Winforms:可拖动的透明矩形

Question

早上,

我现在准备好在这一点上抓住自己的眼睛.我正在使用.NET 3.5上的Windows窗体构建一个基本的图像编辑器,我需要的是一个"选择工具".单击按钮时需要显示此工具,并且该工具将是固定大小,它需要是具有透明中心的拖放式矩形.

这样做的目的就是像"画框"一样,用户可以将矩形拖放到图像的一部分上,然后点击另一个按钮来快照该点矩形内的任何内容.(请注意:我不需要橡皮筋矩形,它必须是固定尺寸,在整个表格上可拖动并且透明).

我花了几天时间在互联网上搜索这个网站寻找可能的解决方案,其中没有任何一个有用.我已设法使控件可拖动 - 但这会带来透明度方面的问题.下面是使控件可拖动的代码,但我不确定这是正确的路径.

 class ControlMover
{
    public enum Direction
    {
        Any,
        Horizontal,
        Vertical
    }

    public static void Init(Control control)
    {
        Init(control, Direction.Any);
    }

    public static void Init(Control control, Direction direction)
    {
        Init(control, control, direction);
    }

    public static void Init(Control control, Control container, Direction direction)
    {
        EditorForm.blnSelectArea = true;
        bool Dragging = false;
        Point DragStart = Point.Empty;
        control.MouseDown += delegate(object sender, MouseEventArgs e)
        {
            Dragging = true;
            DragStart = new Point(e.X, e.Y);
            control.Capture = true;
        };
        control.MouseUp += delegate(object sender, MouseEventArgs e)
        {
            Dragging = false;
            control.Capture = false;
        };
        control.MouseMove += delegate(object sender, MouseEventArgs e)
        {
            if (Dragging)
            {
                if (direction != Direction.Vertical)
                    container.Left = Math.Max(0, e.X + container.Left - DragStart.X);
                if (direction != Direction.Horizontal)
                    container.Top = Math.Max(0, e.Y + container.Top - DragStart.Y);

                control.Invalidate();

            }
        };
    }
}  

任何人都可以指出我正确的方向或建议在哪里看.

非常感谢

Answer 1

我实际上为屏幕捕获做了一个应用,按照你描述的方式工作,使它可以拖动我使用鼠标事件.为了使它透明,我简单地制作了另一个Form控件,使用半透明的png Image作为背景图像.

public partial class Photo : Form
    {
        public delegate void ScreenShotReadyDelegate(Bitmap g);
        public event ScreenShotReadyDelegate ScreenShotReady;

        bool Moving = false;
        Point oldLoc = new Point();

        public Photo()
        {
            InitializeComponent();
            this.FormBorderStyle = FormBorderStyle.None;
            this.DoubleBuffered = true;
            this.SetStyle(ControlStyles.ResizeRedraw, true);
        } 

        private void Photo_MouseDoubleClick(object sender, MouseEventArgs e)
        {
            this.BackgroundImage = null;
            this.Invalidate();
            Rectangle bounds = this.Bounds;
            using (Bitmap bitmap = new Bitmap(bounds.Width, bounds.Height))
            {
                using (Graphics g = Graphics.FromImage(bitmap))
                {
                    g.CopyFromScreen(new Point(bounds.Left, bounds.Top), Point.Empty, bounds.Size);
                }
                ScreenShotReady(bitmap);
            }
            this.BackgroundImage = Properties.Resources.rect;
            this.Invalidate();
        }

        private void Photo_MouseDown(object sender, MouseEventArgs e)
        {
            this.Moving = true;
            this.oldLoc = MousePosition;
        }

        private void Photo_MouseMove(object sender, MouseEventArgs e)
        {
            if (this.Moving)
            {
                Point vector = new Point(MousePosition.X - this.oldLoc.X, MousePosition.Y - this.oldLoc.Y);
                this.Location = new Point(this.Location.X + vector.X, this.Location.Y + vector.Y);
                this.oldLoc = MousePosition;
            }
        }

        private void Photo_MouseUp(object sender, MouseEventArgs e)
        {
            this.Moving = false;
        }
    }