我使用蜡染处理SVG图像。 有没有什么办法让从SVG文件一个java.awt.image.BufferedImage？
我知道有转码器，有了它我就能转码成SVG，例如，一个PNG然后加载PNG与ImageIO.read（）·但我不希望有临时文件。
Answer 1:
使用蜡染 ，是这样的：
public static BufferedImage rasterize(File svgFile) throws IOException {
final BufferedImage[] imagePointer = new BufferedImage[1];
// Rendering hints can't be set programatically, so
// we override defaults with a temporary stylesheet.
// These defaults emphasize quality and precision, and
// are more similar to the defaults of other SVG viewers.
// SVG documents can still override these defaults.
String css = "svg {" +
"shape-rendering: geometricPrecision;" +
"text-rendering: geometricPrecision;" +
"color-rendering: optimizeQuality;" +
"image-rendering: optimizeQuality;" +
"}";
File cssFile = File.createTempFile("batik-default-override-", ".css");
FileUtils.writeStringToFile(cssFile, css);
TranscodingHints transcoderHints = new TranscodingHints();
transcoderHints.put(ImageTranscoder.KEY_XML_PARSER_VALIDATING, Boolean.FALSE);
transcoderHints.put(ImageTranscoder.KEY_DOM_IMPLEMENTATION,
SVGDOMImplementation.getDOMImplementation());
transcoderHints.put(ImageTranscoder.KEY_DOCUMENT_ELEMENT_NAMESPACE_URI,
SVGConstants.SVG_NAMESPACE_URI);
transcoderHints.put(ImageTranscoder.KEY_DOCUMENT_ELEMENT, "svg");
transcoderHints.put(ImageTranscoder.KEY_USER_STYLESHEET_URI, cssFile.toURI().toString());
try {
TranscoderInput input = new TranscoderInput(new FileInputStream(svgFile));
ImageTranscoder t = new ImageTranscoder() {
@Override
public BufferedImage createImage(int w, int h) {
return new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
}
@Override
public void writeImage(BufferedImage image, TranscoderOutput out)
throws TranscoderException {
imagePointer[0] = image;
}
};
t.setTranscodingHints(transcoderHints);
t.transcode(input, null);
}
catch (TranscoderException ex) {
// Requires Java 6
ex.printStackTrace();
throw new IOException("Couldn't convert " + svgFile);
}
finally {
cssFile.delete();
}
return imagePointer[0];
}
Answer 2:
一个非常简单的方法是使用LIB TwelveMonkeys其Java的增加了额外的图像类型支持ImageIO
因此，例如，你只需要添加这些到你的Maven（或复制需要的jar文件）：
<dependency>
<groupId>com.twelvemonkeys.imageio</groupId>
<artifactId>imageio-batik</artifactId> <!-- svg -->
<version>3.2.1</version>
</dependency>
<dependency>
<groupId>batik</groupId>
<artifactId>batik-transcoder</artifactId>
<version>1.6-1</version>
</dependency>
然后你刚才读它
BufferedImage image = ImageIO.read(svg-file);
要检查SVG读者正确注册，你可以打印出图片的读者：
Iterator<ImageReader> readers = ImageIO.getImageReadersByFormatName("SVG");
while (readers.hasNext()) {
System.out.println("reader: " + readers.next());
}
的lib还支持其他参数，可以看到在github自述 。
Answer 3:
这是我使用。 这是BufferedImage的一个扩展都有自己的静态工厂无论是使用BufferedImage，它可以使用。 我写它，以便于getScaledInstance任何呼叫（W，H，提示）将从SVG，没有栅格图像渲染。 这方面的一个副作用是，缩放提示参数没有任何意义; 你可以通过0或默认使用。 它使得懒洋洋地-只有当图形数据请求-这样的负载/规模循环不应该给你太多的开销。
编辑：我使用上述CSS配置缩放质量提示增加了支持。 编辑2：懒惰的渲染并没有始终如一地工作; 我把渲染（）调用到构造。
它具有以下依存关系：
- org.apache.xmlgraphics：蜡染阿尼姆
- org.apache.xmlgraphics：蜡染桥
- org.apache.xmlgraphics：蜡染GVT
- org.apache.xmlgraphics：蜡染代码转换器
- org.apache.xmlgraphics：蜡染UTIL
- XML的API：XML的API-EXT
- 共享记录：共享记录
当我做了这个，我用蜡染1.8; 因人而异。
import java.awt.AlphaComposite;
import java.awt.Composite;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.awt.image.Raster;
