How do I scale a picture with a point as the center?

卓越暗影大人

Hello everyone!
    I put a picturebox in the panel. If the picture is too large, the panel cannot display the whole picture. I want to scale a part of the picture displayed by the panel, and the center of the rectangle is the center to scale the picture.
    Another problem is how to call the middle mouse button to achieve zooming.
    Thank you!

lygzgs

Just set the SizeMode property of the picturebox to Zoom.

qianliniu

Upstairs solution

卓越暗影大人

So how to call the middle mouse wheel to zoom? Thank you

irwin8888

The pulley seems to be triggered by an event

ak41sl

Even here is a demo, very simple zooming. You can contact me if needed.

ak41sl

I post the code here.

ak41sl

private Point mousePosition = new Point (0, 0);

        public Form1 ()
        {
            InitializeComponent ();
        }

        private void minPanel_Paint (object sender, PaintEventArgs e)
        {
            Graphics g = this.minPanel.CreateGraphics ();
            Image img = Image.FromFile (Application.StartupPath + @ "\7.jpg");
            g.DrawImage (img, this.minPanel.ClientRectangle, 0, 0, img.Width, img.Height, System.Drawing.GraphicsUnit.Pixel);

        }

        private void minPanel_MouseDown (object sender, MouseEventArgs e)
        {
            this.controlframe.Left = e.X;
            this.controlframe.Top = e.Y;
            DrawBig ();
            DrawSmall ();
        }

        private void controlframe_Paint (object sender, PaintEventArgs e)
        {
            DrawSmall ();
        }

        private void controlframe_MouseUp (object sender, MouseEventArgs e)
        {
            DrawSmall ();

            DrawBig ();
        }

        private void controlframe_MouseMove (object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                if (e.X> = 0&&e.X <= this.minPanel.ClientRectangle.Width&&e.Y> = 0&&e.Y <= this.minPanel.ClientRectangle.Height)
                {
                    this.controlframe.Left = e.X + this.mousePosition.X;
                    this.controlframe.Top = e.Y + this.mousePosition.Y;
                    DrawSmall ();
                    DrawBig ();
                }
            }
        }

        private void controlframe_MouseDown (object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                this.mousePosition.X = this.controlframe.Left;
                this.mousePosition.Y = this.controlframe.Top;
                this.DrawSmall ();
                this.DrawBig ();
                //this.Dispose;
            }
        }

        private void DrawSmall ()
        {
            Graphics g = this.controlframe.CreateGraphics ();
            Bitmap bmp = new Bitmap ((Bitmap) Bitmap.FromFile (Application.StartupPath + @ "\7.jpg"), new Size (this.minPanel.Width, this.minPanel.Height));
            g.DrawImage (bmp, this.controlframe.ClientRectangle, this.controlframe.Left, this.controlframe.Top, this.controlframe.ClientRectangle.Width, this.controlframe.ClientRectangle.Height, System.Drawing.GraphicsUnit.Pixel);
            g.Dispose ();
            this.controlframe.Update ();
        }

        private void DrawBig ()
        {
            Graphics g = this.maxPanel.CreateGraphics ();
            Image img = Image.FromFile (Application.StartupPath + @ "\7.jpg");
            g.DrawImage (img, this.maxPanel.ClientRectangle, this.controlframe.Left, this.controlframe.Top, this.maxPanel.ClientRectangle.Width, this.maxPanel.ClientRectangle.Height, System.Drawing.GraphicsUnit.Pixel);
            g.Dispose ();
            this.minPanel.Update ();
        }

kobexyn

up

卓越暗影大人

The pulley is triggered by an event, but how to judge
Does the pulley roll up and down?