playn.html.HtmlCanvasLayerCanvas.java Source code

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Here is the source code for playn.html.HtmlCanvasLayerCanvas.java

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/**
 * Copyright 2011 The PlayN Authors
 * 
 * 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 playn.html;

import com.google.gwt.canvas.dom.client.Context2d;
import com.google.gwt.dom.client.CanvasElement;
import com.google.gwt.dom.client.Document;

import playn.core.Asserts;

import playn.core.Canvas;
import playn.core.CanvasLayer;

class HtmlCanvasLayerCanvas extends HtmlLayerCanvas implements CanvasLayer {

    private HtmlCanvas canvas;

    HtmlCanvasLayerCanvas(int width, int height) {
        CanvasElement canvas = Document.get().createCanvasElement();
        canvas.setWidth(width);
        canvas.setHeight(height);

        this.canvas = new HtmlCanvas(canvas, width, height);
    }

    @Override
    public void destroy() {
        super.destroy();
        canvas = null;
    }

    @Override
    public Canvas canvas() {
        return canvas;
    }

    @Override
    public float width() {
        Asserts.checkNotNull(canvas, "Canvas must not be null");
        return canvas.width();
    }

    @Override
    public float height() {
        Asserts.checkNotNull(canvas, "Canvas must not be null");
        return canvas.height();
    }

    @Override
    public float scaledWidth() {
        return transform().scaleX() * width();
    }

    @Override
    public float scaledHeight() {
        return transform().scaleY() * height();
    }

    @Override
    void paint(Context2d ctx, float parentAlpha) {
        ctx.save();
        transform(ctx);

        ctx.setGlobalAlpha(parentAlpha * alpha);
        ctx.drawImage(canvas.canvas(), 0, 0);

        ctx.restore();
    }
}