[Kst] [Bug 90196] New: Suggestions for really nice black & white plots

[Nicolas Brisset]

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http://bugs.kde.org/show_bug.cgi?id=90196        
           Summary: Suggestions for really nice black & white plots
           Product: kst
           Version: unspecified
          Platform: Compiled Sources
        OS/Version: Solaris
            Status: UNCONFIRMED
          Severity: wishlist
          Priority: NOR
         Component: general
        AssignedTo: kst kde org
        ReportedBy: nicolas.brisset eurocopter com


Version:           1.0.0_devel (using KDE KDE 3.3.0)
Installed from:    Compiled From Sources
Compiler:          gcc 3.3.2 
OS:                Solaris

This is somehow related to bug #90124 and bug #86501 (where it seems I failed to convince Barth !), you'll understand why just below. But for once, I will not reopen resolved bugs :-)

Basically, what we all need is to be able to differentiate curves. I see only 4 ways to do that, but all have limitations and some apply only for curves with a line and not isolated points:
- change colors (not suited for B&W printing)
- change line style (OK but there aren't that many styles available so that it has to be used together with something else)
- change line width (limited in that differences in width have to be big to be visible, but we don't want too thick curves)
- use symbols (potentially unlimited in number of variants if you allow any character to be used as a symbol, but there should not be too many symbols if you still want to see the curves).

kst currently primarily uses curve colors for differentiation, and actually does  a good job at that. The major problem is that it is not so great for B&W printing :-(

As a matter of fact, xmgrace even offers more options with symbols as you can use a symbol color different from that of the line, scale it and use different patterns/transparency. I think it is good to have so much choice as nobody will force you to use all options, but it is probably not all useful. 
I'd say that especially in the context of B&W printing, it would be enough to add scaling, and it would be NECESSARY to add the symbol skip option as found in xmgrace (hence wish #86501).

All in all, the most useful options to differentiate curves in B&W are line style and symbols, possibly also line widths or gray levels (with only 2 or 3 steps).

To sum up, I'd suggest implementing a new action (it may for instance go to a Edit->Change to B&W menu) that would:
- set plot backgrounds to white
- set the curve color of all curves to black (or optionally 2 or 3 _distinguisable_ levels of gray)
- cycle line styles first and then symbols (glyph and/or size) or the other way around, based on user preference
- optionally cycle line widths.
I believe this would require a basic dialog so that the user can choose the order (like symbol type then line style then line width, or line style then symbol size then line color, you get the idea...) and number of symbols to draw for each curve so it doesn't get overcrowded (see #86501).

Thoughts ?