Mailing list archives : pcb-rnd

ID:4740
From:rn...@igor2.repo.hu
Date:Wed, 3 Feb 2021 09:55:20 +0100 (CET)
Subject:[pcb-rnd] [lht8] text clearance field in tight_clearance mode
Hi all,
 
the first new feature in lihata v8 is text clearance value for 
tight_clearance text. Reminder: tight_clearance is when we render text 
clearance not as a round corner box but tracing the shape of the text. The 
original writeup on this:
 
http://repo.hu/cgi-bin/pool.cgi?project=pcb-rnd&cmd=show&node=tight_clearance
 
There was an incosistency we inherited from geda/pcb: most layer objects 
(arc, line) and global objects (padstacks) had a clearance value, except 
for text. For text objects we used to use a calculated clearance value and 
the user couldn't change it on a per object basis as with other objects.
 
For compatibility we are keeping this for the old, box-shaped clearances, 
which is also the default for now.
 
But for the new, tight_clearance I've introduced the standard clearance 
field in text objects. It is accessible in the property editor as 
p/text/clearance and as @.clearance in query(). When the text has a 
clearance in a poly and the tight_clearance attribute is true, if the 
clearance field is non-zero this value is used for calculating the 
clearance within the polygon. If the clearance value is 0, the
hardwired calculation is used for the clearance value. I recommend always 
setting the clearance when setting tight_clearance.
 
NOTE: we had a few minor bugs in the original tight_clearance 
implementation, with the hardwired setup (when clearance==0 in the new 
setup). I've fixed them, and the fix may change tight_clearance text 
clearances by a few mils on existing boards. These fixes do _not_ affect 
the old rectangle-clearance text objects, so the risk of breaking anything 
is very small.
 
Best regards,
 
Igor2
 
 

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