handleScreenshotRequest() reinterpret-cast every DisplayDriver* first to
SH1106Display* then to SSD1306Display*; both casts always produce a
non-null pointer, so the SSD1306 fallback was unreachable and on any
SSD1306 build we called SH1106::getBuffer() on a SSD1306 object — UB
that only happened to work because both backing classes share an
Adafruit_GFX layout at offset zero.
Replace the cast hack with virtual getBuffer()/getBufferSize() on
DisplayDriver, overridden in SH1106Display and SSD1306Display. MyMesh
no longer needs to know about either concrete type. const-correct the
buffer pointer and widen bufferSize to uint16_t while passing through.
Also fix the matching Python decoder: it sanity-checked length before
dispatching on resp_code, so a 2-byte RESP_CODE_ERR frame was reported
as "Frame too short" instead of the actual device error. Move the
length check after the resp_code dispatch and log the error code byte.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
- Adds the possibility to capture the device screen and save it as a PNG
image
- Wrap the code behind ENABLE_SCREENSHOT build flag, as per instructions
in README
- Added getTextWidth method to DisplayDriver interface
- Implemented getTextWidth in all display classes
- Updated examples to use getTextWidth directly
