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Re: Coordinate system
From: |
Alexander Malmberg |
Subject: |
Re: Coordinate system |
Date: |
Thu, 01 May 2003 14:31:08 +0200 |
Stefan Urbanek wrote:
>
> Hi,
>
> I am confused. What is the coordinate system for drawing
> in gnustep? Is it pixels or points? Or is it pixels on screen
> and points on PostScript output?
Points, always. ((Well, the default matrix is such that one unit in user
space is one point; you can change this so one unit is one mm, or one
meter, or anything else that you can get as a multiple of a point. There
is no way to get at device pixels through the dps interface.))
All(?) current backends assume that the display is 72dpi, so that 1
pixel==1 point, but this is an implementation limitation. back-art has
no problems rendering at other resolutions, but we'd still need to fix
back/Source/x11/* to convert sizes and coordinates of events and windows
between points and pixels.
[snip]
> Another problem should be drawing between pixels, but this can
> be solved by rounding to integer values in backend.
Handling this is up to the backend. back-art can do (and, currently,
always does) subpixel rendering. When clarity is more important than
accurate rendering, you use strokeadjust (not implemented in back-art)
and screen fonts (implemented in back-art).
- Alexander Malmberg
- Coordinate system, Stefan Urbanek, 2003/05/01
- Re: Coordinate system,
Alexander Malmberg <=