png.cpp

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#include "roo_display/image/png/png.h"
 
#include "roo_display.h"
#include "roo_display/color/color_mode_indexed.h"
#include "roo_display/image/png/lib/png.inl"
 
PNG_STATIC int PNGInit(PNGIMAGE *pPNG);
PNG_STATIC int DecodePNG(PNGIMAGE *pImage, void *pUser, int iOptions);
// Include the C code which does the actual work
// #include "png.inl"
 
namespace roo_display {
 
int32_t png_read(PNGFILE *pFile, uint8_t *pBuf, int32_t iLen) {
  PngDecoder *decoder = (PngDecoder *)pFile->fHandle;
  return decoder->input_->read((roo::byte *)pBuf, iLen);
}
 
int32_t png_seek(PNGFILE *pFile, int32_t iPosition) {
  PngDecoder *decoder = (PngDecoder *)pFile->fHandle;
  decoder->input_->seek(iPosition);
  // The library ignores the return value anyway.
  return 1;
}
 
namespace {
 
struct User {
  const Surface *surface;
  const Palette *palette;
};
 
}  // namespace
 
void png_draw(PNGDRAW *pDraw) {
  User &user = *((User *)pDraw->pUser);
  const Surface *surface = user.surface;
  int16_t y = pDraw->y;
  if (y + surface->dy() < surface->clip_box().yMin() ||
      y + surface->dy() > surface->clip_box().yMax()) {
    return;
  }
  Box box(0, y, pDraw->iWidth - 1, y);
  ResumeOutput resume(surface->out());
  switch (pDraw->iPixelType) {
    case PNG_PIXEL_TRUECOLOR_ALPHA: {
      ConstDramRaster<Rgba8888> raster(box,
                                       (const roo::byte *)pDraw->pPixels);
      surface->drawObject(raster);
      break;
    }
    case PNG_PIXEL_TRUECOLOR: {
      ConstDramRaster<Rgb888> raster(box, (const roo::byte *)pDraw->pPixels);
      surface->drawObject(raster);
      break;
    }
    case PNG_PIXEL_GRAYSCALE: {
      ConstDramRaster<Grayscale8> raster(box,
                                         (const roo::byte *)pDraw->pPixels);
      surface->drawObject(raster);
      break;
    }
    case PNG_PIXEL_GRAY_ALPHA: {
      ConstDramRaster<GrayAlpha8> raster(box,
                                         (const roo::byte *)pDraw->pPixels);
      surface->drawObject(raster);
      break;
    }
    case PNG_PIXEL_INDEXED: {
      switch (pDraw->iBpp) {
        case 8: {
          ConstDramRaster<Indexed8> raster(box,
                                           (const roo::byte *)pDraw->pPixels,
                                           Indexed8(user.palette));
          surface->drawObject(raster);
          break;
        }
        case 4: {
          ConstDramRaster<Indexed4> raster(box,
                                           (const roo::byte *)pDraw->pPixels,
                                           Indexed4(user.palette));
          surface->drawObject(raster);
          break;
        }
        case 2: {
          ConstDramRaster<Indexed2> raster(box,
                                           (const roo::byte *)pDraw->pPixels,
                                           Indexed2(user.palette));
          surface->drawObject(raster);
          break;
        }
        case 1: {
          ConstDramRaster<Indexed1> raster(box,
                                           (const roo::byte *)pDraw->pPixels,
                                           Indexed1(user.palette));
          surface->drawObject(raster);
          break;
        }
      }
    }
  }
}
 
PngDecoder::PngDecoder() : pngdec_(new PNGIMAGE()), input_(nullptr) {}
 
bool PngDecoder::getDimensions(const roo_io::MultipassResource &resource,
                               int16_t &width, int16_t &height) {
  if (!open(resource, width, height)) {
    width = 0;
    height = 0;
    return false;
  }
  close();
  return true;
}
 
bool PngDecoder::open(const roo_io::MultipassResource &resource, int16_t &width,
                      int16_t &height) {
  input_ = resource.open();
  if (input_ == nullptr) return false;
  *pngdec_ = {};
  pngdec_->pfnRead = png_read;
  pngdec_->pfnSeek = png_seek;
  pngdec_->pfnDraw = png_draw;
  pngdec_->pfnOpen = nullptr;
  pngdec_->pfnClose = nullptr;
  pngdec_->PNGFile.iSize = input_->size();
 
  pngdec_->PNGFile.fHandle = this;
  if (PNGInit(pngdec_.get()) != PNG_SUCCESS) return false;
  width = pngdec_->iWidth;
  height = pngdec_->iHeight;
  return true;
}
 
void PngDecoder::draw(const roo_io::MultipassResource &resource,
                      const Surface &s, uint8_t scale, int16_t &width,
                      int16_t &height) {
  PauseOutput pause(s.out());
  if (!open(resource, width, height)) {
    return;
  }
  Box extents(0, 0, pngdec_->iWidth - 1, pngdec_->iHeight - 1);
  if (Box::Intersect(s.clip_box(), extents.translate(s.dx(), s.dy())).empty()) {
    close();
    return;
  }
  if (pngdec_->ucPixelType == PNG_PIXEL_INDEXED) {
    palette_ =
        Palette::ReadOnly((Color *)pngdec_->ucPalette, 1 << pngdec_->ucBpp);
  }
  User user{.surface = &s, .palette = &palette_};
  DecodePNG(pngdec_.get(), (void *)&user, 0);
  close();
}
 
}  // namespace roo_display