QTextBrowser and application font

Robert Hairgrove

I have a help file viewer which uses QTextBrowser to display HTML pages. These, as well as a global CSS file, are stored in the application's resources. The styles set in the CSS file are used if I set the text browser's searchPaths property so that the CSS file is found.

Since I am allowing the user to change the global application font at runtime, I would expect that the text browser would use that if there is no other CSS rule pertaining to font-family, etc. However, although all the other GUI elements reflect the user's choice of font, the HTML pages stubbornly use the default system font (in my case, "Ubuntu").

I have tried all of the "usual suspects" (setting the default stylesheet for the document, setting a style sheet for the widget "body { font-family:'%1'}" and filling in the arg() in the help viewer's constructor, setting a style sheet in the application). Nothing seems to work.

Is there some kind of CSS "wild card" I could use which would use the application font at runtime? Obviously, I cannot change the CSS rule once the program is running.

JonB

@Robert-Hairgrove
This is purely scribbled in haste. I do not fully understand your situation, but does anything in either https://forum.qt.io/topic/44582/qtextbrowser-stylesheet-font-problem or https://stackoverflow.com/questions/14111126/how-to-use-system-font-in-qtextbrowser help you at all?

Robert Hairgrove

@JonB Thanks for the two links. The first thread is particularly interesting, although no real solution was offered there yet.

I will probably end up generating an additional CSS file at runtime and save that as a temporary file or something.

JonB

@Robert-Hairgrove
The way I do "dynamic" CSS where I have to is: I put like a %variable% into the CSS file. While I'm reading the file in at start-up to set it as global application stylesheet, I preprocess such a sequence to required substitution. So my style.css might have

body { font-size: %FONT_SIZE%px; }

or whatever.

I wasn't sure what you meant by

Obviously, I cannot change the CSS rule once the program is running.

Robert Hairgrove

@JonB All of the HTML files (about 80 of them in English, plus an equal amount in German or whatever language is active) have this:

<link rel="stylesheet" type="text/css" href="sbbl.css">
<link rel="stylesheet" type="text/css" href="sbbl_font.css">

I generate a new CSS file sbbl_font.css at runtime depending on the user setting. I have to add the path to the searchPaths of the QTextBrowser.

In the meantime, I discovered that in the German CSS file, I had forgotten to remove the body { font-family:[etc.] } from the CSS file, so I couldn't find the source of the problem until I did a grep -R ... on my project files.

It is working now ... I put the "dynamic" CSS into a new file generated at runtime, after adding the additional <link> element to all of the HTML files.

Thanks again!

JonB

@Robert-Hairgrove
Ah, I thought you were doing the stylesheet by setting it yourself on the Qt application, I didn't realise you were doing external <link href="...">.

Robert Hairgrove

Now that I removed the font-family rule from the CSS file(s), I discovered that the application font is used after all! So I only need one CSS file which merely avoids specifying any font family at all ... exactly as I had imagined it SHOULD have worked!