+ }
+
+ /**
+ * Build a masking image of hidden columns and rows to be applied on top of
+ * the main overview image.
+ *
+ * @param rows
+ * collection of rows the overview is built over
+ * @param cols
+ * collection of columns the overview is built over
+ * @param width
+ * width of overview in pixels
+ * @param height
+ * height of overview in pixels
+ * @return BufferedImage containing mask of hidden regions
+ */
+ private BufferedImage buildHiddenImage()
+ {
+ // new masking image
+ BufferedImage hiddenImage = new BufferedImage(w, h,
+ BufferedImage.TYPE_INT_ARGB);
+
+ Color hidden = resColFinder.getHiddenColour();
+
+ Graphics2D g2d = (Graphics2D) hiddenImage.getGraphics();
+
+ g2d.setColor(hidden);
+ // set background to transparent
+ // g2d.setComposite(AlphaComposite.Clear);
+ // g2d.fillRect(0, 0, width, height);
+
+ // set next colour to opaque
+ g2d.setComposite(AlphaComposite.Src);