C++ image::at方法代码示例

  // merge float channels
  bool mergeOCPToImage::apply(const matrix<float>& c1,
                              const matrix<float>& c2,
                              const matrix<float>& c3,
                              image& img) const {

    point p;              // coordinates
    float r,g,b;          // unnormed RGB channels
    float RG, BY, WB;     // opponent colour channels

    if ((c1.size() != c2.size()) || (c1.size() != c3.size())) {
      setStatusString("sizes of channels do not match");
      return false;
    }

    img.resize(c1.size(),rgbPixel(),false,false);

    for (p.y=0;p.y<img.rows();p.y++) {
      for (p.x=0;p.x<img.columns();p.x++) {

	RG = c1.at(p);
	BY = c2.at(p);
	WB = c3.at(p);

        b = BY*0.666666666667f;
        //
	r = WB + RG - b;
	g = WB - RG - b;
	b = WB + BY*1.3333333333333f;

	// truncate r,g and b if the value is not in intervall [0..1]
	// can happen due to rounding errors in split operation
	if (r<0.0f) {
          r=0.0f;
        } else if (r>1.0f) {
          r=1.0f;
        }

	if (g<0.0f) {
          g=0.0f;
        } else if (g>1.0f) {
          g=1.0f;
        }

	if (b<0.0f) {
          b=0.0f;
        } else if (b>1.0f) {
          b=1.0f;
        }

	img.at(p).set(static_cast<ubyte>(255.0f*r),
                      static_cast<ubyte>(255.0f*g),
                      static_cast<ubyte>(255.0f*b),
                      0);
      }
    }

    return true;
  };

  // split image into 8-bit channels
  // N.B.: when casting the transformation result to unsigned shorts
  // (8-bit channel), major rounding errors will occur.
  // As a result, the merging operation might
  // produce negative values or values > 1,  which are truncated subsequently.
  // When accurate X, Y and Z channels are required, prefer float channels!
  bool splitImageToxyY::apply(const image& img,
                              channel8& c1,
                              channel8& c2,
                              channel8& c3) const {
    point p;       // coordinates
    rgbPixel pix;          // single Pixel Element in RGB-values...
    float Y;               // channels
    float X, XYZ;          // help variables

    // make the channels size of source image...
    c1.resize(img.rows(),img.columns(),0,false,false);
    c2.resize(img.rows(),img.columns(),0,false,false);
    c3.resize(img.rows(),img.columns(),0,false,false);

    for (p.y=0;p.y<img.rows();p.y++)
      for (p.x=0;p.x<img.columns();p.x++) {
        // take pixel at position p
        pix = img.at(p);

  // see Gonzales & Woods for explanation of magic numbers
        X   = (((float)(pix.getRed())) *0.412453f +
               ((float)(pix.getGreen())) *0.357580f +
               ((float)(pix.getBlue())) *0.180423f)/255.0f;   // x
        Y   = (((float)(pix.getRed())) *0.212671f +
               ((float)(pix.getGreen())) *0.715160f +
               ((float)(pix.getBlue())) *0.072169f)/255.0f;   // y
        XYZ = (((float)(pix.getRed())) *0.644458f +
               ((float)(pix.getGreen())) *1.191933f +
               ((float)(pix.getBlue())) *1.202819f)/255.0f;   // Y

        if (XYZ>0.0f) {
          c1.at(p) = (ubyte)(X/XYZ*255.0f);  // x
          c2.at(p) = (ubyte)(Y/XYZ*255.0f);  // y
        }
        else {
          c1.at(p) = 0;   // x
          c2.at(p) = 0;   // y
        }

        c3.at(p) = (ubyte)(Y*255.0f);     // Y
      } // loop
    return true;
  }

void texture4::loadImage( image &in )
    {
    jAssert( in.isValid() );

    if( img != 0 )
        {
        glDeleteTextures( 1, &img );
        }

    width = in.width();
    height = in.height();

    float *tempBuf = new float[ 4 * width * height ];

    glGenTextures( 1, &img );
    glBindTexture( GL_TEXTURE_2D, img );

    // select modulate to mix texture with color for shading
    glTexEnvf( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE );

