RE: [avr-gcc-list] tinyurl trick (WAS: Trick for creating WYSIWYG bitmaps in C [was: howto specifiy a binary constant])

[Derric Tubbs]

Point taken and to each his own.

Tubbs

--- address@hidden wrote:

> Good advice Derric, except that I disagree about the
> tinyurl trick; It
> encourages the ability to "spoof" undesirable web
> pages in email. When I
> click a link, I like to see *exactly* where I'm
> linking to, before
> linkage occurs. Otherwise, there's no telling where
> I might end up...
> 
> Cheers,
> Matthew van de Werken - Electronics Engineer
> CSIRO E&M - Rock Mass Characterisation - 1
> Technology Court - Pullenvale
> - 4069
> p: (07) 3327 4142 * f: (07) 3327 4455 * e:
> address@hidden
> "Backups are for wimps. Real Men upload their data
> to an FTP site and
> have everyone else mirror it." 
> -- Linus Torvalds
> 
> -----Original Message-----
> From:
>
address@hidden
>
[mailto:address@hidden
> On
> Behalf Of Derric Tubbs
> Sent: Friday, 23 September 2005 1:49 PM
> To: address@hidden
> Subject: Re: [avr-gcc-list] Trick for creating
> WYSIWYG bitmaps in C
> [was: howto specifiy a binary constant]
> 
> 
> Firstly, everyone needs to know about tinyurl.com,
> which allows you to send a tiny URL like
> http://tinyurl.com/92eaj to
> point to long URLs (open this one and you'll see it
> that takes you to a
> book on Amazon.com that I'm about to refer to).
> 
> Secondly, I got this little trick from the book that
> the link above points to, the book is called "Expert
> C Programming".
> Anyhow for an 8 bit LCD bitmap like Vincent
> mentioned below, do the
> following:
> 
> #define X )*2+1
> #define _ )*2
> #define s ((((((((0 /* 8 parens for 8 bit, 16 for
> 16,
> etc) */
> 
> Then you just "draw" your bitmap as such:
> 
> uint8_t lcd_char_P[] =
> {
>   sXXXXXX__,
>   sX_____X_,
>   sX______X,
>   sX_____X_,
>   sXXXXXX__,
>   sX_______,
>   sX_______,
>   sX_______
> }
> 
> and then make sure you undef the X,s, and _.  Now
> doesn't that look like a big P right in your code ;)
> 
> Pretty cool little trick.  Kind of extravegant but
> something similar to this sure would have made
> things
> clearer when I was looking at some code that defined
> characters on a graphic LCD the other day ;)
> 
> Tubbs
> 
> --- Vincent Trouilliez
> <address@hidden> wrote:
> 
> > On Thu, 2005-09-22 at 18:00 -0700, Derric Tubbs
> > wrote:
> > > I believe the original poster said he was new to
> programming.  If 
> > > so, just remember that each hex
> > digit
> > > represents four binary bits/digits with decimal
> > values
> > > of 0-15.  It won't take long at all to get where
> > > reading hex, both for decimal value and bit
> > pattern,
> > > happens without thinking about it.
> > 
> > Yeah I am fairly new to C programming (only one
> year epxerience, on
> > Microchip PIC's...and that was 5 years ago !), but
> > not to electronics
> > engineering, so I have long got the hang of Hex
> > notation ;-)
> > 
> > > Is there some reason you can't specify your
> > constant
> > > as hex?
> > 
> > It's not that I can't, it' just that in some
> cases,
> > a binary notation is
> > natural, and a hex one doesn't make sense.
> > 
> > Typical example is when I want to define a few
> > custom characters for a
> > text LCD module. if you use a binary notation, it
> > actually gives you a
> > very convenient visual representation of each
> > character, since one bit
> > represents a pixel, and one byte represents one
> row
> > for one character.
> > So you can very easily define the characters,
> > whereas if using a hex
> > notation, it's a nightmare to define the
> characters,
> > and you can't check
> > them visually for correctness, and making
> > corrections is awkward.
> > That's just an example.
> > 
> > 
> > 
> > On Thu, 2005-09-22 at 20:03 -0500, David Kelly
> > wrote:
> > > We may make a FreeBSD user out of you yet.
> > 
> > Not a ray of hope in the current state of things
> ;-)
> > I happen to have
> > eventually found the perfect Linux distro for me,
> so
> > they would have to
> > go seriously wrong for to consider the hassle of
> > changing 'home' ;-) ...
> > 
> > 
> > > Joerg included a/the patch for binary constants
> in
> > the FreeBSD Ports
> > > version of avr-gcc, which he maintains.
> > > 
> > Oh, I wonder what we would become without Joerg.
> > Thank you for the patch
> > Herr Joerg :-)
> > 
> > 
> > > If this long URL survives then it will download
> > the patch. You are  a
> > > Linux user so you have lots of practice applying
> > patches, right?  :-)
> > > 
> > > 
> > You said it, I am Linux "user", not developper !!
> > ;o)
> > I did once try to apply a patch to some program,
> but
> > I failed miserably,
> > both because I couldn't find anywhere on the web
> the
> > exact command line
> > to use, all where suggesting different options,
> and
> > also because the
> > source code I had didn't exactly match what the
> > patch was expecting.
> > Tried to apply the patch by hand, but the patch
> and
> > source code were so
> > different, I really didn't know what to do with
> the
> > patch.
> > > 
> > I guess I will just take the easy route, and wait
> > patiently for the
> > patch to make it into the next stable release of
> > gcc-avr ;-)
> > 
> > 
> > 
> > --
> > Vince
> > 
> > 
> > 
> > _______________________________________________
> > AVR-GCC-list mailing list
> > address@hidden
> >
>
http://lists.nongnu.org/mailman/listinfo/avr-gcc-list
> > 
> 
> 
> 
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