Fix relative background image

flying-saucer-core/src/main/java/org/xhtmlrenderer/simple/ImageRenderer.java

@@ -0,0 +1,95 @@
+/*
+ * {{{ header & license
+ * Copyright (c) 2007 Patrick Wright
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * }}}
+ */
+package org.xhtmlrenderer.simple;
+
+import org.xhtmlrenderer.swing.Java2DRenderer;
+import org.xhtmlrenderer.util.FSImageWriter;
+
+import java.awt.image.BufferedImage;
+import java.io.BufferedOutputStream;
+import java.io.File;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.net.URL;
+import java.nio.file.Paths;
+
+import static java.nio.file.Files.newOutputStream;
+
+/**
+ * <p>
+ * ImageRenderer supports rendering of XHTML documents to image formats, writing out the generated image to an output stream
+ * or a file in a given image format. There are two static utility methods, one for rendering
+ * a {@link java.net.URL}, {@link #renderToImage(String, String, int)} and one
+ * for rendering a {@link java.io.File}, {@link #renderToImage(File, String, int)}</p>
+ *
+ * <p>You can use this utility from the command line by passing in
+ * the URL or file location as first parameter, and output file path as second
+ * parameter:
+ * <pre>{@code
+ * java -cp %classpath% org.xhtmlrenderer.simple.ImageRenderer <url> <img>
+ * }</pre>
+ * <p>If the second parameters is not provided, a PNG-format image will be created
+ * in the same directory as the source (if source is a file) or as a temp file
+ * in the standard temp directory; the output file name will be printed out
+ * in either case.</p>
+ *
+ * <p>Image width must always be supplied; height is determined automatically.</p>
+ *
+ * @author Pete Brant
+ * @author Patrick Wright
+ */
+public class ImageRenderer {
+    /**
+     * Renders the XML file at the given URL as an image file at the target location. Width must be provided,
+     * height is determined automatically based on content and CSS.
+     *
+     * @param url	 url for the XML file to render
+     * @param path path to the PDF file to create
+     * @param width Width in pixels to which the document should be constrained.
+     *
+     * @throws java.io.IOException if the input URL, or output path location is invalid
+     */
+    public static BufferedImage renderToImage(String url, String path, int width) throws IOException {
+        try (OutputStream os = new BufferedOutputStream(newOutputStream(Paths.get(path)))) {
+            Java2DRenderer renderer = new Java2DRenderer(url, url, width);
+            BufferedImage image = renderer.getImage();
+            new FSImageWriter().write(image, os);
+            return image;
+        }
+    }
+
+    /**
+     * Renders the XML file as an image file at the target location. Width must be provided, height is determined
+     * automatically based on content and CSS.
+     *
+     * @param xhtmlFile  XML file to render
+     * @param path path to the image file to create
+     * @param width Width in pixels to which the document should be constrained.
+     *
+     * @throws java.io.IOException if the input URL, or output path location is invalid
+     */
+    public static BufferedImage renderToImage(File xhtmlFile, String path, int width) throws IOException {
+        return renderToImage(xhtmlFile.toURI().toURL().toExternalForm(), path, width);
+    }
+
+    public static BufferedImage renderToImage(URL xhtmlUrl, String path, int width) throws IOException {
+        return renderToImage(xhtmlUrl.toExternalForm(), path, width);
+    }
+}

flying-saucer-core/src/main/java/org/xhtmlrenderer/swing/Java2DRenderer.java

@@ -353,10 +353,14 @@ public boolean isFocus(Element e) {
 
     public static BufferedImage htmlAsImage(String html, int widthInPixels) throws SAXException {
         try (InputStream in = new ByteArrayInputStream(html.getBytes(UTF_8))) {
-            Document document = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(in);
-            return new Java2DRenderer(document, widthInPixels).getImage();
+            return htmlAsImage(in, widthInPixels);
         } catch (IOException | ParserConfigurationException e) {
             throw new RuntimeException(e);
         }
     }
+
+    public static BufferedImage htmlAsImage(InputStream source, int widthInPixels) throws SAXException, IOException, ParserConfigurationException {
+        Document document = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(source);
+        return new Java2DRenderer(document, widthInPixels).getImage();
+    }
 }

