Java tutorial
/******************************************************************************* * Copyright (c) 2000, 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.graphics; import org.eclipse.swt.*; import org.eclipse.swt.internal.*; import org.eclipse.swt.internal.gdip.*; import org.eclipse.swt.internal.win32.*; /** * Instances of this class represent patterns to use while drawing. Patterns * can be specified either as bitmaps or gradients. * <p> * Application code must explicitly invoke the <code>Pattern.dispose()</code> * method to release the operating system resources managed by each instance * when those instances are no longer required. * </p> * <p> * This class requires the operating system's advanced graphics subsystem * which may not be available on some platforms. * </p> * * @see <a href="http://www.eclipse.org/swt/snippets/#path">Path, Pattern snippets</a> * @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: GraphicsExample</a> * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a> * * @since 3.1 */ public class Pattern extends Resource { /** * the OS resource for the Pattern * (Warning: This field is platform dependent) * <p> * <b>IMPORTANT:</b> This field is <em>not</em> part of the SWT * public API. It is marked public only so that it can be shared * within the packages provided by SWT. It is not available on all * platforms and should never be accessed from application code. * </p> * * @noreference This field is not intended to be referenced by clients. */ public long handle; /** * Constructs a new Pattern given an image. Drawing with the resulting * pattern will cause the image to be tiled over the resulting area. * <p> * This operation requires the operating system's advanced * graphics subsystem which may not be available on some * platforms. * </p> * <p> * You must dispose the pattern when it is no longer required. * </p> * * @param device the device on which to allocate the pattern * @param image the image that the pattern will draw * * @exception IllegalArgumentException <ul> * <li>ERROR_NULL_ARGUMENT - if the device is null and there is no current device, or the image is null</li> * <li>ERROR_INVALID_ARGUMENT - if the image has been disposed</li> * </ul> * @exception SWTException <ul> * <li>ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are not available</li> * </ul> * @exception SWTError <ul> * <li>ERROR_NO_HANDLES if a handle for the pattern could not be obtained</li> * </ul> * * @see #dispose() */ public Pattern(Device device, Image image) { super(device); if (image == null) SWT.error(SWT.ERROR_NULL_ARGUMENT); if (image.isDisposed()) SWT.error(SWT.ERROR_INVALID_ARGUMENT); this.device.checkGDIP(); long[] gdipImage = image.createGdipImage(); long img = gdipImage[0]; int width = Gdip.Image_GetWidth(img); int height = Gdip.Image_GetHeight(img); handle = Gdip.TextureBrush_new(img, Gdip.WrapModeTile, 0, 0, width, height); Gdip.Bitmap_delete(img); if (gdipImage[1] != 0) { long hHeap = OS.GetProcessHeap(); OS.HeapFree(hHeap, 0, gdipImage[1]); } if (handle == 0) SWT.error(SWT.ERROR_NO_HANDLES); init(); } /** * Constructs a new Pattern that represents a linear, two color * gradient. Drawing with the pattern will cause the resulting area to be * tiled with the gradient specified by the arguments. * <p> * This operation requires the operating system's advanced * graphics subsystem which may not be available on some * platforms. * </p> * <p> * You must dispose the pattern when it is no longer required. * </p> * * @param device the device on which to allocate the pattern * @param x1 the x coordinate of the starting corner of the gradient * @param y1 the y coordinate of the starting corner of the gradient * @param x2 the x coordinate of the ending corner of the gradient * @param y2 the y coordinate of the ending corner of the gradient * @param color1 the starting color of the gradient * @param color2 the ending color of the gradient * * @exception IllegalArgumentException <ul> * <li>ERROR_NULL_ARGUMENT - if the device is null and there is no current device, * or if either color1 or color2 is null</li> * <li>ERROR_INVALID_ARGUMENT - if either color1 or color2 has been disposed</li> * </ul> * @exception SWTException <ul> * <li>ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are not available</li> * </ul> * @exception SWTError <ul> * <li>ERROR_NO_HANDLES if a handle for the pattern could not be obtained</li> * </ul> * * @see #dispose() */ public Pattern(Device