
2005.11.27

	I am improving the functionality of kapa so that it does not
	need to have an X server to build PNG / PPM / PS plots.
	Before, I generated the PNG / PPM plots from the screen image
	by using an X function to examine the color of each pixel and
	generate the corresponding PNG/PPM image.  This implied that
	an X server was required even if the window was not being
	looked at.  The PS version of the plots were not quite so
	difficult: the PS code is generated from the plot when the PS
	output file is constructed.  I decided to implement the
	equivalent concept for the PNG/PPM images. 

	I have build a set of drawing functions which are used by the
	PNG function (PPM not yet implemented) to create the PNG image
	buffer from the graphic objects stored by Kapa.  This
	subsystem is called bDraw.  Most of the drawing functions
	correspond to just the primitive point, line, and circle
	functions.  I have implemented bDrawPoint, bDrawLine,
	bDrawCircle, and demonstrated the complete concept.  At this
	point, only a few features are missing:

	- line weight.  the bDraw functions do not respect the value
          of the line weight (which is available to them).  All lines
          and circles are drawn as line weight 1.

	- line type.  no line type data is used. (Kapa probably over
          respects it: it should not apply the line type to the point
          plotting)

	- rectangles and triangles.  several of the point-types are
          constructed by calling bDrawRect, bDrawTri, neither of which
          are implemented at this time.


