1

我有一个 userControl 库，它由主面板和一个 PictureBox 组成，我想做一个可缩放的 PictureBox 工具，我使用主面板的 mouseWheel 事件放大和缩小，我无法弄清楚我该怎么做的问题通过图像上的鼠标位置放大，所以每当我放大时，缩放都会转到面板的左上角，那么我该如何解决呢？

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，它看起来像工作，但不完全是应该的！有任何想法吗？

    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);
        }
    }
4

2 回答 2

2

问题是你的控件就像一个视口 - 原点在左上角，所以每次你从那个角落拉伸图像时 - 结果是你最终放大到左上角，你需要偏移拉伸的图像并将用户放大的点居中。

  • 图像大小：200,200
  • 用户点击 100,50 并放大 x2
  • 拉伸图像
  • 图像大小为 400,400，用户点击的位置现在有效为 200,100
  • 您需要将图像向左滑动 100 px 并向上滑动 50 px 以纠正重新调整图像大小

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 是由您的图片框控件定义的 Rectangle

这是一个可能有帮助的线程。

于 2012-05-22T00:41:25.870 回答
2

这是鼠标位置缩放图像的示例......经过测试验证。

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));
            }
        }
    }
}
于 2015-06-12T07:47:20.700 回答