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
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 articlesT220 - Tcl/Tk - Frames and Other Topics 
Tk - laying out your GUI with frames, pack and grid - (2006-06-30) 
Expanding a grid - Tcl/Tk - (2007-09-07) 
Managing the window size (and layout) in Tcl/Tk - (2015-03-12)
Some other Articles
Tcl/Tk - updating your display while tasks are runningUsing Tcl/Tk resource files for flexible applicationsMaking a variable dynamically visible in a Tcl/Tk GUIThe Horse goes on and onCliff Lift simulator- Lynton to Lynmouth - in Tcl/Tkfill and expand on Tcl/Tk pack commandCurley brackets v double quotes - Tcl, Tk, ExpectLexical v Arithemetic testing, Bash and Perlstdout v stderr (Tcl, Perl, Shell)Effective Java training - the bootcamp approach
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