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Re: [matplotlib-devel] Incorporating TikZ into Matplotlib
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From: Thomas C. <tca...@gm...> - 2015-05-14 03:27:27
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Sorry, I may have been being a bit dramatic In mpl.patches: Arrow, FancyArrow, YAArrow, FancyArrowPatch, ConnectionPatch + annotation related artists + some classes in axisartist which now that I look at them are not really general purpose arrow tools. I had not been counting quiver (or barbs) or sankey. Neil: Those are all great questions! Much of the arrow related code was written by Joe-Joon Lee who (by having read a good deal of his code) has a habit of writing very power but very opaque python. I believe that the line join style is controlled by `joinstyle` on the graphics context and it is up to the backends to implement that correctly. Tom On Wed, May 13, 2015 at 10:58 PM Neil Girdhar <mis...@gm...> wrote: > Okay, I'm looking at this in more detail and there may be some design > concerns: > > The arrow placement is decided without asking the arrow any questions, > such as its bounding box. Instead, the arrow should return a bounding box > and then the line should retreat until the bounding box no longer > intersects the target node. Then the arrow should be placed. This doesn't > matter so much when you have a simple arrow like this: ---->, but it's a > big deal when you have an arrow like ----| . In this case, the sides of > the arrow risk intersecting with the target node. > > I'm not keen on implementing every arrow three times: <-, ->, <->. This > really should be handled by the code placing the arrows for many reasons: > 1. It should also be possible to have a different arrowhead at either end > of the line. > 2. It should be possible to stack the arrows, for example having two heads > one after another (to represent two kinds of relationships). This is > another reason to be able to ask the arrowhead its length and so on. > > I don't understand the "monolithic" keyword. How can the arrow draw the > line as well when it doesn't know the line style, color and so on? > > I think I like the design of the transmute function. I'm curious: > ultimately, where does the mutation_size come from? Is it a global scale > applied to the figure, or is it based on the linewidth, or? > > When you emit a set of lines, how are they joined? If I draw a line > having linewidth 0.1 from the origin to (1, 0), and back to (0, 0.5), what > happens at the tip? Are two rectangles drawn (each having width 0.1, but > oriented differently)? Is a bevel created? A miter? Or is the tip > rounded? Can this be controlled? See page 166 of the manual I sent > earlier (search for tikz/line join). > > Best, > > Neil > > On Wed, May 13, 2015 at 10:14 PM, Neil Girdhar <mis...@gm...> > wrote: > >> Thanks, it works! >> >> I needed to add: >> >> import matplotlib.patches >> >> to one file and >> >> plt.show() >> >> to the other. >> >> Any word on the locations in the code of the seven arrow drawing methods? >> >> I've located the arrow drawing code in tikz, and so I can start porting >> it over. I'm curious, do we know the linewidth of the edge being decorated >> by the arrow? To make arrows scale nicely, most of the arrow dimensions >> are given in two pieces: an absolute value (in points for example) and a >> line width factor. The dimension is the absolute value plus the line width >> factor times the line width. The TikZ manual explains: "This makes it easy >> to vary the size of an arrow tip in accordance with the line width – >> usually a very good idea since thicker lines will need thicker arrow tips." >> >> Best, >> >> Neil >> >> On Wed, May 13, 2015 at 10:07 PM, Benjamin Reedlunn <bre...@gm...> >> wrote: >> >>> Neil, >>> >>> I have attached code to draw the arrowhead. >>> >>> -Ben >>> >>> >>> >>> On May 13, 2015, at 7:44 PM, Neil Girdhar <mis...@gm...> wrote: >>> >>> Do you have the code that you used to draw the arrowhead? I'm up to >>> date now on the development workflow ( >>> http://matplotlib.org/devel/gitwash/development_workflow.html), so I'm >>> ready to start working. >>> >>> Thanks, >>> >>> Neil >>> >>> On Wed, May 13, 2015 at 9:10 PM, Benjamin Reedlunn <bre...@gm...> >>> wrote: >>> >>>> Yes, I fully agree that we need to unify the many different ways to >>>> draw arrows. >>>> >>>> Neil, in case an example would be helpful for you, I have attached a >>>> module that includes a custom arrowhead class. The arrowhead class works >>>> with the with the ax.annotate() method. (I like the annotate method >>>> because it allows me to easily mix and match coordinate systems for arrow >>>> placement.) As you can see in the attached pdf, the custom arrowhead >>>> doesn't include fancy Bezier curves, but that could be added. >>>> >>>> -Ben >>>> >>>> >>>> >>>> On May 13, 2015, at 2:54 PM, Thomas Caswell <tca...