Primo commit di questa repo, è un bel progettino molto semplice da funzioni esplicative

libImg.cpp

@@ -0,0 +1,169 @@
+#include "libImg.h"
+
+#define ASSERT_MSG(cond, msg) \
+	do { if (!(cond)) { std::cerr << msg << std::endl; assert(cond); } } while (0)
+
+// Salva un immagine in formato ppm P6 255
+bool save(const std::string& path, const image& matrix){
+	std::ofstream f(path, std::ios::binary);
+	if(!f){
+		std::cerr<<"Errore in save"<<std::endl;
+		return false;
+	}
+	int w = matrix[0].size();
+	int h = matrix.size();
+	f << "P6\n" << w << " " << h <<"\n255\n";
+
+	for (int y = 0; y < h; y++) {
+		for(int x = 0; x < w; x++){
+			f.write(reinterpret_cast<const char*>(&matrix[y][x]), 3);
+		}
+	}
+
+	f.close();
+	std::cout << "Fine salvato"<<std::endl;
+	return true;
+}
+
+//Carica un immagine in formato ppm P6 255
+image load(const std::string& path, int& w, int& h){
+	std::ifstream f(path, std::ios::binary);
+	if (!f) {
+		std::cerr << "File non aperto" <<std::endl;
+		w = 1;
+		h = 1;
+		return errore;
+	}
+	std::string magic;
+	int val;
+	f >> magic >> w >> h >> val;
+	if(magic != "P6"){
+		std::cerr << " Magic Sbagliato"<<std::endl;
+		w = 1;
+		h = 1;
+		return errore;
+	}
+	if(val != 255){
+		std::cerr << "Dimensione sbagliata dei colori "<<val<<std::endl;
+		w = 1;
+		h = 1;
+		return errore;
+	}
+
+	char sep;
+	f.get(sep);
+
+	image matrix(h, std::vector<pixel>(w));
+	for(int y = 0; y < h; y++){
+		for(int x = 0; x < w; x++){
+			f.read(reinterpret_cast<char*>(&matrix[y][x]), 3);
+			if(f.gcount() != 3){
+				std::cerr << "Distanza sbagliata" <<std::endl;
+				w = 1;
+				h = 1;
+				std::cerr << "Strano, mancano i pixel"<<std::endl;
+				return errore;
+			}
+		}
+	}
+	return matrix;
+}
+
+//Controlla l'ugualianza di 2 immagini
+// usa tutte le tecniche che sono standard + comparatore tra pixel
+bool images_equal(const image& a, const image& b) {
+    if (a.size() != b.size() || a[0].size() != b[0].size()) return false;
+    return a == b;
+}
+
+//Genera rumore pseudo-casuale
+image randomImage(int w, int h){
+  image matrix(h, std::vector<pixel>(w));
+  
+  for(int y = 0; y < h; ++y){
+		for(int x = 0; x < w; ++x){
+			matrix[y][x] = {
+				static_cast<unsigned char>(dist(rng)),
+				static_cast<unsigned char>(dist(rng)),
+				static_cast<unsigned char>(dist(rng))
+			};
+		}
+	}
+  return matrix;
+}
+
+//converte un immagini in bianco e nero
+void BWimage(image &matrix, float lim){
+  ASSERT_MSG(lim >= 0 && lim <= 1, "Il valore limite deve essere tra 0-1");
+
+	const pixel t = {
+		static_cast<unsigned char>(lim*255),
+		static_cast<unsigned char>(lim*255),
+		static_cast<unsigned char>(lim*255)
+	};
+
+  for(auto &i: matrix){
+		for(auto &p: i){
+			if(p >= t)
+				p = {255,255,255};
+			else
+				p = {0, 0, 0};
+		}
+	}
+}
+
+//converte un immagine in scala di grigi
+void Grayimage(image &matrix){
+	for(auto &i: matrix){
+		for(auto &p: i){
+			short s = (short) p.lum();
+			p = {
+				static_cast<unsigned char>(s),
+				static_cast<unsigned char>(s),
+				static_cast<unsigned char>(s)
+			};
+		}
+	}
+}
+
+unsigned long long countW(image &matrix){
+	int ans = 0;
+	pixel max = {255, 255, 255};
+	for(const auto &y:matrix){
+		for(const auto &p: y){
+			if(p == max)ans++;
+		}
+	}
+	return ans;
+}
+// +- 0,25 0,125 ...
+float BWAimage(image &matrix){
+	image test;
+	float lim = 0.5f;
+	unsigned long long avg = matrix.size() * matrix[0].size() / 2;
+	for(int i = 4; i <= 1<<6; i = i<<1){
+		test = matrix;
+		BWimage(test, lim);
+		if(countW(test) < avg){
+			lim -= 1.0f/i;
+		}
+		else{
+			lim += 1.0f/i;
+		}
+		// Ez debug
+		// std::cout<<"Il lim è: "<<lim<<std::endl;
+	}
+	matrix = test;
+	return lim;
+}
+
+void invertImage(image &matrix){
+	for(auto &y:matrix){
+		for(auto &p:y){
+			p.r ^= 0xFF;
+			p.g ^= 0xFF;
+			p.b ^= 0xFF;
+		}
+	}
+}
+