import java.awt.image.WritableRaster;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
import org.apache.batik.anim.dom.SAXSVGDocumentFactory;
import org.apache.batik.bridge.BridgeContext;
import org.apache.batik.bridge.DocumentLoader;
import org.apache.batik.bridge.GVTBuilder;
import org.apache.batik.bridge.UserAgent;
import org.apache.batik.bridge.UserAgentAdapter;
import org.apache.batik.gvt.GraphicsNode;
import org.apache.batik.transcoder.TranscoderException;
import org.apache.batik.transcoder.TranscoderInput;
import org.apache.batik.transcoder.TranscoderOutput;
import org.apache.batik.transcoder.TranscodingHints;
import org.apache.batik.transcoder.image.ImageTranscoder;
import org.apache.batik.util.SVGConstants;
import org.apache.batik.util.XMLResourceDescriptor;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.w3c.dom.svg.SVGDocument;
public class SVGImage extends BufferedImage {
private static class BufferedImageTranscoder extends ImageTranscoder {
private BufferedImage image = null;
@Override
public BufferedImage createImage(int arg0, int arg1) {
return image;
}
private void setImage(BufferedImage image) {
this.image = image;
}
@Override
public void writeImage(BufferedImage arg0, TranscoderOutput arg1) throws TranscoderException {
}
}
final static GVTBuilder builder = new GVTBuilder();
final static SAXSVGDocumentFactory factory = new SAXSVGDocumentFactory(XMLResourceDescriptor.getXMLParserClassName());
final static UserAgent userAgent = new UserAgentAdapter();
final static DocumentLoader loader = new DocumentLoader(userAgent);
final static BridgeContext bridgeContext = new BridgeContext(userAgent, loader);
static {
bridgeContext.setDynamicState(BridgeContext.STATIC);
}
final static private Log log = LogFactory.getLog(SVGImage.class);
private static final Map<Integer, String> scaleQuality = new HashMap<Integer, String>();
static {
String css = "svg {" +
"shape-rendering: %s;" +
"text-rendering: %s;" +
"color-rendering: %s;" +
"image-rendering: %s;" +
"}";
String precise = "geometricPrecision";
String quality = "optimizeQuality";
String speed = "optimizeSpeed";
String crisp = "crispEdges";
String legible = "optimizeLegibility";
String auto = "auto";
scaleQuality.put(SCALE_DEFAULT, String.format(css, auto, auto, auto, auto));
scaleQuality.put(SCALE_SMOOTH, String.format(css, precise, precise, quality, quality));
scaleQuality.put(SCALE_REPLICATE, String.format(css, speed, speed, speed, speed));
scaleQuality.put(SCALE_AREA_AVERAGING, String.format(css, crisp, legible, auto, auto));
scaleQuality.put(SCALE_FAST, String.format(css, speed, speed, speed, speed));
}
final static BufferedImageTranscoder transcoder = new BufferedImageTranscoder();
public static SVGImage fromSvg(URL resource) throws IOException {
InputStream rs = null;
try {
rs = resource.openStream();
SVGDocument svg = factory.createSVGDocument(resource.toString(), rs);
return fromSvgDocument(resource, svg);
} finally {
if (rs != null) {
try { rs.close(); } catch (IOException ioe) {}
}
}
}
public static SVGImage fromSvgDocument(URL resource, SVGDocument doc) {
GraphicsNode graphicsNode = builder.build(bridgeContext, doc);
Double width = graphicsNode.getBounds().getWidth();
