即使被滚动条隐藏,也可以打印swt组件

Question

我尝试将swt TreeViewer打印到png文件.附:

Tree tree = treeViewer.getTree();
Image image = new Image(display, tree.getSize().x, tree.getParent().getSize().y);
GC gc = new GC(image);

System.out.println(new File(pathToSave).getAbsolutePath());
tree.print(gc);

ImageLoader loader = new ImageLoader();
loader.data = new ImageData[] { image.getImageData() };
loader.save(pathToSave, SWT.IMAGE_PNG);
gc.dispose();
image.dispose();

png仅包含树的可见部分.树有一个滚动条,因为它包含的元素多于表单上的元素.

我想打印所有元素可见而没有滚动条的树.有任何想法吗？

在swing组件上我可以使用.paintall().. swt组件似乎不知道.

Answer 1

首先,图像的大小应该具有树没有滚动的大小,而不是当前大小.为此你应该使用computeSize(SWT.DEFAULT, SWT.DEFAULT, true).然后你应该调整大小的树,打印,然后重新调整大小.由于您不希望用户注意到这一点,因此在此操作期间您应禁用绘图setRedraw(false).

这是一个完整的片段,完成所有这些:

public static void main(String[] args) {
    final Display display = new Display();
    final Shell shell = new Shell(display);
    shell.setLayout(new FillLayout());
    Composite composite = new Composite(shell, SWT.NONE);
    composite.setLayout(new FillLayout());

    final Tree tree = new Tree(composite, SWT.NONE);
    for (int i = 0; i < 100; i++) {
        final TreeItem treeItem = new TreeItem(tree, SWT.NONE);
        treeItem.setText(String.format("item %d long                      name", i));
    }
    tree.addListener(SWT.DefaultSelection, new Listener() {
        @Override
        public void handleEvent(Event event) {
            tree.getParent().setRedraw(false);
            final Point originalSize = tree.getSize();
            final Point size = tree.computeSize(SWT.DEFAULT, SWT.DEFAULT, true);
            final Image image = new Image(display, size.x, size.y);
            final GC gc = new GC(image);

            tree.setSize(size);
            tree.print(gc);
            tree.setSize(originalSize);

            final ImageLoader loader = new ImageLoader();
            loader.data = new ImageData[]{image.getImageData()};
            final String pathToSave = "out.png";
            System.out.println(new File(pathToSave).getAbsolutePath());
            loader.save(pathToSave, SWT.IMAGE_PNG);
            gc.dispose();
            image.dispose();
            tree.getParent().setRedraw(true);
        }
    });

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

按enter键保存文件.