如何将BMP像素值读入数组？ 我在C++中编写代码（在Windows上），我试图提取灰度BMP的像素值。我不关心保留任何元数据，只想将像素值存储在一个char数组中。我还没有找到一种标准或“典型”的手动方式，所以我想知道是否有一个简单的库，人们可以用来将位图加载到内存中

提前谢谢

你可以试试这个库的API。

肯定有一些库（见其他答案），但很快，它就是一种简单的文件格式，你可以很容易地解析自己。详情如下:

（我已经离开Win32好几年了，但是

LoadImage

函数可以从BMP文件中获取HBITMAP。我不确定如何直接将其转换为像素阵列，但我可以想象DC会有一些扭曲，可以让您获取值

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更多提示：）

将整个文件读入内存。前面将有一个小标题，其余部分将是像素值

第一部分是结构。您唯一关心的部分是bOffBits，它给出了从文件开始到像素值的字节数

BITMAPFILEHEADER

后面的下一部分将是一个。这将有助于确定像素的格式

如果位深度需要调色板，则随后将显示调色板

像素值有两个陷阱。首先，顺序是（蓝色、绿色、红色），与其他人的做法正好相反。第二，行从图像的底部到顶部，再次从其他所有行向后移动。最后，一行中的字节数将始终填充到4的下一个倍数

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我几乎忘了提到，JPEG或PNG文件可以编码为BMP，但这并不常见。查看

BitMapInfo标头的双压缩字段，如果它不是BI\u RGB，您将需要更多帮助。
您有两个很好的选择：

自己加载并解析BMP文件。BMP文件以BITMAPFILEHADER开头，后跟BitMapInfo标头，后跟0个或多个RGBQUAD（调色板条目）。像素数据的偏移量在BITMAPFILEHADER中，但应检查BitMapInfo标头以确保图像格式符合您的期望/支持

使用LR_CREATEDIBSECTION标志调用LoadImage（）API，它将返回DIB节的句柄。接下来调用GetObject（），传入返回的句柄和指向DIBSECTION结构的指针。然后读取位图大小、格式、指向像素数据的指针等的DIBSECTION结构

如果您在Windows上，选项2会更好，因为LoadImage（）可能会为您检查无效的文件格式，并且可以加载的不仅仅是BMP文件

访问Windows BMP像素时，请记住线条始终是DWORD对齐的。
和准备就绪的代码，使用g++进行测试（不是Windows，但可能会帮助某些人）：

如果在Visual Studio中编码，在声明tagBITMAPFILEHEADER和TagBitMapInfo结构（如Yola的响应中所示）之前，请确保包含“#pragma pack（2）”。Ohterwise结构将填充到下一个4字节边界，而不是下一个2字节边界，数据将是垃圾

参考资料
扩展了Yola所写的内容，应该能够读入和输出文件。它没有经过很好的测试，但似乎有效。它使用输出时读入的文件格式

#include <iostream>
#include <unistd.h>
#include <fstream>

using std::cout;
using std::endl;
using std::ofstream;
using std::ifstream;

#pragma pack(1)
#pragma once

typedef int LONG;
typedef unsigned short WORD;
typedef unsigned int DWORD;

typedef struct tagBITMAPFILEHEADER {
    WORD bfType;
    DWORD bfSize;
    WORD bfReserved1;
    WORD bfReserved2;
    DWORD bfOffBits;
} BITMAPFILEHEADER, *PBITMAPFILEHEADER;

typedef struct tagBITMAPINFOHEADER {
    DWORD biSize;
    LONG biWidth;
    LONG biHeight;
    WORD biPlanes;
    WORD biBitCount;
    DWORD biCompression;
    DWORD biSizeImage;
    LONG biXPelsPerMeter;
    LONG biYPelsPerMeter;
    DWORD biClrUsed;
    DWORD biClrImportant;
} BITMAPINFOHEADER, *PBITMAPINFOHEADER;

unsigned char** reds;
unsigned char** greens;
unsigned char** blues;
int rows;
int cols;

void ColorTest() {
    // Makes Red Rectangle in top left corner. Rectangle stretches to right alot
    for (int i = rows / 10; i < 3 * rows / 10; i++)
        for (int j = cols / 10; j < 7 * cols / 10; j++)
            reds[i][j] = 0xff;

