White and black

examples/drawing/drawing/drawing.go

@@ -55,23 +55,23 @@ func (g *Game) Update() error {
 	}
 
 	if koebiten.IsKeyPressed(koebiten.Key0) {
-		g.draw(g.canvas, g.pointer.x, g.pointer.y, black)
+		g.draw(g.canvas, g.pointer.x, g.pointer.y, white) // eraser
 	}
 	if koebiten.IsKeyPressed(koebiten.Key1) || koebiten.IsKeyPressed(koebiten.Key2) ||
 		koebiten.IsKeyPressed(koebiten.Key3) || koebiten.IsKeyPressed(koebiten.Key4) ||
 		koebiten.IsKeyPressed(koebiten.Key5) || koebiten.IsKeyPressed(koebiten.Key6) ||
 		koebiten.IsKeyPressed(koebiten.Key7) || koebiten.IsKeyPressed(koebiten.Key8) ||
 		koebiten.IsKeyPressed(koebiten.Key9) || koebiten.IsKeyPressed(koebiten.Key10) ||
 		koebiten.IsKeyPressed(koebiten.Key11) {
-		g.draw(g.canvas, g.pointer.x, g.pointer.y, white)
+		g.draw(g.canvas, g.pointer.x, g.pointer.y, black)
 	}
 
 	return nil
 }
 
 func (g *Game) Draw(screen *koebiten.Image) {
 	g.canvas.DrawImage(screen, koebiten.DrawImageOptions{})
-	koebiten.DrawFilledCircle(screen, g.pointer.x, g.pointer.y, g.thick+1, white)
+	koebiten.DrawFilledCircle(screen, g.pointer.x, g.pointer.y, g.thick+1, black)
 }
 
 func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {

games/blocks/blocks/blocks.go

@@ -11,8 +11,8 @@ import (
 )
 
 var (
-	backgroundColor = pixel.NewMonochrome(0x00, 0x00, 0x00)
-	frameColor      = pixel.NewMonochrome(0xFF, 0xFF, 0xFF)
+	backgroundColor = pixel.NewMonochrome(0xFF, 0xFF, 0xFF)
+	frameColor      = pixel.NewMonochrome(0x00, 0x00, 0x00)
 )
 
 const (

games/jumpingopher/jumpingopher/game.go

@@ -79,7 +79,6 @@ func drawTitle() {
 }
 
 func drawGame() {
-	koebiten.DrawImageFS(nil, fsys, "sky.png", 0, 0)
 	koebiten.Println("Score", score)
 	koebiten.DrawImageFS(nil, fsys, "platform.png", 0, 60)
 

games/snakegame/snakegame/snakegame.go

@@ -174,9 +174,9 @@ func (g *Game) Draw(screen *koebiten.Image) {
 	}
 
 	for _, s := range g.snake {
-		koebiten.DrawFilledRect(screen, s.x*gridSize, s.y*gridSize, gridSize, gridSize, white)
+		koebiten.DrawFilledRect(screen, s.x*gridSize, s.y*gridSize, gridSize, gridSize, black)
 	}
-	koebiten.DrawFilledRect(screen, g.food.x*gridSize, g.food.y*gridSize, gridSize, gridSize, white)
+	koebiten.DrawFilledRect(screen, g.food.x*gridSize, g.food.y*gridSize, gridSize, gridSize, black)
 	koebiten.Println("Score:", g.score)
 }
 

hardware/conf2025badge.go

@@ -21,7 +21,7 @@ func (z CONF2025BADGE) Init() error {
 }
 
 func (z CONF2025BADGE) GetDisplay() koebiten.Displayer {
-	return Display
+	return whiteBGDisplay{Display}
 }
 
 func (z CONF2025BADGE) KeyUpdate() error {

hardware/gopher-badge.go

@@ -159,7 +159,7 @@ func InitDisplay(dev *st7789.Device, width, height int) *Display {
 
 	ox, oy := d.getImageTopLeftForCentering()
 	w, h := d.img.Size()
-	tinydraw.Rectangle(dev, ox-1, oy-1, int16(w)+2, int16(h)+2, white)
+	tinydraw.Rectangle(dev, ox-1, oy-1, int16(w)+2, int16(h)+2, black)
 
