cristian-5 / epdisplay

e-paper display software controller for 1.54" B/W 200x200 WaveShare

EPDisplay

Sofware controller for e-paper Display 1.54" B/W 200x200 WaveShare for Arduino.

To initialize the display use the using EPD = EPDisplay<200, 200>; directive.
To start using the display call EPD::wake(), EPD::clear().
To begin drawing use EPD::displayPartBaseWhiteImage() while to refresh the display use EPD::displayPartFrame().
Don't forget to call EPD::sleep() after usage to set deep-sleep mode.

Bitmaps

Bitmaps are stored in the bitmap data structure as a 1-dimensional array of bytes, along with width (in pixels, divisible by 8) and height (not restricted). That is problematic because 1 byte corresponds to 8 pixels hence pictures can only be drawn x-aligned and every padding bit will override the existing pixels on the screen so keep that in mind.

There is a Deno Javascript file resources/png2bitmap.js that is able to convert (RGBA or RGBA color space, 8-bit depth) .png pictures into header files that can be directly included and used in the code.

#include "epdisplay.hpp"
#include "bitmaps/casper.hpp"

/// e-Paper Display 1.54" 200x200 W / B Waveshare
using EPD = EPDisplay<200, 200>;

void setup() {

	EPD::wake();
	EPD::clear();
	EPD::displayPartBaseImage();

	EPD::draw(casper_BITMAP, 8, 8);
	EPD::draw<2>(casper_BITMAP, 32, 32); // scale 2x
	EPD::draw<3>(casper_BITMAP, 72, 72); // scale 3x

	EPD::displayPartFrame();
	EPD::sleep();

}

void loop() { }

Fonts

Fonts are stored in the (monospaced) font data structure along with real width and height (without padding, in pixels) and vertical and horizontal spacing. The padded width is calculated automatically.

Courier New (8pt, 12pt, 16pt, 20pt and 24pt) is provided here.

The text bitmap data needs to contain the following characters with this specific order, to minimize PROGMEM space:

ABCDEFGHIJKLMNOPQRSTUVWXYZ
abcdefghijklmnopqrstuvwxyz
"#$%&'?!*+,-./0123456789:;

As you can see it resembles chunks of ASCII but with the difference being the ? and ! characters in place of ( and ).

Text can be drawn using the EPD::text method which calulates line-width and wraps when necessary as well as when it finds \n LF.

#include "epdisplay.hpp"
#include "fonts/Courier_New/Courier_New.hpp"

/// e-Paper Display 1.54" 200x200 W / B Waveshare
using EPD = EPDisplay<200, 200>;

void setup() {

	EPD::wake();
	EPD::clear();
	EPD::displayPartBaseImage();

	EPD::text("Hello World!", 0, 0, Courier_New(20));

	EPD::displayPartFrame();
	EPD::sleep();

}

void loop() { }