On 12/12/2011 08:53 AM, Will Robinson wrote:
Hello,
I'm trying to do a simple Roguelike game as an exercise in learning the
language, particularly racket/gui. I'm using draw-text to place
characters on the screen. Ideally, I'd just call this once and put up
huge string full of newlines to represent a block of text. My problem
is that I want to have control of the color of each character in this
block of text. It seems to me that the color controls for draw-text are
applied to the entire block at once. Should I just call draw-text for
each character in the block, individually assigning color? That seems
to be very slow computationally, not to mention more work on the poor coder.
Take a look at the `slideshow/pict' module, specifically these functions:
* `text': creates a pict that draws text (see `tt' in `slideshow' for
how to make monospace text, or just use `tt' itself)
* `hbl-append': horizontally appends picts, matching up their baselines
* `draw-pict': draws a pict on a dc<%> at a certain x,y
* `colorize': returns a pict with a different color
You might consider making a string parser that outputs `hbl-append'-ed
picts and recognizes two-character escapes like "^3" as commands to
change the color for the remainder of the string.
(You could even use `para' (from `slideshow') instead of `hbl-append',
which will decode and wrap text. That's a bit hacky, though, as it might
depend on slideshow parameters in ways you don't expect.)
By the way, compared to actually drawing the text, any overhead from
parsing or constructing picts is computationally cheap.
Neil T
_________________________________________________
For list-related administrative tasks:
http://lists.racket-lang.org/listinfo/users