 	return d
 }
@@ -170,29 +170,17 @@ func (d *Display) Size() (x, y int16) {
 
 func (d *Display) SetPixel(x, y int16, c color.RGBA) {
 	mx, my := d.Size()
-	if 0 <= x && x < int16(mx) && 0 <= y && y < int16(my) {
-		d.img.Set(int(x*2+0), int(y*2+0), pixelWhite)
-		d.img.Set(int(x*2+1), int(y*2+0), pixelWhite)
-		d.img.Set(int(x*2+0), int(y*2+1), pixelWhite)
-		d.img.Set(int(x*2+1), int(y*2+1), pixelWhite)
+	if x < 0 || x >= int16(mx) || y < 0 || y >= int16(my) {
+		return
 	}
-	return
-	cnt := 0
-	if c.R < 0x80 {
-		cnt++
+	px := pixelWhite
+	if int(c.R)+int(c.G)+int(c.B) <= 128*3 {
+		px = pixelBlack
 	}
-	if c.G < 0x80 {
-		cnt++
-	}
-	if c.B < 0x80 {
-		cnt++
-	}
-	if cnt >= 2 {
-		d.img.Set(int(x), int(y), pixelWhite)
-	} else {
-		d.img.Set(int(x), int(y), pixelBlack)
-	}
-	//d.d.SetPixel(x, y, c)
+	d.img.Set(int(x*2+0), int(y*2+0), px)
+	d.img.Set(int(x*2+1), int(y*2+0), px)
+	d.img.Set(int(x*2+0), int(y*2+1), px)
+	d.img.Set(int(x*2+1), int(y*2+1), px)
 }
 
 func (d *Display) Display() error {
@@ -201,7 +189,7 @@ func (d *Display) Display() error {
 }
 
 func (d *Display) ClearBuffer() {
-	d.img.FillSolidColor(pixelBlack)
+	d.img.FillSolidColor(pixelWhite)
 }
 
 func (d *Display) ClearDisplay() {

hardware/gopher-board-i2c.go

@@ -36,7 +36,7 @@ const (
 )
 
 func (z *device) GetDisplay() koebiten.Displayer {
-	return Display
+	return whiteBGDisplay{Display}
 }
 
 func (z *device) Init() error {

hardware/gopher-board-spi.go

@@ -163,7 +163,7 @@ func InitDisplay(dev *st7789.Device, width, height int) *Display {
 
 	ox, oy := d.getImageTopLeftForCentering()
 	w, h := d.img.Size()
-	tinydraw.Rectangle(dev, ox-1, oy-1, int16(w)+2, int16(h)+2, white)
+	tinydraw.Rectangle(dev, ox-1, oy-1, int16(w)+2, int16(h)+2, black)
 
 	return d
 }
@@ -174,29 +174,17 @@ func (d *Display) Size() (x, y int16) {
 
 func (d *Display) SetPixel(x, y int16, c color.RGBA) {
 	mx, my := d.Size()
-	if 0 <= x && x < int16(mx) && 0 <= y && y < int16(my) {
-		d.img.Set(int(x*2+0), int(y*2+0), pixelWhite)
-		d.img.Set(int(x*2+1), int(y*2+0), pixelWhite)
-		d.img.Set(int(x*2+0), int(y*2+1), pixelWhite)
-		d.img.Set(int(x*2+1), int(y*2+1), pixelWhite)
+	if x < 0 || x >= int16(mx) || y < 0 || y >= int16(my) {
+		return
 	}
-	return
-	cnt := 0
-	if c.R < 0x80 {
-		cnt++
+	px := pixelWhite
+	if int(c.R)+int(c.G)+int(c.B) <= 128*3 {
+		px = pixelBlack
 	}
-	if c.G < 0x80 {
-		cnt++
-	}
-	if c.B < 0x80 {
-		cnt++
-	}
-	if cnt >= 2 {
-		d.img.Set(int(x), int(y), pixelWhite)
-	} else {
-		d.img.Set(int(x), int(y), pixelBlack)
-	}
-	//d.d.SetPixel(x, y, c)
+	d.img.Set(int(x*2+0), int(y*2+0), px)
+	d.img.Set(int(x*2+1), int(y*2+0), px)
+	d.img.Set(int(x*2+0), int(y*2+1), px)
+	d.img.Set(int(x*2+1), int(y*2+1), px)
 }
 
