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Open HTML to PDF is a CSS 2.1 renderer written in Java. This artifact contains the core rendering and layout code.
package com.openhtmltopdf.test;
import org.w3c.dom.Element;
import com.openhtmltopdf.extend.FSImage;
import com.openhtmltopdf.extend.ReplacedElement;
import com.openhtmltopdf.extend.UserAgentCallback;
import com.openhtmltopdf.layout.LayoutContext;
import com.openhtmltopdf.render.BlockBox;
import com.openhtmltopdf.swing.AWTFSImage;
import com.openhtmltopdf.swing.EmptyReplacedElement;
import com.openhtmltopdf.swing.ImageReplacedElement;
import com.openhtmltopdf.util.ImageUtil;
import com.openhtmltopdf.util.XRLog;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.logging.Level;
import java.util.*;
import java.util.List;
/**
* @author patrick
*/
public class SwingImageReplacer extends ElementReplacer {
private final Map imageComponents;
public SwingImageReplacer() {
imageComponents = new HashMap();
}
public boolean isElementNameMatch() {
return true;
}
public String getElementNameMatch() {
return "img";
}
public boolean accept(final LayoutContext context, final Element element) {
return context.getNamespaceHandler().isImageElement(element);
}
public ReplacedElement replace(LayoutContext context, BlockBox box, UserAgentCallback uac, int cssWidth, int cssHeight) {
return replaceImage(uac, context, box.getElement(), cssWidth, cssHeight);
}
public void clear(Element element) {
System.out.println("*** cleared image components for element " + element);
imageComponents.remove(element);
}
public void reset() {
System.out.println("*** cleared image componentes");
imageComponents.clear();
}
/**
* Handles replacement of image elements in the document. May return the same ReplacedElement for a given image
* on multiple calls. Image will be automatically scaled to cssWidth and cssHeight assuming these are non-zero
* positive values. The element is assume to have a src attribute (e.g. it's an <img> element)
*
* @param uac Used to retrieve images on demand from some source.
* @param context
* @param elem The element with the image reference
* @param cssWidth Target width of the image
* @param cssHeight Target height of the image @return A ReplacedElement for the image; will not be null.
*/
protected ReplacedElement replaceImage(UserAgentCallback uac, LayoutContext context, Element elem, int cssWidth, int cssHeight) {
ReplacedElement re = null;
// lookup in cache, or instantiate
re = lookupImageReplacedElement(elem);
if (re == null) {
Image im = null;
String imageSrc = context.getNamespaceHandler().getImageSourceURI(elem);
if (imageSrc == null || imageSrc.length() == 0) {
XRLog.layout(Level.WARNING, "No source provided for img element.");
re = newIrreplaceableImageElement(cssWidth, cssHeight);
} else {
//FSImage is here since we need to capture a target H/W
//for the image (as opposed to what the actual image size is).
FSImage fsImage = uac.getImageResource(imageSrc).getImage();
if (fsImage != null) {
im = ((AWTFSImage) fsImage).getImage();
}
if (im != null) {
re = new ImageReplacedElement(im, cssWidth, cssHeight);
} else {
// TODO: Should return "broken" image icon, e.g. "not found"
re = newIrreplaceableImageElement(cssWidth, cssHeight);
}
}
storeImageReplacedElement(elem, re);
}
return re;
}
/**
* Adds a ReplacedElement containing an image to a cache of images for quick lookup.
*
* @param e The element under which the image is keyed.
* @param cc The replaced element containing the image, or another ReplacedElement to be used in its place
* (like a placeholder if the image can't be loaded).
*/
protected void storeImageReplacedElement(Element e, ReplacedElement cc) {
System.out.println("\n*** Cached image for element");
imageComponents.put(e, cc);
}
/**
* Retrieves a ReplacedElement for an image from cache, or null if not found.
*
* @param e The element by which the image is keyed
* @return The ReplacedElement for the image, or null if there is none.
*/
protected ReplacedElement lookupImageReplacedElement(Element e) {
if (imageComponents.size() == 0) {
return null;
}
ReplacedElement replacedElement = (ReplacedElement) imageComponents.get(e);
return replacedElement;
}
/**
* Returns a ReplacedElement for some element in the stream which should be replaceable, but is not. This might
* be the case for an element like img, where the source isn't provided.
*
* @param cssWidth Target width for the element.
* @param cssHeight Target height for the element
* @return A ReplacedElement to substitute for one that can't be generated.
*/
protected ReplacedElement newIrreplaceableImageElement(int cssWidth, int cssHeight) {
BufferedImage missingImage = null;
ReplacedElement mre;
try {
// TODO: we can come up with something better; not sure if we should use Alt text, how text should size, etc.
missingImage = ImageUtil.createCompatibleBufferedImage(cssWidth, cssHeight, BufferedImage.TYPE_INT_RGB);
Graphics2D g = missingImage.createGraphics();
g.setColor(Color.BLACK);
g.setBackground(Color.WHITE);
g.setFont(new Font("Serif", Font.PLAIN, 12));
g.drawString("Missing", 0, 12);
g.dispose();
mre = new ImageReplacedElement(missingImage, cssWidth, cssHeight);
} catch (Exception e) {
mre = new EmptyReplacedElement(
cssWidth < 0 ? 0 : cssWidth,
cssHeight < 0 ? 0 : cssHeight);
}
return mre;
}
}