epd2in13: added rotation

waveshare-epd/epd2in13/epd2in13.go

@@ -12,8 +12,10 @@ import (
 )
 
 type Config struct {
-	Width  int16
+	Width        int16 // Width is the display resolution
-	Height int16
+	Height       int16
+	LogicalWidth int16    // LogicalWidth must be a multiple of 8 and same size or bigger than Width
+	Rotation     Rotation // Rotation is clock-wise
 }
 
 type Device struct {
@@ -22,12 +24,16 @@ type Device struct {
 	dc           machine.Pin
 	rst          machine.Pin
 	busy         machine.Pin
+	logicalWidth int16
 	width        int16
 	height       int16
 	buffer       []uint8
 	bufferLength uint32
+	rotation     Rotation
 }
 
+type Rotation uint8
+
 // Look up table for full updates
 var lutFullUpdate = [30]uint8{
 	0x22, 0x55, 0xAA, 0x55, 0xAA, 0x55, 0xAA, 0x11,
@@ -61,17 +67,23 @@ func New(bus machine.SPI, csPin, dcPin, rstPin, busyPin machine.Pin) Device {
 
 // Configure sets up the device.
 func (d *Device) Configure(cfg Config) {
+	if cfg.LogicalWidth != 0 {
+		d.logicalWidth = cfg.LogicalWidth
+	} else {
+		d.logicalWidth = 128
+	}
 	if cfg.Width != 0 {
 		d.width = cfg.Width
 	} else {
-		d.width = 128
+		d.width = 122
 	}
 	if cfg.Height != 0 {
 		d.height = cfg.Height
 	} else {
 		d.height = 250
 	}
-	d.bufferLength = (uint32(d.width) * uint32(d.height)) / 8
+	d.rotation = cfg.Rotation
+	d.bufferLength = (uint32(d.logicalWidth) * uint32(d.height)) / 8
 	d.buffer = make([]uint8, d.bufferLength)
 	for i := uint32(0); i < d.bufferLength; i++ {
 		d.buffer[i] = 0xFF
@@ -158,10 +170,11 @@ func (d *Device) SetLUT(fullUpdate bool) {
 // We use RGBA(0,0,0, 255) as white (transparent)
 // Anything else as black
 func (d *Device) SetPixel(x int16, y int16, c color.RGBA) {
-	if x < 0 || x >= d.width || y < 0 || y >= d.height {
+	x, y = d.xy(x, y)
+	if x < 0 || x >= d.logicalWidth || y < 0 || y >= d.height {
 		return
 	}
-	byteIndex := (x + y*d.width) / 8
+	byteIndex := (x + y*d.logicalWidth) / 8
 	if c.R == 0 && c.G == 0 && c.B == 0 { // TRANSPARENT / WHITE
 		d.buffer[byteIndex] |= 0x80 >> uint8(x%8)
 	} else { // WHITE / EMPTY
@@ -171,12 +184,12 @@ func (d *Device) SetPixel(x int16, y int16, c color.RGBA) {
 
 // Display sends the buffer to the screen.
 func (d *Device) Display() error {
-	d.setMemoryArea(0, 0, d.width-1, d.height-1)
+	d.setMemoryArea(0, 0, d.logicalWidth-1, d.height-1)
 	for j := int16(0); j < d.height; j++ {
 		d.setMemoryPointer(0, j)
 		d.SendCommand(WRITE_RAM)
-		for i := int16(0); i < d.width/8; i++ {
+		for i := int16(0); i < d.logicalWidth/8; i++ {
-			d.SendData(d.buffer[i+j*(d.width/8)])
+			d.SendData(d.buffer[i+j*(d.logicalWidth/8)])
 		}
 	}
 
@@ -188,15 +201,28 @@ func (d *Device) Display() error {
 }
 
 // DisplayRect sends only an area of the buffer to the screen.
+// The rectangle points need to be a multiple of 8 in the screen.
+// They might not work as expected if the screen is rotated.
 func (d *Device) DisplayRect(x int16, y int16, width int16, height int16) error {
-	if x < 0 || y < 0 || x >= d.width || y >= d.height || width < 0 || height < 0 {
+	x, y = d.xy(x, y)
+	if x < 0 || y < 0 || x >= d.logicalWidth || y >= d.height || width < 0 || height < 0 {
 		return errors.New("wrong rectangle")
 	}
+	if d.rotation == ROTATION_90 {
+		width, height = height, width
+		x -= width
+	} else if d.rotation == ROTATION_180 {
+		x -= width - 1
+		y -= height - 1
+	} else if d.rotation == ROTATION_270 {
+		width, height = height, width
+		y -= height
+	}
 	x &= 0xF8
 	width &= 0xF8
 	width = x + width // reuse variables
-	if width >= d.width {
+	if width >= d.logicalWidth {
-		width = d.width
+		width = d.logicalWidth
 	}
 	height = y + height
 	if height > d.height {
@@ -209,7 +235,7 @@ func (d *Device) DisplayRect(x int16, y int16, width int16, height int16) error
 		d.setMemoryPointer(8*x, y)
 		d.SendCommand(WRITE_RAM)
 		for i := int16(x); i < width; i++ {
-			d.SendData(d.buffer[i+y*d.width/8])
+			d.SendData(d.buffer[i+y*d.logicalWidth/8])
 		}
 	}
 
@@ -222,7 +248,7 @@ func (d *Device) DisplayRect(x int16, y int16, width int16, height int16) error
 
 // ClearDisplay erases the device SRAM
 func (d *Device) ClearDisplay() {
-	d.setMemoryArea(0, 0, d.width-1, d.height-1)
+	d.setMemoryArea(0, 0, d.logicalWidth-1, d.height-1)
 	d.setMemoryPointer(0, 0)
 	d.SendCommand(WRITE_RAM)
 	for i := uint32(0); i < d.bufferLength; i++ {
@@ -274,5 +300,28 @@ func (d *Device) ClearBuffer() {
 
 // Size returns the current size of the display.
 func (d *Device) Size() (w, h int16) {
-	return d.width, d.height
+	if d.rotation == ROTATION_90 || d.rotation == ROTATION_270 {
+		return d.height, d.logicalWidth
+	}
+	return d.logicalWidth, d.height
+}
+
+// SetRotation changes the rotation (clock-wise) of the device
+func (d *Device) SetRotation(rotation Rotation) {
+	d.rotation = rotation
+}
+
+// xy chages the coordinates according to the rotation
+func (d *Device) xy(x, y int16) (int16, int16) {
+	switch d.rotation {
+	case NO_ROTATION:
+		return x, y
+	case ROTATION_90:
+		return d.width - y - 1, x
+	case ROTATION_180:
+		return d.width - x - 1, d.height - y - 1
+	case ROTATION_270:
+		return y, d.height - x - 1
+	}
+	return x, y
 }

waveshare-epd/epd2in13/registers.go

@@ -23,4 +23,9 @@ const (
 	SET_RAM_X_ADDRESS_COUNTER            = 0x4E
 	SET_RAM_Y_ADDRESS_COUNTER            = 0x4F
 	TERMINATE_FRAME_READ_WRITE           = 0xFF
+
+	NO_ROTATION  Rotation = 0
+	ROTATION_90  Rotation = 1 // 90 degrees clock-wise rotation
+	ROTATION_180 Rotation = 2
+	ROTATION_270 Rotation = 3
 )