Re: Bug in plotutils-2.5.1::tek2plot

[Poul-Henning Kamp]

In message <address@hidden>, Poul-Henning Kamp writes:
>
>Hi there,
>
>I found a subtle bug in the tek2plot utility of plotutils 2.5.1.

Following up to my message yesterday, here is a patch, it transpires
that the trouble is that the egm byte is not saved between coordinate
pairs, so it gets reset to zero all the time.

Attached a patch and a .tek file which shows the problem, look for the
vertial 'tick' marked A on the bottom plot.

Fell free to include this file in the example collection if you want.

I have a copyright assignment on file with FSF btw.

Poul-Henning


diff -ur tek2plot/tek2plot.c tek2plot/tek2plot.c
--- tek2plot/tek2plot.c 2008-07-16 04:00:16.000000000 +0000
+++ tek2plot/tek2plot.c 2008-11-08 11:04:49.000000000 +0000
@@ -559,7 +559,7 @@
   int temp_three = 0;
 
   /* following variables are saved from point to point */
-  static int saved_lo_y = 0, saved_hi_x = 0, saved_hi_y = 0;
+  static int saved_lo_y = 0, saved_hi_x = 0, saved_hi_y = 0, saved_egm = 0;
   static bool margin_reset = false;
 
   int byte_read, type;
@@ -709,10 +709,12 @@
            lo_y = got_lo_y ? lo_y : saved_lo_y;              
            hi_x = got_hi_x ? hi_x : saved_hi_x;
            hi_y = got_hi_y ? hi_y : saved_hi_y;
+           egm = got_egm ? egm : saved_egm;
            
            saved_lo_y = lo_y;
            saved_hi_x = hi_x;
            saved_hi_y = hi_y;        
+           saved_egm = egm;          
            
            /* On a genuine Tektronix 4014, the MSB of the 5-bit EGM
               byte sets the margin to equal Margin2 (2048) */


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-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
address@hidden         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.