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SWT实现图片查看

时间:22/04/2007
作者：网络
来源：网络

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此程序演示了如何在窗体上绘制图片，以及滚动条的使用方法。
代码十分简单，我就因此不做过多的解释了。
本代码在Windows XP pro, Eclipse 2.1下测试通过。
运行此程序需要进行一些有别于普通Java Application的地方，请参见我的另一篇文章，在《Eclipse Workbench之外使用SWT和JFace》。
如果文中有不妥之处，还请指正。

import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;
public class d {
public static void main (java/lang/String.java.html" target="_blank">String [] args) {
Display display = new Display ();
final Shell shell = new Shell (display,
SWT.SHELL_TRIM | SWT.NO_BACKGROUND |
SWT.NO_REDRAW_RESIZE | SWT.V_SCROLL | SWT.H_SCROLL);
Image originalImage = null;
FileDialog dialog = new FileDialog (shell, SWT.OPEN);
dialog.setText ("选择一个图片文件或者取消");
java/lang/String.java.html" target="_blank">String string = dialog.open ();
if (string != null) {
originalImage = new Image (display, string);
}
if (originalImage == null) {
int width = 150, height = 200;
originalImage = new Image (display, width, height);
GC gc = new GC (originalImage);
gc.fillRectangle (0, 0, width, height);
gc.drawLine (0, 0, width, height);
gc.drawLine (0, height, width, 0);
gc.drawText ("默认图片", 10, 10);
gc.dispose ();
}
final Image image = originalImage;
final Point origin = new Point (0, 0);
final ScrollBar hBar = shell.getHorizontalBar ();
hBar.addListener (SWT.Selection, new Listener () {
public void handleEvent (Event e) {
int hSelection = hBar.getSelection ();
int destX = -hSelection - origin.x;
origin.x = -hSelection;
Rectangle rect = image.getBounds ();
shell.scroll (destX, 0, 0, 0, rect.width, rect.height, false);
}
});
final ScrollBar vBar = shell.getVerticalBar ();
vBar.addListener (SWT.Selection, new Listener () {
public void handleEvent (Event e) {
int vSelection = vBar.getSelection ();
int destY = -vSelection - origin.y;
origin.y = -vSelection;
Rectangle rect = image.getBounds ();
shell.scroll (0, destY, 0, 0, rect.width, rect.height, false);
}
});
shell.addListener (SWT.Resize, new Listener () {
public void handleEvent (Event e) {
Rectangle rect = image.getBounds ();
Rectangle client = shell.getClientArea ();
hBar.setMaximum (rect.width);
vBar.setMaximum (rect.height);
hBar.setThumb (java/lang/Math.java.html" target="_blank">Math.min (rect.width, client.width));
vBar.setThumb (java/lang/Math.java.html" target="_blank">Math.min (rect.height, client.height));
int hPage = rect.width - client.width;
int vPage = rect.height - client.height;
int hSelection = hBar.getSelection ();
int vSelection = vBar.getSelection ();
if (hSelection >= hPage) {
if (hPage <= 0) hSelection = 0;
origin.x = -hSelection;
}
if (vSelection >= vPage) {
if (vPage <= 0) vSelection = 0;
origin.y = -vSelection;
}
shell.redraw ();
}
});
shell.addListener (SWT.Paint, new Listener () {
public void handleEvent (Event e) {
GC gc = e.gc;
gc.drawImage (image, origin.x, origin.y);
Rectangle rect = image.getBounds ();
Rectangle client = shell.getClientArea ();
int marginWidth = client.width - rect.width;
if (marginWidth > 0) {
gc.fillRectangle (rect.width, 0, marginWidth, client.height);
}
int marginHeight = client.height - rect.height;
if (marginHeight > 0) {
gc.fillRectangle (0, rect.height, client.width, marginHeight);
}
}
});
shell.setSize (200, 150);
shell.open ();
while (!shell.isDisposed ()) {
if (!display.readAndDispatch ()) display.sleep ();
}
display.dispose ();
}
}