// Makes small green box in bottom right
    for (int i = 8 * rows / 10; i < rows; i++)
        for (int j = 8 * cols / 10; j < cols; j++)
            greens[i][j] = 0xff;

// Makes White box in the middle of the screeene    
    for (int i = rows * 4 / 10; i < rows * 6 / 10; i++)
        for (int j = cols * 4 / 10; j < cols * 6 / 10; j++) {
            greens[i][j] = 0xff;
            reds[i][j] = 0xff;
            blues[i][j] = 0xff;
        }

// Blue verticle rectangle bottom left
    for (int i = rows * 6 / 10; i < rows; i++)
        for (int j = cols * 0; j < cols * 1 / 10; j++)
            blues[i][j] = 0xff;
}

void RGB_Allocate(unsigned char**& dude) {
    dude = new unsigned char*[rows];
    for (int i = 0; i < rows; i++)
        dude[i] = new unsigned char[cols];
}

bool FillAndAllocate(char*& buffer, const char* Picture, int& rows, int& cols, int& BufferSize) { //Returns 1 if executed sucessfully, 0 if not sucessfull
    std::ifstream file(Picture);

    if (file) {
        file.seekg(0, std::ios::end);
        std::streampos length = file.tellg();
        file.seekg(0, std::ios::beg);

        buffer = new char[length];
        file.read(&buffer[0], length);

        PBITMAPFILEHEADER file_header;
        PBITMAPINFOHEADER info_header;

        file_header = (PBITMAPFILEHEADER) (&buffer[0]);
        info_header = (PBITMAPINFOHEADER) (&buffer[0] + sizeof(BITMAPFILEHEADER));
        rows = info_header->biHeight;
        cols = info_header->biWidth;
        BufferSize = file_header->bfSize;
        return 1;
    }
    else {
        cout << "File" << Picture << " don't Exist!" << endl;
        return 0;
    }
}

void GetPixlesFromBMP24(unsigned char** reds, unsigned char** greens, unsigned char** blues, int end, int rows, int cols, char* FileReadBuffer) { // end is BufferSize (total size of file)
    int count = 1;
int extra = cols % 4; // The nubmer of bytes in a row (cols) will be a multiple of 4.
    for (int i = 0; i < rows; i++){
count += extra;
    for (int j = cols - 1; j >= 0; j--)
        for (int k = 0; k < 3; k++) {
                switch (k) {
                case 0:
                    reds[i][j] = FileReadBuffer[end - count++];
                    break;
                case 1:
                    greens[i][j] = FileReadBuffer[end - count++];
                    break;
                case 2:
                    blues[i][j] = FileReadBuffer[end - count++];
                    break;
                }
            }
            }
}

void WriteOutBmp24(char* FileBuffer, const char* NameOfFileToCreate, int BufferSize) {
    std::ofstream write(NameOfFileToCreate);
    if (!write) {
        cout << "Failed to write " << NameOfFileToCreate << endl;
        return;
    }
    int count = 1;
    int extra = cols % 4; // The nubmer of bytes in a row (cols) will be a multiple of 4.
    for (int i = 0; i < rows; i++){
        count += extra;
        for (int j = cols - 1; j >= 0; j--)
            for (int k = 0; k < 3; k++) {
                switch (k) {
                case 0: //reds
                    FileBuffer[BufferSize - count] = reds[i][j];
                    break;
                case 1: //green
                    FileBuffer[BufferSize - count] = greens[i][j];
                    break;
                case 2: //blue
                    FileBuffer[BufferSize - count] = blues[i][j];
                    break;
                }
                count++;
            }
            }
    write.write(FileBuffer, BufferSize);
}


int main(int args, char** cat) {
char* FileBuffer; int BufferSize;

#define Picture "ReadInPicture.bmp"
if (!FillAndAllocate(FileBuffer, Picture, rows, cols, BufferSize)){cout << "File read error" << endl; return 0;}
cout << "Rows: " << rows << " Cols: " << cols << endl;

