first version

.gitignore

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+/src/a.out
+

src/image_sharpener.cpp

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+#include <iostream>
+#include "libppm.h"
+#include <cstdint>
+
+using namespace std;
+
+struct image_t* S1_smoothen(struct image_t *input_image)
+{
+	// TODO
+	// remember to allocate space for smoothened_image. See read_ppm_file() in libppm.c for some help.
+	return 0;
+}
+
+struct image_t* S2_find_details(struct image_t *input_image, struct image_t *smoothened_image)
+{
+	// TODO
+	return 0;
+}
+
+struct image_t* S3_sharpen(struct image_t *input_image, struct image_t *details_image)
+{
+	// TODO
+	return input_image; //TODO remove this line when adding your code
+}
+
+int main(int argc, char **argv)
+{
+	if(argc != 3)
+	{
+		cout << "usage: ./a.out <path-to-original-image> <path-to-transformed-image>\n\n";
+		exit(0);
+	}
+	
+	struct image_t *input_image = read_ppm_file(argv[1]);
+	
+	struct image_t *smoothened_image = S1_smoothen(input_image);
+	
+	struct image_t *details_image = S2_find_details(input_image, smoothened_image);
+	
+	struct image_t *sharpened_image = S3_sharpen(input_image, details_image);
+	
+	write_ppm_file(argv[2], sharpened_image);
+	
+	return 0;
+}

src/libppm.cpp

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+#include "libppm.h"
+#include <iostream>
+#include <fstream>
+
+using namespace std;
+
+uint8_t skip_blanks_comments_while_reading(ifstream *read_stream) //returns the byte at the first position after the skipping of the blank space
+{
+	uint8_t val;
+	while(true)
+	{
+		val = read_stream->get();
+		if(val == '#')
+		{
+			while(val != '\n')
+			{
+				val = read_stream->get();
+			}
+		}
+		if(val == '\n' || val == ' ' || val == '\t')
+		{
+			continue;
+		}
+		else if(val != '#')
+			return val;
+	}
+	return val;
+}
+
+struct image_t* read_ppm_file(char* path_to_input_file)
+{
+	//cout << "input image file = " << path_to_input_file << "\n";
+	
+	ifstream read_stream(path_to_input_file, ios::binary | ios::in);
+	
+	if(read_stream.is_open())
+	{
+		struct image_t* image = new struct image_t;
+		
+		uint8_t val = skip_blanks_comments_while_reading(&read_stream); // 'P'
+		val = read_stream.get(); //'6'
+		
+		// width
+		val = skip_blanks_comments_while_reading(&read_stream);		
+		while(true)
+		{
+			if(val == ' ' || val == '\t' || val == '\n')
+				break;
+			image->width = image->width * 10 + (val - '0');
+			val = read_stream.get();
+		}
+		//cout << "width = " << image->width << "\n";
+		
+		// height
+		val = skip_blanks_comments_while_reading(&read_stream);		
+		while(true)
+		{
+			if(val == ' ' || val == '\t' || val == '\n')
+				break;
+			image->height = image->height * 10 + (val - '0');
+			val = read_stream.get();
+		}
+		//cout << "height = " << image->height << "\n";
+		
+		image->image_pixels = new uint8_t**[image->height];
+		for(int i = 0; i < image->height; i++)
+		{
+			image->image_pixels[i] = new uint8_t*[image->width];
+			for(int j = 0; j < image->width; j++)
+				image->image_pixels[i][j] = new uint8_t[3];
+		}
+		
+		// maxval
+		val = skip_blanks_comments_while_reading(&read_stream);		
+		while(true)
+		{
+			if(val == ' ' || val == '\t' || val == '\n')
+				break;
+			val = read_stream.get();
+		}
+		
+		// get pixel values
+		val = skip_blanks_comments_while_reading(&read_stream);		
+		/*for(int i = 0; i < image->height; i++)
+		{
+			for(int j = 0; j < image->width; j++)
+			{
+				for(int k = 0; k < 3; k++)
+				{
+					image->image_pixels[i][j][k] = val;
+					val = read_stream.get(); //assuming maxval of <=255
+				}
+			}
+		}*/
+		read_stream.seekg(-1, ios_base::cur);
+		read_stream.read(((char*)image->image_pixels), image->height * image->width * 3); //assuming maxval of <=255
+		
+		read_stream.close();
+		
+		return image;
+	}
+	else
+	{
+		cerr << "failed to open file " << path_to_input_file << "\n\n";
+		exit(1);
+	}
+}
+
+void write_ppm_file(char * path_to_output_file, struct image_t* image)
+{
+	//cout << "output image file = " << path_to_output_file << "\n";
+	
+	ofstream write_stream(path_to_output_file, ios::binary | ios::out);
+	
+	if(write_stream.is_open())
+	{
+		write_stream.write("P6\n", 3);
+		std::string width_string = std::to_string(image->width);
+		//cout << "width = " << width_string << "\n";
+		write_stream.write(width_string.c_str(), width_string.length());
+		write_stream.write(" ", 1);
+		std::string height_string = std::to_string(image->height);
+		//cout << "height = " << height_string << "\n";
+		write_stream.write(height_string.c_str(), height_string.length());
+		write_stream.write("\n255\n", 5);
+		write_stream.write(((char*)image->image_pixels), image->height * image->width * 3);
+		write_stream.close();
+	}
+	else
+	{
+		cerr << "failed to open file " << path_to_output_file << "\n\n";
+		exit(1);
+	}
+}

src/libppm.h

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+#ifndef LIBPPM_H
+#define LIBPPM_H
+#include <cstdint>
+
+struct image_t
+{
+	int width;
+	int height;
+	uint8_t*** image_pixels;
+};
+
+struct image_t* read_ppm_file(char* path_to_input_file);
+void write_ppm_file(char* path_to_output_file, struct image_t* image);
+
+#endif

src/makefile

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+build-sharpen: ./a.out
+
+./a.out: image_sharpener.cpp libppm.cpp
+	g++ -g image_sharpener.cpp libppm.cpp
+
+run-sharpen: ./a.out
+	./a.out ../images/$(INPUT).ppm ../images/$(OUTPUT).ppm
+
+clean:
+	rm a.out