Function checkColorValidity

external/lodepng/lodepng.cpp:2930–2941

checks if the colortype is valid and the bitdepth bd is allowed for this colortype. Return value is a LodePNG error code.*/

/*checks if the colortype is valid and the bitdepth bd is allowed for this colortype.
Return value is a LodePNG error code.*/
static unsigned checkColorValidity(LodePNGColorType colortype, unsigned bd) {
  switch(colortype) {
    case LCT_GREY:       if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8 || bd == 16)) return 37; break;
    case LCT_RGB:        if(!(                                 bd == 8 || bd == 16)) return 37; break;
    case LCT_PALETTE:    if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8            )) return 37; break;
    case LCT_GREY_ALPHA: if(!(                                 bd == 8 || bd == 16)) return 37; break;
    case LCT_RGBA:       if(!(                                 bd == 8 || bd == 16)) return 37; break;
    case LCT_MAX_OCTET_VALUE: return 31; /* invalid color type */
    default: return 31; /* invalid color type */
  }
  return 0; /*allowed color type / bits combination*/
}

static unsigned getNumColorChannels(LodePNGColorType colortype) {
  switch(colortype) {