 func (d *Display) Display() error {
@@ -205,7 +193,7 @@ func (d *Display) Display() error {
 }
 
 func (d *Display) ClearBuffer() {
-	d.img.FillSolidColor(pixelBlack)
+	d.img.FillSolidColor(pixelWhite)
 }
 
 func (d *Display) ClearDisplay() {

hardware/macropad-rp2040.go

@@ -13,12 +13,31 @@ var Device = &device{}
 
 type device struct {
 	display  *sh1106.Device
+	whiteBuf []byte
 	gpioPins []machine.Pin
 	state    []State
 	cycle    []int
 	keybuf   [1]koebiten.Key
 }
 
+// whiteBGDisplay wraps sh1106.Device so that clearing the buffer fills the
+// screen with white instead of black. koebiten draws ink in black on a white
+// background. sh1106 does not expose its buffer, so an all-white buffer is
+// copied in via SetBuffer.
+type whiteBGDisplay struct {
+	*sh1106.Device
+	whiteBuf []byte
+}
+
+func (d whiteBGDisplay) ClearBuffer() {
+	d.SetBuffer(d.whiteBuf)
+}
+
+func (d whiteBGDisplay) ClearDisplay() {
+	d.ClearBuffer()
+	d.Display()
+}
+
 const (
 	debounce = 0
 )
@@ -48,6 +67,11 @@ func (z *device) Init() error {
 	d.ClearDisplay()
 	z.display = &d
 
+	z.whiteBuf = make([]byte, 128*64/8)
+	for i := range z.whiteBuf {
+		z.whiteBuf[i] = 0xFF
+	}
+
 	gpioPins := []machine.Pin{
 		machine.KEY1,
 		machine.KEY2,
@@ -96,7 +120,7 @@ func (z *device) Init() error {
 }
 
 func (z *device) GetDisplay() koebiten.Displayer {
-	return z.display
+	return whiteBGDisplay{z.display, z.whiteBuf}
 }
 
 func (z *device) KeyUpdate() error {

hardware/pybadge.go

@@ -149,7 +149,7 @@ func InitDisplay(dev *st7735.Device, width, height int) *Display {
 
 	ox, oy := d.getImageTopLeftForCentering()
 	w, h := d.img.Size()
-	tinydraw.Rectangle(dev, ox-1, oy-1, int16(w)+2, int16(h)+2, white)
+	tinydraw.Rectangle(dev, ox-1, oy-1, int16(w)+2, int16(h)+2, black)
 
 	return d
 }
@@ -160,26 +160,14 @@ func (d *Display) Size() (x, y int16) {
 
 func (d *Display) SetPixel(x, y int16, c color.RGBA) {
 	mx, my := d.Size()
-	if 0 <= x && x < int16(mx) && 0 <= y && y < int16(my) {
-		d.img.Set(int(x), int(y), pixelWhite)
+	if x < 0 || x >= int16(mx) || y < 0 || y >= int16(my) {
+		return
 	}
-	return
-	cnt := 0
-	if c.R < 0x80 {
-		cnt++
+	px := pixelWhite
+	if int(c.R)+int(c.G)+int(c.B) <= 128*3 {
+		px = pixelBlack
 	}
-	if c.G < 0x80 {
-		cnt++
-	}
-	if c.B < 0x80 {
-		cnt++
-	}
-	if cnt >= 2 {
-		d.img.Set(int(x), int(y), pixelWhite)
-	} else {
-		d.img.Set(int(x), int(y), pixelBlack)
-	}
-	//d.d.SetPixel(x, y, c)
+	d.img.Set(int(x), int(y), px)
 }
 
 func (d *Display) Display() error {
@@ -188,7 +176,7 @@ func (d *Display) Display() error {
 }
 
