epd

package
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Published: May 24, 2021 License: Apache-2.0 Imports: 13 Imported by: 0

Documentation

Overview

Package epd controls Waveshare e-paper series displays.

More details

Datasheets

https://www.waveshare.com/w/upload/e/e6/2.13inch_e-Paper_Datasheet.pdf

Product page:

2.13 Inch version: https://www.waveshare.com/wiki/2.13inch_e-Paper_HAT

1.54 inch version: https://www.waveshare.com/wiki/1.54inch_e-Paper_Module

Example
package main

import (
	"image"
	"log"

	"periph.io/x/periph/experimental/devices/epd"

	"periph.io/x/periph/conn/spi/spireg"

	"periph.io/x/periph/devices/ssd1306/image1bit"
	"periph.io/x/periph/host"
)

func main() {
	// Make sure periph is initialized.
	if _, err := host.Init(); err != nil {
		log.Fatal(err)
	}

	// Use spireg SPI bus registry to find the first available SPI bus.
	b, err := spireg.Open("")
	if err != nil {
		log.Fatal(err)
	}
	defer b.Close()

	dev, err := epd.NewSPIHat(b, &epd.EPD2in13) // Display config and size
	if err != nil {
		log.Fatalf("failed to initialize epd: %v", err)
	}

	// Draw on it.
	img := image1bit.NewVerticalLSB(dev.Bounds())
	// Note: this code is commented out so periph does not depend on:
	//    "golang.org/x/image/font"
	//    "golang.org/x/image/font/basicfont"
	//    "golang.org/x/image/math/fixed"
	//
	// f := basicfont.Face7x13
	// drawer := font.Drawer{
	// 	Dst:  img,
	// 	Src:  &image.Uniform{image1bit.On},
	// 	Face: f,
	// 	Dot:  fixed.P(0, img.Bounds().Dy()-1-f.Descent),
	// }
	// drawer.DrawString("Hello from periph!")

	if err := dev.Draw(dev.Bounds(), img, image.Point{}); err != nil {
		log.Fatal(err)
	}
	dev.DisplayFrame() // After drawing on the display, you have to show the frame
}
Output:

Example (Other)
package main

import (
	"image"
	"log"

	"periph.io/x/periph/experimental/devices/epd"

	"periph.io/x/periph/conn/spi/spireg"

	"periph.io/x/periph/host"
)

func main() {
	// Make sure periph is initialized.
	if _, err := host.Init(); err != nil {
		log.Fatal(err)
	}

	// Use spireg SPI bus registry to find the first available SPI bus.
	b, err := spireg.Open("")
	if err != nil {
		log.Fatal(err)
	}
	defer b.Close()

	dev, err := epd.NewSPIHat(b, &epd.EPD2in13) // Display config and size
	if err != nil {
		log.Fatalf("failed to initialize epd: %v", err)
	}

	var img image.Image
	// Note: this code is commented out so periph does not depend on:
	//    "github.com/fogleman/gg"
	//    "github.com/golang/freetype/truetype"
	//    "golang.org/x/image/font/gofont/goregular"
	//
	// bounds := dev.Bounds()
	// w := bounds.Dx()
	// h := bounds.Dy()
	// dc := gg.NewContext(w, h)
	// im, err := gg.LoadPNG("gopher.png")
	// if err != nil {
	// 	panic(err)
	// }
	// dc.SetRGB(1, 1, 1)
	// dc.Clear()
	// dc.SetRGB(0, 0, 0)
	// dc.Rotate(gg.Radians(90))
	// dc.Translate(0.0, -float64(h/2))
	// font, err := truetype.Parse(goregular.TTF)
	// if err != nil {
	// 	panic(err)
	// }
	// face := truetype.NewFace(font, &truetype.Options{
	// 	Size: 16,
	// })
	// dc.SetFontFace(face)
	// text := "Hello from periph!"
	// tw, th := dc.MeasureString(text)
	// dc.DrawImage(im, 120, 30)
	// padding := 8.0
	// dc.DrawRoundedRectangle(padding*2, padding*2, tw+padding*2, th+padding, 10)
	// dc.Stroke()
	// dc.DrawString(text, padding*3, padding*2+th)
	// for i := 0; i < 10; i++ {
	// 	dc.DrawCircle(float64(30+(10*i)), 100, 5)
	// }
	// for i := 0; i < 10; i++ {
	// 	dc.DrawRectangle(float64(30+(10*i)), 80, 5, 5)
	// }
	// dc.Fill()
	// img = dc.Image()
	if err := dev.Draw(dev.Bounds(), img, image.Point{}); err != nil {
		log.Fatal(err)
	}
	dev.DisplayFrame() // After drawing on the display, you have to show the frame
}
Output:

Index

Examples

Constants

This section is empty.

