| /* |
| * Copyright (C) 2017 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package android.graphics; |
| |
| import android.annotation.NonNull; |
| import android.graphics.drawable.AnimatedImageDrawable; |
| import android.graphics.drawable.Drawable; |
| |
| /** |
| * Helper interface for adding custom processing to an image. |
| * |
| * <p>The image being processed may be a {@link Drawable}, a {@link Bitmap}, or |
| * a frame of an {@link AnimatedImageDrawable} produced by {@link ImageDecoder}. |
| * This is called before the requested object is returned.</p> |
| * |
| * <p>This custom processing can even be applied to images that will be returned |
| * as immutable objects, such as a {@link Bitmap} with {@code Config} |
| * {@link Bitmap.Config#HARDWARE} returned by {@link ImageDecoder}.</p> |
| * |
| * <p>On an {@link AnimatedImageDrawable}, the callback will only be called once, |
| * but the drawing commands will be applied to each frame, as if the {@link Canvas} |
| * had been returned by {@link Picture#beginRecording Picture.beginRecording}.<p> |
| * |
| * <p>Supplied to ImageDecoder via {@link ImageDecoder#setPostProcessor setPostProcessor}.</p> |
| */ |
| public interface PostProcessor { |
| /** |
| * Do any processing after (for example) decoding. |
| * |
| * <p>Drawing to the {@link Canvas} will behave as if the initial processing |
| * (e.g. decoding) already exists in the Canvas. An implementation can draw |
| * effects on top of this, or it can even draw behind it using |
| * {@link PorterDuff.Mode#DST_OVER PorterDuff.Mode.DST_OVER}. A common |
| * effect is to add transparency to the corners to achieve rounded corners. |
| * That can be done with the following code:</p> |
| * |
| * <pre class="prettyprint"> |
| * Path path = new Path(); |
| * path.setFillType(Path.FillType.INVERSE_EVEN_ODD); |
| * int width = canvas.getWidth(); |
| * int height = canvas.getHeight(); |
| * path.addRoundRect(0, 0, width, height, 20, 20, Path.Direction.CW); |
| * Paint paint = new Paint(); |
| * paint.setAntiAlias(true); |
| * paint.setColor(Color.TRANSPARENT); |
| * paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC)); |
| * canvas.drawPath(path, paint); |
| * return PixelFormat.TRANSLUCENT; |
| * </pre> |
| * |
| * |
| * @param canvas The {@link Canvas} to draw to. |
| * @return Opacity of the result after drawing. |
| * {@link PixelFormat#UNKNOWN PixelFormat.UNKNOWN} means that the |
| * implementation did not change whether the image has alpha. Return |
| * this unless you added transparency (e.g. with the code above, in |
| * which case you should return |
| * {@link PixelFormat#TRANSLUCENT PixelFormat.TRANSLUCENT}) or you |
| * forced the image to be opaque (e.g. by drawing everywhere with an |
| * opaque color and {@link PorterDuff.Mode#DST_OVER PorterDuff.Mode.DST_OVER}, |
| * in which case you should return {@link PixelFormat#OPAQUE PixelFormat.OPAQUE}). |
| * {@link PixelFormat#TRANSLUCENT PixelFormat.TRANSLUCENT} means that |
| * the implementation added transparency. This is safe to return even |
| * if the image already had transparency. This is also safe to return |
| * if the result is opaque, though it may draw more slowly. |
| * {@link PixelFormat#OPAQUE PixelFormat.OPAQUE} means that the |
| * implementation forced the image to be opaque. This is safe to return |
| * even if the image was already opaque. |
| * {@link PixelFormat#TRANSPARENT PixelFormat.TRANSPARENT} (or any other |
| * integer) is not allowed, and will result in throwing an |
| * {@link java.lang.IllegalArgumentException}. |
| */ |
| @PixelFormat.Opacity |
| public int onPostProcess(@NonNull Canvas canvas); |
| } |