    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
    glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP );
    glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP );

    for( unsigned int y=0; y<height; y++ )
        {
        for( unsigned int x=0; x<width; x++ )
            {
            struct image::colourPacket *here = in.at( x, y );
            int base = 4 * ( x + y * width );
            tempBuf[ base ] = here->r;
            tempBuf[ base + 1 ] = here->g;
            tempBuf[ base + 2 ] = here->b;
            tempBuf[ base + 3 ] = here->a;
            }
        }


    glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_FLOAT, (const GLvoid *)tempBuf );

    delete [] tempBuf;
    }

// convert tiny_dnn::image to cv::Mat and resize
cv::Mat image2mat(image<>& img) {
    cv::Mat ori(static_cast<int>(img.height()), static_cast<int>(img.width()), CV_8U, &img.at(0, 0));
    cv::Mat resized;
    cv::resize(ori, resized, cv::Size(), 3, 3, cv::INTER_AREA);
    return resized;
}

  // Quantization takes place here!
  bool medianCut::performQuantization(const image& src,
                                      image& dest,
                                      channel8& mask,
                                      palette &thePalette) const {

    // parameters and const variables
    const parameters& param = getParameters();
    const int imageRows=src.rows();          // number of rows in src
    const int imageCols=src.columns();       // number of columns in src

    // resize destination containers
    dest.resize(imageRows,imageCols,rgbPixel(),false,false);
    mask.resize(imageRows,imageCols,ubyte(),false,false);

    // Variables
    int row,col;            // row, column counters
    int r,g,b;              // red,green,blue
    ivector iVec(3);        // int-vector

    std::list<boxInfo> theLeaves; // list of leaves (tree without root
                                  // and nodes)
    std::list<boxInfo>::iterator  splitPos;   // position to split
    std::list<boxInfo>::iterator  iter;       // iterator for theLeaves

    // create histogram with desired pre-quantization dimensions from src
    histogram theHist(3,param.preQuant);

    const float factor = param.preQuant/256.0f;

    for (row = 0 ; row < imageRows ; row++) {
      for (col = 0 ; col < imageCols ; col++) {

        r = static_cast<int>(src.at( row,col ).getRed()   * factor);
        g = static_cast<int>(src.at( row,col ).getGreen() * factor);
        b = static_cast<int>(src.at( row,col ).getBlue()  * factor);
        
        // insert point with quantized color
        dest.at(row,col).set((r*256+128)/param.preQuant,
                             (g*256+128)/param.preQuant,
                             (b*256+128)/param.preQuant,0); 

        iVec[0] = r;
        iVec[1] = g;
        iVec[2] = b;

        theHist.put(iVec);
      }
    }

    // initialization of first box of list (the whole histogram)
    boxInfo theBox(rgbPixel(0,0,0),
                   rgbPixel(param.preQuant-1,
                            param.preQuant-1,
                            param.preQuant-1));

    computeBoxInfo(theHist,theBox);

    // return, if desired number of colors smaller than colors in
    // pre-quantized image
    if (theBox.colors < param.numberOfColors) {

      thePalette.resize(theBox.colors,rgbPixel(),false,false);

      // prepare palette     
      int i = 0;
      for (r=0;r<param.preQuant;++r) {
        for (g=0;g<param.preQuant;++g) {
          for (b=0;b<param.preQuant;++b) {
            iVec[0] = r;
            iVec[1] = g;
            iVec[2] = b;
            if (theHist.at(iVec) > 0) {
              thePalette.at(i).set((r*256+128)/param.preQuant,
                                   (g*256+128)/param.preQuant,
                                   (b*256+128)/param.preQuant);
            }
          }
        }
      }

      // use the palette to generate the corresponding channel
      usePalette colorizer;
      colorizer.apply(dest,thePalette,mask);
      
      return true;
    }

    // Push first box into List
    theLeaves.push_back(theBox);

    // MAIN LOOP (do this until you have enough leaves (count), or no
    // splittable boxes (entries))
    int count, entries=1;  // auxiliary variables for the main loop
    for (count=1; (count<param.numberOfColors) && (entries!=0); count++) {

      // find box with largest number of entries from list
      entries = 0;
      for (iter = theLeaves.begin() ; iter != theLeaves.end() ; iter++) {
        if ( (*iter).colorFrequency > entries ) {
//.........这里部分代码省略.........