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Migrate Blob effect to Graphics Example
This PR migrates the Blob (metaball) effect from SWT-OldSchoolEffect to the SWT Graphics Example. Changes: - Implemented BlobTab.java extending AnimatedGraphicsTab - Registered the new tab in GraphicsExample.java - Added descriptive strings to examples_graphics.properties Contributes to #3189 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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‎examples/org.eclipse.swt.examples/src/examples_graphics.properties‎

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@@ -190,3 +190,6 @@ StarPolygonDescription=This tab draws a polygon and shows the effects of setting
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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.
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Blob=Blob
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BlobDescription=This is a miscellaneous demonstration of an animated metaball effect where multiple blobs move randomly and blend together when overlapping.

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

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/*******************************************************************************
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* Copyright (c) 2018 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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* W.P. van Paassen - 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.SWT;
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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.PaletteData;
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import org.eclipse.swt.graphics.RGB;
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/**
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* This tab displays an animated metaball/blob effect where multiple blobs
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* move randomly and blend together when overlapping.
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*/
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public class BlobTab extends AnimatedGraphicsTab {
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private static final int BLOB_RADIUS = 44;
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private static final int BLOB_DRADIUS = BLOB_RADIUS * 2;
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private static final int BLOB_SRADIUS = BLOB_RADIUS * BLOB_RADIUS;
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private static final int NUMBER_OF_BLOBS = 20;
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private int[][] blob;
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private int[] blobX;
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private int[] blobY;
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private ImageData imageData;
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private Image outputImage;
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private int lastWidth;
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private int lastHeight;
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public BlobTab(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("Blob"); //$NON-NLS-1$
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}
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@Override
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public String getDescription() {
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return GraphicsExample.getResourceString("BlobDescription"); //$NON-NLS-1$
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}
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@Override
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public int getInitialAnimationTime() {
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return 10;
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}
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@Override
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public void dispose() {
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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 (blobX == null) {
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return;
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}
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if (width != lastWidth || height != lastHeight) {
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init(width, height);
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}
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// Clear pixel data
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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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imageData.setPixel(x, y, 0);
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}
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}
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// Move and draw blobs
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for (int i = 0; i < NUMBER_OF_BLOBS; i++) {
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blobX[i] += -2 + (int) (5.0 * Math.random());
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blobY[i] += -2 + (int) (5.0 * Math.random());
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}
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for (int k = 0; k < NUMBER_OF_BLOBS; ++k) {
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if (blobX[k] > 0 && blobX[k] < width - BLOB_DRADIUS && blobY[k] > 0 && blobY[k] < height - BLOB_DRADIUS) {
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int start = blobX[k] + blobY[k] * width;
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for (int i = 0; i < BLOB_DRADIUS; ++i) {
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for (int j = 0; j < BLOB_DRADIUS; ++j) {
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int px = (start + j) % width;
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int py = (start + j) / width;
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if (py >= 0 && py < height) {
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int current = imageData.getPixel(px, py);
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int sum = current + blob[i][j];
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imageData.setPixel(px, py, Math.min(sum, 255));
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}
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}
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start += width;
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}
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} else {
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blobX[k] = (width >> 1) - BLOB_RADIUS;
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blobY[k] = (height >> 1) - BLOB_RADIUS;
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}
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}
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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 (blobX == null) {
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init(width, height);
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}
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gc.setBackground(gc.getDevice().getSystemColor(SWT.COLOR_BLACK));
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gc.fillRectangle(0, 0, width, height);
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if (imageData == null) {
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return;
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}
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if (outputImage != null) {
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outputImage.dispose();
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}
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outputImage = new Image(gc.getDevice(), imageData);
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gc.drawImage(outputImage, 0, 0);
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}
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private void init(int width, int height) {
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lastWidth = width;
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lastHeight = height;
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blob = new int[BLOB_DRADIUS][BLOB_DRADIUS];
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blobX = new int[NUMBER_OF_BLOBS];
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blobY = new int[NUMBER_OF_BLOBS];
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// Create blob shape
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for (int i = -BLOB_RADIUS; i < BLOB_RADIUS; ++i) {
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for (int j = -BLOB_RADIUS; j < BLOB_RADIUS; ++j) {
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final int distanceSquared = i * i + j * j;
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if (distanceSquared <= BLOB_SRADIUS) {
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final float fraction = (float) distanceSquared / (float) BLOB_SRADIUS;
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blob[i + BLOB_RADIUS][j + BLOB_RADIUS] = (int) (Math.pow(1.0 - fraction * fraction, 4.0) * 255.0);
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} else {
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blob[i + BLOB_RADIUS][j + BLOB_RADIUS] = 0;
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}
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}
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}
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// Initialize blob positions at center
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for (int i = 0; i < NUMBER_OF_BLOBS; i++) {
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blobX[i] = (width >> 1) - BLOB_RADIUS;
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blobY[i] = (height >> 1) - BLOB_RADIUS;
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}
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// Create grayscale palette image data
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final RGB[] colors = new RGB[256];
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for (int i = 0; i < 256; ++i) {
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colors[i] = new RGB(i, i, i);
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}
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imageData = new ImageData(width, height, 8, new PaletteData(colors));
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}
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}

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

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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 BlobTab(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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