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[code]#include #include #include #include #include #include #include #include #include /* * Include file for users of JPEG library. * You will need to have included system headers that define at least * the typedefs FILE and size_t before you can include jpeglib.h. * (stdio.h is sufficient on ANSI-conforming systems.) * You may also wish to include "jerror.h". */#include "jpeglib.h"int cnt = 0;int x, y;#pragma pack(1)typedef struct tagBmpFileHeader // 文件头{ unsigned short bfType; // 标识该文件为bmp文件,判断文件是否为bmp文件，即用该值与"0x4d42"比较是否相等即可，0x4d42 = 19778 unsigned long bfSize; // 位图文件大小，包罗这14个字节。 unsigned short bfReserved1; // 预保存位，暂不消。 unsigned short bfReserved2; // 预保存位，暂不消。 unsigned long bfOffBits; // 图像数据区的起始位置} BmpFileHeader; // 14字节:short2个,long4个typedef struct tagBmpInfoHeader // 信息头{ unsigned long biSize; // 本布局的长度，为40个字节。 long biWidth; // 宽度 long biHeight; // 高度 unsigned short biPlanes; // 目的设备的级别，必须是1。 unsigned short biBitCount; // 每个像素所占的位数（bit），其值必须为1（黑白图像）、4（16色图）、8（256色）、24（真彩色图），新的BMP格式支持32位色。 unsigned longbiCompression; // 压缩方式，有效的值为BI_RGB（未经压缩）、BI_RLE8、BI_RLE4、BI_BITFILEDS（均为Windows界说常量）。 unsigned longbiSizeImage; // 图像区数据大小，即现实的位图数据占用的字节数 long biXPelsPerMeter; // 水平分辨率，像素每米 long biYPelsPerMeter; // 垂直分辨率，单位是像素/米 unsigned long biClrUsed; // 位图现实用到的颜色数，如果该值为零，则用到的颜色数为2的biBitCount次幂。 unsigned short biClrImportant; // 位图显示过程，重要的颜色数；0--所有都重要} BmpInfoHeader; // 40字节#pragma pack()int *lcd_mp;// 成功返回1 失败返回0int read_JPEG_file(char *filename, int start_x, int start_y){ /* This struct contains the JPEG decompression parameters and pointers to * working space (which is allocated as needed by the JPEG library). */ struct jpeg_decompress_struct cinfo; /* We use our private extension JPEG error handler. * Note that this struct must live as long as the main JPEG parameter * struct, to avoid dangling-pointer problems. */ struct jpeg_error_mgr jerr; /* More stuff */ FILE *infile; /* source file */ unsigned char *buffer; /* Output row buffer */ int row_stride; /* physical row width in output buffer */ /* In this example we want to open the input file before doing anything else, * so that the setjmp() error recovery below can assume the file is open. * VERY IMPORTANT: use "b" option to fopen() if you are on a machine that * requires it in order to read binary files. */ if ((infile = fopen(filename, "rb")) == NULL) { fprintf(stderr, "can't open %s\n", filename); return 0; } /* Step 1: allocate and initialize JPEG decompression object */ /* We set up the normal JPEG error routines, then override error_exit. */ cinfo.err = jpeg_std_error(&jerr); /* Now we can initialize the JPEG decompression object. */ jpeg_create_decompress(&cinfo); /* Step 2: specify data source (eg, a file) */ jpeg_stdio_src(&cinfo, infile); /* Step 3: read file parameters with jpeg_read_header() */ (void)jpeg_read_header(&cinfo, TRUE); /* We can ignore the return value from jpeg_read_header since * (a) suspension is not possible with the stdio data source, and * (b) we passed TRUE to reject a tables-only JPEG file as an error. * See libjpeg.txt for more info. */ /* Step 4: set parameters for decompression */ /* In this example, we don't need to change any of the defaults set by * jpeg_read_header(), so we do nothing here. */ /* Step 5: Start decompressor */ (void)jpeg_start_decompress(&cinfo); /* We can ignore the return value since suspension is not possible * with the stdio data source. */ /* We may need to do some setup of our own at this point before reading * the data. After jpeg_start_decompress() we have the correct scaled * output image dimensions available, as well as the output colormap * if we asked for color quantization. * In this example, we need to make an output work buffer of the right size. */ /* JSAMPLEs per row in output buffer */ row_stride = cinfo.output_width * cinfo.output_components; // 计算一行的大小 /* Make a one-row-high sample array that will go away when done with image */ buffer = calloc(1, row_stride); /* Step 6: while (scan lines remain to be read) */ /* jpeg_read_scanlines(...); */ /* Here we use the library's state variable cinfo.output_scanline as the * loop counter, so that we don't have to keep track ourselves. */ int data = 0; while (cinfo.output_scanline < cinfo.output_height) { /* jpeg_read_scanlines expects an array of pointers to scanlines. * Here the array is only one element long, but you could ask for * more than one scanline at a time if that's more convenient. */ (void)jpeg_read_scanlines(&cinfo, &buffer, 1); // 从上到下，从左到右 RGB RGB RGB RGB for (int i = 0; i < cinfo.output_width; ++i) // 012 345 { data |= buffer[3 * i] |
