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For 2021 - online Python 3 training - see ((here)).

Our plans were to retire in summer 2020 and see the world, but Coronavirus has lead us into a lot of lockdown programming in Python 3 and PHP 7.
We can now offer tailored online training - small groups, real tutors - works really well for groups of 4 to 14 delegates. Anywhere in the world; course language English.

Please ask about private 'maintenance' training for Python 2, Tcl, Perl, PHP, Lua, etc.
Cliff Lift simulator- Lynton to Lynmouth - in Tcl/Tk

In Tk, you can use the variable option to a slider and the textvariable option to a label or button (or some other widgets) to 'project' the value of a variable onto the display - either changing the text on a button, or moving a slider automatically when some value changes otherwise within the code.

Cliff lifts such as the railway that runs up and down the hill between Lynton and Lynmouth on the north coast of Devon work on a counterbalance principle - as one car ascends the hill, a steel cable over a drum at the top lets the other car descend. And the whole lift works by making the car that starts at the top heavier by filling a water tank underneath the floor. That tank is then emptied when the car gets to the bottom.

Here are some Tk sliders ... showing how it works.



With the code that I wrote here, all I need to do is drag one car up or down and the other car moves equally and opposite, using the variable option on the scale command.

Link - Lynton and Lynmouth Cliff Railway
(written 2007-12-14, updated 2007-12-15)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
T220 - Tcl/Tk - Frames and Other Topics
  [787] Tk - laying out your GUI with frames, pack and grid - (2006-06-30)
  [1335] Expanding a grid - Tcl/Tk - (2007-09-07)
  [4459] Managing the window size (and layout) in Tcl/Tk - (2015-03-12)


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Tcl/Tk - updating your display while tasks are running
Using Tcl/Tk resource files for flexible applications
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The Horse goes on and on
Cliff Lift simulator- Lynton to Lynmouth - in Tcl/Tk
fill and expand on Tcl/Tk pack command
Curley brackets v double quotes - Tcl, Tk, Expect
Lexical v Arithemetic testing, Bash and Perl
stdout v stderr (Tcl, Perl, Shell)
Effective Java training - the bootcamp approach
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This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

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