emulator: improvements and integration

README.md

@@ -81,6 +81,15 @@ The image of the header was recorded using this few lines, the running _Mario_ g
 
 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
 -------
 

emulator/emulator.go

@@ -3,10 +3,12 @@ package emulator
 import (
 	"image"
 	"image/color"
-	"log"
+	"os"
 
 	"sync"
 
+	"fmt"
+
 	"golang.org/x/exp/shiny/driver"
 	"golang.org/x/exp/shiny/imageutil"
 	"golang.org/x/exp/shiny/screen"
@@ -14,10 +16,8 @@ import (
 	"golang.org/x/mobile/event/size"
 )
 
-var (
-	black = color.RGBA{0x00, 0x00, 0x00, 0xff}
-	red   = color.RGBA{0x7f, 0x00, 0x00, 0x7f}
-)
+const DefaultPixelPitch = 12
+const windowTitle = "RGB led matrix emulator"
 
 var margin = 10
 
@@ -29,24 +29,42 @@ type Emulator struct {
 
 	leds []color.Color
 	w    screen.Window
+	s    screen.Screen
+	wg   sync.WaitGroup
+
 	isReady bool
+}
 
-	wg sync.WaitGroup
+func NewEmulator(w, h, pixelPitch int, autoInit bool) *Emulator {
+	e := &Emulator{
+		PixelPitch: pixelPitch,
+		Gutter:     int(float64(pixelPitch) * 0.66),
+		Width:      w,
+		Height:     h,
 	}
 
+	if autoInit {
+		e.Init()
+	}
+
+	return e
+}
+
+// Init initialize the emulator, creating a new Window and waiting until is
+// painted. If something goes wrong the function panics
 func (e *Emulator) Init() {
 	e.leds = make([]color.Color, 2048)
 
 	e.wg.Add(1)
-	go e.init()
+	go driver.Main(e.mainWindowLoop)
 	e.wg.Wait()
 }
 
-func (e *Emulator) init() {
-	driver.Main(func(s screen.Screen) {
+func (e *Emulator) mainWindowLoop(s screen.Screen) {
 	var err error
+	e.s = s
 	e.w, err = s.NewWindow(&screen.NewWindowOptions{
-			Title: "Basic Shiny Example",
+		Title: windowTitle,
 	})
 
 	if err != nil {
@@ -60,12 +78,7 @@ func (e *Emulator) init() {
 		evn := e.w.NextEvent()
 		switch evn := evn.(type) {
 		case paint.Event:
-				for _, r := range imageutil.Border(sz.Bounds(), margin) {
-					e.w.Fill(r, red, screen.Src)
-				}
-
-				e.w.Fill(sz.Bounds().Inset(margin), black, screen.Src)
-				e.w.Publish()
+			e.drawContext(sz)
 			if e.isReady {
 				continue
 			}
@@ -77,10 +90,18 @@ func (e *Emulator) init() {
 			sz = evn
 
 		case error:
-				log.Print(e)
+			fmt.Fprintln(os.Stderr, e)
 		}
 	}
-	})
+}
+
+func (e *Emulator) drawContext(sz size.Event) {
+	for _, r := range imageutil.Border(sz.Bounds(), margin) {
+		e.w.Fill(r, color.White, screen.Src)
+	}
+
+	e.w.Fill(sz.Bounds().Inset(margin), color.Black, screen.Src)
+	e.w.Publish()
 }
 
 func (e *Emulator) Geometry() (width, height int) {
@@ -98,8 +119,10 @@ func (e *Emulator) Apply(leds []color.Color) error {
 			x += margin * 2
 			y += margin * 2
 
-			c := e.At(col + (row * e.Width))
-			e.w.Fill(image.Rect(x, y, x+e.PixelPitch, y+e.PixelPitch), c, screen.Over)
+			color := e.At(col + (row * e.Width))
+			led := image.Rect(x, y, x+e.PixelPitch, y+e.PixelPitch)
+
+			e.w.Fill(led, color, screen.Over)
 		}
 	}
 

matrix.go

@@ -29,7 +29,10 @@ import "C"
 import (
 	"fmt"
 	"image/color"
+	"os"
 	"unsafe"
+
+	"github.com/mcuadros/go-rpi-rgb-led-matrix/emulator"
 )
 
 // DefaultConfig default WS281x configuration
@@ -116,8 +119,14 @@ type RGBLedMatrix struct {
 	leds   []C.uint32_t
 }
 
+const MatrixEmulatorENV = "MATRIX_EMULATOR"
+
 // NewRGBLedMatrix returns a new matrix using the given size and config
-func NewRGBLedMatrix(config *HardwareConfig) (*RGBLedMatrix, error) {
+func NewRGBLedMatrix(config *HardwareConfig) (Matrix, error) {
+	if isMatrixEmulator() {
+		return buildMatrixEmulator(config), nil
+	}
+
 	w, h := config.geometry()
 
 	c := &RGBLedMatrix{
@@ -134,6 +143,19 @@ func NewRGBLedMatrix(config *HardwareConfig) (*RGBLedMatrix, error) {
 	return c, nil
 }
 
+func isMatrixEmulator() bool {
+	if os.Getenv(MatrixEmulatorENV) == "1" {
+		return true
+	}
+
+	return false
+}
+
+func buildMatrixEmulator(config *HardwareConfig) Matrix {
+	w, h := config.geometry()
+	return emulator.NewEmulator(w, h, emulator.DefaultPixelPitch, true)
+}
+
 // Initialize initialize library, must be called once before other functions are
 // called.
 func (c *RGBLedMatrix) Initialize() error {