[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Scrolling text
- Subject: Re: Scrolling text
- From: Peter Mason <menakkis(at)my-deja.com>
- Date: Sat, 18 Dec 1999 05:41:51 GMT
- Newsgroups: comp.lang.idl-pvwave
- Organization: Deja.com - Before you buy.
- References: <385923B5.31F820@lamar.colostate.edu> <email@example.com>
- Xref: news.doit.wisc.edu comp.lang.idl-pvwave:17788
Peter Mason <firstname.lastname@example.org> wrote:
> (..without really thinking..)
Oops, sorry Kelly I really botched the DEVICE calls graphics scroll
method there. I have appended a little test program that demonstrates
this technique, in case you'd like to try it out. (It does the
honours with a text file.) The scrolling speed will be affected by
your computer's hardware and will go faster with 8-bit colour depth than
24-bit. If it scrolls too slowly you could try creating the main
window with RETAIN=0 (always a speed-up) and/or knocking out the WAIT.
I tried it with IDL's true-type fonts and, to my surprise, this slowed
things down a lot on my P2/300 machine - there's a noticeable delay
while each line is rendered with XYOUTS. But perhaps try this as well
and see what you think.
; A little program to demonstrate smooth text scrolling.
; Peter Mason, Dec. 99
; The one and only parameter is the filename of an ASCII
; file - this file gets read and displayed.
if n_elements(tfile) eq 0 then tfile='tscroll.pro'
if e ne 0 then return
gx=512L &gy=320L ;main window size
ty=16L ;pixmap window height
window,0,xsiz=gx,ysiz=gy,retain=1 ;retain=0 for max speed
window,1,xsiz=gx,ysiz=ty,/pixmap ;room for 1 line of text
while not eof(u) do begin
xyouts,0,3,t,/dev,font=0 ;render the next line
for j=0L,ty-1L do begin ;copy the text-line to
device,copy=[0,0,gx,gy-1,0,1] ;the main window one
device,copy=[0,ty-j-1,gx,1,0,0,1] ;pixel-line at a time
if keyword_set(j) then goto,bye ;escape hatch
Sent via Deja.com http://www.deja.com/
Before you buy.