| /* |
| * Copyright (C) 2011 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.view; |
| |
| import android.graphics.Canvas; |
| |
| /** |
| * A hardware layer can be used to render graphics operations into a hardware |
| * friendly buffer. For instance, with an OpenGL backend, a hardware layer |
| * would use a Frame Buffer Object (FBO.) The hardware layer can be used as |
| * a drawing cache when a complex set of graphics operations needs to be |
| * drawn several times. |
| */ |
| abstract class HardwareLayer { |
| int mWidth; |
| int mHeight; |
| |
| final boolean mOpaque; |
| |
| /** |
| * Creates a new hardware layer at least as large as the supplied |
| * dimensions. |
| * |
| * @param width The minimum width of the layer |
| * @param height The minimum height of the layer |
| * @param isOpaque Whether the layer should be opaque or not |
| */ |
| HardwareLayer(int width, int height, boolean isOpaque) { |
| mWidth = width; |
| mHeight = height; |
| mOpaque = isOpaque; |
| } |
| |
| /** |
| * Returns the minimum width of the layer. |
| * |
| * @return The minimum desired width of the hardware layer |
| */ |
| int getWidth() { |
| return mWidth; |
| } |
| |
| /** |
| * Returns the minimum height of the layer. |
| * |
| * @return The minimum desired height of the hardware layer |
| */ |
| int getHeight() { |
| return mHeight; |
| } |
| |
| /** |
| * Returns whether or not this layer is opaque. |
| * |
| * @return True if the layer is opaque, false otherwise |
| */ |
| boolean isOpaque() { |
| return mOpaque; |
| } |
| |
| /** |
| * Indicates whether this layer can be rendered. |
| * |
| * @return True if the layer can be rendered into, false otherwise |
| */ |
| abstract boolean isValid(); |
| |
| /** |
| * Resizes the layer, if necessary, to be at least as large |
| * as the supplied dimensions. |
| * |
| * @param width The new desired minimum width for this layer |
| * @param height The new desired minimum height for this layer |
| */ |
| abstract void resize(int width, int height); |
| |
| /** |
| * Returns a hardware canvas that can be used to render onto |
| * this layer. |
| * |
| * @return A hardware canvas, or null if a canvas cannot be created |
| */ |
| abstract HardwareCanvas getCanvas(); |
| |
| /** |
| * Destroys resources without waiting for a GC. |
| */ |
| abstract void destroy(); |
| |
| /** |
| * This must be invoked before drawing onto this layer. |
| * @param currentCanvas |
| */ |
| abstract HardwareCanvas start(Canvas currentCanvas); |
| |
| /** |
| * This must be invoked after drawing onto this layer. |
| * @param currentCanvas |
| */ |
| abstract void end(Canvas currentCanvas); |
| } |