For 2023 (and 2024 ...) - we are now fully retired from IT training. We have made many, many friends over 25 years of teaching about Python, Tcl, Perl, PHP, Lua, Java, C and C++ - and MySQL, Linux and Solaris/SunOS too. Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own risk.
Lisa and I (Graham) now live in what was our training centre in Melksham - happy to meet with former delegates here - but do check ahead before coming round. We are far from inactive - rather, enjoying the times that we are retired but still healthy enough in mind and body to be active!
I am also active in many other area and still look after a lot of web sites - you can find an index ((here)) |
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)
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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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.
Link to Ezine home page (for reading).
Link to Blogging home page (to add comments).
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