[DiagramUtils] Use ImagePrintFigureOperation to generate images

- Needs to use an ImageGraphics for SWTGraphics or get the actual scale some other way. But ImagePrintFigureOperation sets scale on SWTGraphics so not sure if that will work

- This is much slower and uses more memory. Nebula Gallery can run out of memory.

- Needs methods that take a boolean of useImageOperation so that there is a per-method way to get an image with ImagePrintFigureOperation or not.

- Have to guard against small zooms when using the Images in a Nebula Gallery

Author: Phillipus

com.archimatetool.editor/src/com/archimatetool/editor/diagram/util/DiagramUtils.java

@@ -6,8 +6,11 @@
 package com.archimatetool.editor.diagram.util;
 
 import org.eclipse.draw2d.FreeformFigure;
+import org.eclipse.draw2d.Graphics;
 import org.eclipse.draw2d.IFigure;
+import org.eclipse.draw2d.ImagePrintFigureOperation;
 import org.eclipse.draw2d.SWTGraphics;
+import org.eclipse.draw2d.geometry.Dimension;
 import org.eclipse.draw2d.geometry.Rectangle;
 import org.eclipse.gef.EditPartFactory;
 import org.eclipse.gef.GraphicalViewer;
@@ -16,17 +19,19 @@
 import org.eclipse.gef.editparts.FreeformGraphicalRootEditPart;
 import org.eclipse.gef.editparts.LayerManager;
 import org.eclipse.gef.ui.parts.GraphicalViewerImpl;
-import org.eclipse.swt.graphics.AutoscalingMode;
 import org.eclipse.swt.graphics.GC;
 import org.eclipse.swt.graphics.Image;
+import org.eclipse.swt.graphics.ImageData;
 import org.eclipse.swt.layout.FillLayout;
 import org.eclipse.swt.widgets.Composite;
+import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Display;
 import org.eclipse.swt.widgets.Shell;
 
 import com.archimatetool.editor.diagram.DiagramEditorFactoryExtensionHandler;
 import com.archimatetool.editor.diagram.IDiagramEditorFactory;
 import com.archimatetool.editor.diagram.editparts.ArchimateDiagramEditPartFactory;
+import com.archimatetool.editor.diagram.figures.FigureUtils;
 import com.archimatetool.editor.diagram.sketch.editparts.SketchEditPartFactory;
 import com.archimatetool.model.IArchimateDiagramModel;
 import com.archimatetool.model.IDiagramModel;
@@ -70,7 +75,7 @@ else if(model instanceof ISketchModel) {
         }
 
         GraphicalViewerImpl viewer = new GraphicalViewerImpl();
-        viewer.createControl(parent).setAutoscalingMode(AutoscalingMode.ENABLED); // Stops text clipping on Windows
+        viewer.createControl(parent);
 
         viewer.setEditPartFactory(editPartFactory);
 
@@ -155,6 +160,21 @@ private static ModelReferencedImage createModelReferencedImage(IFigure figure, d
             bounds.expand(margin / scale, margin / scale);
         }
 
+        // Use Image Operation
+        // TODO: Use ImageGraphics to set scale
+        if(FigureUtils.isAutoScaleEnabled()) {
+            Shell shell = new Shell();
+            try {
+                ImagePrintDiagramOperation op = new ImagePrintDiagramOperation(shell, figure, scale, bounds);
+                Image image = op.run();
+                return new ModelReferencedImage(image, bounds);   
+            }
+            finally {
+                shell.dispose();
+            }
+        }
+        
+        // Use manual method
         Image image = new Image(Display.getDefault(), (int)(bounds.width * scale), (int)(bounds.height * scale));
         GC gc = new GC(image);
         SWTGraphics graphics = new ImageGraphics(gc); // Use ImageGraphics so we can get actual scale
@@ -220,4 +240,42 @@ public static Rectangle getMinimumBounds(IFigure figure) {
 
         return minimumBounds;
     }
+    
+    /**
+     * ImagePrintDiagramOperation
+     * TODO: Use ImageGraphics to set scale or get scale some other way
+     */
+    private static class ImagePrintDiagramOperation extends ImagePrintFigureOperation {
+        private final Rectangle bounds;
+        private final double scale;
+
+        public ImagePrintDiagramOperation(Control control, IFigure printSource, double scale, Rectangle bounds) {
+            super(control, printSource);
+            this.scale = scale;
+            this.bounds = bounds.getCopy(); // Important to use a copy in case bounds is changed elsewhere
+        }
+
+        @Override
+        protected ImageData getImageDataAtZoom(int zoom) {
+            // Zoom can be < 100 see https://github.com/eclipse-gef/gef-classic/issues/1146
+            if(zoom < 100) {
+                return null;
+            }
+            return super.getImageDataAtZoom(zoom);
+        }
+        
+        @Override
+        protected Dimension getImageSize() {
+            // Scale the size (width and height) of the bounds
+            return bounds.getSize().scale(scale);
+        }
+
+        @Override
+        protected void preparePrintSource(Graphics graphics) {
+            // Scale
+            graphics.scale(scale);
+            // Compensate for negative co-ordinates
+            graphics.translate(bounds.x * -1, bounds.y * -1);
+        }
+    }
 }