Java Tutorial/SWT 2D Graphics/Transform

GC Transform

/*******************************************************************************
 * Copyright (c) 2000, 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
/* 
 * Drawing with transformations, paths and alpha blending
 *
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 * 
 * @since 3.1
 */
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.FontData;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Path;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.graphics.Transform;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;
public class TransformationDrawing {
  public static void main(String[] args) {
    final Display display = new Display();
    final Shell shell = new Shell(display);
    FontData fd = shell.getFont().getFontData()[0];
    final Font font = new Font(display, fd.getName(), 60, SWT.BOLD | SWT.ITALIC);
    final Image image = new Image(display, 640, 480);
    final Rectangle rect = image.getBounds();
    GC gc = new GC(image);
    gc.setBackground(display.getSystemColor(SWT.COLOR_RED));
    gc.fillOval(rect.x, rect.y, rect.width, rect.height);
    gc.dispose();
    shell.addListener(SWT.Paint, new Listener() {
      public void handleEvent(Event event) {
        GC gc = event.gc;
        Transform tr = new Transform(display);
        tr.translate(50, 120);
        tr.rotate(-30);
        gc.drawImage(image, 0, 0, rect.width, rect.height, 0, 0, rect.width / 2, rect.height / 2);
        gc.setAlpha(100);
        gc.setTransform(tr);
        Path path = new Path(display);
        path.addString("SWT", 0, 0, font);
        gc.setBackground(display.getSystemColor(SWT.COLOR_GREEN));
        gc.setForeground(display.getSystemColor(SWT.COLOR_BLUE));
        gc.fillPath(path);
        gc.drawPath(path);
        tr.dispose();
        path.dispose();
      }
    });
    shell.setSize(shell.ruputeSize(rect.width / 2, rect.height / 2));
    shell.open();
    while (!shell.isDisposed()) {
      if (!display.readAndDispatch())
        display.sleep();
    }
    image.dispose();
    font.dispose();
    display.dispose();
  }
}

Rotate by 45 degrees

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.graphics.Transform;
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 Rotate45Degrees {
  public static void main(String[] args) {
    final Display display = new Display();
    final Image image = new Image(display, 110, 60);
    GC gc = new GC(image);
    Font font = new Font(display, "Times", 30, SWT.BOLD);
    gc.setFont(font);
    gc.setBackground(display.getSystemColor(SWT.COLOR_RED));
    gc.fillRectangle(0, 0, 110, 60);
    gc.setForeground(display.getSystemColor(SWT.COLOR_WHITE));
    gc.drawText("SWT", 10, 10, true);
    font.dispose();
    gc.dispose();
    final Rectangle rect = image.getBounds();
    Shell shell = new Shell(display);
    shell.setText("Matrix Tranformations");
    shell.setLayout(new FillLayout());
    final Canvas canvas = new Canvas(shell, SWT.DOUBLE_BUFFERED);
    canvas.addPaintListener(new PaintListener() {
      public void paintControl(PaintEvent e) {
        GC gc = e.gc;
        gc.setAdvanced(true);
        if (!gc.getAdvanced()) {
          gc.drawText("Advanced graphics not supported", 30, 30, true);
          return;
        }
        // Original image
        int x = 30, y = 30;
        gc.drawImage(image, x, y);
        x += rect.width + 30;
        Transform transform = new Transform(display);
        // Rotate by 45 degrees 
        //float cos45 = (float)Math.cos(45);
        float cos45 = (float)Math.cos(Math.PI/4);
        
        //float sin45 = (float)Math.sin(45);
        float sin45 = (float)Math.sin(Math.PI/4);
        
        
        
        transform.setElements(cos45, sin45, -sin45, cos45, 0, 0);
        gc.setTransform(transform);
        gc.drawImage(image, 350, 100);
        
        transform.dispose();
      }
    });
    shell.setSize(350, 550);
    shell.open();
    while (!shell.isDisposed()) {
      if (!display.readAndDispatch())
        display.sleep();
    }
    image.dispose();
    display.dispose();
  }
}

