Method drawPixel

lib/GfxRenderer/GfxRenderer.cpp:326–360

IMPORTANT: This function is in critical rendering path and is called for every pixel. Please keep it as simple and efficient as possible.

// IMPORTANT: This function is in critical rendering path and is called for every pixel. Please keep it as simple and
// efficient as possible.
void GfxRenderer::drawPixel(const int x, const int y, const bool state) const {
  int phyX = 0;
  int phyY = 0;

  // Note: this call should be inlined for better performance
  rotateCoordinates(orientation, x, y, &phyX, &phyY, panelWidth, panelHeight);

  // Bounds checking against runtime panel dimensions
  if (phyX < 0 || phyX >= panelWidth || phyY < 0 || phyY >= panelHeight) {
    LOG_ERR("GFX", "!! Outside range (%d, %d) -> (%d, %d)", x, y, phyX, phyY);
    return;
  }

  // Tiled grayscale: redirect writes to the strip scratch and clip to the
  // current band. Single predictable branch on the hot per-pixel path.
  uint8_t* target = frameBuffer;
  uint32_t rowY = static_cast<uint32_t>(phyY);
  if (_stripActive) {
    if (phyY < _stripY0 || phyY >= _stripY0 + _stripRows) {
      return;  // pixel outside the band currently being rendered
    }
    target = _stripBuf;
    rowY = static_cast<uint32_t>(phyY - _stripY0);
  }

  // Calculate byte position and bit position
  const uint32_t byteIndex = rowY * panelWidthBytes + (phyX / 8);
  const uint8_t bitPosition = 7 - (phyX % 8);  // MSB first

  if (state) {
    target[byteIndex] &= ~(1 << bitPosition);  // Clear bit
  } else {
    target[byteIndex] |= 1 << bitPosition;  // Set bit
  }
}

int GfxRenderer::getTextWidth(const int fontId, const char* text, const EpdFontFamily::Style style,
                              const BidiUtils::BidiBaseDir baseDir) const {