TransformationUtils.java 文件源码

/**
 * Creates a bitmap from a source bitmap and rounds the corners.
 *
 * @param inBitmap the source bitmap to use as a basis for the created bitmap.
 * @param width the width of the generated bitmap.
 * @param height the height of the generated 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.");
  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);

  result.setHasAlpha(true);

  BitmapShader shader = new BitmapShader(toTransform, Shader.TileMode.CLAMP,
      Shader.TileMode.CLAMP);
  Paint paint = new Paint();
  paint.setAntiAlias(true);
  paint.setShader(shader);
  RectF rect = new RectF(0, 0, result.getWidth(), result.getHeight());
  BITMAP_DRAWABLE_LOCK.lock();
  try {
    Canvas canvas = new Canvas(result);
    canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
    canvas.drawRoundRect(rect, roundingRadius, roundingRadius, paint);
    clear(canvas);
  } finally {
    BITMAP_DRAWABLE_LOCK.unlock();
  }

  if (!toTransform.equals(inBitmap)) {
    pool.put(toTransform);
  }

  return result;
}