[reportlab-users] blurry (dithered) lines + font height, descent etc.

Andy Robinson reportlab-users@reportlab.com
Thu, 31 Oct 2002 14:47:07 -0000

> For now, I'll have to go back to piddle and live with its 
> short-comings, as I
> don't have the time to help you adjust reportlab to do "non antialiased"
> drawing.
Last I heard, Raph Levien indicated libart was 'finished' 
and he had no further interest in pursuing it.

Mike, this is a silly question, but are you sure you
are "aligned with the pixel grid"?

If you are using a scaling of 1 unit = 1 pixel (the default) 
and drawing in whole numbers then you MAY need to shift 
things by 0.5 pixels. This could be done with a single 
'group' object and a translation.

Imagine a 200x200 bitmap.  A 1 pixel line from (0,50) to 
(200,50) will actually span space from y=49.5 to y=51.5
resulting in 2 grey pixels rather than one black one,
because it has a thickness and its centre line is
between pixels.  But the same line from (0,49.5) to 
(200,49.5) should a perfect 1-pixel black line. This
Works For Me(tm)

If your artwork really does blur across pixel boundaries
or involves curves then I would argue that antialiasing
is the 'right thing' to do and piddle rendering just
looks uglier.

We have never had a problem drawing a sharp horizontal or 
vertical line before. Hope this helps...

- Andy