c - HDC to HDC for HDC -

i blit hdc other hdc, , hdc blit hdc containing "beginpaint". problem appears, nothing have been drawn.

this code, thanks,

hdc hdcmem3 = createcompatibledc(null);   selectobject(hdcmem3, picture);  bitmap bitmap; getobject(picture, sizeof(bitmap), &bitmap);   hdc hdcmem2 = createcompatibledc(null); bitblt(hdcmem2, 0, 0, bitmap.bmwidth, bitmap.bmheight, hdcmem3, 0, 0, srccopy); deletedc(hdcmem3); bitblt(hdcmem, 0, 0, bitmap.bmwidth, bitmap.bmheight, hdcmem2, 0, 0, srccopy); deletedc(hdcmem2); 

createcompatibledc creates device context 1-pixel monochrome bitmap.

in example, device context referenced hdcmem3 has real bitmap, dc referenced hdcmem2 has 1-pixel monochrome bitmap. when blit hdcmem3 hdcmem2, end 1 black pixel.

what need create memory bitmap select hdcmem2. assume that, eventually, you're going display in window. let's assume have device context window called hdcwindow.

// create memory bitmap that's compatible window (screen) , // same size picture. hbmpmem2 = createcompatiblebitmap(hdcwindow, bitmap.bmwidth, bitmap.bmheight); hbmpold2 = selectobject(hdcmem2, hbmpmem2);     

now when stuff hdcmem2, draw real bitmap.

when you're done hdcmem2, need first take care of hbmpmem2:

selectobject(hdcmem2, hbmpold2); deleteobject(hbmpmem2); destroydc(hdcmem2);