Question

我有一个userControl库，它包含主Panel和PictureBox，我想制作一个可缩放的PictureBox工具，我使用主面板的mouseWheel事件放大和缩小，我无法弄清楚的问题如何通过图像上的鼠标位置放大，因此每当我放大时，缩放都会进入面板的左上角，那么我该如何解决？

private double ZOOMFACTOR = 1.15;   // = 15% smaller or larger
private int MINMAX = 5;
void picPanel_MouseWheel(object sender, MouseEventArgs e)
    {
        if (e.Delta > 0)
        {
            ZoomIn();
        }
        else
        {
            ZoomOut();
        }
    }

    private void ZoomIn()
    {
        if ((picBox.Width < (MINMAX * this.Width)) &&
            (picBox.Height < (MINMAX * this.Height)))
        {
            picBox.Width = Convert.ToInt32(picBox.Width * ZOOMFACTOR);
            picBox.Height = Convert.ToInt32(picBox.Height * ZOOMFACTOR);
        }
    } 
    private void picBox_MouseEnter(object sender, EventArgs e)
    {
        if (picBox.Focused) return;
        picBox.Focus();
    }

更新：

我试过这个，它看起来像是在工作，但不完全是应该的！有什么想法吗？

    private void ZoomIn()
    {
        if ((picBox.Width < (MINMAX * this.Width)) &&
            (picBox.Height < (MINMAX * this.Height)))
        {
            picBox.Width = Convert.ToInt32(picBox.Width * ZOOMFACTOR);
            picBox.Height = Convert.ToInt32(picBox.Height * ZOOMFACTOR);

            Point p = this.AutoScrollPosition;
            int deltaX = e.X - p.X;
            int deltaY = e.Y - p.Y;
            this.AutoScrollPosition = new Point(deltaX, deltaY);
        }
    }

Answer 1

问题在于你的控件就像一个视口 - 原点是左上角，所以每当你从那个角落拉伸你的图像时 - 结果是你最后放大到左上角，你需要偏移拉伸的图像并使用户放大的点居中。

图片大小：200,200
用户点击100,50并放大x2
拉伸图片
图片大小为400,400，用户点击的位置现在实际上为200,100
您需要向左滑动100像素，向上滑动50像素以更正图像重新调整大小

您需要覆盖paint事件处理程序以绘制图像偏移量：

 RectangleF BmpRect = new RectangleF((float)(Offset.X), (float)(Offset.Y), (float)(ZoomedWidth), (float)(ZoomedHeight));
  e.Graphics.DrawImage(Bmp, ViewPort , BmpRect, GraphicsUnit.Pixel);

Bmp是你的形象; ViewPort是由pictureBox控件

定义的Rectangle

以下a thread可能有所帮助。

Answer 2

这是鼠标位置上缩放图像的示例.... 测试非常.. Mrittunjay Sharma 9599720337

protected override void OnMouseWheel(MouseEventArgs ea)
    {
        //  flag = 1;
        // Override OnMouseWheel event, for zooming in/out with the scroll wheel
        if (picmap1.Image != null)
        {
            // If the mouse wheel is moved forward (Zoom in)
            if (ea.Delta > 0)
            {
                // Check if the pictureBox dimensions are in range (15 is the minimum and maximum zoom level)
                if ((picmap1.Width < (15 * this.Width)) && (picmap1.Height < (15 * this.Height)))
                {
                    // Change the size of the picturebox, multiply it by the ZOOMFACTOR
                    picmap1.Width = (int)(picmap1.Width * 1.25);
                    picmap1.Height = (int)(picmap1.Height * 1.25);

                    // Formula to move the picturebox, to zoom in the point selected by the mouse cursor
                    picmap1.Top = (int)(ea.Y - 1.25 * (ea.Y - picmap1.Top));
                    picmap1.Left = (int)(ea.X - 1.25 * (ea.X - picmap1.Left));



                }
            }
            else
            {
                // Check if the pictureBox dimensions are in range (15 is the minimum and maximum zoom level)
                if ((picmap1.Width > (imagemappan.Width)) && (picmap1.Height > (imagemappan.Height)))
                {// Change the size of the picturebox, divide it by the ZOOMFACTOR
                    picmap1.Width = (int)(picmap1.Width / 1.25);
                    picmap1.Height = (int)(picmap1.Height / 1.25);

                    // Formula to move the picturebox, to zoom in the point selected by the mouse cursor
                    picmap1.Top = (int)(ea.Y - 0.80 * (ea.Y - picmap1.Top));
                    picmap1.Left = (int)(ea.X - 0.80 * (ea.X - picmap1.Left));

                }
            }
        }
    }

如何使用该图像上的鼠标位置放大

2 个答案: