crosspoint-reader/lib/GfxRenderer/GfxRenderer.cpp

#include "GfxRenderer.h"

#include <Utf8.h>

void GfxRenderer::insertFont(const int fontId, EpdFontFamily font) { fontMap.insert({fontId, font}); }

void GfxRenderer::rotateCoordinates(const int x, const int y, int* rotatedX, int* rotatedY) const {
  switch (orientation) {
    case Portrait: {
      // Logical portrait (480x800) → panel (800x480)
      // Rotation: 90 degrees clockwise
      *rotatedX = y;
      *rotatedY = EInkDisplay::DISPLAY_HEIGHT - 1 - x;
      break;
    }
    case LandscapeClockwise: {
      // Logical landscape (800x480) rotated 180 degrees (swap top/bottom and left/right)
      *rotatedX = EInkDisplay::DISPLAY_WIDTH - 1 - x;
      *rotatedY = EInkDisplay::DISPLAY_HEIGHT - 1 - y;
      break;
    }
    case PortraitInverted: {
      // Logical portrait (480x800) → panel (800x480)
      // Rotation: 90 degrees counter-clockwise
      *rotatedX = EInkDisplay::DISPLAY_WIDTH - 1 - y;
      *rotatedY = x;
      break;
    }
    case LandscapeCounterClockwise: {
      // Logical landscape (800x480) aligned with panel orientation
      *rotatedX = x;
      *rotatedY = y;
      break;
    }
  }
}

void GfxRenderer::drawPixel(const int x, const int y, const bool state) const {
  uint8_t* frameBuffer = einkDisplay.getFrameBuffer();

  // Early return if no framebuffer is set
  if (!frameBuffer) {
    Serial.printf("[%lu] [GFX] !! No framebuffer\n", millis());
    return;
  }

  int rotatedX = 0;
  int rotatedY = 0;
  rotateCoordinates(x, y, &rotatedX, &rotatedY);

  // Bounds checking against physical panel dimensions
  if (rotatedX < 0 || rotatedX >= EInkDisplay::DISPLAY_WIDTH || rotatedY < 0 ||
      rotatedY >= EInkDisplay::DISPLAY_HEIGHT) {
    Serial.printf("[%lu] [GFX] !! Outside range (%d, %d) -> (%d, %d)\n", millis(), x, y, rotatedX, rotatedY);
    return;
  }

  // Calculate byte position and bit position
  const uint16_t byteIndex = rotatedY * EInkDisplay::DISPLAY_WIDTH_BYTES + (rotatedX / 8);
  const uint8_t bitPosition = 7 - (rotatedX % 8);  // MSB first

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

int GfxRenderer::getTextWidth(const int fontId, const char* text, const EpdFontStyle style) const {
  if (fontMap.count(fontId) == 0) {
    Serial.printf("[%lu] [GFX] Font %d not found\n", millis(), fontId);
    return 0;
  }

  int w = 0, h = 0;
  fontMap.at(fontId).getTextDimensions(text, &w, &h, style);
  return w;
}

void GfxRenderer::drawCenteredText(const int fontId, const int y, const char* text, const bool black,
                                   const EpdFontStyle style) const {
  const int x = (getScreenWidth() - getTextWidth(fontId, text, style)) / 2;
  drawText(fontId, x, y, text, black, style);
}

void GfxRenderer::drawText(const int fontId, const int x, const int y, const char* text, const bool black,
                           const EpdFontStyle style) const {
  const int yPos = y + getLineHeight(fontId);
  int xpos = x;

  // cannot draw a NULL / empty string
  if (text == nullptr || *text == '\0') {
    return;
  }

  if (fontMap.count(fontId) == 0) {
    Serial.printf("[%lu] [GFX] Font %d not found\n", millis(), fontId);
    return;
  }
  const auto font = fontMap.at(fontId);

