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Plotting, hold-on, colors
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Plotting, hold-on, colors
by Ben Boxman
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Hi,
I've compiled the latest Octave (3.0.2) And the latest released gnuplot (4.2.3). I'm vexed by octave/gnuplot not changing colors when plotting additional plots with hold-on. Yes, I know I can set colors manually (or pass all arguments to one big plot call) -- but this is: 1) Cumbersome for normal plots. 2) Even more cumbersome when using hist() and other built-in functions on-top of plot (with hist, you can get the output, and then call yet another function (bar -- that doesn't produce exactly the same results ([x,y] = hist(z); bar(y,x); -- is visually different than hist(z) -- probably some style default?)....). This used to work properly in previous (<2.9.x) versions of octave. I use plots extensively, typically, I'll crunch some numbers in the command line and blurt them out as a plot/histogram (much easier to do this in octave than in gnuplot, any manipulation/processing/filtering is so much easier inside of octave). Just about every second plot I make involves multiple Is there any quick solution for this? Is this a gnuplot issue (e.g. like the zoom problem)? Will this be solved if I compile the unstable gnuplot 4.3? Is there any way I can patch octave to fix this (e.g., changing the default 'blue' to something cyclic, and intercepting hold and resetting said cyclic variable?)? Man thanks, Ben Boxman |
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Re: Plotting, hold-on, colors
by Ben Abbott
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On Sep 1, 2008, at 5:25 PM, Ben Boxman wrote:
The Octave developers are actively working to improve Octave's compatibility with Matlab. Regarding the order of the colors, you can change the order by modifying the "colororder" property associated with the axis. See ... > get (gca, 'colororder') ans =
0.00000 0.00000 1.00000 0.00000 0.50000 0.00000 1.00000 0.00000 0.00000 0.00000 0.75000 0.75000 0.75000 0.00000 0.75000 0.75000 0.75000 0.00000 0.25000 0.25000 0.25000 so you could colors = get (gca, 'colororder') them modify the colors and/or order and then set (gca, 'colororder', colors) Is that sufficient for you needs? Ben _______________________________________________ Help-octave mailing list Help-octave@... https://www-old.cae.wisc.edu/mailman/listinfo/help-octave |
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Re: Plotting, hold-on, colors
by Ben Boxman
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Hi,
I tried "set (gca, 'colororder', colors)", but what this seems to allow me is to change the order of the colors as used by plot (e.g. changing the second used color from green to red). This is isn't my problem -- I'm having a problem with "hold on". My problem is not the actual colors in the color order, but that toggling "hold on" will keep the same color. For instance, if I do the following: x = [1:100] plot(x, sin(x), x, cos(y)) I get a graph with sin(x) showing up with one color, and cos(y) showing up with another (for some reason, blue and green). However, if I do: hold off; plot(x, sin(x)) hold on; plot(x, sin(y)) I get a graph with sin(x) and cos(x) sharing the same color (blue). This used to work properly in the old octave chain (i.e. 2.1.x) and seems to be broken at least from 2.9.x. I want to use hold. It is inconvenient to: 1) Set colors manually for each plot. or: 2) Pass these all off as one plot. And -- if I'm using another function that produces a plot (e.g. hist, or pwelch, or perhaps even one of my own) -- which I wish to superimpose on another, it can get even more difficult. Many thanks, Ben Boxman
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Re: Plotting, hold-on, colors
by Michael Goffioul-2
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On Tue, Sep 2, 2008 at 8:31 AM, Matthias Brennwald
<matthias.brennwald@...> wrote: > As far as I can tell, the above solution works with plots where all > lines (=data sets) are plotted using one single plot command. > > However, the original question was related to the situation, where one > plots the first data set using plot(...), then 'hold on', and the plot > another data set above the first using a second plot(...). I believe to > remember that Matlab does indeed use a different color for the second > plot (but it's a long time since I used Matlab), No, it does not (Matlab 2006b). Michael. _______________________________________________ Help-octave mailing list Help-octave@... https://www-old.cae.wisc.edu/mailman/listinfo/help-octave |
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Re: Plotting, hold-on, colors
by Ben Boxman
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Hi,
If I do this, is there any way I can "overload" the plot() function such that any call to plot(x) or plot(x,y) (one or two argument plots) will go to my_plot() instead of plot()? Or would this require a hack in the code? (pointers as to which files/modules should be changed would be much appreciated). Ben
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Re: Plotting, hold-on, colors
by Ben Abbott
