pnm.cpp 4.63 KiB
#include "pnm.h"
#include <iostream>
#include <stdio.h>
#include <string.h>
// pnm
// The PNM format is just an abstraction of the PBM, PGM, and PPM formats. I.e. the name "PNM" refers collectively to PBM, PGM, and PPM.
// pam has the advanced header
RGBAPNMObject * readPPM(const char* fileName) {
RGBAPNMObject *data=new RGBAPNMObject;
// open the file to read just the header reading
FILE* fr = fopen(fileName, "r");
if (!fr) {
std::cout << "Can't open " << fileName << std::endl;
return nullptr;
}
// formatted read of header
char fileType[11];
int res=0;
res = fscanf(fr, "%9s", fileType);
data->magicNum=fileType;
//std::cout << "fileType:" << fileType << std::endl;
unsigned char bits = 0;
// check to see if it's a PPM image file
if (strncmp(fileType, "P4" , 2) == 0) {
bits = 1; // PBM
} else if (strncmp(fileType, "P5" , 2) == 0) {
bits = 8; // PGM
} else if (strncmp(fileType, "P6" , 2) == 0) {
bits = 24; // PPM
} else if (strncmp(fileType, "P8" , 2) == 0) {
bits = 32; // PPM
}
//std::cout << "bits:" << bits << std::endl;
// read the rest of header
unsigned int width, height;
res = fscanf(fr, "%u\n %u\n", &width, &height);
data->width = width;
data->height = height;
// read maximum
data->maxColVal = 255; // just set a default
if (bits != 1) {
unsigned int maximum;
res = fscanf(fr, "%u\n", &maximum);
data->maxColVal = height;
}
unsigned int size = width * height;
if (bits != 1) {
size *= bits/8;
}
// allocate array for pixels
char* pixels = new char[size];
// unformatted read of binary pixel data
res = fread(pixels, sizeof(int), size, fr);
data->m_Ptr = pixels;
// close file
fclose(fr);
// return the array
return data;
} // end of readPPM
void writePBM4(const char *filename, const RGBAPNMObject &data) {
FILE *fp = fopen(filename, "wb"); /* b - binary mode */
fprintf(fp, "P6\n%d %d\n255\n", data.width, data.height);
for (unsigned int j = 0; j < data.height; ++j) {
for (unsigned int i = 0; i < data.width; ++i) {
static unsigned char color[1];
unsigned int pos = ((i * 4) + (j * 4 * 1024));
//color[0] = data.m_Ptr[pos + 0]; /* red */
//color[1] = data.m_Ptr[pos + 1]; /* green */
//color[2] = data.m_Ptr[pos + 2]; /* blue */
color[0] = static_cast<unsigned char>(data.m_Ptr[pos + 3]); /*
alpha */
fwrite(color, 1, 1, fp);
}
}
fclose(fp);
}
void writePGM5(const char *filename, const RGBAPNMObject &data) {
FILE *fp = fopen(filename, "wb"); /* b - binary mode */
fprintf(fp, "P5\n%d %d\n255\n", data.width, data.height);
for (unsigned int j = 0; j < data.height; ++j) {
for (unsigned int i = 0; i < data.width; ++i) {
static unsigned char color[1];
unsigned int pos = ((i * 4) + (j * 4 * 1024));
color[0] = static_cast<unsigned char>(data.m_Ptr[pos + 0]); /* red
*/
//color[1] = data.m_Ptr[pos + 1]; /* green */
//color[2] = data.m_Ptr[pos + 2]; /* blue */
//color[3] = data.m_Ptr[pos + 3]; /* alpha */
fwrite(color, 1, 1, fp);
}
}
fclose(fp);
}
void writePPM6(const char *filename, const RGBAPNMObject &data) {
FILE *fp = fopen(filename, "wb"); /* b - binary mode */
fprintf(fp, "P6\n%d %d\n255\n", data.width, data.height);
for (unsigned int j = 0; j < data.height; ++j) {
for (unsigned int i = 0; i < data.width; ++i) {
static unsigned char color[3];
unsigned int pos = ((i * 4) + (j * 4 * 1024));
color[0] = static_cast<unsigned char>(data.m_Ptr[pos + 0]); /* red */
color[1] = static_cast<unsigned char>(data.m_Ptr[pos + 1]); /* green */
color[2] = static_cast<unsigned char>(data.m_Ptr[pos + 2]); /* blue */
//color[3] = data.m_Ptr[pos + 3]; /* alpha */
fwrite(color, 1, 3, fp);
}
}
fclose(fp);
}
void writePPM8(const char *filename, const RGBAPNMObject &data) {
FILE *fp = fopen(filename, "wb"); /* b - binary mode */
fprintf(fp, "P8\n%d %d\n255\n", data.width, data.height);
for (unsigned int j = 0; j < data.height; ++j) {
for (unsigned int i = 0; i < data.width; ++i) {
static unsigned char color[4];
unsigned int pos = ((i * 4) + (j * 4 * 1024));
color[0] = static_cast<unsigned char>(data.m_Ptr[pos + 0]); /* red */
color[1] = static_cast<unsigned char>(data.m_Ptr[pos + 1]); /* green */
color[2] = static_cast<unsigned char>(data.m_Ptr[pos + 2]); /* blue */
color[3] = static_cast<unsigned char>(data.m_Ptr[pos + 3]); /* alpha */
fwrite(color, 1, 4, fp);
}
}
fclose(fp);
}