@gm...> wrote: >>>> >>>> The other thing that should be done is to unify the (I think 7?!?) >>>> unique ways to draw arrows in mpl. >>>> >>>> On Wed, May 13, 2015 at 4:52 PM Neil Girdhar <mis...@gm...> >>>> wrote: >>>> >>>>> Yes, I just noticed that as well. That's how the tikz pgf code looks >>>>> (a sequence of line_to and curve_to commands and so on) so it should be >>>>> easy to port over the various shapes. >>>>> >>>>> On Wed, May 13, 2015 at 4:49 PM, Eric Firing <ef...@ha...> >>>>> wrote: >>>>> >>>>>> On 2015/05/13 10:12 AM, Neil Girdhar wrote: >>>>>> >>>>>>> If you want to make arrowheads look at all decent, they really need >>>>>>> to >>>>>>> be enclosed in Bezier curves. See the diagram here: >>>>>>> >>>>>> >>>>>> Mpl paths support Bezier curves. >>>>>> http://matplotlib.org/api/path_api.html?highlight=bezier >>>>>> >>>>>> >>>>>>> >>>>>>> http://tex.stackexchange.com/questions/150289/how-do-you-accomplish-stealth-with-the-new-arrows-meta/230965#230965 >>>>>>> >>>>>>> The first two look like garbage. The last one is the only one that >>>>>>> looks good imho. >>>>>>> >>>>>> >>>>>> That depends on the application, and the observer. >>>>> >>>>> >>>>> Sure, but I may as well port them all of the tikz arrowheads over >>>>> since most of the work would be figuring out how to do it. >>>>> >>>>> >>>>>> >>>>>> >>>>>> Eric >>>>>> >>>>>> >>>>>>> Best, >>>>>>> >>>>>>> Neil >>>>>>> >>>>>>> On Wed, May 13, 2015 at 4:09 PM, Eric Firing <ef...@ha... >>>>>>> <mailto:ef...@ha...>> wrote: >>>>>>> >>>>>>> On 2015/05/13 9:36 AM, Neil Girdhar wrote: >>>>>>> >>>>>>> I don't know matplotlib well enough (yet) to know what the >>>>>>> change would >>>>>>> consist of. >>>>>>> >>>>>>> I suggest you take a look at the beautiful tikz manual: >>>>>>> http://pgf.sourceforge.net/pgf_CVS.pdf >>>>>>> >>>>>>> >>>>>>> Very helpful, thank you. >>>>>>> >>>>>>> >>>>>>> The arrows.meta on page 201–212 are really well-designed and >>>>>>> beautiful. >>>>>>> >>>>>>> Compare this with matplotlib's custom arrows: >>>>>>> >>>>>>> http://stackoverflow.com/questions/16968007/custom-arrow-style-for-matplotlib-pyplot-annotate >>>>>>> >>>>>>> How do I make tikz's arrowheads available for all backends? >>>>>>> >>>>>>> >>>>>>> My guess offhand is that this is a matter of using the mpl API. >>>>>>> I >>>>>>> don't think we would want to add all of these types and options >>>>>>> to >>>>>>> the mpl core; but a toolkit might be ideal for this. The mpl >>>>>>> API, >>>>>>> which generates the same results for all backends, is quite >>>>>>> complete >>>>>>> and flexible. Things like arrowheads are Patch objects, and you >>>>>>> can >>>>>>> specify any path you want. The main trick is figuring out how to >>>>>>> handle transforms--what kind of coordinates should the path be >>>>>>> specifying? How should things scale as a figure is reshaped and >>>>>>> resized? >>>>>>> >>>>>>> For many of these types you could also use mpl Line2D objects, >>>>>>> for >>>>>>> which several properties including cap style can be specified. >>>>>>> Not >>>>>>> all of the TikZ options would be available, but perhaps enough. >>>>>>> >>>>>>> Eric >>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>> ------------------------------------------------------------------------------ >>>>> One dashboard for servers and applications across >>>>> Physical-Virtual-Cloud >>>>> Widest out-of-the-box monitoring support with 50+ applications >>>>> Performance metrics, stats and reports that give you Actionable >>>>> Insights >>>>> Deep dive visibility with transaction tracing using APM Insight. >>>>> http://ad.doubleclick.net/ddm/clk/290420510;117567292;y >>>>> _______________________________________________ >>>>> Matplotlib-devel mailing list >>>>> Mat...@li... >>>>> https://lists.sourceforge.net/lists/listinfo/matplotlib-devel >>>>> >>>> >>>> ------------------------------------------------------------------------------ >>>> One dashboard for servers and applications across >>>> Physical-Virtual-Cloud >>>> Widest out-of-the-box monitoring support with 50+ applications >>>> Performance metrics, stats and reports that give you Actionable Insights >>>> Deep dive visibility with transaction tracing using APM Insight. >>>> >>>> http://ad.doubleclick.net/ddm/clk/290420510;117567292;y_______________________________________________ >>>> Matplotlib-devel mailing list >>>> Mat...@li... >>>> https://lists.sourceforge.net/lists/listinfo/matplotlib-devel >>>> >>>> >>>> >>>> >>> >>> >>> >> > |
