原理: 负像图像处理算法就是用255减去原图的R、G、B分量值。

1.添加头文件, 并定义相关宏和结构体

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <jpeglib.h>

#define JpegStdError jpeg_std_error
#define JpegCreateDecompress jpeg_create_decompress
#define JpegCreateCompress jpeg_create_compress
#define JpegStdioSrc jpeg_stdio_src
#define JpegReadHeader jpeg_read_header
#define JpegStartDecompress jpeg_start_decompress
#define ScanLine output_scanline
#define NextLine next_scanline
#define JpegReadLine jpeg_read_scanlines
#define JpegFinishDecompress jpeg_finish_decompress
#define JpegDestroyDecompress jpeg_destroy_decompress
#define JpegStdioDest jpeg_stdio_dest
#define JpegSetDefault jpeg_set_defaults
#define JpegSetQuality jpeg_set_quality
#define JpegStartCompress jpeg_start_compress
#define JpegWriteLine jpeg_write_scanlines
#define JpegFinishCompress jpeg_finish_compress
#define JpegDestroyCompress jpeg_destroy_compress

typedef JSAMPARRAY JpegArray;
typedef FILE *FilePtr;
typedef struct jpeg_compress_struct JpegComp;
typedef struct jpeg_decompress_struct JpegDecomp;
typedef struct jpeg_error_mgr JpegErrMgr;
typedef struct ImagePicData ImagePicData;

struct ImagePicData
{
    unsigned char FName[256];
    FilePtr FPtr;
    int Width;
    int Height;
    int BitDepth;
    int Flag;
    int ColType;
    unsigned char *RGBA;
};

2.实现图像反转函数

int InvertImageColor(ImagePicData *ImageData, int Flag)
{
    int Pos = 0;
    int i, j;

    if(Flag == 0)
    for(i=0; i<ImageData->Height; i++)
    {
        for(j=0; j<ImageData->Width; j++)
        {
            ImageData->RGBA[4*Pos+0] = 255 - ImageData->RGBA[4*Pos+0];
            ImageData->RGBA[4*Pos+1] = 255 - ImageData->RGBA[4*Pos+1];
            ImageData->RGBA[4*Pos+2] = 255 - ImageData->RGBA[4*Pos+2];
            Pos++;
        }
    }
    else if(Flag == 1)
    for(i=0; i<ImageData->Height; i++)
    {
        for(j=0; j<ImageData->Width; j++)
        {
            ImageData->RGBA[4*Pos+0] = 255 ^ ImageData->RGBA[4*Pos+0];
            ImageData->RGBA[4*Pos+1] = 255 ^ ImageData->RGBA[4*Pos+1];
            ImageData->RGBA[4*Pos+2] = 255 ^ ImageData->RGBA[4*Pos+2];
            Pos++;
        }
    }
    else if(Flag == 2)
    for(i=0; i<ImageData->Height; i++)
    {
        for(j=0; j<ImageData->Width; j++)
        {
            ImageData->RGBA[4*Pos+0] = ~ImageData->RGBA[4*Pos+0];
            ImageData->RGBA[4*Pos+1] = ~ImageData->RGBA[4*Pos+1];
            ImageData->RGBA[4*Pos+2] = ~ImageData->RGBA[4*Pos+2];
            Pos++;
        }
    }


    return 0;
}

3.读写图片

参见《C语言实现色彩平衡算法》

4.添加主函数

int main(int argc, char **argv)
{
    ImagePicData PicData;
    char RGBAData[16*300*300];
    char JpegInputName[256];
    char JpegOutputName[256];
    int Flag;

    memset(&PicData, 0x00, sizeof(PicData));
    memset(JpegInputName, 0x00, sizeof(JpegInputName));
    memset(JpegOutputName, 0x00, sizeof(JpegOutputName));

    if(argc != 4)
    {
        printf("入参个数错误!\n");
        return -1;
    }

    strncpy(JpegInputName, argv[1], 255);
    strncpy(JpegOutputName, argv[2], 255);

    Flag = atoi(argv[3]);

    PicData.RGBA = RGBAData;

    strcpy(PicData.FName, JpegInputName);

    LoadJPG(&PicData);

    InvertImageColor(&PicData, Flag);

    strcpy(PicData.FName, JpegOutputName);

    CreateJPG(&PicData);

    return 0;
}

5.编译运行

$ gcc -o examle examle.c -L$HOME/local/prior/lib -ljpeg
$ ./examle a.jpg b.jpg 0

6.运行结果

原图

986cc94c21f05aa13c748e325ba49d10.jpg

效果

986cc95T.jpg