#157 Colors (and probably other state parameters) inherited in redraw buffer

[Phil Rosenberg]

Changes to colour tables midway through a plot cause problems in the redraw buffer.

On a redraw of a page the page inherits the status left by the previously drawn page. This is fine if the previously drawn page was the previous page, but if the previously drawn page was some other page or the same page then the inherited values can be wrong. If the colour tables have changed for example part way through a page or at the end of a page in preparation fro drawing the next page (particularly relevant if the next page needs a different background colour) then on redraw these colour tables persist.

A good example is x19. Here, just before page 4 is begun the color0 table is changed in preparation for the Exmoor map. However page 3 redraws get contaminated by the colour table change. This can be seen in the wxWidgets driver and by resizing the xWin driver.

Probably other state parameters like line width, curcol(r g b) etc, fill pattern etc are similarly affected.

To overcome this either the buffer must record all state parameters as part of a BOP or the plplot bop function should explicitly call the appropriate state functions with the current values causing them to be recorded in the buffer.