go-rpi-rgb-led-matrix/README.md

# go-rpi-rgb-led-matrix [![GoDoc](https://godoc.org/github.com/mcuadros/go-rpi-rgb-led-matrix?status.svg)](https://godoc.org/github.com/mcuadros/go-rpi-rgb-led-matrix) [![Build Status](https://travis-ci.org/mcuadros/go-rpi-rgb-led-matrix.svg?branch=master)](https://travis-ci.org/mcuadros/go-rpi-rgb-led-matrix) 
<img width="250" src="https://cloud.githubusercontent.com/assets/1573114/20248154/c17c1f2e-a9dd-11e6-805b-bf7d8ee73121.gif" align="right" />

Go binding for [`rpi-rgb-led-matrix`](https://github.com/hzeller/rpi-rgb-led-matrix) an excellent C++ library to control [RGB LED displays](https://learn.adafruit.com/32x16-32x32-rgb-led-matrix/overview) with Raspberry Pi GPIO.

This library includes the basic bindings to control de LED Matrix directly and also a convenient [ToolKit](https://godoc.org/github.com/mcuadros/go-rpi-rgb-led-matrix#ToolKit) with more high level functions. Also some [examples](https://github.com/mcuadros/go-rpi-rgb-led-matrix/tree/master/examples) are included to test the library and the configuration.

The [`Canvas`](https://godoc.org/github.com/mcuadros/go-rpi-rgb-led-matrix#Canvas) struct implements the [`image.Image`](https://golang.org/pkg/image/#Image) interface from the Go standard library. This makes the interaction with the matrix simple as work with a normal image in Go, allowing the usage of any Go library build around the `image.Image` interface.

To learn about the configuration and the wiring go to the [original library](https://github.com/hzeller/rpi-rgb-led-matrix), is highly detailed and well explained. 

Installation
------------

The recommended way to install `go-rpi-rgb-led-matrix` is:

```sh
go get github.com/mcuadros/go-rpi-rgb-led-matrix
```

Then you will get an **expected** error like this:

```
# github.com/mcuadros/go-rpi-rgb-led-matrix
/usr/bin/ld: cannot find -lrgbmatrix
collect2: error: ld returned 1 exit status
```

This happens because you need to compile the `rgbmatrix` C bindings:
```sh
cd $GOPATH/src/github.com/mcuadros/go-rpi-rgb-led-matrix/vendor/rpi-rgb-led-matrix/
git submodule update --init
make
cd $GOPATH/src/github.com/mcuadros/go-rpi-rgb-led-matrix/
go install -v ./...
```

Examples
--------

Setting all the pixels to white:

```go
// create a new Matrix instance with the DefaultConfig
m, _ := rgbmatrix.NewRGBLedMatrix(&rgbmatrix.DefaultConfig)

// create the Canvas, implements the image.Image interface
c := rgbmatrix.NewCanvas(m)
defer c.Close() // don't forgot close the Matrix, if not your leds will remain on
 
// using the standard draw.Draw function we copy a white image onto the Canvas
draw.Draw(c, c.Bounds(), &image.Uniform{color.White}, image.ZP, draw.Src)

// don't forget call Render to display the new led status
c.Render()
``` 

Playing a GIF into your matrix during 30 seconds:

```go
// create a new Matrix instance with the DefaultConfig
m, _ := rgbmatrix.NewRGBLedMatrix(&rgbmatrix.DefaultConfig)

// create a ToolKit instance
tk := rgbmatrix.NewToolKit(m)
defer tk.Close() // don't forgot close the Matrix, if not your leds will remain on

// open the gif file for reading
file, _ := os.Open("mario.gif")

// play of the gif using the io.Reader
close, _ := tk.PlayGIF(f)
fatal(err)

// we wait 30 seconds and then we stop the playing gif sending a True to the returned chan
time.Sleep(time.Second * 30)
close <- true
```

The image of the header was recorded using this few lines, the running _Mario_ gif, and three 32x64 pannels. 
<img src="https://cloud.githubusercontent.com/assets/1573114/20248173/2e2f97ae-a9de-11e6-95e6-e0548199501d.gif" align="right" width="100" />

Check the folder [`examples`](https://github.com/mcuadros/go-rpi-rgb-led-matrix/tree/master/examples) folder for more examples


Matrix Emulation
----------------

As part of the library an small Matrix emulator is provided. The emulator renderize a virtual RGB matrix on a window in your desktop, without needing a real RGB matrix connected to your computer.

To execute the emulator set the `MATRIX_EMULATOR` environment variable to `1`, then when `NewRGBLedMatrix` is used, a `emulator.Emulator` is returned instead of a interface the real board.


License
-------

MIT, see [LICENSE](LICENSE)