GenPlotting90/docs/usage.md

Usage

The genplotting library use, as a backend, an external software who can be installed with the libtthimage and convert scratchfiles to Targa image file.

For drawing an useless graphic, you have to follow three steps: initialize, use and terminating. You can look at some examples and at a full page off UselessGraphics.

Initialize

Call the subroutine genp_init with two parameters. The first is an integer and must be 0. In the futur, it may be used for setting some predefined configurations.

The second is the filename for recording the plottings instructions, I'm using the .scratch extension for naming this file. And if this filename is an empty string, stdout will be used, so you can pipe the data for post-processing purpose. Be warned: if you use this option, don't write anything to the unit 6 !

Use it

• real xa, ya, xb, yb
• integer color
• call genp_move(xa, ya)
• call genp_draw(xa, ya, color)
• call genp_line(xa, ya, xb, yb, color)

Terminator

• call genp_end(0) This procedure end the current plotting, add some bells to the WIP, and close the output file, if an output file was specified.

Rendering

• subroutine genp_do_render(srcfile, tgafile, xsize, ysize)

After doing all that useless computing graphics, you can call the render, only if you have given a filename to genp_init. The render engine that I use can only write Targa file, but I'm going to add PNG to it output in a near futur.