[Plplot-devel] patch to plbox to fix time-axis grid

[Schwartz, S. J <s.s...@im...>]

Dear plplot-devel,

I attach a patch to fix the mis-alignment of the major axes and grid in the case of a time-axis ('d' option). This was due to different algorithms being applied to determine the grid and tick location. In essence, the grid didn't subtract off the start time.

While fixing this, I also found a small bug in the tick routine for the left y-axis again in the case of time ('d') option. This was due to a vpwymi instead of vpwyma at this location. For reasons best known to you, the tick routines work down the left axis and up the right axis, so the two bits of code are different.

I attach some code to test this, plus the before and after outputs.

Steve

PS I submitted a separate patch, also to plbox, last week. If it would be helpful, I can generate a patch that combines both sets of fixes. Both are patched against svn 12298.

PPS in case someone is confused. My test rig plots y-axes as both a float representation of the time (which starts at zero and runs several days) and the plplot time (which starts at t=0 seconds, corresponding to day 001 of the year). So the two plots don't appear to have the same y-limits but are correct.

PPPS I looked at the minor tick grid option ('h'), which works ok but is absent in all cases unless the major grid is also requested. I guess this is probably as intended, but does limit the ability to use different line styles, thicknesses, and/or colours for the major and minor grid.

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Professor Steven J Schwartz        Phone:  +44 (0)207 594 7660
Head, Space & Atmospheric Physics  Fax:    +44 (0)207 594 7772
The Blackett Laboratory            Email:  s.s...@im...
Imperial College London            Office: Huxley 6M67A
London SW7 2AZ, UK                 Web:    www.sp.ph.ic.ac.uk/~sjs
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