Gnuplot contour
Thanks for your cooperation in testing and bug-finding. Because it will touch a lot of code, the change will undoubtedly introduce or uncover more bugs similar to the current one. I've added to my wishlist for version 5 that the use_palette flag should be removed altogether.
GNUPLOT CONTOUR PATCH
So anyhow, I may apply this patch to CVS after more testing, but not yet. For instance I tested with "set term pbm color" and found that setting the already red linetype 1 explicitly to red made it turn unexpectedly black. But it may be handled badly by pen plotters and other legacy devices. My patch sets the use_palette flag unconditionally, which bypasses the mismatch. The current case is an example of what can happen if the color of the stored linetype doesn't match the color in the color field. The idea was that devices that couldn't handle colors could still use the original linetype. color determined by a pm3d palette coordinate or 24-bit RGB value, this went into a separate field that is only used if the flag lp->use_palette is set. When we added more general properties for newer devices, e.g. One is the original gnuplot "linetype" that historically controlled color, dash pattern, and width all in one number. The attached patch bypasses this by always claiming that the color was explicitly set, but it probably has side effects.Ī large part of the problem is that the program carries along two possibly conflicting types of information about each line. In particular if the first linetype used for contouring has not been given an explicit color spec, then color specs for all contours are ignored and the indexing is one off. Passing through linewidth in hidden3d mode would be problematic, but that could maybe be documented as an exceptional case.
This is termed ' grid data ', and is required for drawing a surface, for contouring (set contour) and hidden-line removal (set hidden3d). If all blocks contain the same number of points, gnuplot will draw cross-isolines between points in the blocks, connecting corresponding points.
GNUPLOT CONTOUR CODE
The code currently does the first (modulo possible bugs). No line will join points separated by a blank record. Or is it better to honor the individual line widths as well? That allows monochrome contours distinguished by width rather than color. Is it better to give them all the same width but cycle through colors? That allows you to explicitly give two sets of contours on the same plot where they are distinguished by width. I am of two minds about what the ideal behaviour would be for contours. This is largely due to historical artifact, since in most contexts "linetype" really meant "line color". I agree with you that line width is not handled equivalently to line color. Let's try to figure out what is going on.
So either I misunderstand, or there is something different between our configurations. I get the same results using gnuplot 4.6.0, 4.6.3 and current cvs for 4.7. I attach a test script in which I attempt to reproduce the commands you show above, and the output from it.