Re: Image size, DPI (was Re: Gorm is broken)

[Eric Wasylishen]

On 2011-05-08, at 12:47 AM, Fred Kiefer wrote:

> 
> -------- Original-Nachricht --------
>> Datum: Sun, 08 May 2011 01:32:58 +0200
>> Von: Riccardo Mottola <address@hidden>
>> An: Eric Wasylishen <address@hidden>
>> CC: Developer GNUstep <address@hidden>
>> Betreff: Re: Image size, DPI (was Re: Gorm is broken)
> 
>> Hi,
>>> On a related note, I think the Cairo backend also rounds the coordinates
>> of path points - shouldn't we get rid of that as well?
>>> 
>> I think that perhaps we should. But it is a delicate issue. Try 
>> Graphos:play with it drawing boxes and lines especially, check our 
>> various backends and check cocoa. Try different line widths. My 
>> impression is that on cairo everything is always blurred :) Xlib of 
>> course never since it has no anti-aliasing. But Cocoa isn't as "bad" as 
>> cairo, it usually looks fine for integer line  widths.
> 
> If I remember correctly the code here tries to avoid bluring for lines that 
> the programmer would expect to be exactly horizontal or vertical oriented. 
> This is the standard approach used by all cairo applications I know of. We 
> should add a lot of tests before we change this.

Ok. I agreed it should be well tested if changed. Based on a quick check, 
however, cairo's and Cocoa's default behaviour are exactly the same , i.e. the 
examples here: http://www.cairographics.org/FAQ/#sharp_lines produce the same 
results on Cocoa, so it doesn't appear that cocoa does any rounding below the 
level of NSView implementations.