Support dpi graph attribute

[GoogleCodeExporter]

Support dpi graph attribute

[GoogleCodeExporter]

Here's a sample graph with a nonstandard dpi setting.

Original comment by [email protected] on 19 Oct 2008 at 6:50

Attachments:

• 800dpi.gv

[GoogleCodeExporter]

Partial fix committed in r129 which takes care of the size (setting this.dpi to 
the value in the graph and setting 
this.systemScale to this.dpi / 72). But the line thickness is not right. I need 
to analyze the PNG output at absurdly 
high dpi values to see what the line thickness should be.

Original comment by [email protected] on 19 Oct 2008 at 7:02

• Changed state: Started

[GoogleCodeExporter]

I rendered a graph at 720 dpi and the lines were exactly 10 pixels wide. So I 
must conclude that the line width 
should be this.dpi / 72. Which means I was wrong with r29 and should revert it.

Original comment by [email protected] on 19 Oct 2008 at 7:24

[GoogleCodeExporter]

Reverted r29 in r130. This fixes the line width but there's still something 
funny going on with the arrow in 
800dpi.gv -- the edge going into the arrow isn't centered in the Canviz 
rendering where it is in the PNG 
rendering.

Original comment by [email protected] on 19 Oct 2008 at 7:44

[GoogleCodeExporter]

I'm going to call this fixed. Canviz does support the dpi attribute. It's 
unfortunate that the arrows look a little 
funny at high dpi, but I think it's just the effect of rounding. xdot expresses 
coordinates in integer points. Drawn 
at the default 96 dpi, this amounts to a fraction of a pixel of difference. But 
when scaled up to such a high dpi, 
the rounding becomes noticeable. Canviz can't fix this; the way to fix it would 
be to have Graphviz express 
coordinates in xdot format in floating-point points instead of integer points.

Original comment by [email protected] on 1 Nov 2008 at 8:19

• Changed state: Fixed