RGB_Allocate(reds);
RGB_Allocate(greens);
RGB_Allocate(blues);
GetPixlesFromBMP24( reds,  greens, blues,BufferSize, rows, cols, FileBuffer);
ColorTest();
#define WriteOutFile "OutputPicture.bmp"
WriteOutBmp24(FileBuffer,  WriteOutFile,BufferSize);
    return 1;
}

#包括
#包括
#包括
使用std：：cout；
使用std：：endl；
使用std：：of流；
使用std：：ifstream；
#布拉格语包（1）
#布拉格语一次
typedef int LONG；
typedef无符号短字；
typedef无符号整数双字；
typedef结构tagBITMAPFILEHEADER{
字型；
德沃德尺寸；
保留字1；
保留字2；
德沃德；
}BITMAPFILEHEADER，*PBITMAPFILEHEADER；
typedef结构TagBitMapInfo标头{
德沃德·比西泽；
长双宽；
长双峰高度；
单词双平面；
单词双比特计数；
德沃德双压缩；
德沃德·比西泽迈格；
长双峰渗透计；
长双渗透计；
德沃德·比克尔鲁斯；
德沃德·比克勒；
}BitMapInfo头，*PBITMapInfo头；
未签名字符**红色；
无符号字符**绿色；
未签名字符**蓝色；
int行；
int cols；
void ColorTest（）{
//在左上角形成红色矩形。矩形向右延伸很多
对于（int i=行/10；i<3*行/10；i++）
对于（int j=cols/10；j<7*cols/10；j++）
红色[i][j]=0xff；
//在右下角创建一个绿色的小框
对于（int i=8*行/10；i#pragma once

typedef int LONG;
typedef unsigned short WORD;
typedef unsigned int DWORD;

typedef struct tagBITMAPFILEHEADER {
  WORD  bfType;
  DWORD bfSize;
  WORD  bfReserved1;
  WORD  bfReserved2;
  DWORD bfOffBits;
} BITMAPFILEHEADER, *PBITMAPFILEHEADER;

typedef struct tagBITMAPINFOHEADER {
  DWORD biSize;
  LONG  biWidth;
  LONG  biHeight;
  WORD  biPlanes;
  WORD  biBitCount;
  DWORD biCompression;
  DWORD biSizeImage;
  LONG  biXPelsPerMeter;
  LONG  biYPelsPerMeter;
  DWORD biClrUsed;
  DWORD biClrImportant;
} BITMAPINFOHEADER, *PBITMAPINFOHEADER;

#include <iostream>
#include <unistd.h>
#include <fstream>

using std::cout;
using std::endl;
using std::ofstream;
using std::ifstream;

#pragma pack(1)
#pragma once

typedef int LONG;
typedef unsigned short WORD;
typedef unsigned int DWORD;

typedef struct tagBITMAPFILEHEADER {
    WORD bfType;
    DWORD bfSize;
    WORD bfReserved1;
    WORD bfReserved2;
    DWORD bfOffBits;
} BITMAPFILEHEADER, *PBITMAPFILEHEADER;

typedef struct tagBITMAPINFOHEADER {
    DWORD biSize;
    LONG biWidth;
    LONG biHeight;
    WORD biPlanes;
    WORD biBitCount;
    DWORD biCompression;
    DWORD biSizeImage;
    LONG biXPelsPerMeter;
    LONG biYPelsPerMeter;
    DWORD biClrUsed;
    DWORD biClrImportant;
} BITMAPINFOHEADER, *PBITMAPINFOHEADER;

unsigned char** reds;
unsigned char** greens;
unsigned char** blues;
int rows;
int cols;

void ColorTest() {
    // Makes Red Rectangle in top left corner. Rectangle stretches to right alot
    for (int i = rows / 10; i < 3 * rows / 10; i++)
        for (int j = cols / 10; j < 7 * cols / 10; j++)
            reds[i][j] = 0xff;

// Makes small green box in bottom right
    for (int i = 8 * rows / 10; i < rows; i++)
        for (int j = 8 * cols / 10; j < cols; j++)
            greens[i][j] = 0xff;

