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Diffstat (limited to 'android/graphics/PostProcess.java')
| -rw-r--r-- | android/graphics/PostProcess.java | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/android/graphics/PostProcess.java b/android/graphics/PostProcess.java new file mode 100644 index 00000000..c5a31e82 --- /dev/null +++ b/android/graphics/PostProcess.java @@ -0,0 +1,91 @@ +/* + * 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.IntDef; +import android.annotation.NonNull; +import android.graphics.drawable.Drawable; + + +/** + * Helper interface for adding custom processing to an image. + * + * The image being processed may be a {@link Drawable}, {@link Bitmap} or frame + * of an animated image produced by {@link ImageDecoder}. This is called before + * the requested object is returned. + * + * This custom processing also applies to image types that are otherwise + * immutable, such as {@link Bitmap.Config#HARDWARE}. + * + * On an animated image, the callback will only be called once, but the drawing + * commands will be applied to each frame, as if the {@code Canvas} had been + * returned by {@link Picture#beginRecording}. + * + * Supplied to ImageDecoder via {@link ImageDecoder#setPostProcess}. + * @hide + */ +public interface PostProcess { + /** + * Do any processing after (for example) decoding. + * + * 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}. A common effect is to add transparency + * to the corners to achieve rounded corners. That can be done with the + * following code: + * + * <code> + * Path path = new Path(); + * path.setFillType(Path.FillType.INVERSE_EVEN_ODD); + * 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; + * </code> + * + * + * @param canvas The {@link Canvas} to draw to. + * @param width Width of {@code canvas}. Anything drawn outside of this + * will be ignored. + * @param height Height of {@code canvas}. Anything drawn outside of this + * will be ignored. + * @return Opacity of the result after drawing. + * {@link 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 {@code PixelFormat.TRANSLUCENT}) or you forced the image to + * be opaque (e.g. by drawing everywhere with an opaque color and + * {@code PorterDuff.Mode.DST_OVER}, in which case you should return + * {@code PixelFormat.OPAQUE}). + * {@link 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} 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} (or any other integer) is not + * allowed, and will result in throwing an + * {@link java.lang.IllegalArgumentException}. + */ + @PixelFormat.Opacity + public int postProcess(@NonNull Canvas canvas, int width, int height); +} |