SWT(JFace)体验之Canvas（画布）

来源：互联网发布：哆可梦网络编辑：程序博客网时间：2024/06/05 04:17

说道画图，我们首先要介绍一下SWT的GC类。

package swt_jface.demo10;import org.eclipse.swt.SWT;import org.eclipse.swt.custom.CLabel;import org.eclipse.swt.graphics.GC;import org.eclipse.swt.graphics.Image;import org.eclipse.swt.widgets.Display;import org.eclipse.swt.widgets.Shell;public class GCCreation {Display display = new Display();Shell shell = new Shell(display);public GCCreation() {Image image = new Image(display, "C:/icons/eclipse.gif");Image image2 = new Image(display, image.getImageData());GC gc = new GC(image2);gc.setForeground(display.getSystemColor(SWT.COLOR_WHITE));gc.drawOval(10, 10, 90, 40);gc.dispose();CLabel label = new CLabel(shell, SWT.NULL);label.setImage(image);label.setBounds(10, 10, 130, 130);CLabel label2 = new CLabel(shell, SWT.NULL);label2.setImage(image2);label2.setBounds(150, 10, 130, 130);shell.pack();shell.open();while (!shell.isDisposed()) {if (!display.readAndDispatch()) {display.sleep();}}display.dispose();}public static void main(String[] args) {new GCCreation();}}

接下来请参看以下示例：

演示代码1：

package swt_jface.demo10;import org.eclipse.swt.SWT;import org.eclipse.swt.events.PaintEvent;import org.eclipse.swt.events.PaintListener;import org.eclipse.swt.widgets.Canvas;import org.eclipse.swt.widgets.Display;import org.eclipse.swt.widgets.Shell;public class CanvasExample {Display display = new Display();Shell shell = new Shell(display);public CanvasExample() {Canvas canvas = new Canvas(shell, SWT.NULL);canvas.setBounds(10, 10, 200, 100);canvas.addPaintListener(new PaintListener() {public void paintControl(PaintEvent e) {e.gc.drawRoundRectangle(10, 10, 180, 80, 10, 10);}});shell.pack();shell.open();while (!shell.isDisposed()) {if (!display.readAndDispatch()) {display.sleep();}}display.dispose();}public static void main(String[] args) {new CanvasExample();}}

演示代码2：(三角)

演示代码3：（动态画布）

package swt_jface.demo10;import org.eclipse.swt.SWT;import org.eclipse.swt.events.PaintEvent;import org.eclipse.swt.events.PaintListener;import org.eclipse.swt.graphics.GC;import org.eclipse.swt.graphics.Image;import org.eclipse.swt.graphics.Point;import org.eclipse.swt.graphics.Rectangle;import org.eclipse.swt.layout.FillLayout;import org.eclipse.swt.widgets.Canvas;import org.eclipse.swt.widgets.Display;import org.eclipse.swt.widgets.Shell;public class DoubleBuffer {Display display = new Display();Shell shell = new Shell(display);public DoubleBuffer() {shell.setLayout(new FillLayout());final Canvas canvas = new Canvas(shell, SWT.NULL);canvas.addPaintListener(new PaintListener() {public void paintControl(PaintEvent e) {Point size = canvas.getSize();int x1 = (int) (Math.random() * size.x);int y1 = (int) (Math.random() * size.y);int x2 = Math.max(canvas.getBounds().width - x1 - 10, 50);int y2 = Math.max(canvas.getBounds().height - y1 - 10, 50);e.gc.drawRoundRectangle(x1, y1, x2, y2, 5, 5);display.timerExec(100, new Runnable() {public void run() {canvas.redraw();}});}});final Canvas doubleBufferedCanvas = new Canvas(shell, SWT.NO_BACKGROUND);doubleBufferedCanvas.addPaintListener(new PaintListener() {public void paintControl(PaintEvent e) {Image image = (Image) doubleBufferedCanvas.getData("double-buffer-image");if (image == null|| image.getBounds().width != doubleBufferedCanvas.getSize().x|| image.getBounds().height != doubleBufferedCanvas.getSize().y) {image =new Image(display,doubleBufferedCanvas.getSize().x,doubleBufferedCanvas.getSize().y);doubleBufferedCanvas.setData("double-buffer-image", image);}GC imageGC = new GC(image);imageGC.setBackground(e.gc.getBackground());imageGC.setForeground(e.gc.getForeground());imageGC.setFont(e.gc.getFont());Rectangle imageSize = image.getBounds();imageGC.fillRectangle(0, 0, imageSize.width + 1, imageSize.height + 1);Point size = doubleBufferedCanvas.getSize();int x1 = (int) (Math.random() * size.x);int y1 = (int) (Math.random() * size.y);int x2 = Math.max(doubleBufferedCanvas.getBounds().width - x1 - 10, 50);int y2 = Math.max(doubleBufferedCanvas.getBounds().height - y1 - 10, 50);imageGC.drawRoundRectangle(x1, y1, x2, y2, 5, 5);e.gc.drawImage(image, 0, 0);imageGC.dispose();display.timerExec(100, new Runnable() {public void run() {doubleBufferedCanvas.redraw();}});}});shell.setSize(300, 200);shell.open();while (!shell.isDisposed()) {if (!display.readAndDispatch()) {display.sleep();}}display.dispose();}public static void main(String[] args) {new DoubleBuffer();}}

