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/*******************************************************************************
 * 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.cairo.*;

/**
 * Instances of this class represent patterns to use while drawing. Patterns
 * can be specified either as bitmaps or gradients.
 * 

* Application code must explicitly invoke the Pattern.dispose() * method to release the operating system resources managed by each instance * when those instances are no longer required. *

*

* This class requires the operating system's advanced graphics subsystem * which may not be available on some platforms. *

* * @see Path, Pattern snippets * @see SWT Example: GraphicsExample * @see Sample code and further information * * @since 3.1 */ public class Pattern extends Resource { /** * the OS resource for the Pattern * (Warning: This field is platform dependent) *

* IMPORTANT: This field is not 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. *

* * @noreference This field is not intended to be referenced by clients. */ public long handle; long surface; /** * Constructs a new Pattern given an image. Drawing with the resulting * pattern will cause the image to be tiled over the resulting area. *

* This operation requires the operating system's advanced * graphics subsystem which may not be available on some * platforms. *

*

* You must dispose the pattern when it is no longer required. *

* * @param device the device on which to allocate the pattern * @param image the image that the pattern will draw * * @exception IllegalArgumentException
    *
  • ERROR_NULL_ARGUMENT - if the device is null and there is no current device, or the image is null
  • *
  • ERROR_INVALID_ARGUMENT - if the image has been disposed
  • *
* @exception SWTException
    *
  • ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are not available
  • *
* @exception SWTError
    *
  • ERROR_NO_HANDLES if a handle for the pattern could not be obtained
  • *
* * @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); image.createSurface(); handle = Cairo.cairo_pattern_create_for_surface(image.surface); if (handle == 0) SWT.error(SWT.ERROR_NO_HANDLES); Cairo.cairo_pattern_set_extend(handle, Cairo.CAIRO_EXTEND_REPEAT); surface = image.surface; 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. *

* This operation requires the operating system's advanced * graphics subsystem which may not be available on some * platforms. *

*

* You must dispose the pattern when it is no longer required. *

* * @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
    *
  • ERROR_NULL_ARGUMENT - if the device is null and there is no current device, * or if either color1 or color2 is null
  • *
  • ERROR_INVALID_ARGUMENT - if either color1 or color2 has been disposed
  • *
* @exception SWTException
    *
  • ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are not available
  • *
* @exception SWTError
    *
  • ERROR_NO_HANDLES if a handle for the pattern could not be obtained
  • *
* * @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. *

* This operation requires the operating system's advanced * graphics subsystem which may not be available on some * platforms. *

*

* You must dispose the pattern when it is no longer required. *

* * @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
    *
  • ERROR_NULL_ARGUMENT - if the device is null and there is no current device, * or if either color1 or color2 is null
  • *
  • ERROR_INVALID_ARGUMENT - if either color1 or color2 has been disposed
  • *
* @exception SWTException
    *
  • ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are not available
  • *
* @exception SWTError
    *
  • ERROR_NO_HANDLES if a handle for the pattern could not be obtained
  • *
* * @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); handle = Cairo.cairo_pattern_create_linear(x1, y1, x2, y2); if (handle == 0) SWT.error(SWT.ERROR_NO_HANDLES); GC.setCairoPatternColor(handle, 0, color1, alpha1); GC.setCairoPatternColor(handle, 1, color2, alpha2); Cairo.cairo_pattern_set_extend(handle, Cairo.CAIRO_EXTEND_REPEAT); init(); } @Override void destroy() { Cairo.cairo_pattern_destroy(handle); handle = surface = 0; } /** * Returns true if the Pattern has been disposed, * and false otherwise. *

* 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 true when the Pattern is disposed, and false 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 + "}"; } }





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