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I started to create a custom theme for beamer slides, and I want to change the default aspect ratio for this theme. Of course I can use \documentclass[aspectratio=169]{beamer} in every document, but I'd like to keep everything in *.sty files. In beamer.cls I found definitions of \beamer@paperwidth and \beamer@paperheight, but setting these lengths in bemerthemeMYTHEME.sty as follows has no effect on the result.


What would be a proper way to change the default aspect ratio in *.sty? Shell I use beamerouterthemeMYTHEME.sty or bemerthemeMYTHEME.sty for this?

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Themes really should not be changing the aspect ratio: the two are separate concepts. Can you explain a bit more what you are doing: it sounds like you are making a custom class based on beamer more than a theme. –  Joseph Wright May 3 '13 at 10:06
@Papiro This is not a duplicate, IMO. Based on her/his post, zeliboba already knows how to set the aspect ratio. The question here is how to set the aspect ratio after \documentclass{...}. –  Jubobs May 3 '13 at 10:10
I try to translate corporate PowerPoint style to beamer, they use 16:9 aspect ratio, and I do not want to keep it as an option to \documentclass. Could you please elaborate a bit more on the "concepts"? For me it is just changing the defaults, you can do it with margins, why not with paper size? –  zeliboba May 3 '13 at 10:15
The problem is that a lot of the document settings derive from options passed to the class (such as aspectratio=169). You could probably adjust those settings after \documentclass{...} but you would probably have to rerun a lot of lines from the class file in order to get the desired result. I had a similar problem a while back: I wanted the output to look just as if I had loaded the smaller beamer class option while keeping all my tweaks in my .sty file. It turned out to be unwieldy and I ended up simply passing smaller as an option to the class: \documentclass[smaller]{beamer}. –  Jubobs May 3 '13 at 10:28
So you can do two things: 1) simply pass the class option in the \documentclass{...} command; 2) as Joseph Wright suggested, modify the beamer class file to create your own, which would set the aspect ratio to a different value by default. –  Jubobs May 3 '13 at 10:38
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1 Answer

up vote 5 down vote accepted

A wrapper class beamer16x9.cls can be easily written:


Then starting a document with


is equivalent to saying


The beamer16x9.cls file should be in one of the canonical places where TeX engines look for input.

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That's great; much easier than my approach (I'll delete it). However, the difference between typing \documentclass[<options>]{beamer16x9} and typing \documentclass[aspectratio=169,<options>]{beamer} is marginal. I would personally just resign myself to doing the latter. –  Jubobs May 3 '13 at 11:05
@Jubobs With a custom class you might also make other changes, for example the theme-like stuff the OP asked about. –  Joseph Wright May 3 '13 at 11:15
Perfect! I was looking for something like this, thanks. –  zeliboba May 3 '13 at 12:41
Note: this topic may be useful to understand the details of class loading tex.stackexchange.com/questions/9908/… –  zeliboba May 3 '13 at 14:05
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