Zoom at PictureBox

Nikos Rak

I have a Picture box at dock in parent container . And I want to create a button that it can zoom the picture in the PictureBox and unzoom it !!! have anyone any idea or a tutorial that it could help me ?

12 Replies

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Hemant Srivastava12y ago
Accepted answer
Add a TrackBar and On TrackBarScroll event use the follwoing code:

        private void trackBar1_Scroll(object sender, EventArgs e)
        {
            double zoomlevel = 1+ trackBar1.Value * 0.1;
            ZoomIN(zoomlevel);
        }
        private void ZoomIN(double zoomLevel)
        {
            System.Drawing.Rectangle screenSize = new System.Drawing.Rectangle();
            screenSize.Width = SystemInformation.VirtualScreen.Width;
            screenSize.Height = SystemInformation.VirtualScreen.Height;
            //int zoomFactor = 10;
            Image img = pictureBox1.Image;
            Bitmap bitMapImg = new Bitmap(img);

            if (bitMapImg.Width < screenSize.Width && bitMapImg.Height < screenSize.Height)
            {
                Size newSize = new Size((int)(bitMapImg.Width * zoomLevel), (int)(bitMapImg.Height * zoomLevel));
                Bitmap bmp = new Bitmap(bitMapImg, newSize);
                pictureBox1.Image = (Image)bmp;
            }
        }
Hemant Srivastava12y ago
Find the attached sample project for zoom in and zoom out using track bar.
Nikos Rak12y ago
Yes , I mean gradually zooming out using track bar ! how ?
Hemant Srivastava12y ago
You mean, you want gradually zooming out using track bar ? If yes, you could do it.

I proposed the "Preserving" solution for Unzoom thinking that you mean 'Unzoom' is removing zoom completly at once.
Nikos Rak12y ago
I can't do it with the TrackBar ?
Hemant Srivastava12y ago
It it helped you, please mark the answer accepted.
Hemant Srivastava12y ago
To undo zooming, you can preserve size (Height and Width) of Image at the very first in some variable and when you press the UnZoom button, you may load the image with the same preserved dimensions into the picture box.
Nikos Rak12y ago
First you are awesome :D and second what about unzoom ?
Nikos Rak12y ago
it needs code the trackbar ? ,sure yes but what code ,
Hemant Srivastava12y ago
If you want to do zoom gradually, I think you need to do it by using TrackBar (Slider) instead of button and map the TrackBar value into into a range in which you need zooming.
Nikos Rak12y ago
this zoom it just zoom alot the picture I need to zoom at stages .. I mean if zoom = 1.0 to be 1.1 after 1.1 to 1.2 etc etc ... and for unzoom if zoom = 1.2 to 1.1
Hemant Srivastava12y ago
You can zoom in this way:
        private void btn_ZoomIN_Click(object sender, EventArgs e)
        {
            System.Drawing.Rectangle screenSize = new System.Drawing.Rectangle();
            screenSize.Width = SystemInformation.VirtualScreen.Width;
            screenSize.Height = SystemInformation.VirtualScreen.Height;
            int zoomFactor = 10;
            Image img = pictureBox1.Image;
            Bitmap bitMapImg = new Bitmap(img);

            if (bitMapImg.Width < screenSize.Width && bitMapImg.Height < screenSize.Height)
            {
                Size newSize = new Size((int)(bitMapImg.Width * zoomFactor), (int)(bitMapImg.Height * zoomFactor));
                Bitmap bmp = new Bitmap(bitMapImg, newSize);
                pictureBox1.Image = (Image)bmp;
            }
        }

Note: But to see zooming, you need to add scrollbar on your picture Box.

To get scroll bar on Picture Box:

Place your PictureBox into Panel.
Set 'SizeMode' property of PictureBox to "AutoSize"