Firefly Display

A simple display driver for the ST7789 240x240 display optimized for reduced memory usage.

The screen is broken up into fragments (by default ten 240x24 fragments) and two fragment buffers are allocated. At any point in time there is an "active" buffer being blitted to the display while the next "backbuffer" fragment is passed to the renderFunc provided when the display was initialized.

The renderFunc should populate the fragment with the viewport from (0, y0, 240, FragmentHeight), using RGB565 values.

void renderFunc(uint8_t *buffer, uint32_t y0, void *context) {
  // render the viewport lines from y0 to FfxDisplayFragmentHeight
}

void app_main(void) {
  
  // Context may be NULL; it is passed to each renderFunc invocation
  // The Display can be oriented with either the ribbon to the right
  // or the bottom.
  FfxDisplayContext display = ffx_display_init(bus, pinDC, pinReset,
    FfxDisplayRotationRibbonRight, renderFunc, context);

  while (1) {
    // Calls renderFunc to prepare the next fragment, while blitting
    // the previously prepared fragment.
    uint32_t frameDone = ffx_display_renderFragment(display);
    if (frameDone) {
      // The last fragment of the screen has been drawn

      // To throttle the frame rate use a delayUntil function
    }
  }
}

}

Examples

See the example project which merely displays a static image on the display.

Using Locally

Due to the way ESP IDF uses a component's folder name to determine its package name, the default folder when checking out from GitHub (i.e. component-display) prevents the component from working.

To resolve this, for example if contributing to the repository, checkout out the component in a target folder named firefly-display:

/home/ricmoo> git clone [email protected]:firefly/component-display.git firefly-display
# This is important!! -----------------------------------------------^

License

MIT License.