Getting image position within picturebox

Hello,

Is there a way I can get the position of the image within the picture box at all?

Thanks,
Uni
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Unimatrix_001Asked:
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Bob LearnedCommented:
I don't understand what you are asking...are you talking about something like SizeMode = CenterImage?
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Unimatrix_001Author Commented:
Yes, sort of except I'm having to use SizeMode=Zoom, which has the nasty habit of centering the image within the picturebox. The dark background indicated the picture box:


Screen.JPG
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Bob LearnedCommented:
If the PictureBox has a certain width, and the image has a certain width, and the image is centered, then the image left position is half the difference between the PictureBox width and the image width.
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Unimatrix_001Author Commented:
Hm, I hadn't thought of that!... I'll be back in a little while as that may be what I'm after, I'll just do a few tests. :)
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Unimatrix_001Author Commented:
Hm, I think it may be doable, but perhaps I'm messing up the maths. What I've got is a picture box set to zoom and the picture box is inside a panel which is set to autoscroll, this lets me have a scrollable picture. I've implemented zoom in/out buttons by simply altering the picturebox width and height, although I'm now wanting to be able to 'draw' on the picture, which is fine by handling the picturebox draw event, but I'm having difficulty getting the shape to draw in the same place all the time in relation to the image.
private void picboxMainImage_Paint(object sender, PaintEventArgs e) {
 
	int imgTop=0;
	if(picboxMainImage.Height-picboxMainImage.Image.Height>0)
		imgTop=(picboxMainImage.Height-picboxMainImage.Image.Height)/2;
 
	int imgLeft=0;
	if(picboxMainImage.Width-picboxMainImage.Image.Width>0)
		imgLeft=(picboxMainImage.Width-picboxMainImage.Image.Width)/2;
	else if(picboxMainImage.Image.Width-picboxMainImage.Width>0)
		imgLeft=(picboxMainImage.Image.Width-picboxMainImage.Width)/2;
 
	e.Graphics.FillRectangle(Brushes.AliceBlue, 20+imgLeft, 50+imgTop, 100, 100);
}

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Bob LearnedCommented:
You might think about zooming, by setting the SizeMode = Stretch, and then changing the image size, not the PictureBox size.

PictureBox Zoom
http://www.codeproject.com/KB/graphics/PictureBoxZoom.aspx
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Unimatrix_001Author Commented:
Hi,

I'm unsure how that would help me with the ability to draw on the image?

Thanks,
Uni
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Bob LearnedCommented:
What do you mean by "ability to draw on the image"?  Are drawing and zooming, or just zooming?
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Unimatrix_001Author Commented:
Drawing and zooming.
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Bob LearnedCommented:
In order to draw on the image, you would create a Graphics object from the Image, and then draw with the Graphics object.  It also gives you the ability to change the image dimensions, as shown in the article above.
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Unimatrix_001Author Commented:
Ah, so you're saying I shouldn't be drawing in the PictureBox draw event, but should draw to the actual Image that PictureBox has?
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Bob LearnedCommented:
Here is an example of what I mean:

Draw shapes to the bitmap in memory
http://www.java2s.com/Code/CSharp/2D-Graphics/Drawshapestothebitmapinmemory.htm
        private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
        {
            gForm.FillRectangle(Brushes.White, this.ClientRectangle);
 
            // Create a Bitmap image in memory and set its CompositingMode
            using (Bitmap bmp = new Bitmap(260, 260, PixelFormat.Format32bppArgb))
            {
                Graphics gBmp = Graphics.FromImage(bmp);
                gBmp.CompositingMode = CompositingMode.SourceCopy;
 
                // draw a red circle to the bitmap in memory
                Color red = Color.FromArgb(0x60, 0xff, 0, 0);
                using (Brush redBrush = new SolidBrush(red))
                {
                    gBmp.FillEllipse(redBrush, 70, 70, 160, 160);
 
                    // draw a green rectangle to the bitmap in memory
                    Color green = Color.FromArgb(0x40, 0, 0xff, 0);
                    using (SolidBrush greenBrush = new SolidBrush(green))
                    {
                        gBmp.FillRectangle(greenBrush, 10, 10, 140, 140);
 
                        // draw the bitmap on our window
                        gForm.DrawImage(bmp, 20, 20, bmp.Width, bmp.Height);
 
                    }
                }
            }
        }

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Unimatrix_001Author Commented:
Thank you - I'll see what I come up with. :)
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