src/java/org/apache/poi/sl/draw/DrawSheet.java

/* ====================================================================
   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You 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.apache.poi.sl.draw;

import java.awt.Dimension;
import java.awt.Color;
import java.awt.Graphics2D;

import java.awt.geom.AffineTransform;

import org.apache.poi.sl.usermodel.*;


public class DrawSheet<T extends Sheet<? extends Shape, ? extends SlideShow>> implements Drawable {

    protected final T sheet;
    
    public DrawSheet(T sheet) {
        this.sheet = sheet;
    }
    
    public void draw(Graphics2D graphics) {
        Dimension dim = sheet.getSlideShow().getPageSize();
        Color whiteTrans = new Color(1f,1f,1f,0f);
        graphics.setColor(whiteTrans);
        graphics.fillRect(0, 0, (int)dim.getWidth(), (int)dim.getHeight());
        
        DrawFactory drawFact = DrawFactory.getInstance(graphics);
        MasterSheet<? extends Shape, ? extends SlideShow> master = sheet.getMasterSheet();
        
        if(sheet.getFollowMasterGraphics() && master != null) {
            Drawable drawer = drawFact.getDrawable(master);
            drawer.draw(graphics);
        }
        
        graphics.setRenderingHint(Drawable.GROUP_TRANSFORM, new AffineTransform());

        for (Shape shape : sheet.getShapes()) {
            if(!canDraw(shape)) continue;
            
            // remember the initial transform and restore it after we are done with drawing
            AffineTransform at = graphics.getTransform();

            // concrete implementations can make sense of this hint,
            // for example PSGraphics2D or PDFGraphics2D would call gsave() / grestore
            graphics.setRenderingHint(Drawable.GSAVE, true);

            // apply rotation and flipping
            Drawable drawer = drawFact.getDrawable(shape);
            drawer.applyTransform(graphics);
            // draw stuff
            drawer.draw(graphics);

            // restore the coordinate system
            graphics.setTransform(at);

            graphics.setRenderingHint(Drawable.GRESTORE, true);
        }
    }

    public void applyTransform(Graphics2D context) {
    }

    public void drawContent(Graphics2D context) {
    }

    /**
     * Checks if this <code>sheet</code> displays the specified shape.
     *
     * Subclasses can override it and skip certain shapes from drawings,
     * for instance, slide masters and layouts don't display placeholders
     */
    protected boolean canDraw(Shape shape){
        return true;
    }
}