如何在不透明度为0.3的窗体上绘制零不透明橡皮筋？
(橡皮筋是在 Microsoft例之后制作的
(橡皮筋是在 Microsoft例之后制作的
更新：
我需要那个橡皮筋来做像面具一样的东西.如果您使用Jing或任何其他屏幕截图工具,您将在尝试制作屏幕截图时完全看到我需要做的事情：屏幕变为半透明,当您进行选择时,您将看到0不透明度选择
解决方法
这是你要找的机器人吗？
- public Form1()
- {
- InitializeComponent();
- DoubleBuffered = true;
- }
- bool mouseDown = false;
- Point mouseDownPoint = Point.Empty;
- Point mousePoint = Point.Empty;
- protected override void OnMouseDown(MouseEventArgs e)
- {
- base.OnMouseDown(e);
- mouseDown = true;
- mousePoint = mouseDownPoint = e.Location;
- }
- protected override void OnMouseUp(MouseEventArgs e)
- {
- base.OnMouseUp(e);
- mouseDown = false;
- }
- protected override void OnMouseMove(MouseEventArgs e)
- {
- base.OnMouseMove(e);
- mousePoint = e.Location;
- Invalidate();
- }
- protected override void OnPaint(PaintEventArgs e)
- {
- base.OnPaint(e);
- if (mouseDown)
- {
- Region r = new Region(this.ClientRectangle);
- Rectangle window = new Rectangle(
- Math.Min(mouseDownPoint.X,mousePoint.X),Math.Min(mouseDownPoint.Y,mousePoint.Y),Math.Abs(mouseDownPoint.X - mousePoint.X),Math.Abs(mouseDownPoint.Y - mousePoint.Y));
- r.Xor(window);
- e.Graphics.FillRegion(Brushes.Red,r);
- Console.WriteLine("Painted: " + window);
- }
- }