  // no printable characters
  if (!font.hasPrintableChars(text, style)) {
    return;
  }

  uint32_t cp;
  while ((cp = utf8NextCodepoint(reinterpret_cast<const uint8_t**>(&text)))) {
    renderChar(font, cp, &xpos, &yPos, black, style);
  }
}

void GfxRenderer::drawLine(int x1, int y1, int x2, int y2, const bool state) const {
  if (x1 == x2) {
    if (y2 < y1) {
      std::swap(y1, y2);
    }
    for (int y = y1; y <= y2; y++) {
      drawPixel(x1, y, state);
    }
  } else if (y1 == y2) {
    if (x2 < x1) {
      std::swap(x1, x2);
    }
    for (int x = x1; x <= x2; x++) {
      drawPixel(x, y1, state);
    }
  } else {
    // TODO: Implement
    Serial.printf("[%lu] [GFX] Line drawing not supported\n", millis());
  }
}

void GfxRenderer::drawRect(const int x, const int y, const int width, const int height, const bool state) const {
  drawLine(x, y, x + width - 1, y, state);
  drawLine(x + width - 1, y, x + width - 1, y + height - 1, state);
  drawLine(x + width - 1, y + height - 1, x, y + height - 1, state);
  drawLine(x, y, x, y + height - 1, state);
}

void GfxRenderer::fillRect(const int x, const int y, const int width, const int height, const bool state) const {
  for (int fillY = y; fillY < y + height; fillY++) {
    drawLine(x, fillY, x + width - 1, fillY, state);
  }
}

void GfxRenderer::drawImage(const uint8_t bitmap[], const int x, const int y, const int width, const int height) const {
  // TODO: Rotate bits
  int rotatedX = 0;
  int rotatedY = 0;
  rotateCoordinates(x, y, &rotatedX, &rotatedY);
  einkDisplay.drawImage(bitmap, rotatedX, rotatedY, width, height);
}

void GfxRenderer::drawBitmap(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;
  }

  // Calculate output row size (2 bits per pixel, packed into bytes)
  // IMPORTANT: Use int, not uint8_t, to avoid overflow for images > 1020 pixels wide
  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) {
    Serial.printf("[%lu] [GFX] !! Failed to allocate BMP row buffers\n", millis());
    free(outputRow);
    free(rowBytes);
    return;
  }

  for (int bmpY = 0; bmpY < bitmap.getHeight(); bmpY++) {
    // The BMP's (0, 0) is the bottom-left corner (if the height is positive, top-left if negative).
    // Screen's (0, 0) is the top-left corner.
    int screenY = y + (bitmap.isTopDown() ? bmpY : bitmap.getHeight() - 1 - bmpY);
    if (isScaled) {
      screenY = std::floor(screenY * scale);
    }
    if (screenY >= getScreenHeight()) {
      break;
    }

    if (bitmap.readRow(outputRow, rowBytes, bmpY) != BmpReaderError::Ok) {
      Serial.printf("[%lu] [GFX] Failed to read row %d from bitmap\n", millis(), bmpY);
      free(outputRow);
      free(rowBytes);
      return;
    }

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

      const uint8_t val = outputRow[bmpX / 4] >> (6 - ((bmpX * 2) % 8)) & 0x3;

      if (renderMode == BW && val < 3) {
        drawPixel(screenX, screenY);
      } else if (renderMode == GRAYSCALE_MSB && (val == 1 || val == 2)) {
        drawPixel(screenX, screenY, false);
      } else if (renderMode == GRAYSCALE_LSB && val == 1) {
        drawPixel(screenX, screenY, false);
      }
    }
  }

  free(outputRow);
  free(rowBytes);
}

void GfxRenderer::clearScreen(const uint8_t color) const { einkDisplay.clearScreen(color); }

void GfxRenderer::invertScreen() const {
  uint8_t* buffer = einkDisplay.getFrameBuffer();
  if (!buffer) {
    Serial.printf("[%lu] [GFX] !! No framebuffer in invertScreen\n", millis());
    return;
  }
  for (int i = 0; i < EInkDisplay::BUFFER_SIZE; i++) {
    buffer[i] = ~buffer[i];
  }
}

void GfxRenderer::displayBuffer(const EInkDisplay::RefreshMode refreshMode) const {
  einkDisplay.displayBuffer(refreshMode);
}

