图像格式简单解析（BMP，WebP，JPEG，PNG，GIF)

typedef struct tagBITMAPFILEHEADER {
        WORD    bfType;
        DWORD   bfSize;
        WORD    bfReserved1;
        WORD    bfReserved2;
        DWORD   bfOffBits;
} BITMAPFILEHEADER, FAR *LPBITMAPFILEHEADER, *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, FAR *LPBITMAPINFOHEADER, *PBITMAPINFOHEADER;

typedef struct tagRGBQUAD {
        BYTE    rgbBlue;
        BYTE    rgbGreen;
        BYTE    rgbRed;
        BYTE    rgbReserved;
} RGBQUAD;

#include<Windows.h>
#include <iostream>
#include "webp/decode.h"
//下载地址https://storage.googleapis.com/downloads.webmproject.org/releases/webp/libwebp-1.4.0-windows-x64.zip
#pragma comment(lib, "libwebp.lib")
using namespace std;
struct LogicScreenDescriptor
{
        short width;
        short height;
        UCHAR yasuo;
        char index;
        char widthAndHeight;
};
void printResolution(UINT32 width, UINT32 height)
{
        cout << "分辨率为：" << width << "x" << height << endl;
}
void printResolutionLeve(UINT32 x, UINT32 y)
{
        cout << "水平分辨率为：" << x << ";垂直分辨率为：" << y << endl;
}
void readGif(PCHAR buffer, size_t len)
{
        cout << "当前是GIF文件" << endl;
        LogicScreenDescriptor* lsd = (LogicScreenDescriptor*)buffer;
        printResolution(lsd->width, lsd->height);
}
uint32_t bigToLittleEndian(uint32_t bigEndianValue) {
        return ((bigEndianValue & 0xff) << 24) |
                ((bigEndianValue & 0xff00) << 8) |
                ((bigEndianValue & 0xff0000) >> 8) |
                ((bigEndianValue & 0xff000000) >> 24);
}
void readPNG(PCHAR buffer, size_t len)
{
        cout << "当前是PNG文件" << endl;
        uint32_t length = bigToLittleEndian(*(uint32_t*)buffer);
        const char* chunkTypeCode = (const char*)(buffer + 4);
        char* data = (char*)malloc(length);
        if (data == nullptr)
                return;
        memcpy(data, buffer + 8, length);
        uint32_t width = bigToLittleEndian(*(uint32_t*)data);
        uint32_t height = bigToLittleEndian(*(uint32_t*)(data + 4));
        printResolution(width, height);
        free(data);
}
short swapEndian_short(short value) {
        return ((value & 0xff) << 8) | ((value & 0xff00) >> 8);
}
void readJPG(PCHAR buffer, int len)
{
        cout << "当前是JPG文件" << endl;
        while (len > 0)
        {
                char seg[2] = {};
                memcpy(seg, buffer, 2);
                short length = swapEndian_short(*(short*)(buffer + 2));
                
