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Migrate Ripple effect to Graphics Example
See lcaron/SWT-OldSchoolEffect#3 or https://github.com/lcaron/SWT-OldSchoolEffect for all SWT examples
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‎examples/org.eclipse.swt.examples/src/examples_graphics.properties‎

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@@ -188,3 +188,5 @@ SpiralDescription=Miscellaneous tab that presents a spiral consisting of the num
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StarfieldDescription=This is a miscellaneous demonstration that uses the drawPoint() operation to simulate a moving starfield.
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StarPolygonDescription=This tab draws a polygon and shows the effects of setting different fill rules: SWT.FILL_WINDING or SWT.FILL_EVEN_ODD
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AntialiasingTextDesc=This tab demonstrates antialiasing for text. Antialiasing is used for smoothing jagged edges in graphics. This tab allows the user to see the effects of different antialiasing values.
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Ripple=Ripple
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RippleDescription=This is a miscellaneous demonstration that uses a displacement map to simulate water ripples on an image. Move the mouse over the image to disturb the water.

‎examples/org.eclipse.swt.examples/src/org/eclipse/swt/examples/graphics/GraphicsExample.java‎

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@@ -470,6 +470,7 @@ GraphicsTab[] createTabs() {
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new LineJoinTab(this),
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new RegionClippingTab(this),
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new StarfieldTab(this),
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new RippleTab(this),
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new CustomAlphaTab(this),
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new TextAntialiasTab(this),
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new GraphicAntialiasTab(this),

‎examples/org.eclipse.swt.examples/src/org/eclipse/swt/examples/graphics/RippleTab.java‎

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/*******************************************************************************
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* Copyright (c) 2026 Laurent Caron and others.
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*
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* This program and the accompanying materials
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* are made available under the terms of the Eclipse Public License 2.0
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* which accompanies this distribution, and is available at
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* https://www.eclipse.org/legal/epl-2.0/
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*
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* SPDX-License-Identifier: EPL-2.0
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*
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* Contributors:
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* Neil Wallis (http://www.neilwallis.com/java/water.html) - Original Version
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* Laurent Caron (laurent.caron at gmail dot com) - Conversion to SWT
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* IBM Corporation - adaptation to GraphicsExample
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*******************************************************************************/
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package org.eclipse.swt.examples.graphics;
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import org.eclipse.swt.graphics.GC;
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import org.eclipse.swt.graphics.Image;
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import org.eclipse.swt.graphics.ImageData;
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import org.eclipse.swt.graphics.Rectangle;
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import org.eclipse.swt.widgets.Composite;
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/**
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* This tab displays a ripple effect on an image.
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*/
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public class RippleTab extends AnimatedGraphicsTab {
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private Image sourceImage;
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private ImageData offImageData;
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private int width, height;
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private int hwidth, hheight;
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private int riprad;
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private int size;
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private short[] ripplemap;
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private int[] ripple;
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private int[] texture;
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private int oldind;
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private int newind;
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private Image outputImage;
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public RippleTab(GraphicsExample example) {
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super(example);
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}
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@Override
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public String getCategory() {
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return GraphicsExample.getResourceString("Misc"); //$NON-NLS-1$
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}
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@Override
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public String getText() {
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return GraphicsExample.getResourceString("Ripple"); //$NON-NLS-1$
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}
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@Override
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public String getDescription() {
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return GraphicsExample.getResourceString("RippleDescription"); //$NON-NLS-1$
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}
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@Override
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public int getInitialAnimationTime() {
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return 30;
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}
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@Override
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public void createControlPanel(Composite parent) {
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super.createControlPanel(parent);
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// Add mouse listener to the canvas to disturb the water
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example.canvas.addMouseMoveListener(e -> {
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if (example.getTab() == RippleTab.this) {
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Rectangle rect = example.canvas.getClientArea();
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disturb(e.x, e.y, rect.width, rect.height);
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}
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});
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}
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@Override
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public void dispose() {
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if (sourceImage != null) {
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sourceImage.dispose();
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sourceImage = null;
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}
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if (outputImage != null) {
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outputImage.dispose();
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outputImage = null;
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}
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}
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@Override
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public void next(int width, int height) {
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if (texture == null) return;
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if (Math.random() > 0.98) {
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disturb((int)(Math.random() * width), (int)(Math.random() * height), width, height);
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}
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newframe();
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}
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@Override
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public void paint(GC gc, int width, int height) {
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if (!example.checkAdvancedGraphics()) return;
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if (sourceImage == null) {
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sourceImage = example.loadImage(gc.getDevice(), "ocean.jpg");
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if (sourceImage == null) return;
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ImageData imgData = sourceImage.getImageData();
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this.width = imgData.width;
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this.height = imgData.height;
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hwidth = this.width >> 1;
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hheight = this.height >> 1;
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riprad = 3;
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size = this.width * (this.height + 2) * 2;
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ripplemap = new short[size];
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ripple = new int[this.width * this.height];
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texture = new int[this.width * this.height];
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oldind = this.width;
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newind = this.width * (this.height + 3);
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imgData.getPixels(0, 0, this.width * this.height, texture, 0);
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offImageData = new ImageData(this.width, this.height, imgData.depth, imgData.palette);
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}
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offImageData.setPixels(0, 0, this.width * this.height, ripple, 0);
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if (outputImage != null) outputImage.dispose();
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outputImage = new Image(gc.getDevice(), offImageData);
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int x = (width - this.width) / 2;
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int y = (height - this.height) / 2;
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gc.drawImage(outputImage, x, y);
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}
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private void newframe() {
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int i, a, b;
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// Toggle maps each frame
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i = oldind;
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oldind = newind;
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newind = i;
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i = 0;
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int mapind = oldind;
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for (int y = 0; y < height; y++) {
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for (int x = 0; x < width; x++) {
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short data = (short) (ripplemap[mapind - width] + ripplemap[mapind + width] + ripplemap[mapind - 1] + ripplemap[mapind + 1] >> 1);
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data -= ripplemap[newind + i];
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data -= data >> 5;
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ripplemap[newind + i] = data;
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// where data=0 then still, where data>0 then wave
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data = (short) (1024 - data);
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// offsets
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a = (x - hwidth) * data / 1024 + hwidth;
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b = (y - hheight) * data / 1024 + hheight;
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// bounds check
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if (a >= width) {
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a = width - 1;
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}
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if (a < 0) {
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a = 0;
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}
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if (b >= height) {
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b = height - 1;
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}
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if (b < 0) {
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b = 0;
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}
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ripple[i] = texture[a + b * width];
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mapind++;
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i++;
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}
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}
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}
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private void disturb(int dx, int dy, int canvasWidth, int canvasHeight) {
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if (texture == null) return;
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// Adjust dx, dy based on center alignment in paint()
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int xOffset = (canvasWidth - width) / 2;
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int yOffset = (canvasHeight - height) / 2;
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int x = dx - xOffset;
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int y = dy - yOffset;
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for (int j = y - riprad; j < y + riprad; j++) {
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for (int k = x - riprad; k < x + riprad; k++) {
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if (j >= 0 && j < height && k >= 0 && k < width) {
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ripplemap[oldind + j * width + k] += 512;
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}
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}
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}
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}
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}

‎examples/org.eclipse.swt.examples/src/org/eclipse/swt/examples/graphics/ocean.jpg‎

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