flying-saucer-core/src/main/java/org/xhtmlrenderer/util/FSImageWriter.java

@@ -0,0 +1,177 @@
+/*
+ * {{{ header & license
+ * Copyright (c) 2007 Patrick Wright
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * }}}
+ */
+package org.xhtmlrenderer.util;
+
+import org.jspecify.annotations.Nullable;
+
+import javax.imageio.IIOImage;
+import javax.imageio.ImageIO;
+import javax.imageio.ImageWriteParam;
+import javax.imageio.ImageWriter;
+import javax.imageio.stream.ImageOutputStream;
+import java.awt.image.BufferedImage;
+import java.io.BufferedOutputStream;
+import java.io.File;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.Iterator;
+
+import static java.nio.file.Files.newOutputStream;
+
+/**
+ * <p>Writes out BufferedImages to some output stream, like a file. Allows image writer parameters to be specified and
+ * thus controlled. Uses the java ImageIO libraries--see {@link javax.imageio.ImageIO} and related classes,
+ * especially {@link javax.imageio.ImageWriter}.</p>
+ * <p>
+ * By default, FSImageWriter writes BufferedImages out in PNG format. The simplest possible usage is
+ * <pre>
+ * FSImageWriter writer = new FSImageWriter();
+ * writer.write(img, new File("image.png"));
+ * </pre>
+ * <p>
+ * <p>You can set the image format in the constructor ({@link org.xhtmlrenderer.util.FSImageWriter#FSImageWriter(String)},
+ * and can set compression settings using various setters; this lets you create writer to reuse across a number
+ * of images, all output at the same compression level. Note that not all image formats support compression. For
+ * those that do, you may need to set more than one compression setting, in combination, for it to work. For JPG,
+ * it might look like this</p>
+ * <pre>
+ *      writer = new FSImageWriter("jpg");
+ * 		writer.setWriteCompressionMode(ImageWriteParam.MODE_EXPLICIT);
+ * 		writer.setWriteCompressionType("JPEG");
+ * 		writer.setWriteCompressionQuality(.75f);
+ * </pre>
+ */
+public class FSImageWriter {
+    private final String imageFormat;
+    private final float writeCompressionQuality;
+    private final int writeCompressionMode;
+    @Nullable
+    private final String writeCompressionType;
+
+    /**
+     * New image writer for the PNG image format
+     */
+    public FSImageWriter() {
+        this("png");
+    }
+
+    /**
+     * New writer for a given image format, using the informal format name.
+     *
+     * @param imageFormat Informal image format name, e.g. "jpg", "png", "bmp"; usually the part that appears
+     *                    as the file extension.
+     */
+    public FSImageWriter(String imageFormat) {
+        this.imageFormat = imageFormat;
+        this.writeCompressionMode = ImageWriteParam.MODE_COPY_FROM_METADATA;
+        this.writeCompressionType = null;
+        this.writeCompressionQuality = 1.0f;
+    }
+
+    /**
+     * Writes the image out to the target file, creating the file if necessary, or overwriting if it already
+     * exists.
+     *
+     * @param image     Image to write.
+     * @param filePath Path for file to write. The extension for the file name is not changed; it is up to the
+     *                 caller to make sure this corresponds to the image format.
+     * @throws IOException If the file could not be written.
+     */
+    public void write(BufferedImage image, String filePath) throws IOException {
+        File file = new File(filePath);
+        if (file.exists()) {
+            if (!file.delete()) {
+                throw new IOException("File " + filePath + " exists already, and call to .delete() failed " +
+                        "unexpectedly");
+            }
+        } else {
+            if (!file.createNewFile()) {
+                throw new IOException("Unable to create file at path " + filePath + ", call to .createNewFile() " +
+                        "failed unexpectedly.");
+            }
+        }
+
+        try (OutputStream fos = new BufferedOutputStream(newOutputStream(file.toPath()))) {
+            write(image, fos);
+        }
+    }
+
+    /**
+     * Writes the image out to the target file, creating the file if necessary, or overwriting if it already
+     * exists.
+     *
+     * @param image     Image to write.
+     * @param os output stream to write to
+     * @throws IOException If the file could not be written.
+     */
+    public void write(BufferedImage image, OutputStream os) throws IOException {
+        ImageWriter writer = lookupImageWriterForFormat(imageFormat);
+
+        try (ImageOutputStream ios = ImageIO.createImageOutputStream(os)) {
+            writer.setOutput(ios);
+            ImageWriteParam parameters = getImageWriteParameters(writer);
+
+            writer.write(null, new IIOImage(image, null, null), parameters);
+            ios.flush();
+        } finally {
+            writer.dispose();
+        }
+    }
+
+    /**
+     * Returns the image output parameters to control the output image quality, compression, etc. By default,
+     * this uses the compression values set in this class. Override this method to get full control over the
+     * ImageWriteParam used in image output.
+     *
+     * @param writer The ImageWriter we are going to use for image output.
+     * @return ImageWriteParam configured for image output.
+     */
+    protected ImageWriteParam getImageWriteParameters(ImageWriter writer) {
+        ImageWriteParam param = writer.getDefaultWriteParam();
+        if (param.canWriteCompressed()) {
+            if (writeCompressionMode != ImageWriteParam.MODE_COPY_FROM_METADATA) {
+                param.setCompressionMode(writeCompressionMode);
+
+                // see docs for IWP--only allowed to set type and quality if mode is EXPLICIT
+                if (writeCompressionMode == ImageWriteParam.MODE_EXPLICIT) {
+                    param.setCompressionType(writeCompressionType);
+                    param.setCompressionQuality(writeCompressionQuality);
+                }
+
+            }
+        }
+
+        return param;
+    }
+
+    /**
+     * Utility method to find an image writer.
+     *
+     * @param imageFormat String informal format name, "jpg"
+     * @return ImageWriter corresponding to that format
+     */
+    private ImageWriter lookupImageWriterForFormat(String imageFormat) {
+        Iterator<ImageWriter> iter = ImageIO.getImageWritersByFormatName(imageFormat);
+        if (iter.hasNext()) {
+            return iter.next();
+        }
+        throw new IllegalArgumentException("Image writer not found for format " + imageFormat);
+    }
+}