device, float x1, float y1, float x2, float y2, Color color1, Color color2) { this(device, x1, y1, x2, y2, color1, 0xFF, color2, 0xFF); } /** * Constructs a new Pattern that represents a linear, two color * gradient. Drawing with the pattern will cause the resulting area to be * tiled with the gradient specified by the arguments. * <p> * This operation requires the operating system's advanced * graphics subsystem which may not be available on some * platforms. * </p> * <p> * You must dispose the pattern when it is no longer required. * </p> * * @param device the device on which to allocate the pattern * @param x1 the x coordinate of the starting corner of the gradient * @param y1 the y coordinate of the starting corner of the gradient * @param x2 the x coordinate of the ending corner of the gradient * @param y2 the y coordinate of the ending corner of the gradient * @param color1 the starting color of the gradient * @param alpha1 the starting alpha value of the gradient * @param color2 the ending color of the gradient * @param alpha2 the ending alpha value of the gradient * * @exception IllegalArgumentException <ul> * <li>ERROR_NULL_ARGUMENT - if the device is null and there is no current device, * or if either color1 or color2 is null</li> * <li>ERROR_INVALID_ARGUMENT - if either color1 or color2 has been disposed</li> * </ul> * @exception SWTException <ul> * <li>ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are not available</li> * </ul> * @exception SWTError <ul> * <li>ERROR_NO_HANDLES if a handle for the pattern could not be obtained</li> * </ul> * * @see #dispose() * * @since 3.2 */ public Pattern(Device device, float x1, float y1, float x2, float y2, Color color1, int alpha1, Color color2, int alpha2) { super(device); x1 = DPIUtil.autoScaleUp(x1); y1 = DPIUtil.autoScaleUp(y1); x2 = DPIUtil.autoScaleUp(x2); y2 = DPIUtil.autoScaleUp(y2); if (color1 == null) SWT.error(SWT.ERROR_NULL_ARGUMENT); if (color1.isDisposed()) SWT.error(SWT.ERROR_INVALID_ARGUMENT); if (color2 == null) SWT.error(SWT.ERROR_NULL_ARGUMENT); if (color2.isDisposed()) SWT.error(SWT.ERROR_INVALID_ARGUMENT); this.device.checkGDIP(); int colorRef1 = color1.handle; int foreColor = ((alpha1 & 0xFF) << 24) | ((colorRef1 >> 16) & 0xFF) | (colorRef1 & 0xFF00) | ((colorRef1 & 0xFF) << 16); if (x1 == x2 && y1 == y2) { handle = Gdip.SolidBrush_new(foreColor); if (handle == 0) SWT.error(SWT.ERROR_NO_HANDLES); } else { int colorRef2 = color2.handle; int backColor = ((alpha2 & 0xFF) << 24) | ((colorRef2 >> 16) & 0xFF) | (colorRef2 & 0xFF00) | ((colorRef2 & 0xFF) << 16); PointF p1 = new PointF(); p1.X = x1; p1.Y = y1; PointF p2 = new PointF(); p2.X = x2; p2.Y = y2; handle = Gdip.LinearGradientBrush_new(p1, p2, foreColor, backColor); if (handle == 0) SWT.error(SWT.ERROR_NO_HANDLES); if (alpha1 != 0xFF || alpha2 != 0xFF) { int a = (int) ((alpha1 & 0xFF) * 0.5f + (alpha2 & 0xFF) * 0.5f); int r = (int) (((colorRef1 & 0xFF) >> 0) * 0.5f + ((colorRef2 & 0xFF) >> 0) * 0.5f); int g = (int) (((colorRef1 & 0xFF00) >> 8) * 0.5f + ((colorRef2 & 0xFF00) >> 8) * 0.5f); int b = (int) (((colorRef1 & 0xFF0000) >> 16) * 0.5f + ((colorRef2 & 0xFF0000) >> 16) * 0.5f); int midColor = a << 24 | r << 16 | g << 8 | b; Gdip.LinearGradientBrush_SetInterpolationColors(handle, new int[] { foreColor, midColor, backColor }, new float[] { 0, 0.5f, 1 }, 3); } } init(); } @Override void destroy() { int type = Gdip.Brush_GetType(handle); switch (type) { case Gdip.BrushTypeSolidColor: Gdip.SolidBrush_delete(handle); break; case Gdip.BrushTypeHatchFill: Gdip.HatchBrush_delete(handle); break; case Gdip.BrushTypeLinearGradient: Gdip.LinearGradientBrush_delete(handle); break; case Gdip.BrushTypeTextureFill: Gdip.TextureBrush_delete(handle); break; } handle = 0; } /** * Returns <code>true</code> if the Pattern has been disposed, * and <code>false</code> otherwise. * <p> * This method gets the dispose state for the Pattern. * When a Pattern has been disposed, it is an error to * invoke any other method (except {@link #dispose()}) using the Pattern. * * @return <code>true</code> when the Pattern is disposed, and <code>false</code> otherwise */ @Override public boolean isDisposed() { return handle == 0; } /** * Returns a string containing a concise, human-readable * description of the receiver. * * @return a string representation of the receiver */ @Override public String toString() { if (isDisposed()) return "Pattern {*DISPOSED*}"; return "Pattern {" + handle + "}"; } }