[smokeping-users] Re: Curl probe graph colors?

[Tobias Oetiker]

Yesterday Niko Tyni wrote:

> On Fri, Jan 14, 2005 at 10:46:56AM +0100, Sebastian Wiesinger wrote:
> > It works fine but the graph it outputs has some odd colors:
> >
> > http://alita.karotte.org/smokeping/cgi-bin/smokeping.cgi?target=World.USA.ISC
> >
> > What are these big green blocks (and the black ones in the Last 24
> > Hours)? I've never seen these in normal probes.
>
> Looks like you found a bug in Smokeping. With pings = 5, the smokecol()
> subroutine in Smokeping.pm breaks and calculates a wrong color for the
> ping deviating most from the median.
>
> Details: in the sub
>
> sub smokecol ($) {
>     my $count = ( shift )- 2 ;
>     my $half = int($count/2);
>     my @items;
>     for (my $i=$count; $i> $half; $i--){
>         my $color = int(190/$half * ($i-$half))+50;
>         push @items, "AREA:cp".($i+2)."#".(sprintf("%02x",$color) x 3);
>     };
>     for (my $i=$half; $i >= 0; $i--){
>         my $color = int(190/$half * ($half - $i))+64;
>         push @items, "AREA:cp".($i+2)."#".(sprintf("%02x",$color) x 3);
>     };
>     return \@items;
> }
>
> on the first round of the first for loop: $count = 3, $half = 1, $i = 3
> making $color = int(190/1 * (3-1))+50 = 430
>
> As this is >255, it's got more than two digits in hex (1AE).
> So the rrdtool graph line gets #1AE1AE1AE as the color. Apparently
> it takes just the firs six digits, resulting in RGB value 1A E1 AE,
> which seems to match the color you have.
>
> I'll let Tobi figure out the best fix. If you're in a hurry, I'd
> suggest changing the pings value to either 4 or 6.

I would suggest

--- Smokeping.pm~       Sat Jan 15 11:39:39 2005
+++ Smokeping.pm        Sat Jan 15 11:51:57 2005
@@ -634,13 +634,14 @@

 sub smokecol ($) {
     my $count = ( shift )- 2 ;
-    my $half = int($count/2);
+    return [] unless $count > 0
+    my $half = $count/2;
     my @items;
-    for (my $i=$count; $i> $half; $i--){
+    for (my $i=$count; $i > $half; $i--){
        my $color = int(190/$half * ($i-$half))+50;
        push @items, "AREA:cp".($i+2)."#".(sprintf("%02x",$color) x 3);
     };
-    for (my $i=$half; $i >= 0; $i--){
+    for (my $i=int($half); $i >= 0; $i--){
        my $color = int(190/$half * ($half - $i))+64;
        push @items, "AREA:cp".($i+2)."#".(sprintf("%02x",$color) x 3);
     };


cheers
tobi

>

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