CODEWITHSUNDEEP
c#.netwinformsdrawinggdi+
jay_t55
jay_t55

Reputation: 11652

How do I select a Rectangle that's already been drawn?

I've been learning how to draw lines in winforms apps, and I'd like to be able to select something (rectangle, for example) that has already been drawn by left clicking it, and then be able to move it around to another location by dragging it with the mouse.

How can this be done? I don't see any methods for this so I think I will need to figure out if there is anything where I left-click on the form, and if there is, then somehow figure out the dimensions of it and redraw it appropriately. Is this correct? And how would I know where the reactangle starts, where it ends, how heigh it is, what color(s) it has, and what if it's overlapping another line, rectangle or another shape?

I've not been able to find much on the System.Drawing namespace for things like this, and what I have found so far is just basic "How to draw lines" type stuff.

Upvotes: 0

Views: 1631

Answers (1)

krimog
krimog

Reputation: 1276

Your drawing is a bitmap, not a vectorial image. Basically, it's just lots of pixels. Once your rectangle is drawn, it's just some pixels, but the rectangle itself (with coordinates and size) doesn't exist anymore. What you can do is saving data for every shape (in a List for example). Then, when you click on your image to select something, you test every object in your list in reverse order until the mouse coordinates are within your shape. Then, if, for example, you want to delete the shape, you remove the shape from your list, then you clear your image and redraw every shape in your list.

Upvotes: 2

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