// Note: Internal driver treats screen in command orientation; this library exposes a logical orientation
int GfxRenderer::getScreenWidth() const {
  switch (orientation) {
    case Portrait:
    case PortraitInverted:
      // 480px wide in portrait logical coordinates
      return EInkDisplay::DISPLAY_HEIGHT;
    case LandscapeClockwise:
    case LandscapeCounterClockwise:
      // 800px wide in landscape logical coordinates
      return EInkDisplay::DISPLAY_WIDTH;
  }
  return EInkDisplay::DISPLAY_HEIGHT;
}

int GfxRenderer::getScreenHeight() const {
  switch (orientation) {
    case Portrait:
    case PortraitInverted:
      // 800px tall in portrait logical coordinates
      return EInkDisplay::DISPLAY_WIDTH;
    case LandscapeClockwise:
    case LandscapeCounterClockwise:
      // 480px tall in landscape logical coordinates
      return EInkDisplay::DISPLAY_HEIGHT;
  }
  return EInkDisplay::DISPLAY_WIDTH;
}

int GfxRenderer::getSpaceWidth(const int fontId) const {
  if (fontMap.count(fontId) == 0) {
    Serial.printf("[%lu] [GFX] Font %d not found\n", millis(), fontId);
    return 0;
  }

  return fontMap.at(fontId).getGlyph(' ', REGULAR)->advanceX;
}

int GfxRenderer::getLineHeight(const int fontId) const {
  if (fontMap.count(fontId) == 0) {
    Serial.printf("[%lu] [GFX] Font %d not found\n", millis(), fontId);
    return 0;
  }

  return fontMap.at(fontId).getData(REGULAR)->advanceY;
}

void GfxRenderer::drawButtonHints(const int fontId, const char* btn1, const char* btn2, const char* btn3,
                                  const char* btn4) const {
  const int pageHeight = getScreenHeight();
  constexpr int buttonWidth = 106;
  constexpr int buttonHeight = 40;
  constexpr int buttonY = 40;     // Distance from bottom
  constexpr int textYOffset = 5;  // Distance from top of button to text baseline
  constexpr int buttonPositions[] = {25, 130, 245, 350};
  const char* labels[] = {btn1, btn2, btn3, btn4};

  for (int i = 0; i < 4; i++) {
    // Only draw if the label is non-empty
    if (labels[i] != nullptr && labels[i][0] != '\0') {
      const int x = buttonPositions[i];
      drawRect(x, pageHeight - buttonY, buttonWidth, buttonHeight);
      const int textWidth = getTextWidth(fontId, labels[i]);
      const int textX = x + (buttonWidth - 1 - textWidth) / 2;
      drawText(fontId, textX, pageHeight - buttonY + textYOffset, labels[i]);
    }
  }
}

uint8_t* GfxRenderer::getFrameBuffer() const { return einkDisplay.getFrameBuffer(); }

size_t GfxRenderer::getBufferSize() { return EInkDisplay::BUFFER_SIZE; }

void GfxRenderer::grayscaleRevert() const { einkDisplay.grayscaleRevert(); }

void GfxRenderer::copyGrayscaleLsbBuffers() const { einkDisplay.copyGrayscaleLsbBuffers(einkDisplay.getFrameBuffer()); }

void GfxRenderer::copyGrayscaleMsbBuffers() const { einkDisplay.copyGrayscaleMsbBuffers(einkDisplay.getFrameBuffer()); }

void GfxRenderer::displayGrayBuffer() const { einkDisplay.displayGrayBuffer(); }

void GfxRenderer::freeBwBufferChunks() {
  for (auto& bwBufferChunk : bwBufferChunks) {
    if (bwBufferChunk) {
      free(bwBufferChunk);
      bwBufferChunk = nullptr;
    }
  }
}

