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From: greg <gregor.ebbing@gmx.de>
Newsgroups: comp.lang.tcl
Subject: Re: Performance problems with "photo copy -to"
Date: Fri, 8 Nov 2024 02:36:11 +0100
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Am 07.11.24 um 21:43 schrieb Paul Obermeier:
> I have a simple tiling procedure and noticed a slowdown when using large 
> images,
> i.e. when doing lots of copies.
> 
> I noticed the following behaviours (both on Windows and Linux):
> 1. The time for copying does not grow linearly, as expected, but gets 
> larger the more copies are involved.
> 2. The copy time of Tcl/Tk 9 is nearly twice the time as when using Tcl/ 
> Tk 8.6.15 or the combination
>     Tcl 8.7/Tk 9. So this performance degradation does not seem to stem 
> from Tk9, but from Tcl9. Strange!
> 
> Can anybody confirm my measurements?
> 
> Thanks,
> Paul
> 
> 
> Using Tcl 8.6.15, Tk 8.6.15
> Time for  100 copies:  0.69 seconds (  6 milliseconds / copy)
> Time for  400 copies: 10.26 seconds ( 25 milliseconds / copy)
> Time for  900 copies: 51.12 seconds ( 56 milliseconds / copy)
> 
> Using Tcl 8.7b1, Tk 9.0.0
> Time for  100 copies:  0.70 seconds (  7 milliseconds / copy)
> Time for  400 copies: 10.22 seconds ( 25 milliseconds / copy)
> Time for  900 copies: 51.35 seconds ( 57 milliseconds / copy)
> 
> Using Tcl 9.0.0, Tk 9.0.0
> Time for  100 copies:  1.28 seconds ( 12 milliseconds / copy)
> Time for  400 copies: 19.45 seconds ( 48 milliseconds / copy)
> Time for  900 copies: 98.16 seconds (109 milliseconds / copy)
> 
> 
> package require Tk
> 
> proc Tile { phImg xRepeat yRepeat } {
>      set startTime [clock milliseconds]
>      set w [image width  $phImg]
>      set h [image height $phImg]
>      set w2 [expr {$w * $xRepeat}]
>      set h2 [expr {$h * $yRepeat}]
> 
>      set tileImg [image create photo -width $w2 -height $h2]
> 
>      for { set x 0 } { $x < $xRepeat } { incr x } {
>          for { set y 0 } { $y < $yRepeat } { incr y } {
>              $tileImg copy $phImg -to [expr {$x*$w}] [expr {$y*$h}]
>          }
>      }
>      set endTime [clock milliseconds]
>      puts [format "Time for %4d copies: %5.2f seconds (%3d 
> milliseconds / copy)" \
>           [expr {$xRepeat * $yRepeat}] \
>           [expr { ($endTime - $startTime) / 1000.0 }] \
>           [expr { ($endTime - $startTime) / ($xRepeat * $yRepeat) }]]
>      return $tileImg
> }
> 
> set srcImg [image create photo -width 500 -height 500]
> 
> puts "Using Tcl [info patch], Tk [package version Tk]"
> Tile $srcImg 10 10
> Tile $srcImg 20 20
> Tile $srcImg 30 30
> 
> exit


Hello,


Using Tcl 8.6.15, Tk 8.6.15
Time for  100 copies:  1.52 seconds ( 15 milliseconds / copy)
Time for  400 copies: 23.17 seconds ( 57 milliseconds / copy)
Time for  900 copies: 117.39 seconds (130 milliseconds / copy)


Using Tcl 9.0.0, Tk 9.0.0
Time for  100 copies:  1.50 seconds ( 14 milliseconds / copy)
Time for  400 copies: 23.18 seconds ( 57 milliseconds / copy)
Time for  900 copies: 117.57 seconds (130 milliseconds / copy)


both Tcl/Tk from debian sid


Gregor