Re: Ada and graphics

[beckwb@ois.com (R. William Beckwith)]

John Goodsen (jgoodsen@trinidad.ny) wrote:

: Bindings to Xlib/Xt are not often the solution you need, but many 
: inexperienced developers take off down this path and waste a lot
: of time and money rebuilding something they would have been better
: off buying to get the graphics implemented.

Agreed.

: You should take a serious look at a *real* structured graphics engine,
: rather than hitting the low level Xlib intrinsics for your graphics.
: Unless you are doing anything but the most trivial graphics application,
: you will quickly have a need for a structured graphics toolkit...
: Ask yourself the following questions:

These are nice questions.  I thought I would answer the questions with
regard to X11R6/Fresco/Ada9X for those who've been following Fresco.

:    1.  Will I require pointer hit detection on graphical objects?
:        (e.g. click on a graphical object and detect which object
:         was clicked upon)

Fresco: can do

:    2.  Will you ever have to redraw the screen?  
:        (using raw xlib, graphics are not redrawn.  You have to remember
:         what you drew and always be prepared to redraw it whenever a user
:         moves a window over your graphics)

Fresco: appl programmer doesn't ever do redraws, Fresco double-buffers
	all graphics and uses an advanced damage-based, deferred redisplay
	for high-performance

:    4.  Do you have the need to scale, rotate or otherwise deform your
:        graphical objects?

Fresco: can do, in 3D

:    3.  Do you have a need for hierarchical graphical objects?
:        (e.g. do you want composite graphical objects which allow you to
:         scale, move, rotate a set of graphical objects independently from
:         other graphical objects)

Fresco: can do, actually Fresco allows full DAGs (Directed Acyclic Graphs)
	of graphical objects and is not limited to hierarchies

:    5.  Will you ever need to run your application on a non X-window platform?
:        (e.g. Windows, NT, etc...)  too often this is the case, but is ignored
:        until it becomes a problem at which point it can't be handled well.

Fresco: can do

... Bill