added to strucht graph
Use only these data for plotting.
If zooming a plot windows, set as an extra parameter the graph id
of the 'mother graph'. Copy its color and line data to the new graph.
This is done by an extra parameter sgraphid to the internal plot
command that is issued in fcn PlotWindowProc().
Thus zooming will keep the background, text/line and graph colors.
Function setcolor() will always look into the colorarray of the
current graph.
Prevent a crash of example/FFT_test.cir.
Buffer 'buf' in function drawlingrid() has been too small.
Increase 'buf' size, and add some protection.
The example file examples/plot/test-small-plot.cir
shows the limits of plotting:
difference in two numbers at digit 14 is plotted well.
at digit 15 is plotted with bugs.
at digit 16 is reduced to integer.
consider compiling with
-O1 -D_FORTIFY_SOURCE=2
for gcc, and
/GS
for visual studio.