FrameRenderer.java

package com.xenoage.zong.renderer.frames;

import com.xenoage.utils.math.Units;
import com.xenoage.utils.math.geom.Point2f;
import com.xenoage.utils.math.geom.Rectangle2f;
import com.xenoage.zong.layout.frames.Frame;
import com.xenoage.zong.renderer.RendererArgs;
import com.xenoage.zong.renderer.canvas.Canvas;

/**
 * Abstract renderer class for one type of {@link Frame}.
 * 
 * @author Andreas Wenger
 */
public abstract class FrameRenderer {

	/**
	 * Paints the given {@link Frame} on the
	 * given {@link Canvas} using the given {@link RendererArgs}.
	 */
	public void paint(Frame frame, Canvas canvas, RendererArgs args) {
		//backup old transformation
		canvas.transformSave();
		//apply translation: origin offset in screen space
		canvas.transformTranslate(args.offsetPx.x, args.offsetPx.y);
		//apply scaling
		float scaling = Units.mmToPx(args.scaling, 1);
		canvas.transformScale(scaling, scaling);
		//apply translation: absolute frame position in layout space
		Point2f pos = frame.getAbsolutePosition();
		canvas.transformTranslate(pos.x, pos.y);
		//apply rotation
		canvas.transformRotate(-frame.getAbsoluteRotation());

		//if there is a background, draw it
		if (frame.getBackground() != null) {
			Rectangle2f rect = getLocalRect(frame);
			canvas.fillRect(rect, frame.getBackground());
		}

		//paint the frame
		paintTransformed(frame, canvas, args);

		//restore old transformation
		canvas.transformRestore();
	}

	/**
	 * Paints the given {@link Frame} on the
	 * given {@link Canvas} using the given {@link RendererArgs}.
	 * This method is called by the {@link #paint(Frame, Canvas, RendererArgs)}
	 * method, the transformations are alread done. When painting, 1 unit corresponds
	 * to 1 mm, and the center point is in the middle of the frame.
	 */
	protected abstract void paintTransformed(Frame frame, Canvas canvas, RendererArgs args);
	
	protected Rectangle2f getLocalRect(Frame frame) {
		float x = frame.getSize().width;
		float y = frame.getSize().height;
		Rectangle2f rect = new Rectangle2f(-x/2, -y/2, x, y);
		return rect;
	}

}