Double height = graphicsNode.getBounds().getHeight();
return new SVGImage(resource, doc, width.intValue(), height.intValue(), SCALE_DEFAULT);
}
boolean hasRendered = false;
private int scalingHint = SCALE_DEFAULT;
final SVGDocument svg;
final URL svgUrl;
private SVGImage(URL resource, SVGDocument doc, int width, int height, int hints) {
super(width, height, TYPE_INT_ARGB);
scalingHint = hints;
svgUrl = resource;
svg = doc;
render();
}
@Override
public void coerceData(boolean isAlphaPremultiplied) {
if (!hasRendered) { render(); }
super.coerceData(isAlphaPremultiplied);
}
@Override
public WritableRaster copyData(WritableRaster outRaster) {
if (!hasRendered) { render(); }
return super.copyData(outRaster);
}
private File createCSS(String css) {
FileWriter cssWriter = null;
File cssFile = null;
try {
cssFile = File.createTempFile("batik-default-override-", ".css");
cssFile.deleteOnExit();
cssWriter = new FileWriter(cssFile);
cssWriter.write(css);
} catch(IOException ioe) {
log.warn("Couldn't write stylesheet; SVG rendered with Batik defaults");
} finally {
if (cssWriter != null) {
try {
cssWriter.flush();
cssWriter.close();
} catch (IOException ioe) {}
}
}
return cssFile;
}
@Override
public WritableRaster getAlphaRaster() {
if (!hasRendered) { render(); }
return super.getAlphaRaster();
}
@Override
public Raster getData() {
if (!hasRendered) { render(); }
return super.getData();
}
@Override
public Graphics getGraphics() {
if (!hasRendered) { render(); }
return super.getGraphics();
}
public Image getScaledInstance(int width, int height, int hints) {
SVGImage newImage = new SVGImage(svgUrl, svg, width, height, hints);
return newImage;
}
private void render() {
TranscodingHints hints = new TranscodingHints();
hints.put(ImageTranscoder.KEY_WIDTH, new Float(getWidth()));
hints.put(ImageTranscoder.KEY_HEIGHT, new Float(getHeight()));
hints.put(ImageTranscoder.KEY_XML_PARSER_VALIDATING, Boolean.FALSE);
hints.put(ImageTranscoder.KEY_DOM_IMPLEMENTATION, svg.getImplementation());
hints.put(ImageTranscoder.KEY_DOCUMENT_ELEMENT_NAMESPACE_URI, SVGConstants.SVG_NAMESPACE_URI);
hints.put(ImageTranscoder.KEY_DOCUMENT_ELEMENT, "svg");
String css = scaleQuality.get(scalingHint);
File cssFile = null;
if (css != null) {
cssFile = createCSS(css);
if (cssFile != null) {
hints.put(ImageTranscoder.KEY_USER_STYLESHEET_URI, cssFile.toURI().toString());
}
}
transcoder.setTranscodingHints(hints);
transcoder.setImage(this);
// This may be a re-render, if the scaling quality hint has changed.
// As such, we force the image into overwrite mode, and kick it back when we're done / fail
Graphics2D gfx = (Graphics2D) super.getGraphics();
Composite savedComposite = gfx.getComposite();
gfx.setComposite(AlphaComposite.Clear);
try {
transcoder.transcode(new TranscoderInput(svg), null);
hasRendered = true;
} catch (TranscoderException te) {
log.warn("Could not transcode " + svgUrl.getPath() + " to raster image; you're going to get a blank BufferedImage of the correct size.");
} finally {
gfx.setComposite(savedComposite);
if (cssFile != null) {
cssFile.delete();
}
}
}
public void setScalingHint(int hint) {
this.scalingHint = hint;
// Forces a re-render
this.hasRendered = false;
}
}
文章来源: How to get a BufferedImage from a SVG?
