放大和缩小 PictureBox C#

Question

我正在使用 WinForms。在我的应用程序中，我有一个按钮可以在图片框中打开图片。此应用程序用于使用鼠标滚动放大和缩小图片。我可以很好地放大和缩小，但我的问题是有时当我使用鼠标中的滚轮放大或缩小时，我的应用程序似乎变得混乱。有时混淆的意思是，例如，如果我向前滚动，它会在应该放大的时候开始缩小。我不明白我在代码中做错了什么让程序感到困惑。有没有更好的放大和缩小方法或者我该如何解决这个问题？

我的代码：

    int zoomInt = 0;

    private void Open_btn_Click(object sender, EventArgs e)
    {
        Image image; 

        // open file dialog
        OpenFileDialog open = new OpenFileDialog();
        // image filters
        open.Filter = "Image Files(*.jpg; *.jpeg; *.gif; *.bmp)|*.jpg; *.jpeg; *.gif; *.bmp";
        if (open.ShowDialog() == DialogResult.OK)
        {
            image = Image.FromFile(open.FileName);
            pictureBox1.Image = image; 
        }
    }

    protected override void OnMouseWheel(MouseEventArgs e)
    {
        if (e.Delta > 0)
        {
            zoomInt++;
            if (zoomInt > 4)
            {
                zoomInt = 4;
            }
            zoomPicturebox();
        }
        else if (e.Delta < 0)
        {
            zoomInt--;
            if (zoomInt < -3)
            {
                zoomInt = -3;
            }
            zoomPicturebox();
        }
    }

    public void zoomPicturebox()
    {
        switch (zoomInt)
        {
            case -3:
                this.pictureBox1.Width -= 210; //Zoom width by 210
                this.pictureBox1.Height -= 210; //Zoom height by 210
                break;
            case -2:
                this.pictureBox1.Width -= 155; //Zoom width by 155
                this.pictureBox1.Height -= 155; //Zoom height by 155
                break;
            case -1:
                this.pictureBox1.Width -= 65; //Zoom width by 75
                this.pictureBox1.Height -= 65; //Zoom height by 75
                break;
            case 0:
                pictureBox1.Size = new Size(850, 1100);
                break;
            case 1:
                this.pictureBox1.Width += 75; //Zoom width by 75
                this.pictureBox1.Height += 75; //Zoom height by 75
                break;
            case 2:
                this.pictureBox1.Width += 150; //Zoom width by 150
                this.pictureBox1.Height += 150; //Zoom height by 150
                break;
            case 3:
                this.pictureBox1.Width += 175; //Zoom width by 175
                this.pictureBox1.Height += 175; //Zoom height by 175
                break;
            case 4:
                this.pictureBox1.Width += 200; //Zoom width by 175
                this.pictureBox1.Height += 200; //Zoom height by 175
                break;
        }
        pictureBox1.Refresh(); //Helps causing pictures from getting pixialated: Forces the control to invalidate its client area and immediately redraw itself and any child controls
    }

Answer 1

我通过删除 public void zoomPicturebox() 方法并在下面添加这些更改解决了这个问题：

    protected override void OnMouseWheel(MouseEventArgs e)
    {
        if (e.Delta != 0)
        {
            if (e.Delta <= 0)
            {
                //set minimum size to zoom
                if (pictureBox1.Width < 50)
                // lbl_Zoom.Text = pictureBox1.Image.Size; 
                    return;
            }
            else
            {
                //set maximum size to zoom
                if (pictureBox1.Width > 1000)
                    return;
            }
            pictureBox1.Width += Convert.ToInt32(pictureBox1.Width * e.Delta / 1000);
            pictureBox1.Height += Convert.ToInt32(pictureBox1.Height * e.Delta / 1000);
        }
    }

放大和缩小 PictureBox C#

Zoom In and Zoom out PictureBox C#

.net

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winforms