/** \brief Draw a finish pixel at the specified position. The finishpixel has at the least-significant bit of their rgb-value r: 3, g: 0, b: 0
*
* \param &pixel const Pixel a pixel-struct describing the pixel-position where the finish-pixel should be set.
*/
void SteganoHide::drawFinishPixel(const Pixel &pixel) {
Magick::ColorRGB pixelColor = this->steganoImage.pixelColor(pixel.x, pixel.y);
RGB pixelRGB(convert16BitTo8BitRGB(pixelColor.redQuantum()),
convert16BitTo8BitRGB(pixelColor.greenQuantum()),
convert16BitTo8BitRGB(pixelColor.blueQuantum()));
pixelRGB.red = (pixelRGB.red - (pixelRGB.red % 10)) + 3;
pixelRGB.green = pixelRGB.green - (pixelRGB.green % 10);
pixelRGB.blue = pixelRGB.blue - (pixelRGB.blue % 10);
this->steganoImage.pixelColor(pixel.x, pixel.y, Magick::ColorRGB(pixelRGB.toString()));
}
bool ColorFilter::pixelFilteredIsOn (const QImage &image,
int x,
int y) const
{
bool rtn = false;
if ((0 <= x) &&
(0 <= y) &&
(x < image.width()) &&
(y < image.height())) {
// Pixel is on if it is closer to black than white in gray scale. This test must be performed
// on little endian and big endian systems, with or without alpha bits (which are typically high bits);
const int BLACK_WHITE_THRESHOLD = 255 / 2; // Put threshold in middle of range
int gray = qGray (pixelRGB (image, x, y));
rtn = (gray < BLACK_WHITE_THRESHOLD);
}
return rtn;
}
// TODO: handle wrong input
bool SteganoHide::hideNumberInMagickColorRGB(const unsigned short &smallNumber, Magick::ColorRGB &color) {
RGB pixelRGB(convert16BitTo8BitRGB(color.redQuantum()),
convert16BitTo8BitRGB(color.greenQuantum()),
convert16BitTo8BitRGB(color.blueQuantum()));
RGB roundedRGB;
roundedRGB.red = pixelRGB.red - (pixelRGB.red % 10);
roundedRGB.green = pixelRGB.green - (pixelRGB.green % 10);
roundedRGB.blue = pixelRGB.blue - (pixelRGB.blue % 10);
unsigned char mostSignificantBit = std::floor(smallNumber / 100);
unsigned char middleSigificantBit = std::floor(smallNumber % 100 / 10);
unsigned char leastSignificantBit = smallNumber % 10;
/* if(mostSignificantBit > 5 || middleSigificantBit > 5 || leastSignificantBit > 5) {
throw hideNumber2Big;
}*/
// there was an overflow: eg. roundedRGB.blue = 250 and leastSignificantLetterBit = 8 => 258 => 2
// This way to check overflow is possible, because *SignificantLetterBit >= 0
if(roundedRGB.green + middleSigificantBit > 255) {
return false;
}
if(roundedRGB.blue + leastSignificantBit > 255) {
return false;
}
// std::cout << (int)roundedRGB.blue << "+" << (int)leastSignificantBit << "=";
roundedRGB.red += mostSignificantBit;
roundedRGB.green += middleSigificantBit;
roundedRGB.blue += leastSignificantBit;
//std::cout << (int)roundedRGB.blue << std::endl;
color = Magick::ColorRGB(roundedRGB.toString());
return true;
}
