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Subject: Re: run-time bitmap rotating?

Re: run-time bitmap rotating?

From: Greg Haerr <>
Date: Thu, 12 Sep 2002 08:23:50 -0600

: The font code has this function called rotleft() that seems to rotate the
: font bitmap in run-time.
: This seems like a waste of precious CPU-cycles, don't you agree?

I mentioned in my earlier email that I thought it advantageous to
be able to use more standard font conversion functions and
thus left the font glyph data in non-portrait mode (it appears the
jukebox is running in portrait mode, is that correct?).

My thought is that for the few characters on the screen, the time spent
rotating is quite small. Do you find this the case?

Certainly we can remove the runtime rotation during the font
conversion process, but it gets a bit tricky and I didn't have time
to do all this and wanted to get the new font stuff submitted for 1.4.
I was able to use tested font code from Microwindows and
didn't want to introduce too many variables in the system, as we
try to get the applications converted to a decent text-display convention.

IMHO, as Rockbox gets more graphical, it's to our advantage
not to have to rewrite all image formats to a non-standard format,
but instead let the system rotate into portrait modes at runtime.
This would easily allow, for instance, the entire system to display
upside-down or portrait-right with no applications recoding.
With only 112x64 bits on the screen, it's not that much computation
time. This could be a problem with a larger display, though.


Received on 2002-09-12

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