Hello,
I am developing an application which can be used for digitize a geographical map through GUI and mouse interaction. Well, here are the list of objects that need to be created using mouse clicks.
- Points
- Polyline
- Polygon
- Rectangle/Square
- Ellipse/Circle
- Text
Drawing points on mouse click is very easy and I was able to do it. I am wondering how to go ahead with drawing polyline. Is it necessary that after every mouse click, canvas has to be refreshed? I mean to ask, now suppose I have drawn two points, and now I am going to draw third point. Once mouse click takes place for third point, I say
canvas->Refresh();
As far as my understanding, when this function is invoked, all the OnPaint() method gets executed and thus first two points also get rendered. Am I right? Now since the number of points (or objects in general) is less, it works fine. If there are millions of objects, then won’t the rendering performance come down? If yes, then is there any way, to keep the previous objects intact(without rendering) and only new object should be rendered?
Sorry for such a long question. But this issue is very critical for me to progress.
Thanks in advance
Regards
Rakesh Patil