GUIDrawable.java

/**
 * Copyright 2012 52°North Initiative for Geospatial Open Source Software GmbH
 *
 * 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 org.n52.geoar.ar.view.overlay;

import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.RectF;

public abstract class GUIDrawable {

	protected RectF drawableArea;

	public GUIDrawable(RectF area) {
		this.drawableArea = area;
	}

	public void onRenderCanvas(Canvas canvas) {
		canvas.save(Canvas.MATRIX_SAVE_FLAG);
		onRender(canvas);
		canvas.restore();
	}
	
	protected void setFocusToDrawingArea(Canvas canvas){
		Matrix m = new Matrix();
		m.setTranslate(drawableArea.left, drawableArea.top);
		canvas.setMatrix(m);
	}

	protected void setScaleAndFocusToDrawingArea(Canvas canvas) {
		Matrix m = new Matrix();
		m.setScale(drawableArea.bottom - drawableArea.top, drawableArea.right
				- drawableArea.right);
		m.setTranslate(drawableArea.left, drawableArea.top);
		canvas.setMatrix(m);
	}

	protected abstract void initDrawingTools();

	protected abstract void onRender(Canvas canvas);
}