Re: [avr-gcc-list] Trick for creating WYSIWYG bitmaps in C [was: how to specifiy a binary constant]

[Bob Paddock]

I thought I'd try this bitmap 'trick' via copy&paste of the
#defines and code into the file I was working on, this is what I get:

Name/name.c:692: error: `sXXXXXX__' undeclared here (not in a function)
Name/name.c:692: error: initializer element is not constant
Name/name.c:692: error: (near initialization for `lcd_char_P[0]')
Name/name.c:693: error: `sX_____X_' undeclared here (not in a function)
Name/name.c:693: error: initializer element is not constant
[snip rest of the bitmap erros]

Is this 'trick' compiler or compiler option dependent?

This is usually the problem with 'tricks' they come back and
bite you at some point.

On Thu, 22 Sep 2005 23:48:38 -0400, Derric Tubbs <address@hidden> wrote:

> 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 ;)