Hi.
I just wanted to see how many empeg developers are subscribed
currently. I would like to discuss a few ideas, and I don't think the
UEBBS is the right place to do so.
OK, what I am thinking about is a set of libraries to help develop
programs for the empeg. My main objectives are: Graphics, Sound and
serial/USB/network communication. For a start, I will try and
concentrate on the graphics part. So here is what I think the library
should provide, and I would really appreciate some feedback on this.
The preliminary specs I state below are for a C++ library (with
overloaded functions), but I intend to provide a pure C version as
well, probably using a C++ wrapper around a C lib.
The first goal is to provide a few simple commands to access the
display. I think the following functionality should do for most (if
not all) applications on the empeg (except for applications that
want/need virtual 3D):
Basic display device handling:
- open display / initialise
- close display
- turn on/off display
- clear the display queue
Basic page handling
- create virtual page
- free virtual page
- add virtual page to the display queue
- display virtual page now
- dump virtual page to file (or memory area)
- load file (or memory area) to virtual page
Basic drawing commands
- clear virtual page
- select current page for drawing
- plot(page,color,x,y)
plot(color,x,y) (plots to current page)
plot(x,y) (plots in current colour)
- line(page,color,x1,y1,x2,y2)
line(color,x1,y1,x2,y2)
line(x1,y1,x2,y2) (well, you get the picture)
draws a line from (x1,y1) to (x2,y2)
- circle([[...],fillcolor],x,y,r)
draw a (filled) circle
- triangle([[...],fillcolor],x1,y1,x2,y2,x3,y3)
draw a (filled) triangle with the given edges
- stamp(x,y,*bitmap)
output a bitmap with a lower (or maybe upper) left corner of (x,y)
- grab(x1,y1,x2,y2,*bitmap)
grab a fraction of the display and store it in bitmap
Text functions
- setfont(*font) (set the font to use)
- loadfont(FILE) (load a font from a file)
- text([[...],*font]x,y,*text)
print *text using *font with a lower (upper) left corner of (x,y),
supporting line breaks
Scrolling support
- create big virtual page (xsize,ysize)
(all above commands apply to a big page as well)
- display big virtual page (page,xoffset,yoffset)
- merge big page to page
(normal_page,x,y,xsize,ysize,big_page,xoffset,yoffset)
inserts an xsize*ysize sized fragment of big_page, starting at
(xoffset,yoffset) into normal_page at (x,y)
I intend to add higher level later, but I think this should be a good
starting point. What do you guys think? Did I miss something, should I
leave out something (why)?
I will do a better spec later this week, but would like to get some
feedback first. Don't hold back, I can stand (constructive) criticism.
cu,
sven
--
Sven Mueller Tel: +49-231-401550
Giessereistr. 11a Mobil: +49-172-2323802
D-44289 Dortmund email: sven(a)incase.de
