Java tutorial
/******************************************************************************* * Copyright (c) 2006, 2016 IBM Corporation and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * IBM Corporation - initial API and implementation *******************************************************************************/ package org.eclipse.swt.examples.graphics; import org.eclipse.swt.SWT; import org.eclipse.swt.graphics.Device; import org.eclipse.swt.graphics.GC; import org.eclipse.swt.graphics.Point; import org.eclipse.swt.graphics.Rectangle; import org.eclipse.swt.graphics.Region; import org.eclipse.swt.layout.GridLayout; import org.eclipse.swt.widgets.Button; import org.eclipse.swt.widgets.Combo; import org.eclipse.swt.widgets.Composite; import org.eclipse.swt.widgets.Label; import org.eclipse.swt.widgets.Menu; /** * This tab demonstrates how to apply a region clipping and the effects of * applying one. */ public class RegionClippingTab extends GraphicsTab { private Combo clippingCb; private Button colorButton1, colorButton2; private Menu menu1, menu2; private GraphicsBackground colorGB1, colorGB2; public RegionClippingTab(GraphicsExample example) { super(example); } @Override public String getCategory() { return GraphicsExample.getResourceString("Clipping"); //$NON-NLS-1$ } @Override public String getText() { return GraphicsExample.getResourceString("RegionClipping"); //$NON-NLS-1$ } @Override public String getDescription() { return GraphicsExample.getResourceString("RegionClippingDescription"); //$NON-NLS-1$ } @Override public void dispose() { if (menu1 != null) { menu1.dispose(); menu1 = null; } if (menu2 != null) { menu2.dispose(); menu2 = null; } } /** * Creates the widgets used to control the drawing. */ @Override public void createControlPanel(Composite parent) { // create drop down combo for choosing clipping Composite comp = new Composite(parent, SWT.NONE); comp.setLayout(new GridLayout(2, false)); new Label(comp, SWT.CENTER).setText(GraphicsExample.getResourceString("Clipping")); //$NON-NLS-1$ clippingCb = new Combo(comp, SWT.DROP_DOWN); clippingCb.add(GraphicsExample.getResourceString("Region1")); //$NON-NLS-1$ clippingCb.add(GraphicsExample.getResourceString("Region2")); //$NON-NLS-1$ clippingCb.add(GraphicsExample.getResourceString("Add")); //$NON-NLS-1$ clippingCb.add(GraphicsExample.getResourceString("Sub")); //$NON-NLS-1$ clippingCb.add(GraphicsExample.getResourceString("Inter")); //$NON-NLS-1$ clippingCb.select(0); clippingCb.addListener(SWT.Selection, event -> example.redraw()); // color menu ColorMenu cm = new ColorMenu(); menu1 = cm.createMenu(parent.getParent(), gb -> { colorGB1 = gb; colorButton1.setImage(gb.getThumbNail()); example.redraw(); }); menu2 = cm.createMenu(parent.getParent(), gb -> { colorGB2 = gb; colorButton2.setImage(gb.getThumbNail()); example.redraw(); }); // initialize the color to blue colorGB1 = (GraphicsBackground) menu1.getItem(4).getData(); // initialize the color to red colorGB2 = (GraphicsBackground) menu2.getItem(2).getData(); // color button 1 comp = new Composite(parent, SWT.NONE); comp.setLayout(new GridLayout(2, false)); colorButton1 = new Button(comp, SWT.PUSH); colorButton1.setText(GraphicsExample.getResourceString("Color1")); //$NON-NLS-1$ colorButton1.setImage(colorGB1.getThumbNail()); colorButton1.addListener(SWT.Selection, event -> { final Button button = (Button) event.widget; final Composite parent1 = button.getParent(); Rectangle bounds = button.getBounds(); Point point = parent1.toDisplay(new Point(bounds.x, bounds.y)); menu1.setLocation(point.x, point.y + bounds.height); menu1.setVisible(true); }); // color button 2 comp = new Composite(parent, SWT.NONE); comp.setLayout(new GridLayout(2, false)); colorButton2 = new Button(comp, SWT.PUSH); colorButton2.setText(GraphicsExample.getResourceString("Color2")); //$NON-NLS-1$ colorButton2.setImage(colorGB2.getThumbNail()); colorButton2.addListener(SWT.Selection, event -> { final Button button = (Button) event.widget; final Composite parent1 = button.getParent(); Rectangle bounds = button.getBounds(); Point point = parent1.toDisplay(new Point(bounds.x, bounds.y)); menu2.setLocation(point.x, point.y + bounds.height); menu2.setVisible(true); }); } @Override public void paint(GC gc, int width, int height) { if (!example.checkAdvancedGraphics()) return; Device device = gc.getDevice(); // array of coordinate points of polygon 1 (region 1) int[] polygon1 = new int[] { 10, height / 2, 9 * width / 16, 10, 9 * width / 16, height - 10 }; Region region1 = new Region(device); region1.add(polygon1); // array of coordinate points of polygon 2 (region 2) int[] polygon2 = new int[] { 9 * width / 16, 10, 9 * width / 16, height / 8, 7 * width / 16, 2 * height / 8, 9 * width / 16, 3 * height / 8, 7 * width / 16, 4 * height / 8, 9 * width / 16, 5 * height / 8, 7 * width / 16, 6 * height / 8, 9 * width / 16, 7 * height / 8, 9 * width / 16, height - 10, width - 10, height / 2 }; Region region2 = new Region(device); region2.add(polygon2); gc.setAlpha(127); int clippingIndex = clippingCb.getSelectionIndex(); switch (clippingIndex) { case 0: // region 1 gc.setClipping(region1); gc.setBackground(colorGB1.getBgColor1()); gc.fillPolygon(polygon1); break; case 1: // region 2 gc.setClipping(region2); gc.setBackground(colorGB2.getBgColor1()); gc.fillPolygon(polygon2); break; case 2: // add region1.add(region2); break; case 3: // sub region1.subtract(region2); break; case 4: // intersect region1.intersect(region2); break; } if (clippingIndex > 1) { gc.setClipping(region1); gc.setBackground(colorGB1.getBgColor1()); gc.fillPolygon(polygon1); gc.setBackground(colorGB2.getBgColor1()); gc.fillPolygon(polygon2); } region1.dispose(); region2.dispose(); } }