/**
 * This should be called before grayscale buffers are populated.
 * A `restoreBwBuffer` call should always follow the grayscale render if this method was called.
 * Uses chunked allocation to avoid needing 48KB of contiguous memory.
 */
void GfxRenderer::storeBwBuffer() {
  const uint8_t* frameBuffer = einkDisplay.getFrameBuffer();
  if (!frameBuffer) {
    Serial.printf("[%lu] [GFX] !! No framebuffer in storeBwBuffer\n", millis());
    return;
  }

  // Allocate and copy each chunk
  for (size_t i = 0; i < BW_BUFFER_NUM_CHUNKS; i++) {
    // Check if any chunks are already allocated
    if (bwBufferChunks[i]) {
      Serial.printf("[%lu] [GFX] !! BW buffer chunk %zu already stored - this is likely a bug, freeing chunk\n",
                    millis(), i);
      free(bwBufferChunks[i]);
      bwBufferChunks[i] = nullptr;
    }

    const size_t offset = i * BW_BUFFER_CHUNK_SIZE;
    bwBufferChunks[i] = static_cast<uint8_t*>(malloc(BW_BUFFER_CHUNK_SIZE));

    if (!bwBufferChunks[i]) {
      Serial.printf("[%lu] [GFX] !! Failed to allocate BW buffer chunk %zu (%zu bytes)\n", millis(), i,
                    BW_BUFFER_CHUNK_SIZE);
      // Free previously allocated chunks
      freeBwBufferChunks();
      return;
    }

    memcpy(bwBufferChunks[i], frameBuffer + offset, BW_BUFFER_CHUNK_SIZE);
  }

  Serial.printf("[%lu] [GFX] Stored BW buffer in %zu chunks (%zu bytes each)\n", millis(), BW_BUFFER_NUM_CHUNKS,
                BW_BUFFER_CHUNK_SIZE);
}

/**
 * This can only be called if `storeBwBuffer` was called prior to the grayscale render.
 * It should be called to restore the BW buffer state after grayscale rendering is complete.
 * Uses chunked restoration to match chunked storage.
 */
void GfxRenderer::restoreBwBuffer() {
  // Check if any all chunks are allocated
  bool missingChunks = false;
  for (const auto& bwBufferChunk : bwBufferChunks) {
    if (!bwBufferChunk) {
      missingChunks = true;
      break;
    }
  }

  if (missingChunks) {
    freeBwBufferChunks();
    return;
  }

  uint8_t* frameBuffer = einkDisplay.getFrameBuffer();
  if (!frameBuffer) {
    Serial.printf("[%lu] [GFX] !! No framebuffer in restoreBwBuffer\n", millis());
    freeBwBufferChunks();
    return;
  }

  for (size_t i = 0; i < BW_BUFFER_NUM_CHUNKS; i++) {
    // Check if chunk is missing
    if (!bwBufferChunks[i]) {
      Serial.printf("[%lu] [GFX] !! BW buffer chunks not stored - this is likely a bug\n", millis());
      freeBwBufferChunks();
      return;
    }

    const size_t offset = i * BW_BUFFER_CHUNK_SIZE;
    memcpy(frameBuffer + offset, bwBufferChunks[i], BW_BUFFER_CHUNK_SIZE);
  }

  einkDisplay.cleanupGrayscaleBuffers(frameBuffer);

  freeBwBufferChunks();
  Serial.printf("[%lu] [GFX] Restored and freed BW buffer chunks\n", millis());
}

void GfxRenderer::renderChar(const EpdFontFamily& fontFamily, const uint32_t cp, int* x, const int* y,
                             const bool pixelState, const EpdFontStyle style) const {
  const EpdGlyph* glyph = fontFamily.getGlyph(cp, style);
  if (!glyph) {
    // TODO: Replace with fallback glyph property?
    glyph = fontFamily.getGlyph('?', style);
  }

