写一个eclipse程序，画一个长方形并可以用鼠标滚轮和键盘快捷键进行图形放大缩小

好的，以下是一个简单实现该功能的Eclipse程序：

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.KeyEvent;
import org.eclipse.swt.events.KeyListener;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.events.MouseWheelListener;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.GC;
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 RectangleDrawing {
    public static void main(String[] args) {
        Display display = new Display();
        Shell shell = new Shell(display);
        shell.setLayout(new FillLayout());
        shell.setText("Rectangle Drawing");

        // 创建一个画布并在其中绘制长方形
        Canvas canvas = new Canvas(shell, SWT.NONE);
        canvas.addPaintListener(event -> {
            GC gc = event.gc;
            gc.setForeground(new Color(display, 255, 0, 0));
            gc.drawRectangle(50, 50, 100, 80);
        });

        // 监听鼠标滚轮事件并缩放画布
        canvas.addMouseWheelListener(new MouseWheelListener() {
            @Override
            public void mouseScrolled(MouseEvent event) {
                int zoom = event.count > 0 ? 1 : -1;
                canvas.setScale(canvas.getScale() + zoom);
                canvas.redraw();
            }
        });

        // 监听键盘事件并缩放画布
        canvas.addKeyListener(new KeyListener() {
            @Override
            public void keyPressed(KeyEvent event) {
                if (event.keyCode == '+') {
                    canvas.setScale(canvas.getScale() + 1);
                    canvas.redraw();
                } else if (event.keyCode == '-') {
                    canvas.setScale(canvas.getScale() - 1);
                    canvas.redraw();
                }
            }
            @Override
            public void keyReleased(KeyEvent event) { }
        });

        // 设置画布的缩放和滚动条
        canvas.setScale(1);
        canvas.setOrigin(new Point(0, 0));
        canvas.setMinSize(500, 400);
        canvas.addControlListener(event -> {
            Rectangle clientArea = canvas.getClientArea();
            canvas.setMinSize(clientArea.width, clientArea.height);
        });

        shell.setSize(600, 500);
        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) {
                display.sleep();
            }
        }
        display.dispose();
    }
}

程序中创建了一个画布`Canvas`，使用`GC`对象在其中绘制了一个长方形。同时，监听了鼠标滚轮事件和键盘事件，实现了画布的缩放功能。其中，鼠标滚轮事件通过`Canvas`对象的`setScale`方法实现，键盘事件则根据不同的按键实现缩放的方向。最后，设置了画布的缩放和滚动条的属性，确保画布可以被正确缩放和显示。