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我需要将每像素16位的pgm图像转换为每像素8位的pgm图像,但是我有问题要读取pgm图像16 bpp,我不明白我在做什么错误。这里的代码:当它试图执行istruction IMG打开pgm图像16 bpp
#include "pgm.h"
#include <iterator>
#include <algorithm>
#include <fstream>
#include <sstream>
using namespace std;
bool convert16to8bit(const std::string& inFilename, mat<uint8_t>& img, const std::string& outFilename){
mat<uint16_t> imgTemp;
ifstream is(inFilename, ios::binary);
if (!is)
return false;
string magic;
is >> magic;
if (magic != "P2" && magic != "P5")
return false;
size_t rows, cols, nlevels;
is >> cols >> rows >> nlevels;
if (nlevels < 255)
return false;
is.get();
img = mat<uint8_t>(rows, cols);
if (nlevels == 255){
if (magic == "P5"){
is.unsetf(ios::skipws);
img.data_.assign(istream_iterator<uint8_t>(is), istream_iterator<uint8_t>());
}else
img.data_.assign(istream_iterator<int>(is), istream_iterator<int>());
}
else{
imgTemp = mat<uint16_t>(rows, cols);
if (magic == "P5"){
is.unsetf(ios::skipws);
imgTemp.data_.assign(istream_iterator<uint16_t>(is), istream_iterator<uint16_t>());
}
else
imgTemp.data_.assign(istream_iterator<int>(is), istream_iterator<int>());
for (size_t r = 0; r < rows; r++)
for (size_t c = 0; c < cols; c++)
img(r, c) = imgTemp(r, c);
}
stringstream ss;
ss << outFilename << ".pgm";
ofstream os(ss.str(), ios::binary);
if (!os)
return false;
os << magic <<"\n" << cols << " " << rows << "\n255\n";
if (magic == "P2")
copy(begin(img), end(img), ostream_iterator<int>(os, " "));
else
copy(begin(img), end(img), ostream_iterator<uint8_t>(os));
return true;
}
//mat.h
#if !defined MAT_H
#define MAT_H
#include <vector>
template <typename T>
struct mat {
size_t rows_, cols_;
std::vector<T> data_;
mat(size_t rows = 0, size_t cols = 0) : rows_(rows), cols_(cols), data_(rows*cols) {}
const size_t rows() const { return rows_; }
const size_t cols() const { return cols_; }
const T& operator()(size_t r, size_t c) const { return data_[r*cols_ + c]; }
T& operator()(size_t r, size_t c) { return data_[r*cols_ + c]; }
auto begin() -> decltype(data_.begin()) { return data_.begin(); }
auto end() -> decltype(data_.end()) { return data_.end(); }
auto begin() const -> decltype(data_.begin()) { return data_.begin(); }
auto end() const -> decltype(data_.end()) { return data_.end(); }
};
#endif // MAT_H
此代码创建一个错误(R,C)= imgTemp(R,C)(错误:矢量下标超出范围)与PGM 16bpp的但与一个pgm 8bpp我可以打开它没有问题,并重新创建它没有错误的原始。我认为问题在于istream_iterator < uint16_t>,因为istream_iterator < uint8_t>可以工作(使用pgm 8bit)。任何解决方案
感谢您的帮助
任何解决方案,到底是什么? “我有问题阅读一张pgm图片”不是一个问题陈述。你能更精确地知道什么是不工作的吗? –
我无法阅读和记忆大小为16位的imgTemp.data_像素 –
您是否有例外?编译器错误?带有你不期望的值的变量?这是帮助我们帮助你的那种信息。你能收集他们,并编辑你的问题,包括他们? –