bundles/org.simantics.utils.ui/src/org/simantics/utils/ui/color/ColorGradientCanvas.java

   1 /*******************************************************************************
   2  * Copyright (c) 2007, 2010 Association for Decentralized Information Management
   3  * in Industry THTH ry.
   4  * All rights reserved. This program and the accompanying materials
   5  * are made available under the terms of the Eclipse Public License v1.0
   6  * which accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *     VTT Technical Research Centre of Finland - initial API and implementation
  11  *******************************************************************************/
  12 package org.simantics.utils.ui.color;
  13
  14 import org.eclipse.swt.SWT;
  15 import org.eclipse.swt.events.PaintEvent;
  16 import org.eclipse.swt.events.PaintListener;
  17 import org.eclipse.swt.graphics.GC;
  18 import org.eclipse.swt.graphics.Image;
  19 import org.eclipse.swt.graphics.Rectangle;
  20 import org.eclipse.swt.widgets.Canvas;
  21 import org.eclipse.swt.widgets.Composite;
  22 import org.eclipse.swt.widgets.Display;
  23
  24 /**
  25  *
  26  * Canvas that shows color gradients
  27  *
  28  * @author Marko Luukkainen
  29  *
  30  */
  31 public class ColorGradientCanvas extends Canvas{
  32         ColorGradient gradient;
  33         int style;
  34
  35         public ColorGradientCanvas(Composite parent, int style) {
  36                 super(parent,(style|SWT.BORDER)&(~(SWT.VERTICAL|SWT.HORIZONTAL)));
  37                 this.style = style & (SWT.VERTICAL | SWT.HORIZONTAL) ;
  38                 addPaintListener(createPaintListener());
  39         }
  40
  41         public void setGradient(ColorGradient gradient) {
  42                 this.gradient = gradient;
  43                 this.redraw();
  44         }
  45
  46         protected PaintListener createPaintListener() {
  47                 return new PaintListener() {
  48                 public void paintControl(PaintEvent e) {
  49                         GC gc = e.gc;
  50                         Rectangle clip = gc.getClipping();
  51                         paintGradient(gc, clip);
  52                 }
  53             };
  54         }
  55
  56         protected void paintGradient(GC gc, Rectangle clip) {
  57                 if (gradient != null) {
  58                         Image image = gradient.getGradientImage(clip.width,clip.height,ColorGradientCanvas.this.style);
  59                         gc.drawImage(image, 0, 0);
  60                         image.dispose();
  61                 } else {
  62                         gc.setBackground(Display.getCurrent().getSystemColor(SWT.COLOR_WHITE));
  63                         gc.fillRectangle(clip);
  64                 }
  65         }
  66
  67 }