Shear in the x/y-direction

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.graphics.Transform;
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 SheerXYDirection {
  public static void main(String[] args) {
    final Display display = new Display();
    final Image image = new Image(display, 110, 60);
    GC gc = new GC(image);
    Font font = new Font(display, "Times", 30, SWT.BOLD);
    gc.setFont(font);
    gc.setBackground(display.getSystemColor(SWT.COLOR_RED));
    gc.fillRectangle(0, 0, 110, 60);
    gc.setForeground(display.getSystemColor(SWT.COLOR_WHITE));
    gc.drawText("SWT", 10, 10, true);
    font.dispose();
    gc.dispose();
    final Rectangle rect = image.getBounds();
    Shell shell = new Shell(display);
    shell.setText("Matrix Tranformations");
    shell.setLayout(new FillLayout());
    final Canvas canvas = new Canvas(shell, SWT.DOUBLE_BUFFERED);
    canvas.addPaintListener(new PaintListener() {
      public void paintControl(PaintEvent e) {
        GC gc = e.gc;
        gc.setAdvanced(true);
        if (!gc.getAdvanced()) {
          gc.drawText("Advanced graphics not supported", 30, 30, true);
          return;
        }
        // Original image
        int x = 30, y = 30;
        gc.drawImage(image, x, y);
        x += rect.width + 30;
        Transform transform = new Transform(display);
        // Shear in the x-direction
        transform.setElements(1, 0, -1, 1, 0, 0);
        gc.setTransform(transform);
        gc.drawImage(image, 300, y);
        
        // Shear in y-direction
        transform.setElements(1, -1, 0, 1, 0, 0);
        gc.setTransform(transform);
        gc.drawImage(image, 150, 475);
        transform.dispose();
      }
    });
    shell.setSize(350, 550);
    shell.open();
    while (!shell.isDisposed()) {
      if (!display.readAndDispatch())
        display.sleep();
    }
    image.dispose();
    display.dispose();
  }
}

Transform: Reflect around the x/y axis.

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.graphics.Transform;
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 TransformReflectionXYAxis {
  public static void main(String[] args) {
    final Display display = new Display();
    final Image image = new Image(display, 110, 60);
    GC gc = new GC(image);
    Font font = new Font(display, "Times", 30, SWT.BOLD);
    gc.setFont(font);
    gc.setBackground(display.getSystemColor(SWT.COLOR_RED));
    gc.fillRectangle(0, 0, 110, 60);
    gc.setForeground(display.getSystemColor(SWT.COLOR_WHITE));
    gc.drawText("SWT", 10, 10, true);
    font.dispose();
    gc.dispose();
    final Rectangle rect = image.getBounds();
    Shell shell = new Shell(display);
    shell.setText("Matrix Tranformations");
    shell.setLayout(new FillLayout());
    final Canvas canvas = new Canvas(shell, SWT.DOUBLE_BUFFERED);
    canvas.addPaintListener(new PaintListener() {
      public void paintControl(PaintEvent e) {
        GC gc = e.gc;
        gc.setAdvanced(true);
        if (!gc.getAdvanced()) {
          gc.drawText("Advanced graphics not supported", 30, 30, true);
          return;
        }
        // Original image
        int x = 30, y = 30;
        gc.drawImage(image, x, y);
        x += rect.width + 30;
        Transform transform = new Transform(display);
        // Reflect around the y axis.
        transform.setElements(-1, 0, 0, 1, 0, 0);
        gc.setTransform(transform);
        gc.drawImage(image, -1 * x - rect.width, y);
        x = 30;
        y += rect.height + 30;
        // Reflect around the x axis.
        transform.setElements(1, 0, 0, -1, 0, 0);
        gc.setTransform(transform);
        gc.drawImage(image, x, -1 * y - rect.height);
        transform.dispose();
      }
    });
    shell.setSize(350, 550);
    shell.open();
    while (!shell.isDisposed()) {
      if (!display.readAndDispatch())
        display.sleep();
    }
    image.dispose();
    display.dispose();
  }
}