Xteink-X4-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::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;
  }

  // Rotate coordinates: portrait (480x800) -> landscape (800x480)
  // Rotation: 90 degrees clockwise
  const int rotatedX = y;
  const int rotatedY = EInkDisplay::DISPLAY_HEIGHT - 1 - x;

  // Bounds checking (portrait: 480x800)
  if (rotatedX < 0 || rotatedX >= EInkDisplay::DISPLAY_WIDTH || rotatedY < 0 ||
      rotatedY >= EInkDisplay::DISPLAY_HEIGHT) {
    Serial.printf("[%lu] [GFX] !! Outside range (%d, %d)\n", millis(), x, y);
    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 {
  // Flip X and Y for portrait mode
  einkDisplay.drawImage(bitmap, y, x, height, width);
}

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

void GfxRenderer::invertScreen() const {
  uint8_t* buffer = einkDisplay.getFrameBuffer();
  for (int i = 0; i < EInkDisplay::BUFFER_SIZE; i++) {
    buffer[i] = ~buffer[i];
  }
}

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

// TODO: Support partial window update
// void GfxRenderer::flushArea(const int x, const int y, const int width, const int height) const {
//   const int rotatedX = y;
//   const int rotatedY = EInkDisplay::DISPLAY_HEIGHT - 1 - x;
//
//   einkDisplay.displayBuffer(EInkDisplay::FAST_REFRESH, rotatedX, rotatedY, height, width);
// }

// Note: Internal driver treats screen in command orientation, this library treats in portrait orientation
int GfxRenderer::getScreenWidth() { return EInkDisplay::DISPLAY_HEIGHT; }
int GfxRenderer::getScreenHeight() { 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;
}

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

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

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::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;
}