[haiku-development] Re: Disable BView antialiasing
- From: Caitlin Shaw <rogueeve@xxxxxxxxxxxxx>
- To: haiku-development@xxxxxxxxxxxxx
- Date: Tue, 22 Sep 2009 17:17:05 -0700
> There was a bug floating around on Trac that I took a look at a while
> back to do with the red circle with a line through it on the screen
> saver prefs (for when no active corner was selected iirc). I don't
> know if it's still open (probably) but it was basically that the line
> through the circle wasn't positioned nicely.
>
> I double checked the maths involved and it the coordinates used were
> fine, the problem came from the sub-pixel AA :(
>
>
I never noticed that, but it still isn't, actually, and also now that
you mention it the line is backwards! That is, it's a forward slash,
like "/", whereas the international No symbol is usually a backwards
slash. I looked at the code and sure enough they are using StrokeEllipse
and StrokeLine--I'm surprised, I assumed it was just a bitmap.
If you change the code from:
size -= ceilf(sin(M_PI / 4) * size + 2);
rect.InsetBy(size, size);
StrokeLine(rect.RightTop(), rect.LeftBottom());
to:
rect.left += 3;
rect.top += 2;
rect.right -= (size / 8);
rect.bottom -= (size / 8);
StrokeLine(rect.LeftTop(), rect.RightBottom());
It comes out looking pretty much correct. There's no particular fancy
formula to those numbers, they're just a fudge factor. I looked at in
Magnifier until it looked centered and the line went all the way across.
But it works at the current value of kStopSize, and looks ok over a
certain range of alterations to that constant as well. From playing with
the old code, it seems like it was somewhat of a fudge factor also; I
mean what is the "+2"?
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