Automatically redrawing window contents

[bennyandthejets]

If, for example, I TextOut() something to a window outside WM_PAINT, do I ALWAYS have to manually redraw it if I want it to stay there? Ie, is there some option or API function that remembers what was in the window so that it redraws it automatically, or do I have to place the TextOut() call in WM_PAINT?

[Ken Fitlike]

Unless you store it in an off-screen bitmap you'd have to manually update it each time. Even then, you'd still have to apply the bitmap. I think there are performance issues to take into consideration; WM_PAINT handling with its BeginPaint....EndPaint (which is necessary, ironically, even for gdiplus which 'supersedes and replaces' gdi) is the way to go.

I'd be interested in reading other opinions about this, though.

edit: apostrophe proliferation

[Thantos]

TextOut and DrawText are good for text that doesn't change too much (IMO). One thing I did for text that was bound to change was to create a readonly edit box, and changed the background color. Then you have to get the code to put text into the edit box.

I say this as a novice to window's programming however

[bennyandthejets]

Thanks, that's all I needed to know.

[novacain]

>>Unless you store it in an off-screen bitmap

This is the best way.

For complex apps have a back buffer to swap with as drawing can take some time.