Obtain the correct size Bitmap in TransformationUtils.roundedCorners.

Previously we were obtaining the requested image size. The requested
image size is ignored in roundedCorners because the transformation 
doesn’t scale. As a result we were weirdly stretching the image with
some combinations of image and requested dimensions.

Fixes #2472.

library/src/main/java/com/bumptech/glide/load/resource/bitmap/RoundedCorners.java

@@ -5,6 +5,7 @@
 import android.support.annotation.NonNull;
 import com.bumptech.glide.load.engine.bitmap_recycle.BitmapPool;
 import com.bumptech.glide.util.Preconditions;
+import com.bumptech.glide.util.Util;
 import java.nio.ByteBuffer;
 import java.security.MessageDigest;
 
@@ -51,18 +52,22 @@ public RoundedCorners(@SuppressWarnings("unused") Context context, int roundingR
   @Override
   protected Bitmap transform(
       @NonNull BitmapPool pool, @NonNull Bitmap toTransform, int outWidth, int outHeight) {
-    return TransformationUtils.roundedCorners(pool, toTransform, outWidth, outHeight,
-        roundingRadius);
+    return TransformationUtils.roundedCorners(pool, toTransform, roundingRadius);
   }
 
   @Override
   public boolean equals(Object o) {
-    return (o instanceof RoundedCorners) && ((RoundedCorners) o).roundingRadius == roundingRadius;
+    if (o instanceof RoundedCorners) {
+      RoundedCorners other = (RoundedCorners) o;
+      return roundingRadius == other.roundingRadius;
+    }
+    return false;
   }
 
   @Override
   public int hashCode() {
-    return ID.hashCode() + roundingRadius;
+    return Util.hashCode(ID.hashCode(),
+        Util.hashCode(roundingRadius));
   }
 
   @Override

library/src/main/java/com/bumptech/glide/load/resource/bitmap/TransformationUtils.java

@@ -14,6 +14,7 @@
 import android.os.Build;
 import android.support.annotation.NonNull;
 import android.util.Log;
+import com.bumptech.glide.load.Transformation;
 import com.bumptech.glide.load.engine.bitmap_recycle.BitmapPool;
 import com.bumptech.glide.util.Preconditions;
 import com.bumptech.glide.util.Synthetic;
@@ -397,16 +398,41 @@ private static Bitmap getAlphaSafeBitmap(@NonNull BitmapPool pool,
    * @param roundingRadius the corner radius to be applied (in device-specific pixels).
    * @return a {@link Bitmap} similar to inBitmap but with rounded corners.
    * @throws IllegalArgumentException if roundingRadius, width or height is 0 or less.
+   *
+   * @deprecated Width and height are unused and ignored. Use
+   * {@link #roundedCorners(BitmapPool, Bitmap, int)} instead.
+   */
+  @Deprecated
+  public static Bitmap roundedCorners(
+      @NonNull BitmapPool pool,
+      @NonNull Bitmap inBitmap,
+      @SuppressWarnings("unused") int width,
+      @SuppressWarnings("unused") int height,
+      int roundingRadius) {
+    return roundedCorners(pool, inBitmap, roundingRadius);
+  }
+
+  /**
+   * Creates a bitmap from a source bitmap and rounds the corners.
+   *
+   * <p>This method does <em>NOT</em> resize the given {@link Bitmap}, it only rounds it's corners.
+   * To both resize and round the corners of an image, consider
+   * {@link com.bumptech.glide.request.RequestOptions#transforms(Transformation[])} and/or
+   * {@link com.bumptech.glide.load.MultiTransformation}.
+   *
+   * @param inBitmap the source bitmap to use as a basis for the created bitmap.
+   * @param roundingRadius the corner radius to be applied (in device-specific pixels).
+   * @return a {@link Bitmap} similar to inBitmap but with rounded corners.
+   * @throws IllegalArgumentException if roundingRadius, width or height is 0 or less.
    */
-  public static Bitmap roundedCorners(@NonNull BitmapPool pool, @NonNull Bitmap inBitmap,
-      int width, int height, int roundingRadius) {
-    Preconditions.checkArgument(width > 0, "width must be greater than 0.");
-    Preconditions.checkArgument(height > 0, "height must be greater than 0.");
+  public static Bitmap roundedCorners(
+      @NonNull BitmapPool pool, @NonNull Bitmap inBitmap, int roundingRadius) {
     Preconditions.checkArgument(roundingRadius > 0, "roundingRadius must be greater than 0.");
 
     // Alpha is required for this transformation.
     Bitmap toTransform = getAlphaSafeBitmap(pool, inBitmap);
-    Bitmap result = pool.get(width, height, Bitmap.Config.ARGB_8888);
+    Bitmap result =
+        pool.get(toTransform.getWidth(), toTransform.getHeight(), Bitmap.Config.ARGB_8888);
 
     result.setHasAlpha(true);