演示代码4：（图片）

演示代码5：（画线）

package swt_jface.demo10;import org.eclipse.swt.SWT;import org.eclipse.swt.events.PaintEvent;import org.eclipse.swt.events.PaintListener;import org.eclipse.swt.layout.FillLayout;import org.eclipse.swt.widgets.Canvas;import org.eclipse.swt.widgets.Display;import org.eclipse.swt.widgets.Shell;public class Drawings {Display display = new Display();Shell shell = new Shell(display);public Drawings() {shell.setLayout(new FillLayout());Canvas canvas = new Canvas(shell, SWT.BORDER);canvas.setBackground(display.getSystemColor(SWT.COLOR_WHITE));canvas.addPaintListener(new PaintListener() {public void paintControl(PaintEvent e) {e.gc.drawString("SWT.LINE_SOLID (default)", 10, 10);e.gc.drawString("SWT.LINE_DASH", 10, 30);e.gc.drawString("SWT.LINE_DOT", 10, 50);e.gc.drawString("SWT.LINE_DASHDOT", 10, 70);e.gc.drawString("SWT.LINE_DASHDOTDOT", 10, 90);e.gc.drawString("Line width = 1 (default)", 10, 120);e.gc.drawString("Line width = 3", 10, 140);int start = 150;e.gc.setLineWidth(1);e.gc.setLineStyle(SWT.LINE_SOLID);e.gc.drawLine(start, 15, start + 200, 15);e.gc.setLineStyle(SWT.LINE_DASH);e.gc.drawLine(start, 35, start + 200, 35);e.gc.setLineStyle(SWT.LINE_DOT);e.gc.drawLine(start, 55, start + 200, 55);e.gc.setLineStyle(SWT.LINE_DASHDOT);e.gc.drawLine(start, 75, start + 200, 75);e.gc.setLineStyle(SWT.LINE_DASHDOTDOT);e.gc.drawLine(start, 95, start + 200, 95);e.gc.setLineStyle(SWT.LINE_SOLID);e.gc.drawLine(start, 125, start + 200, 125);e.gc.setLineWidth(3);e.gc.drawLine(start, 145, start + 200, 145);int[] points = new int[3 * 2];points[0] = 10;points[1] = 10;points[2] = 10; points[3] = 100;points[4] = 100; points[5] = 100;e.gc.drawPolyline(points);e.gc.setLineStyle(SWT.LINE_SOLID);e.gc.setBackground(display.getSystemColor(SWT.COLOR_DARK_GREEN));e.gc.fillArc(10, 10, 200, 100, 0, -90);e.gc.setLineStyle(SWT.LINE_DOT);e.gc.drawLine(0, 60, 220, 60);e.gc.drawLine(110, 0, 110, 120);}});shell.pack();shell.open();while (!shell.isDisposed()) {if (!display.readAndDispatch()) {display.sleep();}}display.dispose();}public static void main(String[] args) {new Drawings();}}

演示代码6：（文本效果）

演示代码7：（T型）

package swt_jface.demo10;import org.eclipse.swt.SWT;import org.eclipse.swt.events.PaintEvent;import org.eclipse.swt.events.PaintListener;import org.eclipse.swt.graphics.Image;import org.eclipse.swt.graphics.ImageData;import org.eclipse.swt.graphics.PaletteData;import org.eclipse.swt.graphics.RGB;import org.eclipse.swt.layout.FillLayout;import org.eclipse.swt.widgets.Canvas;import org.eclipse.swt.widgets.Display;import org.eclipse.swt.widgets.Shell;public class Palettes {Display display = new Display();Shell shell = new Shell(display);public Palettes() {shell.setLayout(new FillLayout());PaletteData paletteData = new PaletteData(0xFF0000, 0x00FF00, 0x0000FF);ImageData imageData = new ImageData(100, 100, 24, paletteData);for (int i = 0; i < 100; i++) { // each column.for (int j = 0; j < 100; j++) { // each row.if (j < 30 || (i > 35 && i < 65))imageData.setPixel(i, j, 0xFF);elseimageData.setPixel(i, j, 0xFFFF00);}}//int pixelValue = imageData.getPixel(50, 50);//int redComponent = pixelValue & imageData.palette.redMask;//int greenComponent = pixelValue & imageData.palette.greenMask;//int blueComponent = pixelValue & imageData.palette.blueMask;PaletteData paletteData2 =new PaletteData(new RGB[] { new RGB(0, 0, 255), // bluenew RGB(255, 255, 0) // yellow});ImageData imageData2 = new ImageData(100, 100, 1, paletteData2);for (int i = 0; i < 100; i++) { // each column.for (int j = 0; j < 100; j++) { // each row.if (j < 30 || (i > 35 && i < 65))imageData2.setPixel(i, j, 0);elseimageData2.setPixel(i, j, 1);}}System.out.println(imageData.palette.getRGB(imageData.getPixel(50, 50)));final Image image2 = new Image(display, imageData2);//final Image image = new Image(display, imageData);final Canvas canvas = new Canvas(shell, SWT.NULL);canvas.setBackground(display.getSystemColor(SWT.COLOR_WHITE));canvas.addPaintListener(new PaintListener() {public void paintControl(PaintEvent e) {e.gc.drawImage(image2, 0, 0);}});shell.pack();shell.open();while (!shell.isDisposed()) {if (!display.readAndDispatch()) {display.sleep();}}display.dispose();}public static void main(String[] args) {new Palettes();}}

演示代码8：（三环）

演示代码9：（Transparency）