flying-saucer-core/src/test/java/org/xhtmlrenderer/simple/ImageRendererTest.java

@@ -0,0 +1,24 @@
+package org.xhtmlrenderer.simple;
+
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.awt.image.BufferedImage;
+import java.io.File;
+
+import static java.util.Objects.requireNonNull;
+import static org.assertj.core.api.Assertions.assertThat;
+
+class ImageRendererTest {
+    private static final Logger log = LoggerFactory.getLogger(ImageRendererTest.class);
+
+    @Test
+    public void backgroundImageWithRelativePath() throws Exception {
+        File result = new File("target/%s.png".formatted(getClass().getSimpleName()));
+        BufferedImage image = ImageRenderer.renderToImage(requireNonNull(getClass().getResource("/text-with-background-image.xhtml")), result.getAbsolutePath(), 600);
+        assertThat(image.getWidth()).isEqualTo(600);
+        assertThat(image.getHeight()).isBetween(100, 200);
+        log.info("Generated image from html: {}", result.getAbsolutePath());
+    }
+}

flying-saucer-core/src/test/java/org/xhtmlrenderer/swing/QuotingExampleTest.java

@@ -8,38 +8,15 @@
 import java.awt.image.BufferedImage;
 import java.io.File;
 
+import static java.util.Objects.requireNonNull;
 import static org.xhtmlrenderer.swing.Java2DRenderer.htmlAsImage;
 
 public class QuotingExampleTest {
     private static final Logger log = LoggerFactory.getLogger(QuotingExampleTest.class);
 
-    //currently we cannot display different quotes based on depth
-    private static final String DOCUMENT =
-            """
-                    <html>
-                      <head>
-                        <style type='text/css'><![CDATA[
-                          * { quotes: '"' '"' "'" "'" }
-                          q:before { content: open-quote }
-                          q:after { content: close-quote }
-                          blockquote p:before     { content: open-quote }
-                          blockquote p:after      { content: no-close-quote }
-                          blockquote p.last:after { content: close-quote }
-                        ]]></style>
-                      </head>
-                      <body>
-                        <blockquote>
-                          <p>This is just a test of the emergency <q>quoting</q> system.</p>
-                          <p>This is only a test.</p>
-                          <p class='last'>Thank you for your cooperation during this <q>test.</q></p>
-                        </blockquote>
-                      </body>
-                    </html>
-                    """;
-
     @Test
     public void exampleWithQuotes() throws Exception {
-        BufferedImage image = htmlAsImage(DOCUMENT, 600);
+        BufferedImage image = htmlAsImage(requireNonNull(getClass().getResourceAsStream("/quotes.xhtml")), 600);
         File result = new File("target/%s.png".formatted(getClass().getSimpleName()));
         ImageIO.write(image, "png", result);
         log.info("Generated image from html: {}", result.getAbsolutePath());

flying-saucer-core/src/test/resources/quotes.xhtml

@@ -0,0 +1,23 @@
+<!--
+    currently we cannot display different quotes based on depth
+-->
+<html lang="en">
+<head>
+    <style type='text/css'><![CDATA[
+      * { quotes: '"' '"' "'" "'" }
+    q:before { content: open-quote }
+    q:after { content: close-quote }
+    blockquote p:before     { content: open-quote }
+    blockquote p:after      { content: no-close-quote }
+    blockquote p.last:after { content: close-quote }
+    ]]></style>
+    <title>Page with quotes</title>
+</head>
+<body>
+<blockquote>
+    <p>This is just a test of the emergency <q>quoting</q> system.</p>
+    <p>This is only a test.</p>
+    <p class='last'>Thank you for your cooperation during this <q>test.</q></p>
+</blockquote>
+</body>
+</html>

flying-saucer-core/src/test/resources/text-with-background-image.xhtml

@@ -0,0 +1,12 @@
+<html lang="en">
+<head>
+    <title>Page with background image</title>
+</head>
+<body>
+
+    <p>AAA AAA AAA AAA AAA AAA </p>
+    <p style="background-image: url(transgrey.png); background-repeat: no-repeat;">BBB BBB BBB BBB BBB BBB BBB </p>
+    <p class='last'>CCC CCC CCC CCC CCC CCC CCC </p>
+
+</body>
+</html>