rpi_epaper

A python library to easy draw on Waveshare e-Paper HAT on Raspberry Pi.

Depends:

• python-pillow
• RPi.GPIO
• spidev

Pin

E-Paper Screen	Raspberry Pi
VCC	3.3
GND	GND
DIN	MOSI
CLK	SCLK
CS	24 (Physical, BCM: CE0, 8)
D/C	22 (Physical, BCM: 25)
RES	11 (Physical, BCM: 17)
BUSY	18 (Physical, BCM: 24)

Supported epaper

waveshare 2.7inch_e-Paper (http://www.waveshare.net/wiki/2.7inch_e-Paper_HAT)

Support BW mode , 4gray mode and partial reflash.

GDEW042T2 (http://www.e-paper-display.cn/products_detail/productId=333.html)

Support BW mode , 4gray mode and partial reflash. I guess it also support waveshare 4.2inch_e-Paper HAT(Not tested).

Usage(Here using epd2in7 for example)

This library uses GPIO, so you must have permission to access them.
Complete demo see demo/test_demo/test_demo.py

Initialize the e-paper hardware:

from libepd import epd2in7
epd = epd2in7.EPD()
epd.init()

Clear Screen

It will reflash full screen to white or black. (Default is 0xFF white)

epd.clear(0xFF)

Display frame

Just call epd.display_frame(img,mode)
mode can be BW,GRAY,PARTIAL,FAST.(Default is BW)

BW -> black and white
GRAY -> 4 levels of gray
PARTIAL > same as BW, but no flash.

BW and GRAY will flush and reflash screen within a few cycles - inverse image, black, white, black again. That can reduces burn-in and ghosting. Note using fast mode may make your e-paper display permanently unrecoverable damage.
example:

Himage = Image.new('L', (epd.height, epd.width), 255)
epd.display_frame(Himage,epd2in7.BW)

Partial display frame

Different from the previous, this function will only reflash the screen in a specific area, rather than full screen. The area size will depending on your give image.
This function have it's limit, see the specific file for details.

partial_display_frame(img,x_start,y_start,mode=PARTIAL)

example:

image_2 = Image.new('L', (60,60), 0)
epd.partial_display_frame(image_2,0,0)

Sleep mode

According to wiki, if you needn't refresh the e-paper but need to power on your development board or Raspberry Pi for long time, you neet set e-paper to sleep mode. Otherwise, the voltage of panel keeps high and it will damage the panel.

epd.sleep()

If you want to use module_exit, you can

from libepd import epdconfig
epdconfig.module_exit()