# GxEPD2
New Simplified Version of GxEPD for Arduino

## for SPI e-paper displays from Dalian Good Display 
## and SPI e-paper boards from Waveshare

### important note :
### - these displays are for 3.3V supply and 3.3V data lines.
### - never connect data lines directly to 5V data pins.

### Paged Drawing, Picture Loop
#### - This library uses paged drawing to limit RAM use and cope with missing single pixel update support
#### - buffer size can be selected in the application by template parameter page_height, see GxEPD2_Example
#### - Paged drawing is implemented as picture loop, like in U8G2 (Oliver Kraus)
#### - see https://github.com/olikraus/u8glib/wiki/tpictureloop
#### - Paged drawing is also available using drawPaged() and drawCallback(), like in GxEPD
#### - // GxEPD style paged drawing; drawCallback() is called as many times as needed
#### - void drawPaged(void (*drawCallback)(const void*), const void* pv)
#### - paged drawing is done using Adafruit_GFX methods inside picture loop or drawCallback

### Full Screen Buffer Support
#### - full screen buffer is selected by setting template parameter page_height to display height
#### - drawing to full screen buffer is done using Adafruit_GFX methods without picture loop or drawCallback
#### - and then calling method display()

### Low Level Bitmap Drawing Support
#### - bitmap drawing support to the controller memory and screen is available:
#### - either through the template class instance methods that forward calls to the base display class
#### - or directy using an instance of a base display class and calling its methods directly

### Supporting Arduino Forum Topics:

- Waveshare e-paper displays with SPI: http://forum.arduino.cc/index.php?topic=487007.0
- Good Dispay ePaper for Arduino : https://forum.arduino.cc/index.php?topic=436411.0

### Version 1.0.4
- add GxEPD2_GFX base class support (optional, selectable, uses slightly more code)
- base class GxEPD2_GFX can be used to pass references or pointers to the display instance as parameter
- add GxEPD2_GFX_MultiDisplayExample, uses  GxEPD2_GFX reference parameter
- modify GxEPD2_MultiDisplayExample for ESP8266 (template issue: class expected instead of typename)
#### Version 1.0.3
- fix GxEPD2_SD_Example & GxEPD2_SD_AVR_Example
- add GxEPD2_MultiDisplayExample (preliminary version)
#### Version 1.0.2
- initial release version 1.0.2
- tested with ESP8266, ESP32, STM32F103C8T6, AVR Arduino (Pro Mini 3.3V)
- 1.54" 3-color GxEPD2_154c can be used with paging for AVR
- wave tables in program space,  4.2" b/w can be used with GxEPD2_SD_AVR_Example
- issues enabled and welcome, please use Forum Topic for enhancement suggestions
#### Version 1.0.1
- pre-release test version
- GxEPD2_SD_AVR_Example added, has no graphics buffer to reduce RAM usage (base display class use)
- issues disabled so far, use Arduino Forum Topics instead
- in this version 1.54" 3-color GxEPD2_154c can only be used with full size buffer (or with no buffer base display class)
#### Version 1.0.0
- preliminary version, under construction