michael@0: /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: package org.mozilla.gecko.gfx;
michael@0: 
michael@0: public class VirtualLayer extends Layer {
michael@0:     public VirtualLayer(IntSize size) {
michael@0:         super(size);
michael@0:     }
michael@0: 
michael@0:     @Override
michael@0:     public void draw(RenderContext context) {
michael@0:         // No-op.
michael@0:     }
michael@0: 
michael@0:     void setPositionAndResolution(int left, int top, int right, int bottom, float newResolution) {
michael@0:         // This is an optimized version of the following code:
michael@0:         // beginTransaction();
michael@0:         // try {
michael@0:         //     setPosition(new Rect(left, top, right, bottom));
michael@0:         //     setResolution(newResolution);
michael@0:         //     performUpdates(null);
michael@0:         // } finally {
michael@0:         //     endTransaction();
michael@0:         // }
michael@0: 
michael@0:         // it is safe to drop the transaction lock in this instance (i.e. for the
michael@0:         // VirtualLayer that is just a shadow of what gecko is painting) because
michael@0:         // the position and resolution of this layer are always touched on the compositor
michael@0:         // thread, and therefore do not require synchronization.
michael@0:         mPosition.set(left, top, right, bottom);
michael@0:         mResolution = newResolution;
michael@0:     }
michael@0: }