Object Type:
xcoredraw
Description:
Foundation object class for displaying pixes. All other
draw classes (at present: dumbdraw, draw, and graph) are
subclassed from coredraw. Therefore these subclasses perform
a superset of the operations described here.
Coredraw and its subclasses can be thought of as providing
a window into a space where pixes reside, or a screen onto
which pixes are projected. One can select the size,
orientation and other parameters of this window/screen
according to the set of functions described below.
The functions provided by coredraw, which are inherited or
overridden by its subclasses, include:
Displaying and managing pixes.
Handling forward transforms for drawing pixes
Handling backward transforms for identifying
location of mouse events
Keyboard control over transformation parameters
such as zoom and pan.
Providing a mechanism for deciding which child
pix should recieve mouse events
Coredraw and subclassses do not display anything on their
own.
The pixes provide the actual images and drawing routines
displayed in a coredraw widget/subclasses. It is important
to note that since the pix display, transformation and event
handling functions are present in the coredraw class, any pix
can be displayed in any draw subclass.
The coredraw widget can only display pixes using planar
orthographic projections in the xy plane. In other
words, x is to the right, y is up and the z coordinate
of pixes is ignored.
In a future revision the z coordinate will be used to
determine
the order of redrawing pixes to enable pixes to obscure
each other according to depth.
Unless flexibility in transformation options would be
a handicap (e.g., in displaying a simulation layout where
alternative projections would just confuse matters) the
coredraw widget is not especially useful for displays.
The draw widget is recommended for all cases where
flexibility is desired, since the overhead in performing
the general transformations is minimal.
Author:
Upi Bhalla Caltech April 93
---------------------------------------------------------------------------ELEMENT PARAMETERS
DataStructure:
xcoredraw_type [in src/Xodus/draw/xcoredraw_struct.h
Size:
?
Fields:
fg
Foreground color of coredraw (not used)
bg
Background color.
xgeom Position of left edge of coredraw.
ygeom Position of upper edge of coredraw.
wgeom Width of coredraw
hgeom Height of coredraw
xmin left edge of window for displaying pixes.
ymin bottom edge of window for displaying pixes.
xmax right edge of window for displaying pixes.
ymax top edge of window for displaying pixes.
script
Script operation(s) to perform on a mouse
click. The script calls to the coredraw widget
are only made if none of the child pixes has
expressed an interest in the event.
--------------------------------------------------------------------------SIMULATION PARAMETERS
Function:
XCoreDraw [in src/Xodus/widg/xcoredraw.c]
Classes:
widget output
Actions:
XUPDATE: update internal fields when
displayed widget is changed.
XOCOMMAND: an action that can invoke the functions
in the 'script' field
XODROP: Called when a pix is dropped into the widget.
Messages:
none.
--------------------------------------------------------------------------Notes:
Can only be displayed in a form widget
The xcoredraw does not perform any computational operations
driven by the simulation clock.
Example:
create xform /form [0,0,500,500]
create xcoredraw /form/coredraw [0,0,100%,100%] \
-bg red -script "echo Hello, I am a coredraw widget"
setfield /form/coredraw xmin -2 xmax 2 ymin -2 ymax 2
// display the pixes here
create xsphere /form/coredraw/sphere -fg green -r 1\
-script "echo Hello, I am a sphere pix"
xshow /form
See also:
XODUS documentation, pix documentation, documentation
for coredraw subclasses.