlying drawable with a pivot in the center of the
+ * drawable bounds based on a rotation angle.
+ */
+public class OrientedBitmapDrawable extends BitmapDrawable {
+
+  private static final int UNKNOWN_ROTATION_ANGLE = -1;
+
+  @VisibleForTesting final Matrix mRotationMatrix;
+  private int mRotationAngle;
+
+  /**
+   * Creates a new OrientedBitmapDrawable. The only rotation angles allowed are multiples of 90 or
+   * -1 if the angle is unknown.
+   */
+  public OrientedBitmapDrawable(Resources res, Bitmap bitmap, int rotationAngle) {
+    super(res, bitmap);
+    Preconditions.checkArgument(rotationAngle == UNKNOWN_ROTATION_ANGLE || rotationAngle % 90 == 0);
+    mRotationMatrix = new Matrix();
+    mRotationAngle = rotationAngle;
+  }
+
+  @Override
+  public void draw(Canvas canvas) {
+    Rect bounds = getBounds();
+    if (mRotationAngle <= 0) {
+      super.draw(canvas);
+      return;
+    }
+    mRotationMatrix.setRotate(mRotationAngle, bounds.centerX(), bounds.centerY());
+    int saveCount = canvas.save();
+    canvas.concat(mRotationMatrix);
+    super.draw(canvas);
+    canvas.restoreToCount(saveCount);
+  }
+
+}

drawee/src/test/java/com/facebook/drawee/drawable/OrientedBitmapDrawableTest.java

@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+package com.facebook.drawee.drawable;
+
+import android.content.res.Resources;
+import android.graphics.Bitmap;
+import android.graphics.Canvas;
+import android.graphics.Matrix;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link OrientedBitmapDrawable}
+ */
+@RunWith(RobolectricTestRunner.class)
+public class OrientedBitmapDrawableTest {
+
+  private Resources mResources;
+  private Bitmap mBitmap;
+  private Canvas mCanvas;
+
+  @Before
+  public void setUp() {
+    mResources = Resources.getSystem();
+    mBitmap = mock(Bitmap.class);
+    mCanvas = mock(Canvas.class);
+  }
+
+  @Test
+  public void testCreation_invalidAngle() {
+    try {
+      new OrientedBitmapDrawable(mResources, mBitmap, 20);
+      fail();
+    } catch (IllegalArgumentException e) {
+      // Do nothing, expected.
+    }
+  }
+
+  @Test
+  public void testCreation_unknownAngle() {
+    OrientedBitmapDrawable drawable = new OrientedBitmapDrawable(mResources, mBitmap, -1);
+    drawable.draw(mCanvas);
+    assertTrue(drawable.mRotationMatrix.isIdentity());
+  }
+
+  @Test
+  public void testCreation_zeroDegrees() {
+    OrientedBitmapDrawable drawable = new OrientedBitmapDrawable(mResources, mBitmap, 0);
+    drawable.draw(mCanvas);
+    assertTrue(drawable.mRotationMatrix.isIdentity());
+
+  }
+
+  @Test
+  public void testCreation_nintyDegrees() {
+    OrientedBitmapDrawable drawable = new OrientedBitmapDrawable(mResources, mBitmap, 90);
+    drawable.draw(mCanvas);
+
+    Matrix expectedMatrix = new Matrix();
+    expectedMatrix.setRotate(90, drawable.getBounds().centerX(), drawable.getBounds().centerY());
+    assertFalse(drawable.mRotationMatrix.isIdentity());
+    AndroidGraphicsTestUtils.assertEquals(expectedMatrix, drawable.mRotationMatrix);
+  }
+
+  @Test
+  public void testCreation_hundredAndEightyDegrees() {
+    OrientedBitmapDrawable drawable = new OrientedBitmapDrawable(mResources, mBitmap, 180);
+    drawable.draw(mCanvas);
+
+    Matrix expectedMatrix = new Matrix();
+    expectedMatrix.setRotate(180, drawable.getBounds().centerX(), drawable.getBounds().centerY());
+    assertFalse(drawable.mRotationMatrix.isIdentity());
+    AndroidGraphicsTestUtils.assertEquals(expectedMatrix, drawable.mRotationMatrix);
+  }
+
+  @Test
+  public void testCreation_twoHundredAndSeventyDegrees() {
+    OrientedBitmapDrawable drawable = new OrientedBitmapDrawable(mResources, mBitmap, 270);
+    drawable.draw(mCanvas);
+
+    Matrix expectedMatrix = new Matrix();
+    expectedMatrix.setRotate(270, drawable.getBounds().centerX(), drawable.getBounds().centerY());
+    assertFalse(drawable.mRotationMatrix.isIdentity());
+    AndroidGraphicsTestUtils.assertEquals(expectedMatrix, drawable.mRotationMatrix);
+  }
+
+}