ASCII visualization (used for debugging 2d scalar fields)

ascii-2d.cpp

#include <string>
#include <array>
#include <algorithm>
#include <functional>
 
using namespace std;
 
// assumes that values returned by data is normalized between 0.0 and 1.0
string get_grayscale_image(int width, int height, function<float(int,int)> data){
    const int size = 10;
    const array<char,size+1> ascii {" .:-=+*#%@"};
    string res = "";
    for (int y=0;y<height;y++){
        for (int x=0;x<width;x++){
            float value = data(x,y);
            float clampedValue = max(0.0f,min(1.0f, value));
            int mappedInt = min(size-1,(int)(clampedValue*10));
            res += ascii[mappedInt];
        }
        res += "\n";
    }
    return res;
}