Use cimage dual-buffering

Void cxxxbutton: onpaint () {cpaintdc DC (this); crect rect; this-> getclientrect (& rect); int imagew = m_pimage-> getwidth (); // m_pimage: define your own member variables. Int imageh = m_pimage-> getheight (); cimage memimg; // create a cimage cache for memimg. create (rect. width (), rect. height (), m_pimage-> getbpp (); HDC tmpdc = memimg. getdc (); CDC memdc; memdc. attach (tmpdc); // use memdc to start memdc. fillsolidrect (rect, RGB (255,255,255); m_pimage-> draw (tmpdc, 0, 0, imagew/m_nstates, imageh, imagew * 0/m_nstates, 0, imagew/m_nstates, imageh); // use memdc to end memimg. draw (DC. m_hdc, 0, 0, rect. width (), rect. height (); // paste the cimage cache to the DC for memdc. detach (); // release the two. Do not release crash memimg. releasedc ();}