Adding scroll functionality for ili9341 (#121)

* ili9341: Adding scroll functionality

examples/ili9341/scroll/main.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"image/color"
+	"machine"
+	"time"
+
+	"tinygo.org/x/drivers/ili9341"
+)
+
+var (
+	display = ili9341.NewParallel(
+		machine.LCD_DATA0,
+		machine.TFT_WR,
+		machine.TFT_DC,
+		machine.TFT_CS,
+		machine.TFT_RESET,
+		machine.TFT_RD,
+	)
+
+	red   = color.RGBA{255, 0, 0, 255}
+	blue  = color.RGBA{0, 0, 255, 255}
+	green = color.RGBA{0, 255, 0, 255}
+	black = color.RGBA{0, 0, 0, 255}
+	white = color.RGBA{255, 255, 255, 255}
+)
+
+func main() {
+
+	machine.TFT_BACKLIGHT.Configure(machine.PinConfig{machine.PinOutput})
+
+	display.Configure(ili9341.Config{})
+	width, height := display.Size()
+
+	display.FillScreen(black)
+	machine.TFT_BACKLIGHT.High()
+
+	display.FillRectangle(0, 0, width/2, height/2, white)
+	display.FillRectangle(width/2, 0, width/2, height/2, red)
+	display.FillRectangle(0, height/2, width/2, height/2, green)
+	display.FillRectangle(width/2, height/2, width/2, height/2, blue)
+	display.FillRectangle(width/4, height/4, width/2, height/2, black)
+
+	for scroll := int16(0); ; scroll = (scroll + 1) % 320 {
+		time.Sleep(7500 * time.Microsecond)
+		display.SetScroll(scroll)
+	}
+
+}