fix pixels staying on after render

Makefile

@@ -2,7 +2,7 @@ setup:
 	cd go-rpi-rgb-led-matrix/lib/rpi-rgb-led-matrix && make
 
 run:
-	sudo go run cmd/rpi/main.go --led-slowdown-gpio=2
+	sudo go run cmd/rpi/main.go --led-slowdown-gpio=2 --led-pwm-dither-bits=1
 
 build:
 	go build cmd/rpi/main.go

cmd/rpi/main.go

@@ -61,6 +61,11 @@ func main() {
 		log.Fatal(err)
 	}
 
+	currentPrice, err := mp.CurrentPrice()
+	if err != nil {
+		log.Fatal(err)
+	}
+
 	var blockHeight int
 	blockHeightMutex := &sync.Mutex{}
 	var fees mempool.Fees
@@ -72,6 +77,7 @@ func main() {
 	fees.FastestFee = highfee
 	fees.HalfHourFee = medfee
 	fees.HourFee = lowfee
+	price = currentPrice
 
 	go mp.Listen(ctx, msgs, errs, mdone)
 
@@ -105,7 +111,6 @@ func main() {
 			return
 		case <-ticker.C:
 			d.Clear()
-			d.Render()
 			err = updateSlots(d, price, blockHeight, fees.HourFee, fees.HalfHourFee, fees.FastestFee)
 			if err != nil {
 				log.Fatal(err)

display/slot.go

@@ -27,6 +27,7 @@ func (s *Segment) Draw(canvas *rgbmatrix.Canvas, x, y int) {
 
 func drawRow(canvas *rgbmatrix.Canvas, row []color.RGBA, x, y int) {
 	for i := 0; i < len(row); i++ {
+		canvas.Set(x+i, y, color.Black)
 		canvas.Set(x+i, y, row[i])
 	}
 }

fonts/fonts.go

@@ -26,7 +26,7 @@ func (f Font) ToColor(char string, c color.RGBA) ([][]color.RGBA, error) {
 			crowColor.R = crowColor.R * pixel
 			crowColor.G = crowColor.G * pixel
 			crowColor.B = crowColor.B * pixel
-			crowColor.A = 0xff * pixel
+			crowColor.A = 0xff
 			crow = append(crow, crowColor)
 		}
 

mempool/mempool.go

@@ -9,6 +9,7 @@ import (
 	"net/http"
 	"net/url"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/gorilla/websocket"
@@ -134,6 +135,47 @@ func (m *mempool) CurrentFees() (int, int, int, error) {
 	return data.Fastest, data.HalfHour, data.Hour, err
 }
 
+func (m *mempool) CurrentPrice() (int, error) {
+	req, err := http.NewRequest(http.MethodGet, "https://api.coincap.io/v2/assets/bitcoin", nil)
+	if err != nil {
+		return 0, err
+	}
+
+	resp, err := m.httpClient.Do(req)
+	if err != nil {
+		return 0, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode >= http.StatusInternalServerError {
+		return 0, err
+	}
+
+	if resp.StatusCode >= http.StatusBadRequest {
+		return 0, err
+	}
+
+	b, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return 0, err
+	}
+
+	var data struct {
+		Data struct {
+			PriceUSD string `json:"priceUsd"`
+		} `json:"data"`
+	}
+
+	err = json.Unmarshal(b, &data)
+	if err != nil {
+		return 0, err
+	}
+
+	parts := strings.Split(data.Data.PriceUSD, ".")
+	i, err := strconv.Atoi(parts[0])
+	return i, err
+}
+
 func (m *mempool) Listen(ctx context.Context, messages chan Message, errs chan error, done chan struct{}) {
 	for {
 		select {