 func (d *Display) ClearBuffer() {
-	d.img.FillSolidColor(pixelBlack)
+	d.img.FillSolidColor(pixelWhite)
 }
 
 func (d *Display) ClearDisplay() {

hardware/ssd1306-white.go

@@ -0,0 +1,26 @@
+//go:build tinygo && (zero_kb02 || conf2025badge || gopher_board_i2c)
+
+package hardware
+
+import (
+	"tinygo.org/x/drivers/ssd1306"
+)
+
+// whiteBGDisplay wraps ssd1306.Device so that clearing the buffer fills the
+// screen with white instead of black. koebiten draws ink in black on a white
+// background.
+type whiteBGDisplay struct {
+	*ssd1306.Device
+}
+
+func (d whiteBGDisplay) ClearBuffer() {
+	buf := d.GetBuffer()
+	for i := range buf {
+		buf[i] = 0xFF
+	}
+}
+
+func (d whiteBGDisplay) ClearDisplay() {
+	d.ClearBuffer()
+	d.Display()
+}

hardware/wasm.go

@@ -98,7 +98,7 @@ func (d *Display) ClearDisplay() {
 
 func (d *Display) ClearBuffer() {
 	for i := range d.buf {
-		d.buf[i] = 0
+		d.buf[i] = 0xFF // white background
 	}
 }
 

hardware/wioterminal.go

@@ -175,7 +175,7 @@ func InitDisplay(dev *ili9341.Device, width, height int) *Display {
 
 	ox, oy := d.getImageTopLeftForCentering()
 	w, h := d.img.Size()
-	tinydraw.Rectangle(dev, ox-1, oy-1, int16(w)+2, int16(h)+2, white)
+	tinydraw.Rectangle(dev, ox-1, oy-1, int16(w)+2, int16(h)+2, black)
 
 	return d
 }
@@ -186,29 +186,17 @@ func (d *Display) Size() (x, y int16) {
 
 func (d *Display) SetPixel(x, y int16, c color.RGBA) {
 	mx, my := d.Size()
-	if 0 <= x && x < int16(mx) && 0 <= y && y < int16(my) {
-		d.img.Set(int(x*2+0), int(y*2+0), pixelWhite)
-		d.img.Set(int(x*2+1), int(y*2+0), pixelWhite)
-		d.img.Set(int(x*2+0), int(y*2+1), pixelWhite)
-		d.img.Set(int(x*2+1), int(y*2+1), pixelWhite)
+	if x < 0 || x >= int16(mx) || y < 0 || y >= int16(my) {
+		return
 	}
-	return
-	cnt := 0
-	if c.R < 0x80 {
-		cnt++
+	px := pixelWhite
+	if int(c.R)+int(c.G)+int(c.B) <= 128*3 {
+		px = pixelBlack
 	}
-	if c.G < 0x80 {
-		cnt++
-	}
-	if c.B < 0x80 {
-		cnt++
-	}
-	if cnt >= 2 {
-		d.img.Set(int(x), int(y), pixelWhite)
-	} else {
-		d.img.Set(int(x), int(y), pixelBlack)
-	}
-	//d.d.SetPixel(x, y, c)
+	d.img.Set(int(x*2+0), int(y*2+0), px)
+	d.img.Set(int(x*2+1), int(y*2+0), px)
+	d.img.Set(int(x*2+0), int(y*2+1), px)
+	d.img.Set(int(x*2+1), int(y*2+1), px)
 }
 
 func (d *Display) Display() error {
@@ -217,7 +205,7 @@ func (d *Display) Display() error {
 }
 
 func (d *Display) ClearBuffer() {
-	d.img.FillSolidColor(pixelBlack)
+	d.img.FillSolidColor(pixelWhite)
 }
 
 func (d *Display) ClearDisplay() {

hardware/zero-kb02.go

@@ -21,7 +21,7 @@ func (z ZERO_KB02) Init() error {
 }
 
 func (z ZERO_KB02) GetDisplay() koebiten.Displayer {
-	return Display
+	return whiteBGDisplay{Display}
 }
 
 func (z ZERO_KB02) KeyUpdate() error {