Subj : Re: WM_PAINT or TWindow::Paint
To   : borland.public.cpp.borlandcpp
From : maeder
Date : Tue Aug 09 2005 08:33 pm

"MarvinAvery" <marvin.avery@hrdc-drhc.gc.ca> writes:

> I am using BC5.02 and OWLNext.
>
> I have a window in which I am displaying lines of text with a
> fixed-pitch font.
> This window can be scrolled horizontally. To do this, I call:
>
>     ScrollWindowEx (dx, 0, &rect, &rect, 0, 0, SW_INVALIDATE|SW_ERASE);
>     UpdateWindow();
>
> UpdateWindow() causes a WM_PAINT message to be generated.

More specifically, it causes it to be sent (rather than posted).


> In my TMyWindow::Paint() routine, I pant a line as follows:

[SCNR] That must look interesting. Do you also paint it? :-)]


>    dc.TextOut (x_pos, y_pos, line_of_text);
>
> Now, if I scroll 1 column to the left (dx = width of 1 character in
> screen units), Windows physically scrolls my window one column left
> and, because I use UpdateWindow(), Windows "marks" only the
> right-most column for painting.

The Windows term for this is "invalidating". IIRC, ScrollWindowEx()
invalidates just the rectangle that moves on screen because of the
scrolling.


> Thus, when calling dc.TextOut() even though I am writing the entire
> line, only the last character actually gets written (or painted).

Which is typically more efficient than writing the whole line.


> Now for my question.......
>
> Is there a way of telling or forcing Windows, for specific lines
> only, to actually paint the *entire* line?

You should be able to use InvalidateRect() for the rectangles occupied
by these lines.

BUT: I don't see the point of your question. What's the difference of
painting N-1 characters over their own graphical representation?

.