WinAPI C++: Reprogramming Window Resize

Question

I have a window, and I want to implement the borders as resizing borders, like any other window. Taking in suggestions from comments and answers, I have rewritten my code. F

Answer 1

You only need is to process the WM_NCCALCSIZE message , increase your left rgrc rectangle with your border width and increase the top with your CaptionBar height , and decrease your right with border width and your bottom with your CaptionBar height . For the border corner you should change your window region on the WM_SIZE message .