Fast, interactive Julia/GTK+ plots (+Smith charts +Gtk widget +Cairo-only images)


:art: Galleries (Sample Output) :art:

:chart_with_upwards_trend: Sample plots (might be out of date).

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InspectDR.jl: Fast, Interactive Plots

Build Status


InspectDR is a fast plotting tool with a responsive GUI, targeting quick navigation of simulation results. In design applications, InspectDR allows for efficient, interactive data exploration, thus shortening each iteration of the design cycle.

Motivation: Despite their great quality, most of Julia's current plotting options were found to be either too slow, and/or provide inadequate interactivity for the author's needs.

The InspectDR library is implemented using 3 distinct plot layers:

  • Plot image layer: Implemented with the Cairo library, the plot image layer allows the user to render (multi-) plots as simple images.
  • Plot widget layer: Library users can also integrate plots to their own GTK+ application by instantiating a single InspectDR widget.
  • Plot application layer: Most end users will likely display/interact with plots/data using the built-in Julia/GTK+ multi-plot application.

Users are encouraged to open an issue if it is unclear how to utilize a particular layer. Documentation is a bit limited at the moment.


The following highlights a few interesting features of InspectDR:

  • Publication-quality output.
  • Included as a "backend" of JuliaPlots/Plots.jl.
  • Relatively short load times / time to first plot.
  • Designed with larger datasets in mind:
    • Responsive even with moderate (>200k points) datasets.
    • Confirmed to handle 2GB datsets with reasonable speed on older desktop running Windows 7 (drag+pan of data area highly discouraged).
  • Support for Smith charts (admittance & impedance - see Plot Templates).
  • Support for various types of annotation:
    • User-programmable text, polyline, vertical & horizontal bars.
    • Drag & drop Δ-markers (Measures/displays Δx, Δy & slope).
  • Interactive mouse/keybindings.
    • Fast & simple way to pan/zoom into data.
    • In line with other similar tools.
    • Create drag & drop Δ-markers.
  • Layout & Stylesheets.

See following subsections for more information.


Quick to first plot, and easy to navigate data using supported mouse/keybindings

"F1" Acceleration

InspectDR.jl includes specialized algorithms to accellerate plotting of large "F1" datasets (functions of 1 argument) in order to maintain a good "real-time" (interactive) user experience.

A dataset is defined as a function of 1 argument ("F1") if it satisfies:

y = f(x), where x: sorted, real vector

Examples of "F1" datasets include time domain (y(x=time)) and frequncy domain (X(w)) data.

"F1" acceleration is obtained by dropping points in order to speed up the rendering process.

IMPORTANT: "F1" acceleration tends to generate erroneous-looking plots whenever glyphs are displayed. This is because the dropped points may become very noticeable. Consequently, InspectDR will, by default, only apply "F1" acceleration on datasets drawn without glyphs (lines only).

To change when InspectDR applies "F1" acceleration to drop points, look for the :droppoints entry in the Configuration/Defaults section.

2D Plot Support

InspectDR.jl also supports generic 2D plotting. More specifically, the tool is capable of plotting arbitrary 2D datasets that satisfy:

(x,y) = (u[i], v[i]), for i in [1...N]

Examples of of such plots (where x-values are not guaranteed to be sorted) include:

  • Nyquist plots
  • Lissajous plots
  • Smith/polar (S-Parameter) charts


InspectDR.jl supports keybindings to improve/accelerate user control. The following tables lists supported bindings:

Pan/Zoom Function Mouse/Key
Zoom out to full extents CTRL + f
Zoom out horizontally to full extents CTRL + h
Zoom out vertically to full extents CTRL + v
Box zoom (in) right-click + mousemove
Zoom in / zoom out + / -
Zoom in / zoom out CTRL + mousewheel
Pan up / pan down ⇑ / ⇓
Pan up / pan down mousewheel
Pan left / pan right ⇐ / ⇒
Pan left / pan right SHIFT + mousewheel
Pan anywhere (SHIFT + left-click) + mousemove
Annotate Function Mouse/Key
Add reference marker r
Add Δ-marker (rel. to last reference) d
Add Δ-marker & set as reference D
Move marker left-click + mousemove control point
Delete marker DEL (when moving marker)
Move Δ-marker info box left-click + mousemove box
Re-center Δ-marker info box 0 (when moving box)

Mouse Pan/Zoom Locks

There are also keybindings to lock directionnality during mouse pan / zoom operations:

Function Key
Lock along horizontal h
Lock along vertical v
Allow both directions b

Select Documentation

Note that many types & functions are not exported from InspectDR in order to avoid namespace pollution. That being said, the module name will often be omitted below in an attempt to improve readability.

