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I have a Canvass (PictureBox) and Shapes, Images or Text can be drawn on it as seen int he picture below. What I want to do now is to save them all into one BITMAP File. I have no idea so how do I start?

PS: I'm using different Graphics object to draw each.

Found a workaround, this will save the drawings in my pictureBox/Canvass.

private void button2_Click(object sender, EventArgs e)
 
 SaveFileDialog save = new SaveFileDialog();

 //Creates a filter fir saving the Project File
 save.Filter = "Image Files(*.jpg; *.jpeg; *.gif; *.bmp); *.PNG

SAMPLE OUTPUT

Graphics is a "device context" object. It handles drawings on to Bitmap, but it cannot be converted back to Bitmap.

You can however copy the bits already painted on your window, and draw on to Graphics. For example:

protected override void OnMouseClick(MouseEventArgs e)

 base.OnMouseClick(e);

 //get the screen coordinates for this window
 var rect = this.RectangleToScreen(this.ClientRectangle);

 //copy bits from screen to bitmap
 using (var bmp = new Bitmap(rect.Width, rect.Height))
 
 var gr = Graphics.FromImage(bmp);
 gr.CopyFromScreen(rect.Left, rect.Top, 0, 0, rect.Size);

 //save to file
 bmp.Save(@"c:testtest.bmp");
 

Or you can do this right after drawing in response to Windows messages, but you have to call Graphics::Flush to let Windows know when you have finished painting. This method assumes the target window is visible. There might be a lag between commands, or part of the window is not visible, and you don't get the desired output.

A better solution is suggested in the other answer: Create a memory bitmap and draw on to it.

If you don't want to repeat the code, you can make a function that handles all the paintings for both window's device context and memory device context:

public void do_all_paintings(Graphics gr)

 //paint something random, add all other drawings
 gr.Clear(Color.Red);

Now paint in response to Windows paint request:

protected override void OnPaint(PaintEventArgs e)

 base.OnPaint(e);
 do_all_paintings(e.Graphics);

Use the same do_all_paintings function to create a file in response to a command:

protected override void OnMouseClick(MouseEventArgs e)

 base.OnMouseClick(e);

 var rect = this.RectangleToScreen(this.ClientRectangle);
 using (var bmp = new Bitmap(rect.Width, rect.Height))
 
 do_all_paintings(Graphics.FromImage(bmp));
 bmp.Save(@"c:testtest.bmp");