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My question is that i am having video stream from my webcam.i am displaying it on my picture box.Now i want user to to click on four locations and i want a rectangle drawn on using those four locations i-e first click will be the starting point so on.
I am a beginner so please excuse if you feel its too simple.I can draw a rectangle using hard coded locations.Following is the code i have in my event handler that has the new frame.
Pen pen = new Pen(Color.Red, 2);
Graphics g = Graphics.FromImage(bitmap);
g.DrawRectangle(pen, 30, 30, 60, 30);

but as you see i have hard coded initial x,y,width,height i want them to be user defined clicks.

Sergey Alexandrovich Kryukov 12-Nov-12 1:29am    
What do you want it to draw on, ultimately, on a screen or a bitmap? If a bitmap, and the mouse is on the screen, how it supposed to be?
loraloper_22 12-Nov-12 1:46am    
i want to draw it on the bitmap now when user clicks on four locations i want to store them
Sergey Alexandrovich Kryukov 12-Nov-12 2:27am    
Do you mean that a bitmap is rendered in some control, than -- what? Do you need to draw a rectangle as you move the mouse? Otherwise you would not see the data. And are you sure you really want to draw on a bitmap? What's the goal of all of it?
loraloper_22 12-Nov-12 2:34am    
I have done it anyways.The goal was to draw an out of bound region when ever an object moves into it raise an alarm.

1 solution

First off, you don't want four locations - they will not necessarily describe a rectangle, or even a parallelogram. Two points define a rectangle: either TLHC and BRHC or TRHC and BLHC is sufficient.

Exactly how you pick up the mouse locations will depend on where you are drawing your bitmap: if it is on a form surface then just handle the Form.MouseDown or Form.MouseClick event - they both give your the mouse coordinates as part of the MouseEventArgs parameter.
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