Mailman 3 July 2021 - Tkinter-discuss

4k HiDPI displays and tkinter
by Vasilis Vlachoudis July 14, 2021

July 14, 2021

Recently I've got a 4k laptop, and the first experience with linux and the 4k display is quite painful. I am still trying to tune it but for the moment my tkinter applications do not render nicely on such a display. - all widths like borderwidths, decorations, separators etc, set in pixels do not scale with the dpi settings. Could we use "mm" for their settings instead? - checkbox, radiobox the indicator appears tiny wrt the text Is there a way to detect from tkinter a high res display and force a window scaling x2 for everything? What is your experience with such displays? Vasilis

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[Solved] Re: Trying to center the output of Canvas.postscript() onto A4 page
by Michael Lange July 3, 2021

July 3, 2021

Hi, thanks for the feedback! On Fri, 2 Jul 2021 09:17:41 -0300 Emiliano Gavilan <emilianogavilan(a)gmail.com> wrote: > You can achieve what you want with the correct set of options to the > canvas postscript() method, documented here: > > https://www.tcl.tk/man/tcl8.6/TkCmd/canvas.html#M61 yes, I have been looking at that man page the other day for what felt like an hour, but failed to get the point :-) Well, maybe at least I can partially blame that failure on the man page authors, since there is nothing mentioned that the default values are apparently pagex=306.0, pagey=396.0 which appears to be half the size of a page in U.S. letter format measured in printer points. This sort of information might have helped :-) > > In your case: > > canvas.postscript(pagex=0, pagey=0, pagewidth=594, pageheight=841, > pageanchor="sw", file="test.eps") > > This will scale the output to fit into an A4 page. The final result > will depend also of the area of the canvas > being exported, controlled by the x, y, width and height options (the > default is to export the visible part). > A bit of experimentation will get you the correct values of these > options. No, maybe I did not describe what I want to achieve accurately; I do not want the output to be scaled, but to be printed in the exact requested millimeter-size. I got it now though that this can be achieved by setting the pagex and pagey values accordingly; I gather that for an A4 page this should be approx. pagex=298, pagey=421 with pageanchor='center'. For some reason here this is still a little bit off, but maybe this can be blamed on the worn mechanics of my cheap old printer. Or maybe the printer has some sort of hard-wired margin on each side that it cannot print on and that ought to be taken into account (if the users only knew about it). Anyway, I wasted some paper and found that for this particular printer values of pagex=290.2 and pagey=419.5 seem to be as close to perfect as it gets with that sort of hardware. Thanks again, and have a nice day :) Michael .-.. .. ...- . .-.. --- -. --. .- -. -.. .--. .-. --- ... .--. . .-. History tends to exaggerate. -- Col. Green, "The Savage Curtain", stardate 5906.4

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Trying to center the output of Canvas.postscript() onto A4 page
by Michael Lange July 2, 2021

July 2, 2021

Hi, I want to print the contents of a Canvas widget by feeding the output of the postscript() command to lpr (I am working with linux here). I would like that Canvas "screenshot" to be centered on the printed page (in my case these are A4 pages which are standard here). Unfortunately I do not seem to be able to do this. After a number of unsuccessful tries to fiddle with lpr I finally found that the problem appears to be that the generated postscript file always seems to be designed for pages in U.S. letter format, obviously this part in the postscript: %%Page: 1 1 save 306.0 396.0 translate is responsible for that; I tried and manually changed the coords that (as it seems) are passed to the "translate" command and the position of the Canvas rectangle (which might be for example 12x12 cm or so) on the page changes. So, is there any way to tell the postscript() command to use a page size other than U.S. letter for its output that I missed, or alternatively, does anyone know about a 3rd party tool available for linux that could be used to "convert" the postscript() output from letter to A4 format? Thanks in advance Michael .-.. .. ...- . .-.. --- -. --. .- -. -.. .--. .-. --- ... .--. . .-. "Get back to your stations!" "We're beaming down to the planet, sir." -- Kirk and Mr. Leslie, "This Side of Paradise", stardate 3417.3

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