[kanonenfutter]

Tja, also alpha ist ein double, disp.mouse_y() ist ein integer.

Kompletter Quelltext:

#include "CImg.h"
using namespace cimg_library;

int main()
{
    CImg<int>img("leucht.jpg");
    CImgList<double>visu(img, CImg<int>(100,450,1,3,0));
    CImgDisplay disp(visu,"Test");
    
    int pw, mw, neu, i, j, valR, valG, valB, avg = 0;
    int tsize = 24;

    const unsigned char white[] = {255,255,255};    
    const unsigned char blue[] = {0,0,255};    
    const unsigned char lblue[] = {0,0,192};    
    const unsigned char dblue[] = {0,0,128};

    for (double alpha = 0.5; !disp.is_closed() && !disp.is_keyQ() && !disp.is_keyESC(); ) 
    {
        for(int x=1; x<img.width()-1; x++)
        {
            for(int y=1; y<img.height()-1; y++)
            {        
                pw = img(x,y,0,0);
                mw = 0;
    
                for(i=-1; i<=1; i++)
                {
                    for(j=-1; j<=1; j++)
                    {
                        mw += img(x+i, y+j, 0, 0);
                    }
                }

                mw /= 9;
                neu = (int)((pw - (alpha*mw)) / (1.0-alpha));

                if(neu > 255)
                {
                    neu = 255;
                }
                else if(neu < 0)
                {
                    neu = 0;
                }
                visu[0](x,y,0,0) = neu;

                valR = visu[0](x,y,0,0);                    // Read the red component
                valG = visu[0](x,y,0,1);                    // Read the green component
                valB = visu[0](x,y,0,2);                    // Read the blue component (Z


                avg = (int)((valR + valG + valB)/3);            // Compute average pixel value.

                visu[0](x,y,0,0) = visu[0](x,y,0,1) = visu[0](x,y,0,2) = avg;    //Graubild                
                
            }
        } 

        visu[1].fill(0).draw_text(25,5,"Alpha",white,0,1,tsize).
            draw_text(35,450-tsize-5,"%.2f",white,0,1,tsize,alpha);
        visu[0].draw_line(img.width()-1,0,img.width()-1,img.height(),white,1);
    
        const int yb = (int)((450-tsize-25)-(alpha*(450-50-(2*tsize))));
    
        visu[1].draw_rectangle(38, 450-tsize-23, 62, tsize+23, lblue, 1).
        draw_rectangle(39, 450-tsize-24, 61, tsize+24, dblue, 1).draw_rectangle(40, 450-tsize-25, 60, yb, blue, 1);
    
        if ((disp.button()) && (disp.mouse_x()>=img.width() + 38) && (disp.mouse_x()<=img.width() + 62) && 
            (disp.mouse_y()>=tsize + 25) && (disp.mouse_y()<=450-tsize-25))
        {
            alpha = ((disp.mouse_y() -450 +25 +tsize) / ((50 +(2*tsize) -450)/100));
            alpha/= 100;

            if(alpha>0.999)
            {
                alpha = 0.999;
            }
        }

        disp.resize(disp,false).display(visu).wait();
    }
}

Kommentare zu jeder einzelnen Zeile spare ich mir mal

mfg