Plot Objects

Principal objects:

  • InspectDR.Plot: An abstract plot object.
  • InspectDR.Plot2D <: Plot: A 2D plot object. Construct empty 2D plot using InspectDR.Plot2D(title="Plot Title").
  • InspectDR.Multiplot: A multi-plot object. Construct empty multi-plot using: InspectDR.Multiplot(title="Multiplot Title").

Subplots (T<:Plot) are added to a multi-plot object using the add() method:

mplot = InspectDR.Multiplot()
plot1 = InspectDR.Plot2D()
plot2 = InspectDR.Plot2D()

add(mplot, plot1)
add(mplot, plot2)

Similarly, the add() method adds waveforms to plots/subplots:

wfrm = add(plot1, x, y, id="Waveform label")

WARNING: Only Vector data can be added (AbstractVector/Range not currently supported).

Displaying Plots

InspectDR provides the GtkDisplay object derived from Base.Multimedia.Display. GtkDisplay is used in combination with Base.display(), to spawn a new instance of a GTK-based GUI.

To display a single plot::Plot object, one simply calls:

gplot = display(InspectDR.GtkDisplay(), plot)

Similarly, to display mplot::Multiplot object, one calls:

gplot = display(InspectDR.GtkDisplay(), mplot)

To programmatically close a Gtk plot window, the close() function can be used:


Plot Templates/Axis Scales

In order to support stacked graphs with independent y-axes (tied to the same x-axis), specifying axis scales is a bit involved:

  • InspectDR.Plot2D.xscale controls the x-axis scale.
  • InspectDR.Plot2D.strips[STRIP_INDEX].yscale controls the y-axis scale.

To streamline control over plot axes/grids/labels/..., it is highly recommended to use the following plot templates:

  1. Plot2D(xscale, yscalelist; kwargs...): Generic 2D plot template.
- `Plot2D(:lin, :log, title="title", xlabel="X", ylabels=["log(Y)"])`: Construct plot with a linear X-axis & log10 Y-axis.
- `Plot2D(:log10, [:dB20, :lin, :lin], title="title", xlabel="X", ylabels=["Y1 (dB)", "Y2", "Y3"])`: Construct plot with a log10 X-axis, and 2 Y-strips: the top-most with a dB20 Y-scale, and the next two with linear Y-scale.
  1. bodeplot(; kwargs...): Template for generating Bode plots.
    • bodeplot(): Default kwargsjulia-observer-quote-cut-paste-68_work`julia-observer-quote-cut-paste-59work, ylabels=["Magnitude (dB)", "Phase (°)]"julia-observer-quote-cut-paste-60worktransientplot(yscalelist; kwargs...)julia-observer-quote-cut-paste-61worktransientplot([:lin, :lin, :lin], title="title", ylabels=["Voltage", "Voltage", "Current"])julia-observer-quote-cut-paste-62workxlabeljulia-observer-quote-cut-paste-63work"Time (s)"julia-observer-quote-cut-paste-64worksmithchart(TYPE; ref, kwargs...)julia-observer-quote-cut-paste-65worksmithchart(:Z, ref=50)julia-observer-quote-cut-paste-66workZjulia-observer-quote-cut-paste-67workkwargs already set: xlabel="Real(Γ)"julia-observer-quote-cut-paste-69workylabels=["Imaginary(Γ)"]"julia-observer-quote-cut-paste-70worksmithchart(:Y, ref=75)julia-observer-quote-cut-paste-71workYjulia-observer-quote-cut-paste-72work::Symbolsjulia-observer-quote-cut-paste-73work:linjulia-observer-quote-cut-paste-74work:log10julia-observer-quote-cut-paste-75work:logjulia-observer-quote-cut-paste-76work:log10julia-observer-quote-cut-paste-77work:lnjulia-observer-quote-cut-paste-78work:log2julia-observer-quote-cut-paste-79work:dB20julia-observer-quote-cut-paste-80work:dB10julia-observer-quote-cut-paste-81work`julia-observer-quote-cut-paste-87work`julia-observer-quote-cut-paste-82work::Plot2Djulia-observer-quote-cut-paste-83work::Multiplotjulia-observer-quote-cut-paste-84work`julia-observer-quote-cut-paste-89work`julia-observer-quote-cut-paste-85work`julia-observer-quote-cut-paste-90work`julia-observer-quote-cut-paste-86work``` html julia-observer-html-cut-paste-5_work ```

The .layout properties should be accessed using the [] operators, using the field names names of PlotLayout / MultiplotLayout as arguments:

plot.layout[:valloc_top] = 20 #Modify space above data area

Pre-defined Stylesheets

InspectDR uses "Stylesheets" to control the default values of plot elements. To apply a different stylesheet to a given plot, use the setstyle! methods:

InspectDR.setstyle!(::Plot2D, stylesheet::Symbol; kwargs...)
InspectDR.setstyle!(::Multiplot, stylesheet::Symbol; kwargs...)

