Juliaでインタラクティブプロット(Rectangle Selector編)

本稿ではJuliaによるmatplotlibを使ったインタラクティブプロット(Rectangle Selector編)について紹介します．
基本的には本家サイトにあるmatplotlib.widgetsのサンプルソースの移植版です．

rectangle_selector.jl

#Translated from python to julia (reffer to https://matplotlib.org/examples/widgets/rectangle_selector.html)
#Julia v0.6.2
#PyCall v3.6.4

using PyCall
using PyPlot
const RectangleSelector = matplotlib[:widgets][:RectangleSelector]

function line_select_callback(eclick, erelease)
    #eclick and erelease are the press and release events
    x1 = eclick[:xdata]
    y1 = eclick[:ydata]
    x2 = erelease[:xdata]
    y2 = erelease[:ydata]
    @printf "(%3.2f, %3.2f) --> (%3.2f, %3.2f)" x1 y1 x2 y2
    @printf " The button you used were: %s %s" eclick[:button] erelease[:button]
end

function toggle_selector(event)
    println("Key pressed.")
    if event[:key] in ["Q", "q"] && toggle_selector[:RS][:active]
        println("RectangleSelector deactivated.")
        toggle_selector[:RS][:set_active](false)
    end
    if event[:key] in ["A", "a"] && !toggle_selector[:RS][:active]
        println("RectangleSelector activated.")
        toggle_selector[:RS][:set_active](true)
    end
end

fig, current_ax = plt[:subplots]()                 # make a new plotting range
N = 10                                       # If N is large one can see
x = 0:0.01:N

plt[:plot](x, sin.(.2*π*x), lw=3.5, c="b", alpha=.7)  # plot something
plt[:plot](x, cos.(.2*π*x), lw=3.5, c="r", alpha=.5)
plt[:plot](x, -sin.(.2*π*x), lw=3.5, c="g", alpha=.3)

@printf "\n click  -->  release"

# drawtype is 'box' or 'line' or 'none'
RS = RectangleSelector(current_ax,
                        line_select_callback,
                        drawtype="box",
                        useblit=true,
                        button=[1, 3],
                        minspanx=5,
                        minspany=5,
                        spancoords="pixels",
                        interactive=true)
connect("key_press_event", toggle_selector)
show()