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On Sep 2, 2008, at 2:54 AM, Ben Boxman wrote: > > Hi, > > I tried "set (gca, 'colororder', colors)", but what this seems to > allow me > is to change the order of the colors as used by plot (e.g. changing > the > second used color from green to red). This is isn't my problem -- > I'm having > a problem with "hold on". > > My problem is not the actual colors in the color order, but that > toggling > "hold on" will keep the same color. For instance, if I do the > following: > x = [1:100] > plot(x, sin(x), x, cos(y)) > I get a graph with sin(x) showing up with one color, and cos(y) > showing up > with another (for some reason, blue and green). > > However, if I do: > hold off; > plot(x, sin(x)) > hold on; > plot(x, sin(y)) > I get a graph with sin(x) and cos(x) sharing the same color (blue). > > This used to work properly in the old octave chain (i.e. 2.1.x) and > seems to > be broken at least from 2.9.x. > > I want to use hold. It is inconvenient to: > 1) Set colors manually for each plot. > or: > 2) Pass these all off as one plot. > And -- if I'm using another function that produces a plot (e.g. > hist, or > pwelch, or perhaps even one of my own) -- which I wish to > superimpose on > another, it can get even more difficult. > > > Many thanks, > > Ben Boxman is the following to much trouble? hold off plot (x, sin(x), 'b') hold on plot (x, cos(x), 'r') Ben _______________________________________________ Help-octave mailing list Help-octave@... https://www-old.cae.wisc.edu/mailman/listinfo/help-octave |
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Re: Plotting, hold-on, colors
by Ben Boxman
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Setting colors manually works if you are dealing with a "simple" plot (though this is somewhat annoying). This becomes a bit more "icky" if you're using other functions that end up calling plot (for instance: hist, pwelch, or a user function) -- there is a work-around (in that you can receive the raw plot data, and then call plot (or bar), rewrite said user function to set a color externally (in lieu of the default color)), but this requires multiple steps + setting colors for each and every one. (e.g. two hists() with hold on also aren't satisfactory) My primary reason for using octave is convenience -- I can both process & visualize my data (which is often produced by a non-octave environment) -- and I can do both in a simple/efficient manner -- which I can't do, as easily, outside of octave. Ben
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Re: Plotting, hold-on, colors
by David Bateman
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Ben Boxman wrote:
> Setting colors manually works if you are dealing with a "simple" plot > (though this is somewhat annoying). This becomes a bit more "icky" if you're > using other functions that end up calling plot (for instance: hist, pwelch, > or a user function) -- there is a work-around (in that you can receive the > raw plot data, and then call plot (or bar), rewrite said user function to > set a color externally (in lieu of the default color)), but this requires > multiple steps + setting colors for each and every one. > (e.g. two hists() with hold on also aren't satisfactory) > > My primary reason for using octave is convenience -- I can both process & > visualize my data (which is often produced by a non-octave environment) -- > and I can do both in a simple/efficient manner -- which I can't do, as > easily, outside of octave. > > Ben > The behavior you describe is the Matlab compatible behavior, and many users seem to want strict compatibility. That being said I can think of an easy way to get the behavior you want. Try overloading the __next_line_color__ function. For example add the function function rgb = __next_line_color__ (reset) persistent color_rotation = []; persistent num_colors = []; persistent color_index = []; if (nargin < 2) if (nargin == 1 && reset) color_rotation = get (gca (), "colororder"); num_colors = rows (color_rotation); ## Don't reset the color_index except if this is first call if (isempty (color_index) || color_index > num_colors) color_index = 1; endif else ## Need this as original __next_line_color__ called first if (! isempty (color_rotation)) color_rotation = get (gca (), "colororder"); num_colors = rows (color_rotation); endif if (isempty (color_index)) color_index = 1; endif rgb = color_rotation(color_index,:); if (++color_index > num_colors) color_index = 1; endif color_index rgb endif else print_usage (); endif endfunction in the front of your path. The color_index variable is never reset in the above and so you'll cycle through the plot colors even if __next_line_color__(true) is called to reset it. D. -- David Bateman David.Bateman@... Motorola Labs - Paris +33 1 69 35 48 04 (Ph) Parc Les Algorithmes, Commune de St Aubin +33 6 72 01 06 33 (Mob) 91193 Gif-Sur-Yvette FRANCE +33 1 69 35 77 01 (Fax) The information contained in this communication has been classified as: [x] General Business Information [ ] Motorola Internal Use Only [ ] Motorola Confidential Proprietary _______________________________________________ Help-octave mailing list Help-octave@... https://www-old.cae.wisc.edu/mailman/listinfo/help-octave |
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Re: Plotting, hold-on, colors
by Ben Boxman
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Many thanks, this worked like a charm -- I might do some more poking around in the plot scripts now that I know where they are, :-). I like Octave's non-matlab compatible features. Octave being more forgiving to "C" style syntax (e.g. " vs. ') is a boon to my ingrained "C" ways. And some octave packages are superior, in functionality, to the Matlab packages. Ben
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