所以我写了一个程序,它根据给定的“模型”生成一个水平“时间线”条,高度为 50 像素,长度约为 84600 像素。每个像素代表一秒,因为它在 24 小时内以秒为单位对事件进行建模。
问题是,在 32768 像素之后,条被切断。
我已经阅读了解决方案,例如使用 ScrolledComposite 仅显示画布的一部分并在显示新数据时进行滚动,因为滚动条是通过缓冲拖动完成的,但我根本不熟悉如何执行此操作。
我看到的另一个解决方案是不使用 ScrolledComposite 而只使用 canvas.scroll,如果我的源代码运行(测试程序来说明我的问题),问题很明显,滚动条不会滚动以允许显示整个画布,此“解决方案”的测试程序如下所示。请帮忙!
package canvas;
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.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.ScrollBar;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Event;
public class Test {
static int shellStyle = SWT.NO_REDRAW_RESIZE | SWT.NO_BACKGROUND | SWT.H_SCROLL;
static int canvasStyle = SWT.NO_REDRAW_RESIZE;// | SWT.H_SCROLL | SWT.V_SCROLL;
public static void main(String[] args) {
final Display display = new Display();
final Shell shell = new Shell(display, shellStyle);
shell.setLayout(new FillLayout());
shell.setBackground(display.getSystemColor((SWT.COLOR_CYAN)));
shell.setText("Canvas Test");
Image image;
final Canvas canvas = new Canvas(shell, canvasStyle);
canvas.setLayout(new FillLayout());
canvas.setBackground(display.getSystemColor(SWT.COLOR_WHITE));
final Point origin = new Point(0,0);
final ScrollBar hBar = shell.getHorizontalBar();
Rectangle size = canvas.getBounds();
hBar.setMaximum(size.width);
hBar.setMinimum(0);
// Create a paint handler for the canvas
canvas.addPaintListener(new PaintListener() {
public void paintControl(PaintEvent e) {
// Do some drawing
e.gc.setBackground(display.getSystemColor(SWT.COLOR_DARK_YELLOW));
e.gc.fillRectangle(100, 200, 100, 200);
e.gc.setBackground(display.getSystemColor(SWT.COLOR_DARK_CYAN));
e.gc.fillRectangle(900, 200, 600, 200);
e.gc.setBackground(display.getSystemColor(SWT.COLOR_DARK_MAGENTA));
e.gc.fillRectangle(500, 200, 300, 200);
e.gc.setBackground(display.getSystemColor(SWT.COLOR_GRAY));
e.gc.fillRectangle(1600, 200, 300, 200);
}
});
// The below event handlers allow for horizontal scrolling functionality
hBar.addListener(SWT.Selection, new Listener() {
public void handleEvent(Event e) {
int x = 0;
int hSelection = hBar.getSelection();
int destX = -hSelection - origin.x;
Rectangle rect = shell.getBounds();
canvas.scroll(destX, 0, x, 0, rect.width, rect.height, false);
origin.x = -hSelection;
x = destX;
}
});
shell.addListener(SWT.Resize, new Listener() {
public void handleEvent(Event e) {
Rectangle rect = canvas.getClientArea();
Rectangle client = shell.getClientArea();
hBar.setMaximum(rect.width);
hBar.setThumb(Math.min(rect.width, client.width));
int hPage = rect.width - client.width;
int hSelection = hBar.getSelection();
if (hSelection >= hPage) {
if (hPage <= 0)
hSelection = 0;
origin.x = -hSelection;
}
shell.redraw();
}
});
shell.open();
while(!shell.isDisposed()) {
if(!display.readAndDispatch()) {
display.sleep();
}
}
display.dispose();
}
}
编辑:嘿谢谢p12t! 只是一个问题...这一行:final Point timelineSize = new Point(84600, 50);
那么这是否意味着每个 x 轴像素都有一个“点”,但向下 50 个 y 轴像素?如:++++++++++
. . . . . . . . . .
因此,每个“+ 号”是一个水平 x 轴像素,84600 个“点”是“周期”,如图所示 50 个 y 轴像素向下。我对此的理解正确吗?(顺便说一句,我上面显示的示例说明了 10 个点)
您还认为我做错了什么?或者我错误地实现了它..