Fonts wider than 8 pixels

[dylanhall]

Hi, I'd like to use the CScreenDevice class with a 12x24 or a 16x32 font.

My goal is to use the 12x24 font on a 1024x768 monitor to get a console close to 80x30 or use a 16x32 font where the resolution is greater than 1024x768.

I don't believe CCharGenerator will support this because each row in the font_data array is 8 bits wide (char).

I could use the width and height doubling for the 16x32 font, but doubling a 6x12 font will produce a low quality font compared with a native 12x24 font.

I think the easy fix would be to change the fonts to use a u16 or u32 for storing font_data.
An alternative would be to allow passing a custom CharGenerator class to CScreenDevice.

Have I missed a better solution?

If there is interest, I can try and submit a pull request changing the font storage to u16 or u32?

[rsta2]

I think only CCharGenerator has to be changed. The different provided fonts do not need to be changed, because any font storage can be seen and defined as a simple byte stream. One can use rFont.width in CCharGenerator::CCharGenerator() to set a new member variable m_nBytesPerPixelLine as: m_nBytesPerPixelLine = (rFont.width + 7) / 8; In CCharGenerator::GetPixelLine() a switch() statement can be used for the different values of m_nBytesPerPixelLine (1, 2, 3 or 4) to return the font data in the right format. Of course the definition of TPixelLine has to be changed to: typedef u32 TPixelLine; I don't know, if this description is clear enough. If not, I can also provide the modified code for CCharGenerator.

[dylanhall]

Thank you. I'll try to make the changes myself, but let you know if I need help.

A further question. Do you have any tools or scripts you used to covert the fonts into arrays?

[rsta2]

This is a simple C program, which converts a Linux console font with 8 pixel width and also corrects the charset, so it can be used in Circle:

fontconv.c.txt

[rsta2]

Forgot to mention: On Raspberry Pi 1-4 and Zero (2) you can set nearly any wanted display resolution, for example 640*570 using width=640 height=570 in cmdline.txt. This is probably quicker for your purpose, instead of using a greater font. Especially CCharGenerator::GetPixelLine() is critical for the performance. Be careful when you modify it.

[rsta2]

The class CCharGenerator supports font widths with up to 32 pixels now on the develop branch. Also a Font12x22 has been added there.

[dylanhall]

Thanks! That's working nicely.

Regarding using a resolution like 640x570. The monitor I'm using has a native resolution of 1024x768. When you use a lower resolution for the frame buffer the fonts are distorted a little so it doesn't look as nice as a higher resolution font with the frame buffer using the native resolution. If I was using a modern high resolution display I think setting the frame buffer to 640x570 would make more sense as it would still look nice and there wouldn't be the performance penalty of rendering so many pixels.

[rsta2]

That makes sense. You are welcome.