Method drawBitmap1Bit

lib/GfxRenderer/GfxRenderer.cpp:1169–1236

}

void GfxRenderer::drawBitmap1Bit(const Bitmap& bitmap, const int x, const int y, const int maxWidth,
                                 const int maxHeight) const {
  float scale = 1.0f;
  bool isScaled = false;
  if (maxWidth > 0 && bitmap.getWidth() > maxWidth) {
    scale = static_cast<float>(maxWidth) / static_cast<float>(bitmap.getWidth());
    isScaled = true;
  }
  if (maxHeight > 0 && bitmap.getHeight() > maxHeight) {
    scale = std::min(scale, static_cast<float>(maxHeight) / static_cast<float>(bitmap.getHeight()));
    isScaled = true;
  }

  // For 1-bit BMP, output is still 2-bit packed (for consistency with readNextRow)
  const int outputRowSize = (bitmap.getWidth() + 3) / 4;
  auto* outputRow = static_cast<uint8_t*>(malloc(outputRowSize));
  auto* rowBytes = static_cast<uint8_t*>(malloc(bitmap.getRowBytes()));

  if (!outputRow || !rowBytes) {
    LOG_ERR("GFX", "!! Failed to allocate 1-bit BMP row buffers");
    free(outputRow);
    free(rowBytes);
    return;
  }

  for (int bmpY = 0; bmpY < bitmap.getHeight(); bmpY++) {
    // Read rows sequentially using readNextRow
    if (bitmap.readNextRow(outputRow, rowBytes) != BmpReaderError::Ok) {
      LOG_ERR("GFX", "Failed to read row %d from 1-bit bitmap", bmpY);
      free(outputRow);
      free(rowBytes);
      return;
    }

    // Calculate screen Y based on whether BMP is top-down or bottom-up
    const int bmpYOffset = bitmap.isTopDown() ? bmpY : bitmap.getHeight() - 1 - bmpY;
    int screenY = y + (isScaled ? static_cast<int>(std::floor(bmpYOffset * scale)) : bmpYOffset);
    if (screenY >= getScreenHeight()) {
      continue;  // Continue reading to keep row counter in sync
    }
    if (screenY < 0) {
      continue;
    }

    for (int bmpX = 0; bmpX < bitmap.getWidth(); bmpX++) {
      int screenX = x + (isScaled ? static_cast<int>(std::floor(bmpX * scale)) : bmpX);
      if (screenX >= getScreenWidth()) {
        break;
      }
      if (screenX < 0) {
        continue;
      }

      // Get 2-bit value (result of readNextRow quantization)
      const uint8_t val = outputRow[bmpX / 4] >> (6 - ((bmpX * 2) % 8)) & 0x3;

      // For 1-bit source: 0 or 1 -> map to black (0,1,2) or white (3)
      // val < 3 means black pixel (draw it)