[WASTE-list] Artifacts appear in the waste text window

[Marco Piovanelli]

On Tue, 9 May 2006 14:49:48 +0530,
Vinay Prabhu (vinayprabhu at tataelxsi.co.in) wrote:



>Hi,

>

>Artifacts appears on the top most line of the window.

>When the window is moved to background and foreground.

>

>If I type any normal characters and accented characters, with font Helvetica

>and font size 12.

>Then scroll the text.

>

>The black dots starts appearing on top of the view rect.

>

>I have used WEUpdate(nil, wereference);

>But still the artifacts doesn't go away.

>

>It looks like artifacts appear one pixel above the view rect.


From the screenshot you sent me privately (itself marred by JPEG
compression artifacts), it looks like the stray pixels might be
left by oversize glyphs that extend beyond the space between the
ascent and descent lines.

Since you're still using WASTE 2.1, you could try the following:

    1.  Set the Quickdraw clip region to the view rectangle before
        calling a WASTE API that may draw, like WEUpdate or WEScroll.

or, perhaps more straightforwardly:

    2.  If your view rectangle is inset by a one- or two-pixel
        margin from the scrollable rectangle (the content area
        of your window minus the scroll bars and the grow widget),
        you could erase the whole scrollable rectangle yourself
        before calling WEUpdate, upon receiving an update event.

Also, I don't know whether you're working on old application dating
from the OS 9 days, a brand-new project, or something in between,
but for new code, I think you should consider adopting WASTE 3.0.
Quickdraw is now officially deprecated by Apple, and WASTE 2.1
will not be maintained or supported any longer.


                                        -- marco

-- 
It's not the data universe only, it's human conversation.
They want to turn it into a one-way flow that they have entirely
monetized. I look at the collective human mind as a kind of
ecosystem. They want to clear cut it. They want to go into the
rainforest of human thought and mow the thing down.