Variables

View Source
var EPD1in54 = Opts{
	W: 200,
	H: 200,
	FullUpdate: LUT{
		0x02, 0x02, 0x01, 0x11, 0x12, 0x12, 0x22, 0x22,
		0x66, 0x69, 0x69, 0x59, 0x58, 0x99, 0x99, 0x88,
		0x00, 0x00, 0x00, 0x00, 0xF8, 0xB4, 0x13, 0x51,
		0x35, 0x51, 0x51, 0x19, 0x01, 0x00,
	},
	PartialUpdate: LUT{
		0x10, 0x18, 0x18, 0x08, 0x18, 0x18, 0x08, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x13, 0x14, 0x44, 0x12,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	},
}

EPD1in54 is the config for the 1.54 inch display.

View Source
var EPD2in13 = Opts{
	W: 128,
	H: 250,
	FullUpdate: LUT{
		0x22, 0x55, 0xAA, 0x55, 0xAA, 0x55, 0xAA, 0x11,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x1E, 0x1E, 0x1E, 0x1E, 0x1E, 0x1E, 0x1E, 0x1E,
		0x01, 0x00, 0x00, 0x00, 0x00, 0x00,
	},
	PartialUpdate: LUT{
		0x18, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x0F, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	},
}

EPD2in13 is the config for the 2.13 inch display.

Functions

This section is empty.

Types

type Dev

type Dev struct {
	// contains filtered or unexported fields
}

Dev is an open handle to the display controller.

func NewSPI

func NewSPI(p spi.Port, dc, cs, rst gpio.PinOut, busy gpio.PinIO, opts *Opts) (*Dev, error)

NewSPI returns a Dev object that communicates over SPI to a E-Paper display controller.

func NewSPIHat

func NewSPIHat(p spi.Port, opts *Opts) (*Dev, error)

NewSPIHat returns a Dev object that communicates over SPI and have the default config for the e-paper hat for raspberry pi

func (*Dev) Bounds

func (d *Dev) Bounds() image.Rectangle

Bounds implements display.Drawer. Min is guaranteed to be {0, 0}.

func (*Dev) ClearFrameMemory

func (d *Dev) ClearFrameMemory(color byte) error

ClearFrameMemory clear the frame memory with the specified color. this won't update the display.

func (*Dev) ColorModel

func (d *Dev) ColorModel() color.Model

ColorModel implements display.Drawer. It is a one bit color model, as implemented by image1bit.Bit.

func (*Dev) DisplayFrame

func (d *Dev) DisplayFrame() error

DisplayFrame update the display.

There are 2 memory areas embedded in the e-paper display but once this function is called, the next action of SetFrameMemory or ClearFrame will set the other memory area.

func (*Dev) Draw

func (d *Dev) Draw(r image.Rectangle, src image.Image, sp image.Point) error

Draw implements display.Drawer.

func (*Dev) Halt

func (d *Dev) Halt() error

Halt turns off the display.

func (*Dev) Init

func (d *Dev) Init() error

Init initialize the display config. This method is already called when creating a device using NewSPI and NewSPIHat methods.

It should be only used when you put the device to sleep and need to re-init the device.

func (*Dev) Reset

func (d *Dev) Reset()

Reset can be also used to awaken the device

func (*Dev) Sleep

func (d *Dev) Sleep() error

Sleep after this command is transmitted, the chip would enter the deep-sleep mode to save power.

The deep sleep mode would return to standby by hardware reset. You can use Reset() to awaken and Init to re-initialize the device.

func (*Dev) String

func (d *Dev) String() string

type LUT

type LUT []byte

LUT contains the display specific waveform for the pixel programming of the display.

type Opts

type Opts struct {
	W             int
	H             int
	FullUpdate    LUT
	PartialUpdate LUT
}

Opts defines the options for the ePaper Device.

type PartialUpdate

type PartialUpdate bool

PartialUpdate represents if updates to the display should be full or partial.

const (
	// Full LUT config to update all the display
	Full PartialUpdate = false
	// Partial LUT config only a part of the display
	Partial PartialUpdate = true
)

Directories

Path Synopsis
Package image2bit implements two bit gray scale (white, light gray, dark gray, black) 2D graphics.
Package image2bit implements two bit gray scale (white, light gray, dark gray, black) 2D graphics.

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