  // no glyph?
  if (!glyph) {
    Serial.printf("[%lu] [GFX] No glyph for codepoint %d\n", millis(), cp);
    return;
  }

  const int is2Bit = fontFamily.getData(style)->is2Bit;
  const uint32_t offset = glyph->dataOffset;
  const uint8_t width = glyph->width;
  const uint8_t height = glyph->height;
  const int left = glyph->left;

  const uint8_t* bitmap = nullptr;
  bitmap = &fontFamily.getData(style)->bitmap[offset];

  if (bitmap != nullptr) {
    for (int glyphY = 0; glyphY < height; glyphY++) {
      const int screenY = *y - glyph->top + glyphY;
      for (int glyphX = 0; glyphX < width; glyphX++) {
        const int pixelPosition = glyphY * width + glyphX;
        const int screenX = *x + left + glyphX;

        if (is2Bit) {
          const uint8_t byte = bitmap[pixelPosition / 4];
          const uint8_t bit_index = (3 - pixelPosition % 4) * 2;
          // the direct bit from the font is 0 -> white, 1 -> light gray, 2 -> dark gray, 3 -> black
          // we swap this to better match the way images and screen think about colors:
          // 0 -> black, 1 -> dark grey, 2 -> light grey, 3 -> white
          const uint8_t bmpVal = 3 - (byte >> bit_index) & 0x3;

          if (renderMode == BW && bmpVal < 3) {
            // Black (also paints over the grays in BW mode)
            drawPixel(screenX, screenY, pixelState);
          } else if (renderMode == GRAYSCALE_MSB && (bmpVal == 1 || bmpVal == 2)) {
            // Light gray (also mark the MSB if it's going to be a dark gray too)
            // We have to flag pixels in reverse for the gray buffers, as 0 leave alone, 1 update
            drawPixel(screenX, screenY, false);
          } else if (renderMode == GRAYSCALE_LSB && bmpVal == 1) {
            // Dark gray
            drawPixel(screenX, screenY, false);
          }
        } else {
          const uint8_t byte = bitmap[pixelPosition / 8];
          const uint8_t bit_index = 7 - (pixelPosition % 8);

          if ((byte >> bit_index) & 1) {
            drawPixel(screenX, screenY, pixelState);
          }
        }
      }
    }
  }

  *x += glyph->advanceX;
}

void GfxRenderer::getOrientedViewableTRBL(int* outTop, int* outRight, int* outBottom, int* outLeft) const {
  switch (orientation) {
    case Portrait:
      *outTop = VIEWABLE_MARGIN_TOP;
      *outRight = VIEWABLE_MARGIN_RIGHT;
      *outBottom = VIEWABLE_MARGIN_BOTTOM;
      *outLeft = VIEWABLE_MARGIN_LEFT;
      break;
    case LandscapeClockwise:
      *outTop = VIEWABLE_MARGIN_LEFT;
      *outRight = VIEWABLE_MARGIN_TOP;
      *outBottom = VIEWABLE_MARGIN_RIGHT;
      *outLeft = VIEWABLE_MARGIN_BOTTOM;
      break;
    case PortraitInverted:
      *outTop = VIEWABLE_MARGIN_BOTTOM;
      *outRight = VIEWABLE_MARGIN_LEFT;
      *outBottom = VIEWABLE_MARGIN_TOP;
      *outLeft = VIEWABLE_MARGIN_RIGHT;
      break;
    case LandscapeCounterClockwise:
      *outTop = VIEWABLE_MARGIN_RIGHT;
      *outRight = VIEWABLE_MARGIN_BOTTOM;
      *outBottom = VIEWABLE_MARGIN_LEFT;
      *outLeft = VIEWABLE_MARGIN_TOP;
      break;
  }
}