📈 μPlot

A small (~30 KB min), fast chart for time series, lines, areas, ohlc & bars (MIT Licensed)

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Introduction

μPlot is a fast, memory-efficient Canvas 2D-based chart for plotting time series, lines, areas, ohlc & bars; from a cold start it can create an interactive chart containing 150,000 data points in 135ms, scaling linearly at ~25,000 pts/ms. In addition to fast initial render, the zooming and cursor performance is by far the best of any similar charting lib; at ~30 KB, it's likely the smallest and fastest time series plotter that doesn't make use of context-limited WebGL shaders or WASM, both of which have much higher startup cost and code size.

166,650 point bench: https://leeoniya.github.io/uPlot/bench/uPlot.html

However, if you're looking for true real-time 60fps performance with massive datasets, uPlot can only get you so far. WebGL should still be the tool of choice for applications like realtime signal or waveform visualizations: Try danchitnis/webgl-plot, huww98/TimeChart, epezent/implot.

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Features

• Multiple series w/toggle
• Multiple y-axes, scales & grids
• Temporal or numeric x-axis
• Linear, uniform or logarithmic scales
• Line & Area styles (stroke, fill, width, dash)
• Pluggable path renderers linear, spline, stepped, bars
• Zoom with auto-rescale
• Legend with live values
• Support for IANA Time Zone Names & DST
• Support for missing data
• Cursor sync for multiple charts
• Focus closest series
• Data streaming (live update)
• High / Low bands
• A lean, consistent, and powerful API with hooks & plugins

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Non-Features

In order to stay lean, fast and focused the following features will not be added:

• No data parsing, aggregation, summation or statistical processing - just do it in advance. e.g. https://simplestatistics.org/, https://www.papaparse.com/
• No transitions or animations - they're always pure distractions.
• No collision avoidance for axis tick labels, so may require manual tweaking of spacing metrics if label customization significiantly increases default label widths.
• No stacked series: see "Stacked Area Graphs Are Not Your Friend" and a horrific demo. While smooth spline interpolation is available, its use is strongly discouraged: Your data is misrepresented!. Both visualizations are terrible at accurately communicating information.
• No built-in drag scrolling/panning due to ambiguous native zoom/selection behavior. However, this can be added externally via the plugin/hooks API: zoom-wheel, zoom-touch.

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Documentation (WIP)

The docs are a perpetual work in progress, it seems. Start with /docs/README.md for a conceptual overview. The full API is further documented via comments in /dist/uPlot.d.ts. Additionally, an ever-expanding collection of runnable /demos covers the vast majority of uPlot's API.

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Performance

Benchmarks done on a ThinkPad T480S:

• Date: 2020-12-25
• Windows 10 x64, Chrome 87.0.4280.88 (Official Build) (64-bit)
• Core i5-8350U @ 1.70GHz, 16GB RAM
• Intel HD 620 GPU, 2560x1440 res

Full size: https://leeoniya.github.io/uPlot/demos/multi-bars.html

Raw data: https://github.com/leeoniya/uPlot/blob/master/bench/results.json

| lib             | size    | done    | js,rend,paint,sys | heap peak,final | interact (10s)      |
| --------------- | ------- | ------- | ----------------- | --------------- | ------------------- |
| uPlot           |   38 KB |   65 ms |   93   2   1   50 |  13 MB   3 MB   |  167  384  128  223 |
| ECharts         |  954 KB |  114 ms |  149   2   2   55 |  13 MB   5 MB   | 2783  495  147  698 |
| Flot            |  494 KB |  110 ms |  166   5   2   73 |  32 MB  18 MB   | ---                 |
| dygraphs        |  125 KB |  155 ms |  200   4   1   98 |  72 MB  49 MB   | 1663  237  113  374 |
| Chart.js-next   |  219 KB |  250 ms |  290   2   1   65 |  33 MB  20 MB   | 6256   50   79 1313 |
| LightningChart® | 1000 KB |  --- ms |  359   3   1   54 |  26 MB  18 MB   | 9308   87   71  279 |
| CanvasJS        |  479 KB |  292 ms |  340   3   1   80 |  38 MB  27 MB   | 1782  431  112  354 |
| Highcharts      |  319 KB |  --- ms |  370   8   2   61 |  52 MB  38 MB   | 1806  661  176  243 |
| dvxcharts       |  362 KB |  310 ms |  518  26   2   68 |  62 MB  24 MB   | 1033  592  146  189 |
| Chart.js        |  245 KB |  616 ms |  661   3   2   70 |  92 MB  79 MB   | 8471    6    9 1152 |
| Plotly.js       | 3500 KB |  449 ms |  769   8   2   82 |  56 MB  23 MB   | 1522  201   52  172 |
| ApexCharts      |  471 KB |  --- ms | 2070  25   2   76 | 154 MB  95 MB   | 8593  713  106  174 |
| ZingChart       |  856 KB | 2476 ms | 2640   7   1   47 | 140 MB 111 MB   | ---                 |
| amCharts        | 1200 KB | 5564 ms | 6057  40  11   80 | 235 MB 231 MB   | 6309  650  248  375 |

• size includes the lib itself plus any dependencies required to render the benchmark, e.g. Moment, jQuery, etc.
• Flot does not make available any minified assets and all their examples use the uncompressed sources; they also use an uncompressed version of jQuery :/

TODO (all of these use SVG, so performance should be similar to Highcharts):

• Chartist.js
• d3-based
  • C3.js
  • dc.js
  • MetricsGraphics
  • rickshaw

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Acknowledgements

• Dan Vanderkam's dygraphs was a big inspiration; in fact, my stale pull request #948 was a primary motivator for μPlot's inception.
• Adam Pearce for #15 - remove redundant lineTo commands.