Currently supported values for stylesheet include:

  • :screen
  • :IEEE

Custom stylesheets are added by extending InspectDR.getstyle(), as done in stylesheets.jl (Search for: StyleID{:screen} & StyleID{:IEEE}).


At this point in time, legends have limited configurability. When displayed, legends will consume fixed horizontal real-estate. The idea is to display a large number of labels without hiding the data area.

In order to display the legend of a plot::Plot2D object, one would set:

plot.layout[:enable_legend] = true #Enables legend
plot.layout[:halloc_legend] = 150 #Control size of legend


Default InspectDR.jl settings can be overwritten once the module is loaded by editing the InspectDR.defaults structure:

#Dissalow SVG MIME output for performance reasons:
InspectDR.defaults.rendersvg = false

#Change when plots drop points to enable "F1"-acceleration:
#(One of: {:always, :never, :noglyph, :hasline})
InspectDR.defaults.pointdropmatrix = InspectDR.PDM_DEFAULTS[:always]

#Enable time stamp & legend:
InspectDR.defaults.plotlayout[:enable_timestamp] = true
InspectDR.defaults.plotlayout[:enable_legend] = true

#Set data-area dimensions (saving single plot):
InspectDR.defaults.plotlayout[:halloc_data] = 500
InspectDR.defaults.plotlayout[:valloc_data] = 350

#Set plot dimensions (saving multi-plot):
InspectDR.defaults.mplotlayout[:halloc_plot] = 500
InspectDR.defaults.mplotlayout[:valloc_plot] = 350

#Configure # of columns in multi-plot outputs:
InspectDR.defaults.mplotlayout[:ncolumns] = 2

Until better documentation is available, one is encouraged to look at the fields of the PlotLayout for more information:


Defaults can also be specified before importing InspectDR.jl with the help of Main.DEFAULTS_INSPECTDR::Dict. Simply create the variable in your ~/.juliarc.jl file, using the following pattern:

	:rendersvg => false,

	#Special options available @ initialization:
	:droppoints => :always, #One of: {:always, :never, :noglyph, :hasline}
	:notation_x => :SI,   #Change x-axis notation
	:notation_y => :SI,   #Change y-axis notation
	:fontname => "Sans",  #Change default font family
	:fontscale => 1.2,    #Scale up/down font default sizes

	#Basic plot options:
	:enable_timestamp => true,
	:enable_legend => true,
	:halloc_legend => 150,

	#Supported multiplot options:
	:ncolumns => 2,
	:halloc_plot => 500,
	:valloc_plot => 350,

Sample Usage

  • Sample code to construct InspectDR objects can be found here.
  • Sample IJulia (Jupyter) notebooks can be found here.
  • Sample Blink (Electron backend) projects can be found here.

Known Limitations

  • Stability of IJulia (Jupyter) notebooks is not very good at the moment. Also: many examples are not yet ported to Julia 1.0.
  • Documentation is a bit limited at the moment. See Sample Usage to learn from examples.
  • API is still a bit rough. User often has to manipulate data structures directly.
  • Font control is not ideal. The default font might not be available on all platforms - and the fallback font might not have Unicode characters to display exponent values (ex: 10⁻¹⁵). Some Greek characters might also be missing.
  • Legends not very configurable (currently optimized to display many labels @ cost of horizontal real-estate).
  • Does not yet render plot data in separate thread (will improve interactive experience with large datasets).
  • Mouse events currently function even outside data area (a bit odd).
  • Significant slowdowns observed when zooming deep into non-F1 data... Can likely be solved by discarding data outside plot extents.
    • Workaround: make sure x-values are sorted (F1-acceleration discards data & is less prone to slowdowns).
  • By default, "F1"-acceleration is only applied to datasets drawn without glyphs (lines only).


Extensive compatibility testing of InspectDR.jl has not been performed. The module has been tested using the following environment(s):

  • Windows / Linux / Julia-1.1.1 / Gtk 0.17.0 (GTK+ 3) / Cairo 0.6.0


The InspectDR.jl module is not yet mature. Expect significant changes.

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