PNG의 데이터를 2D 배열로 읽는 간단한 프로그램이 있습니다. 그 데이터를 .RAW 파일에 저장하여 Raw Studio 또는 Irfanview이 내 프로그램에서 my_out.raw로 출력하는 원시 이미지를 볼 수 있습니다. 현재 원시 이진 데이터를 my_out.raw 파일에 쓰는 경우 두 응용 프로그램 모두 실제로 파일을 읽을 수는 있지만 이미지를 볼 수는 없습니다. 이미지를 볼 수 있도록하기 위해 아래 프로그램에서해야 할 일은 무엇입니까?바이트 배열을 RAW 파일 형식으로 저장
코드 PNG 파일을 읽을 수는 다음과 같습니다
// MAIN.cpp
#include "pngfilereader.h"
#include <string>
#include <vector>
#include <fstream>
int main (int argc, char *argv[])
{
PNGFileReader pngfr;
if (!pngfr.decompress_png_to_raw(std::string("/home/matt6809/Downloads"
"/City.png"))) {
std::cout << "File decompression error: " << std::endl;
} else {
std::ofstream out;
out.open("./my_out.raw", std::ios_base::out);
std::vector<std::vector<unsigned char> > data;
pngfr.get_image_data(data);
typedef std::vector<std::vector<unsigned char> >::iterator row_it;
typedef std::vector<unsigned char>::iterator col_it;
for(row_it rit= data.begin(); rit != data.end(); ++rit) {
for(col_it cit = rit->begin(); cit != rit->end(); ++cit) {
out << (*cit);
}
}
out << std::endl;
}
return 0;
}
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <png.h>
#include <iostream>
#include <vector>
#include <string>
class PNGFileReader
{
public:
PNGFileReader();
~PNGFileReader();
// Public exposed API:
bool compress_raw_to_png(uint8_t data, int size);
bool decompress_png_to_raw(const std::string &path);
// Getters
long unsigned int get_image_width();
long unsigned int get_image_height();
void get_image_data(std::vector<std::vector<unsigned char> > &data);
private:
// Helper functions:
bool read_png(const std::string &path);
bool create_png_structs(FILE *fp);
bool free_data();
bool alloc_data();
// Member variables:
png_structp m_pPNG;
png_infop m_pPNGInfo;
png_infop m_pPNGEndInfo;
png_bytepp m_Data;
long unsigned int m_ImageWidth;
long unsigned int m_ImageHeight;
// Enums
enum PNGBOOL {NOT_PNG, PNG};
enum PNGERRORS {ERROR, SUCCESS};
};
#include "pngfilereader.h"
#include <stdexcept>
PNGFileReader::PNGFileReader() :
m_pPNG(NULL),
m_pPNGInfo(NULL),
m_pPNGEndInfo(NULL),
m_Data(NULL),
m_ImageWidth(0),
m_ImageHeight(0)
{
}
PNGFileReader::~PNGFileReader()
{
for (unsigned long int i = 0; i < m_ImageHeight; ++i) {
if (m_Data[i]) {
delete m_Data[i];
m_Data[i] = NULL;
}
}
if (m_Data) {
delete m_Data;
m_Data = NULL;
}
}
// Public Exposed API
bool PNGFileReader::compress_raw_to_png(uint8_t m_Data, int size)
{
return PNGFileReader::SUCCESS;
}
bool PNGFileReader::decompress_png_to_raw(const std::string &path)
{
return read_png(path);
}
// Getters
long unsigned int PNGFileReader::get_image_width()
{
return m_ImageWidth;
}
long unsigned int PNGFileReader::get_image_height()
{
return m_ImageHeight;
}
void PNGFileReader::get_image_data(
std::vector<std::vector<unsigned char> > &data)
{
for (unsigned long int i = 0; i < m_ImageHeight; ++i) {
std::vector<unsigned char> v;
data.push_back(v);
for (unsigned long int j = 0; j < m_ImageWidth; ++j) {
std::vector<unsigned char> *vp = &data[i];
vp->push_back(m_Data[i][j]);
}
}
}
// Private Methods
bool PNGFileReader::read_png(const std::string &path)
{
/*
* Open up the file to read (path) in binary mode
* first so that if anything goes wrong with libpng
* we won't have much to undo
*/
const char *c_path = path.c_str();
FILE *fp = fopen(c_path, "rb");
if (!fp)
return PNGFileReader::ERROR;
/*
* Read the first BYTES_TO_READ bytes from file
* then determine if it is a png file or
* not. If png_sig_cmp == 0 all is okay
*/
enum {BYTES_TO_READ = 8};
unsigned char sig[BYTES_TO_READ];
if (!fread(sig, 1, BYTES_TO_READ, fp)) {
fclose(fp);
return PNGFileReader::ERROR;
}
bool is_png = !png_sig_cmp(sig, 0, BYTES_TO_READ);
if (!is_png) {
fclose(fp);
return PNGFileReader::ERROR;
}
if (!this->create_png_structs(fp)) {
fclose(fp);
return PNGFileReader::ERROR;
}
/*
* For error handling purposes. Set a long pointer
* back to this function to handle all error related
* to file IO
*/
if (setjmp(png_jmpbuf(m_pPNG)))
{
png_destroy_read_struct(&m_pPNG, &m_pPNGInfo, &m_pPNGEndInfo);
fclose(fp);
return PNGFileReader::ERROR;
}
/*
* Set up the input code for FILE openend in binary mode,
* and tell libpng we have already read BYTES_TO_READ btyes from
* signature
*/
png_init_io(m_pPNG, fp);
png_set_sig_bytes(m_pPNG, BYTES_TO_READ);
/*
* Using the lowlevel interface to lib png ...
