support image attribute also for js engines (see #101)

Author: nidi3

graphviz-java/src/main/java/guru/nidi/graphviz/attribute/Image.java

@@ -0,0 +1,84 @@
+/*
+ * Copyright © 2015 Stefan Niederhauser ([email protected])
+ *
+ * Licensed 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 guru.nidi.graphviz.attribute;
+
+public final class Image implements Attributes<ForNode> {
+    public enum Position {
+        TOP_LEFT("tl"),
+        TOP_CENTER("tc"),
+        TOP_RIGHT("tr"),
+        MIDDLE_LEFT("ml"),
+        MIDDLE_CENTER("mc"),
+        MIDDLE_RIGHT("mr"),
+        BOTTOM_LEFT("bl"),
+        BOTTOM_CENTER("bc"),
+        BOTTOM_RIGHT("br");
+
+        String value;
+
+        Position(String value) {
+            this.value = value;
+        }
+    }
+
+    public enum Scale {
+        NONE("false"),
+        FIT("true"),
+        WIDTH("width"),
+        HEIGHT("height"),
+        BOTH("both");
+
+        String value;
+
+        Scale(String value) {
+            this.value = value;
+        }
+    }
+
+    private final String path;
+    private final Position position;
+    private final Scale scale;
+
+    private Image(String path, Position position, Scale scale) {
+        this.path = path;
+        this.position = position;
+        this.scale = scale;
+    }
+
+    public static Image of(String path) {
+        return new Image(path, Position.MIDDLE_CENTER, Scale.NONE);
+    }
+
+    public Image position(Position position) {
+        return new Image(path, position, scale);
+    }
+
+    public Image scale(Scale scale) {
+        return new Image(path, position, scale);
+    }
+
+    @Override
+    public Attributes<? super ForNode> applyTo(MapAttributes<? super ForNode> attrs) {
+        attrs.add("image", path);
+        if (position != Position.MIDDLE_CENTER) {
+            attrs.add("imagepos", position.value);
+        }
+        if (scale != Scale.NONE) {
+            attrs.add("imagescale", scale.value);
+        }
+        return attrs;
+    }
+}

graphviz-java/src/main/java/guru/nidi/graphviz/engine/AbstractGraphvizEngine.java

@@ -18,10 +18,16 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.io.File;
 import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 public abstract class AbstractGraphvizEngine implements GraphvizEngine {
     private static final Logger LOG = LoggerFactory.getLogger(AbstractGraphvizEngine.class);
+    protected static final Pattern IMG_SRC = Pattern.compile("<img .*?src\\s*=\\s*['\"]([^'\"]*)");
+    protected static final Pattern IMAGE_ATTR = Pattern.compile("\"?image\"?\\s*=\\s*\"(.*?)\"");
 
     private final boolean sync;
 
@@ -48,6 +54,25 @@ private void initTask(Consumer<GraphvizEngine> onOk, Consumer<GraphvizEngine> on
         }
     }
 
+    protected String replacePaths(String src, Pattern pattern, Function<String, String> replacer) {
+        final Matcher matcher = pattern.matcher(src);
+        final StringBuilder s = new StringBuilder();
+        int last = 0;
+        while (matcher.find()) {
+            final String attr = matcher.group(1);
+            s.append(src, last, matcher.start(1));
+            s.append(replacer.apply(attr));
+            last = matcher.end(1);
+        }
+        return s.append(src.substring(last)).toString();
+    }
+
+    protected String replacePath(String path, File basedir) {
+        return path.startsWith("http://") || path.startsWith("https://") || new File(path).isAbsolute()
+                ? path
+                : new File(basedir, path).getAbsolutePath();
+    }
+
     @Override
     public void close() {
     }

graphviz-java/src/main/java/guru/nidi/graphviz/engine/AbstractJsGraphvizEngine.java

@@ -17,6 +17,8 @@
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.AbstractMap.SimpleEntry;
+import java.util.Map.Entry;
 
 public abstract class AbstractJsGraphvizEngine extends AbstractGraphvizEngine {
     public AbstractJsGraphvizEngine(boolean sync) {
@@ -31,12 +33,24 @@ public String execute(String src, Options options) {
     protected abstract String jsExecute(String jsCall);
 
     protected String jsVizExec(String src, Options options) {
-        return src.startsWith("render") ? src : ("render('" + preprocessCode(src) + "'," + options.toJson(false) + ");");
+        final Entry<String, Options> srcAndOptions = preprocessCode(src, options);
+        return src.startsWith("render")
+                ? src
+                : ("render('" + srcAndOptions.getKey() + "'," + srcAndOptions.getValue().toJson(false) + ");");
     }
 
-    protected String preprocessCode(String src) {
-        if (src.contains("<img")) throw new IllegalArgumentException("Found <img> tag. This is not supported by JS engines. Either use the GraphvizCmdLineEngine or a node with image attribute.");
-        return jsEscape(src);
+    protected Entry<String, Options> preprocessCode(String src, Options options) {
+        if (src.contains("<img")) {
+            throw new GraphvizException("Found <img> tag. This is not supported by JS engines. "
+                    + "Either use the GraphvizCmdLineEngine or a node with image attribute.");
+        }
+        final Options[] opts = new Options[]{options};
+        final String pathsReplaced = replacePaths(src, IMAGE_ATTR, path -> {
+            final String realPath = replacePath(path, options.basedir);
+            opts[0] = opts[0].image(realPath);
+            return realPath;
+        });
+        return new SimpleEntry<>(jsEscape(pathsReplaced), opts[0]);
     }
 
     protected String jsEscape(String js) {

graphviz-java/src/main/java/guru/nidi/graphviz/engine/GraphvizCmdLineEngine.java

@@ -26,8 +26,6 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.Optional;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
 
 import static java.util.Locale.ENGLISH;
 
@@ -38,7 +36,6 @@
  */
 public class GraphvizCmdLineEngine extends AbstractGraphvizEngine {
     private static final Logger LOG = LoggerFactory.getLogger(AbstractGraphvizEngine.class);
-    private static final Pattern IMG_SRC = Pattern.compile("<img .*?src\\s*=\\s*['\"]([^'\"]*)");
 
     private final String envPath;
     private final CommandRunner cmdRunner;
@@ -97,18 +94,8 @@ public String execute(String src, Options options) {
     }
 
     protected String preprocessCode(String src, Options options) {
-        final Matcher matcher = IMG_SRC.matcher(src);
-        final StringBuilder s = new StringBuilder();
-        int last = 0;
-        while (matcher.find()) {
-            final String attr = matcher.group(1);
-            s.append(src, last, matcher.start(1));
-            s.append((attr.startsWith("http://") || attr.startsWith("https://") || new File(attr).isAbsolute())
-                    ? attr
-                    : new File(options.basedir, attr).getAbsolutePath());
-            last = matcher.end(1);
-        }
-        return s.append(src.substring(last)).toString();
+        final String imgReplaced = replacePaths(src, IMG_SRC, path -> replacePath(path, options.basedir));
+        return replacePaths(imgReplaced, IMAGE_ATTR, path -> replacePath(path, options.basedir));
     }
 
     private String getEngineExecutable(@Nullable Engine engine) {