// Makes White box in the middle of the screeene    
    for (int i = rows * 4 / 10; i < rows * 6 / 10; i++)
        for (int j = cols * 4 / 10; j < cols * 6 / 10; j++) {
            greens[i][j] = 0xff;
            reds[i][j] = 0xff;
            blues[i][j] = 0xff;
        }

// Blue verticle rectangle bottom left
    for (int i = rows * 6 / 10; i < rows; i++)
        for (int j = cols * 0; j < cols * 1 / 10; j++)
            blues[i][j] = 0xff;
}

void RGB_Allocate(unsigned char**& dude) {
    dude = new unsigned char*[rows];
    for (int i = 0; i < rows; i++)
        dude[i] = new unsigned char[cols];
}

bool FillAndAllocate(char*& buffer, const char* Picture, int& rows, int& cols, int& BufferSize) { //Returns 1 if executed sucessfully, 0 if not sucessfull
    std::ifstream file(Picture);

    if (file) {
        file.seekg(0, std::ios::end);
        std::streampos length = file.tellg();
        file.seekg(0, std::ios::beg);

        buffer = new char[length];
        file.read(&buffer[0], length);

        PBITMAPFILEHEADER file_header;
        PBITMAPINFOHEADER info_header;

        file_header = (PBITMAPFILEHEADER) (&buffer[0]);
        info_header = (PBITMAPINFOHEADER) (&buffer[0] + sizeof(BITMAPFILEHEADER));
        rows = info_header->biHeight;
        cols = info_header->biWidth;
        BufferSize = file_header->bfSize;
        return 1;
    }
    else {
        cout << "File" << Picture << " don't Exist!" << endl;
        return 0;
    }
}

void GetPixlesFromBMP24(unsigned char** reds, unsigned char** greens, unsigned char** blues, int end, int rows, int cols, char* FileReadBuffer) { // end is BufferSize (total size of file)
    int count = 1;
int extra = cols % 4; // The nubmer of bytes in a row (cols) will be a multiple of 4.
    for (int i = 0; i < rows; i++){
count += extra;
    for (int j = cols - 1; j >= 0; j--)
        for (int k = 0; k < 3; k++) {
                switch (k) {
                case 0:
                    reds[i][j] = FileReadBuffer[end - count++];
                    break;
                case 1:
                    greens[i][j] = FileReadBuffer[end - count++];
                    break;
                case 2:
                    blues[i][j] = FileReadBuffer[end - count++];
                    break;
                }
            }
            }
}

void WriteOutBmp24(char* FileBuffer, const char* NameOfFileToCreate, int BufferSize) {
    std::ofstream write(NameOfFileToCreate);
    if (!write) {
        cout << "Failed to write " << NameOfFileToCreate << endl;
        return;
    }
    int count = 1;
    int extra = cols % 4; // The nubmer of bytes in a row (cols) will be a multiple of 4.
    for (int i = 0; i < rows; i++){
        count += extra;
        for (int j = cols - 1; j >= 0; j--)
            for (int k = 0; k < 3; k++) {
                switch (k) {
                case 0: //reds
                    FileBuffer[BufferSize - count] = reds[i][j];
                    break;
                case 1: //green
                    FileBuffer[BufferSize - count] = greens[i][j];
                    break;
                case 2: //blue
                    FileBuffer[BufferSize - count] = blues[i][j];
                    break;
                }
                count++;
            }
            }
    write.write(FileBuffer, BufferSize);
}


int main(int args, char** cat) {
char* FileBuffer; int BufferSize;

#define Picture "ReadInPicture.bmp"
if (!FillAndAllocate(FileBuffer, Picture, rows, cols, BufferSize)){cout << "File read error" << endl; return 0;}
cout << "Rows: " << rows << " Cols: " << cols << endl;

RGB_Allocate(reds);
RGB_Allocate(greens);
RGB_Allocate(blues);
GetPixlesFromBMP24( reds,  greens, blues,BufferSize, rows, cols, FileBuffer);
ColorTest();
#define WriteOutFile "OutputPicture.bmp"
WriteOutBmp24(FileBuffer,  WriteOutFile,BufferSize);
    return 1;
}