*/
png_read_info(m_pPNG, m_pPNGInfo);
m_ImageHeight = png_get_image_height(m_pPNG, m_pPNGInfo);
m_ImageWidth = png_get_rowbytes(m_pPNG, m_pPNGInfo);
this->alloc_data();
png_read_image(m_pPNG, m_Data);
png_read_end(m_pPNG, NULL);
png_destroy_read_struct(&m_pPNG, &m_pPNGInfo, &m_pPNGEndInfo);
fclose(fp);
return PNGFileReader::SUCCESS;
}
bool PNGFileReader::create_png_structs(FILE *fp)
{
/*
* Create the pointer to main libpng struct, as well as
* two info structs to maintain information after, and
* prior to all operations on png m_Data. Only necessary
* to release resource after function succeeds.
*/
m_pPNG = png_create_read_struct(PNG_LIBPNG_VER_STRING, (png_voidp)NULL,
NULL, NULL);
if (!m_pPNG)
{
fclose(fp);
return PNGFileReader::ERROR;
}
m_pPNGInfo = png_create_info_struct(m_pPNG);
if (!m_pPNGInfo)
{
png_destroy_read_struct(&m_pPNG, (png_infopp)NULL,(png_infopp)NULL);
fclose(fp);
return PNGFileReader::ERROR;
}
m_pPNGEndInfo = png_create_info_struct(m_pPNG);
if (!m_pPNGEndInfo)
{
png_destroy_read_struct(&m_pPNG, &m_pPNGInfo, (png_infopp)NULL);
fclose(fp);
return PNGFileReader::ERROR;
}
return PNGFileReader::SUCCESS;
}
bool PNGFileReader::free_data()
{
if (m_ImageHeight == 0 || m_ImageWidth == 0)
return PNGFileReader::ERROR;
for (unsigned long int i = 0; i < m_ImageHeight; ++i) {
if (m_Data[i]) {
delete m_Data[i];
m_Data[i] = NULL;
}
}
if (m_Data) {
delete m_Data;
m_Data = NULL;
}
return PNGFileReader::SUCCESS;
}
bool PNGFileReader::alloc_data()
{
if (m_ImageHeight == 0 || m_ImageWidth == 0)
return PNGFileReader::ERROR;
if (m_Data != NULL)
this->free_data();
m_Data = new png_bytep[m_ImageHeight]();
for (unsigned long int i = 0; i < m_ImageHeight; ++i) {
m_Data[i] = NULL;
}
try {
for (unsigned long int i = 0; i < m_ImageHeight; ++i) {
m_Data[i] = new png_byte[m_ImageWidth];
}
}
catch (std::bad_alloc e) {
for (unsigned long int i = 0; i < m_ImageHeight; ++i) {
if (m_Data[i]) {
delete m_Data[i];
m_Data[i] = NULL;
}
}
if (m_Data) {
delete m_Data;
m_Data = NULL;
}
throw e;
}
return PNGFileReader::SUCCESS;
}
귀하의 질문에 대한 명확한 답변을 드릴 수 있습니까? –
@ George Skoptsov 편집이 완료되면 추가 설명이 필요하면 알려주세요. –