                char app0[] = { 0xFF, 0xE0 };
                char sof0[] = { 0xff, 0xc0 };
                if (memcmp(buffer, app0, 2) == 0)
                {
                        short length = (*(short*)(buffer + 2));
                        const char* type = (const char*)(buffer + 4);
                        char* mversion = (buffer + 9);
                        char* sversion = (buffer + 10);
                        char* danwei = (buffer + 11);
                        short width = swapEndian_short((*(short*)(buffer + 12)));
                        short height = swapEndian_short((*(short*)(buffer + 14)));
                        printResolutionLeve(width, height);
                }
                else if (memcmp(buffer, sof0, 2) == 0)
                {
                        short heigth = swapEndian_short((*(short*)(buffer + 5)));
                        short width = swapEndian_short((*(short*)(buffer + 7)));
                        printResolution(width, heigth);
                }
                len -= length;
                buffer = buffer + length + 2;
        }
}
void readBMP(PCHAR buffer, int len)
{
        cout << "当前是BMP文件" << endl;
        BITMAPFILEHEADER* bitmapFileHeader = (PBITMAPFILEHEADER)buffer;
        PBITMAPINFOHEADER bitmapInfoHeader = (PBITMAPINFOHEADER)(buffer + sizeof(BITMAPFILEHEADER));
        printResolution(bitmapInfoHeader->biWidth, bitmapInfoHeader->biHeight);
}
void readWebP(const uint8_t* buffer, int len)
{
        cout << "当前是WebP文件" << endl;
        int width, height;
        WebPGetInfo(buffer, len, &width, &height);
        printResolution(width, height);
}
int main()
{
        std::string fileName = R"(C:\Users\stdio\AppData\Roaming\Tencent\WeMeet\Global\Data\DynamicResource\3e1fa3ae1923bb4bacdabc661bc53ec5\remote_control_privilege_elevate_guide\remote_control_privilege_elevate_guide_zh-cn.gif)";
        fileName = R"(C:\Users\stdio\AppData\Roaming\kingsoft\office6\wpsassist\onlinetemplates\online\54b472eceb9de061adafdfa33b11780c_ds.png)";
        fileName = R"(C:\Users\stdio\Documents\WXWork\1688854706571334\Cache\Image\2024-11\海报.png)";
        fileName = R"(C:\Users\stdio\Documents\WXWork\1688854706571334\Cache\Image\2024-12\2.1每日一句 (1)(5).jpg)";
        fileName = R"(C:\Users\stdio\Documents\WXWork\1688854706571334\Avator\2024-12\d8142a10d6690d8f96a979eee418051c.jpg)";
        fileName = R"(C:\Users\stdio\AppData\Local\Packages\Microsoft.Windows.Search_cw5n1h2txyewy\AC\INetCache\LUF4768K\th0PBG8C9P.jpg)";
        fileName = R"(C:\Users\stdio\AppData\Local\Packages\Microsoft.Windows.Search_cw5n1h2txyewy\AC\INetCache\DY0N0B04\thQOHNB4RX.jpg)";
        fileName = R"(C:\Users\stdio\Documents\WXWork\1688854706571334\Cache\Image\2024-12\企业微信截图_17338795688595.jpg)";
        fileName = R"(D:\Github\TrafficMonitor-master\TrafficMonitor\skins\皮肤06\background.bmp)";
        fileName = R"(D:\Downloads\CppGuide-master\articles\imgs\zhyz7.webp)";
        fileName = R"(D:\Downloads\CppGuide-master\articles\imgs\zhyz25.webp)";
        FILE* file = nullptr;
        fopen_s(&file, fileName.c_str(), "rb");
        if (file)
        {
                cout << "当前文件：" << fileName << endl;
                fseek(file, 0, SEEK_END);
                long len = ftell(file);
                fseek(file, 0, SEEK_SET);
                PCHAR buffer = (PCHAR)malloc(len);
                if (buffer == nullptr)
                        return 1;
                size_t rlen = fread(buffer, 1, len, file);
                fclose(file);
                char gif89a[] = "GIF89a";
                size_t gif89aCount = sizeof(gif89a);
                char pngFileHead[] = {0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a};
                size_t pngFileHeadCount = sizeof(pngFileHead);
                char jpgFileHead[] = { 0xff, 0xd8};
                size_t jpgFileHeadCount = sizeof(jpgFileHead);
                char bmpFileHead[] = { 0x42, 0x4d };
                size_t bmpFileHeadCount = sizeof(bmpFileHead);
                char webpFileHead[] = { 'R', 'I', 'F', 'F' };
                size_t webpFileHeadCount = sizeof(webpFileHead);
                if (memcmp(buffer, gif89a, gif89aCount) == 0)
                {
                        readGif(buffer + gif89aCount, len - gif89aCount);
                }
                else if (memcmp(buffer, pngFileHead, pngFileHeadCount) == 0)
                {
                        readPNG(buffer + pngFileHeadCount, len - pngFileHeadCount);
                }
                else if (memcmp(buffer, jpgFileHead, jpgFileHeadCount) == 0)
                {
                        readJPG(buffer + jpgFileHeadCount, len - jpgFileHeadCount);
                }
                else if (memcmp(buffer, bmpFileHead, bmpFileHeadCount) == 0)
                {
                        readBMP(buffer, len);
                }
                else if (memcmp(buffer, webpFileHead, webpFileHeadCount) == 0)
                {
                        readWebP((const uint8_t*)buffer, len);
                }
                else
                {
                        cout << "未知文件" << endl;
                }
                free(buffer);
        }
}

转载：图像格式简单解析（BMP，WebP，JPEG，PNG，GIF) - 这种人 - 博客园