96 lines
3.2 KiB
Markdown
96 lines
3.2 KiB
Markdown
go-chart
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========
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[](https://circleci.com/gh/wcharczuk/go-chart) [](https://goreportcard.com/report/github.com/wcharczuk/go-chart)
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Package `chart` is a very simple golang native charting library that supports timeseries and continuous line charts.
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Master should now be on the v3.x codebase, which overhauls the api significantly. Per usual, see `examples` for more information.
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# Installation
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To install `chart` run the following:
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```bash
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> go get -u github.com/wcharczuk/go-chart
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```
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Most of the components are interchangeable so feel free to crib whatever you want.
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# Output Examples
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Spark Lines:
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Single axis:
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Two axis:
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# Other Chart Types
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Pie Chart:
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The code for this chart can be found in `examples/pie_chart/main.go`.
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Stacked Bar:
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The code for this chart can be found in `examples/stacked_bar/main.go`.
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# Code Examples
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Actual chart configurations and examples can be found in the `./examples/` directory. They are simple CLI programs that write to `output.png` (they are also updated with `go generate`.
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# Usage
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Everything starts with the `chart.Chart` object. The bare minimum to draw a chart would be the following:
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```golang
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import (
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...
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"bytes"
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...
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"github.com/wcharczuk/go-chart" //exposes "chart"
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)
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graph := chart.Chart{
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Series: []chart.Series{
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chart.ContinuousSeries{
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XValues: []float64{1.0, 2.0, 3.0, 4.0},
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YValues: []float64{1.0, 2.0, 3.0, 4.0},
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},
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},
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}
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buffer := bytes.NewBuffer([]byte{})
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err := graph.Render(chart.PNG, buffer)
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```
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Explanation of the above: A `chart` can have many `Series`, a `Series` is a collection of things that need to be drawn according to the X range and the Y range(s).
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Here, we have a single series with x range values as float64s, rendered to a PNG. Note; we can pass any type of `io.Writer` into `Render(...)`, meaning that we can render the chart to a file or a resonse or anything else that implements `io.Writer`.
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# API Overview
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Everything on the `chart.Chart` object has defaults that can be overriden. Whenever a developer sets a property on the chart object, it is to be assumed that value will be used instead of the default.
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The best way to see the api in action is to look at the examples in the `./_examples/` directory.
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# Design Philosophy
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I wanted to make a charting library that used only native golang, that could be stood up on a server (i.e. it had built in fonts).
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The goal with the API itself is to have the "zero value be useful", and to require the user to not code more than they absolutely needed.
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# Contributions
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Contributions are welcome though this library is in a holding pattern for the forseable future.
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