org.apache.fop.render.awt.viewer.ImageProxyPanel Maven / Gradle / Ivy
/*
* 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.
*/
/* $Id: ImageProxyPanel.java 1681435 2015-05-24 11:14:22Z adelmelle $ */
package org.apache.fop.render.awt.viewer;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Insets;
import java.awt.image.BufferedImage;
import java.lang.ref.Reference;
import java.lang.ref.SoftReference;
import javax.swing.JPanel;
import org.apache.fop.apps.FOPException;
import org.apache.fop.render.awt.AWTRenderer;
/**
* Panel used to display a single page of a document.
* This is basically a lazy-load display panel which
* gets the size of the image for layout purposes but
* doesn't get the actual image data until needed.
* The image data is then accessed via a soft reference,
* so it will be garbage collected when moving through
* large documents.
*/
public class ImageProxyPanel extends JPanel {
/** The reference to the BufferedImage storing the page data */
private transient Reference imageRef;
/** The maximum and preferred size of the panel */
private Dimension size;
/** The renderer. Shared with PreviewPanel and PreviewDialog. */
private AWTRenderer renderer;
/** The page to be rendered. */
private int page;
/**
* Panel constructor. Doesn't allocate anything until needed.
* @param renderer the AWTRenderer instance to use for painting
* @param page initial page number to show
*/
public ImageProxyPanel(AWTRenderer renderer, int page) {
this.renderer = renderer;
this.page = page;
try {
Dimension size = renderer.getPageImageSize(page);
Insets insets = getInsets();
size.width += insets.left + insets.right;
size.height += insets.top + insets.bottom;
this.size = size;
} catch (Exception e) {
this.size = new Dimension(10, 10);
}
// Allows single panel to appear behind page display.
// Important for textured L&Fs.
setOpaque(false);
}
/**
* @return the size of the page plus the border.
*/
public Dimension getMinimumSize() {
return getPreferredSize();
}
/**
* @return the size of the page plus the border.
*/
public Dimension getPreferredSize() {
return size;
}
/**
* Sets the number of the page to be displayed and refreshes the display.
* @param pg the page number
*/
public synchronized void setPage(int pg) {
if (page != pg) {
page = pg;
imageRef = null;
repaint();
}
}
/**
* Gets the image data and paints it on screen. Will make
* calls to getPageImage as required.
* @param graphics a graphics context
* @see javax.swing.JComponent#paintComponent(Graphics)
* @see org.apache.fop.render.java2d.Java2DRenderer#getPageImage(int)
*/
public synchronized void paintComponent(Graphics graphics) {
try {
if (isOpaque()) { //paint background
graphics.setColor(getBackground());
graphics.fillRect(0, 0, getWidth(), getHeight());
}
super.paintComponent(graphics);
BufferedImage image = null;
if (imageRef == null || imageRef.get() == null) {
image = renderer.getPageImage(page);
imageRef = new SoftReference(image);
} else {
image = (BufferedImage)imageRef.get();
}
if (image != null) {
int x = (getWidth() - image.getWidth()) / 2;
int y = (getHeight() - image.getHeight()) / 2;
graphics.drawImage(image, x, y, image.getWidth(), image.getHeight(), null);
}
} catch (FOPException fopEx) {
fopEx.printStackTrace();
}
}
}