mxchip_iotdevkit_gfx

Enable simple graphics on the MXCHIP IoT DevKit OLED display

Intro

The MXCHIP IoT DevKit is pretty cool but out of the box its display capabilities are pretty basic. It does have bitmap capabilities though so it seemed to me we should be able to use that get us a pixel-addressable display. Long story short, it took a bit of figuring out but here that is...

Demo

Basic usage

#include "GFXDisplay.h"

GFXDisplay display; // Don't call this Screen, you'll get link confusion

void setup() {
    display.init();
    display.setPixel(0, 0);
    display.flush(); // <- Nothing on screen until this
}

void loop() {
    // etc
}

API

    /**
     * @brief Clear the off-screen buffer. Will not clear the display until 
     * flush() is called.
     */
    void clear();

    /**
     * @brief Copy the contents of the off-screen buffer to the display
     */
    void flush();

    /**
     * @brief Set the pixel at x,y. Origin (0,0) is top left corner
     */
    void setPixel(int x, int y);

    /**
     * @brief Write text at position x,y. font.h provides the font definition
     */
    void drawText(int x, int y, const char *s);

    /**
     * @brief Draw line from x0,y0 to x1,y1
     */
    void drawLine(int x0, int y0, int x1, int y1);

    /**
     * @brief Draw rect with defined by top-left x0,y0 to bottom-right x1,y1
     */
    void drawRect(int x0, int y0, int x1, int y1);

    /**
     * @brief Draw circle of radius r centred on xm,ym
     */
    void drawCircle (int xm, int ym, int r);

    /**
     * Draw bitmap of dimensions w*h at position x,y
     * bmp is an array of 1's or 0's
     */
    void drawBitmap(int x, int y, int w, int h, const byte *bmp);

Acknowledgements

Full credit to [https://gist.github.com/bert] for the Bresenham drawing implementation. Thanks!!