Allow Transparent Background for Ditaa Diagrams

src/net/sourceforge/plantuml/ditaa/PSystemDitaa.java

@@ -34,6 +34,7 @@
  */
 package net.sourceforge.plantuml.ditaa;
 
+import java.awt.Color;
 import java.awt.Font;
 import java.awt.image.BufferedImage;
 import java.io.IOException;
@@ -62,12 +63,13 @@ public class PSystemDitaa extends AbstractPSystem {
 	private final boolean dropShadows;
 	private final String data;
 	private final float scale;
+	private final boolean transparentBackground;
 	private final Font font;
 	private final boolean performSeparationOfCommonEdges;
 	private final boolean allCornersAreRound;
 
 	public PSystemDitaa(UmlSource source, String data, boolean performSeparationOfCommonEdges, boolean dropShadows,
-			boolean allCornersAreRound, float scale, Font font) {
+			boolean allCornersAreRound, boolean transparentBackground, float scale, Font font) {
 		super(source);
 		this.data = data;
 		this.dropShadows = dropShadows;
@@ -85,13 +87,14 @@ public class PSystemDitaa extends AbstractPSystem {
 			e.printStackTrace();
 			this.processingOptions = null;
 		}
+		this.transparentBackground = transparentBackground;
 		this.scale = scale;
 		this.font = font;
 	}
 
 	PSystemDitaa add(String line) {
 		return new PSystemDitaa(getSource(), data + line + BackSlash.NEWLINE, performSeparationOfCommonEdges,
-				dropShadows, allCornersAreRound, scale, font);
+				dropShadows, allCornersAreRound, transparentBackground, scale, font);
 	}
 
 	public DiagramDescription getDescription() {
@@ -116,6 +119,10 @@ public class PSystemDitaa extends AbstractPSystem {
 			final Field f_renderingOptions = options.getClass().getField("renderingOptions");
 			final Object renderingOptions = f_renderingOptions.get(options);
 
+			// renderingOptions.setBackgroundColor(font);
+			final Method setBackgroundColor = renderingOptions.getClass().getMethod("setBackgroundColor", Color.class);
+			setBackgroundColor.invoke(renderingOptions, transparentBackground ? new Color(0, 0, 0, 0) : Color.WHITE);
+
 			// renderingOptions.setFont(font);
 			final Method setFont = renderingOptions.getClass().getMethod("setFont", Font.class);
 			setFont.invoke(renderingOptions, font);

src/net/sourceforge/plantuml/ditaa/PSystemDitaaFactory.java

@@ -70,12 +70,16 @@ public class PSystemDitaaFactory extends PSystemBasicFactory<PSystemDitaa> {
 		if (startLine != null && (startLine.contains("-r") || startLine.contains("--round-corners")))
 			allCornersAreRound = true;
 
+		boolean transparentBackground = false;
+		if (startLine != null && (startLine.contains("-T") || startLine.contains("--transparent")))
+			transparentBackground = true;
+
 		final float scale = extractScale(startLine);
 		final Font font = extractFont(startLine);
 		if (getDiagramType() == DiagramType.UML)
 			return null;
 		else if (getDiagramType() == DiagramType.DITAA)
-			return new PSystemDitaa(source, "", performSeparationOfCommonEdges, dropShadows, allCornersAreRound, scale, font);
+			return new PSystemDitaa(source, "", performSeparationOfCommonEdges, dropShadows, allCornersAreRound, transparentBackground, scale, font);
 		else
 			throw new IllegalStateException(getDiagramType().name());
 
@@ -96,9 +100,13 @@ public class PSystemDitaaFactory extends PSystemBasicFactory<PSystemDitaa> {
 			if (line.contains("-r") || line.contains("--round-corners"))
 				allCornersAreRound = true;
 
+			boolean transparentBackground = false;
+			if (line.contains("-T") || line.contains("--transparent"))
+				transparentBackground = true;
+
 			final float scale = extractScale(line);
 			final Font font = extractFont(line);
-			return new PSystemDitaa(source, "", performSeparationOfCommonEdges, dropShadows, allCornersAreRound, scale, font);
+			return new PSystemDitaa(source, "", performSeparationOfCommonEdges, dropShadows, allCornersAreRound, transparentBackground, scale, font);
 		}
 		if (system == null)
 			return null;

src/org/stathissideris/ascii2image/core/RenderingOptions.java

@@ -42,6 +42,8 @@ public class RenderingOptions {
 	
 	private float scale = 1;
 
+	private Color backgroundColor = Color.white;
+
 	private Font font = new Font("Dialog", Font.BOLD, 12);
 
 	/**
@@ -116,6 +118,18 @@ public class RenderingOptions {
 		antialias = b;
 	}
 
+	public Color getBackgroundColor() {
+		return backgroundColor;
+	}
+
+	public void setBackgroundColor(Color backgroundColor) {
+		this.backgroundColor = backgroundColor;
+	}
+	
+	public boolean needsTransparency() {
+		return backgroundColor.getAlpha() < 255;
+	}
+
 	public Font getFont()
 	{
 		return font;

src/org/stathissideris/ascii2image/graphics/BitmapRenderer.java

@@ -55,13 +55,19 @@ public class BitmapRenderer {
 	Stroke normalStroke;
 	Stroke dashStroke; 
 
-	
 	public RenderedImage renderToImage(Diagram diagram, RenderingOptions options){
-		BufferedImage image = new BufferedImage(
+		BufferedImage image;
+		if(options.needsTransparency()) {
+			image = new BufferedImage(
+					diagram.getWidth(),
+					diagram.getHeight(),
+					BufferedImage.TYPE_INT_ARGB);
+		} else {
+			image = new BufferedImage(
 					diagram.getWidth(),
 					diagram.getHeight(),
 					BufferedImage.TYPE_INT_RGB);
-		
+		}
 		return render(diagram, image, options);
 	}
 
@@ -75,7 +81,7 @@ public class BitmapRenderer {
 		
 		g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, antialiasSetting);
 
-		g2.setColor(Color.white);
+		g2.setColor(options.getBackgroundColor());
 		//TODO: find out why the next line does not work
 		g2.fillRect(0, 0, image.getWidth()+10, image.getHeight()+10);
 		/*for(int y = 0; y < diagram.getHeight(); y ++)