Go初接触之缩略图

 1 #ifndef CompressImage_C
 2 #define CompressImage_C
 3 
 4 #include <stdio.h>
 5 #include <math.h>
 6 #include <string.h>
 7 #include "/opt/libjpeg-turbo/include/jpeglib.h"
 8 #include <stdlib.h>
 9 
10 typedef struct JPEGHEAD {
11     unsigned int height;
12     unsigned int width;
13     unsigned int isRBG;
14     unsigned char* msg;
15 }JPEGINFO;
16 
17 /**
18 * Paramater: image file name, a struct JPEGINFO to save information as the return value, the height of new image
19 */
20 int ReadJPEGImage(char* fileName, void* ret, int height);
21 
22 /**
23 * Paramater: new image file name, a struct JPEGINFO to save information, the quality of new image
24 */
25 int WriteJPEGImage(char* fileName, void* jpeginfo, int quality);
26 
27 /**
28 * Paramater: image file name, new image file name, the height of new image, the quality of new image
29 */
30 int CompressImageByName(char* fileNameSrc, char* fileNameDst, int height, int quality);
31 
32 void initStructInfo(void** ppret, void* msg, int height, int width, int isRGB);
33 
34 void freeStructInfo(void* pret);
35 
36 #endif

  1 #include <stdio.h>
  2 #include <math.h>
  3 #include <string.h>
  4 #include "CompressImage_C.h"
  5 #include "/opt/libjpeg-turbo/include/jpeglib.h"
  6 
  7 
  8 int ReadJPEGImage(char* fileName, void* jpeginfo, int height) {
  9     JPEGINFO* ret = (JPEGINFO*)jpeginfo;
 10     //定义变量
 11     struct jpeg_decompress_struct info;
 12     struct jpeg_error_mgr err;
 13     FILE* infile;
 14     JSAMPARRAY buffer;
 15     int rowStride, nowLine = 0;
 16     double standardProportion[4] = {0.125, 0.25, 0.5, 1.0};
 17 
 18     //初始化对象
 19     jpeg_create_decompress(&info);
 20 
 21     //绑定错误结构
 22     info.err = jpeg_std_error(&err);
 23 
 24     //打开图片并填入info对象
 25     if((infile = fopen(fileName, "rb")) == NULL) {
 26         fprintf(stderr, "can‘t open %s\n", fileName);
 27         return 1;
 28     }
 29     jpeg_stdio_src(&info, infile);
 30     //读取文件信息
 31     jpeg_read_header(&info, TRUE);
 32 
 33     //设定压缩比例
 34     //这里找的是比当前比例小的最大比例
 35     info.scale_num = 1;
 36     info.scale_denom = 1;
 37     double proportion = (double)(height) / (double)(info.image_height);
 38     for(int i = 0; i < 4; i ++) {
 39         if(proportion > standardProportion[i]) {
 40             if(i == 0) {
 41                 info.scale_denom = 8;
 42                 break;
 43             }
 44             else {
 45                 info.scale_denom = (int)(pow(2, i - 1));
 46                 break;
 47             }
 48         }
 49     }
 50 
 51     //开始解压缩
 52     jpeg_start_decompress(&info);
 53 
 54     //存入图片信息
 55     ret->height = info.output_height;
 56     ret->width = info.output_width;
 57     ret->isRBG = (info.output_components == 3) ? 1 : 0;
 58     rowStride = info.output_width * info.output_components;
 59     buffer = (*info.mem -> alloc_sarray)((j_common_ptr)&info, JPOOL_IMAGE, rowStride, 1);
 60     ret->msg = (unsigned char*)malloc(rowStride * ret->height + 1);
 61     nowLine = 0;
 62     while(info.output_scanline < info.output_height) {
 63         //从in中读取数据并写入out中
 64         jpeg_read_scanlines(&info, buffer, 1);
 65         memcpy(ret->msg + (nowLine * (ret->width) * 3), buffer[0], rowStride);
 66         nowLine ++;
 67         //for(int i = 0; i < rowStride; i ++) {
 68         //    ret->msg[nowLine * ret->width * 3 + i] = buffer[0][i];
 69         //}
 70     }
 71 
 72     //释放资源
 73     jpeg_finish_decompress(&info);
 74     jpeg_destroy_decompress(&info);
 75     fclose(infile);
 76     return 0;
 77 }
 78 
 79 int WriteJPEGImage(char* fileName, void* jpeginfo, int quality) {
 80     JPEGINFO* ret = (JPEGINFO*)jpeginfo;
 81     //定义变量
 82     struct jpeg_error_mgr err;
 83     struct jpeg_compress_struct info;
 84     FILE* outfile;
 85     int rowStride;
 86 
 87     //初始化对象
 88     jpeg_create_compress(&info);
 89 
 90     //绑定错误结构
 91     info.err = jpeg_std_error(&err);
 92 
 93     //打开图片并填入info对象
 94     if((outfile = fopen(fileName, "wb")) == NULL) {
 95         fprintf(stderr, "can‘t open %s\n", fileName);
 96         return 1;
 97     }
 98     jpeg_stdio_dest(&info, outfile);
 99 
100     //设定图片参数s
101     info.image_width = ret->width;
102     info.image_height = ret->height;
103     info.in_color_space = (ret->isRBG == 1) ? JCS_RGB : JCS_GRAYSCALE;
104     info.input_components = (ret->isRBG == 1) ? 3 : 1;
105     jpeg_set_defaults(&info);
106     jpeg_set_quality(&info, quality, TRUE);
107 
108     //开始压缩
109     jpeg_start_compress(&info, TRUE);
110 
111     //写入图片
112     rowStride = info.image_width * info.num_components;
113     unsigned char* now = ret->msg;
114     while(info.next_scanline < info.image_height) {
115         jpeg_write_scanlines(&info, &now, 1);
116         now += rowStride;
117     }
118 
119     //释放资源
120     jpeg_finish_compress(&info);
121     jpeg_destroy_compress(&info);
122     fclose(outfile);
123 
124     return 0;
125 }
126 
127 int CompressImageByName(char* fileNameSrc, char* fileNameDst, int height, int quality) {
128     JPEGINFO* jpeginfo;
129     int ret = 0;
130     jpeginfo = (JPEGINFO*)malloc(sizeof(JPEGINFO));
131     if((ret = ReadJPEGImage(fileNameSrc, (void*)jpeginfo, height)) == 1) {
132         free(jpeginfo);
133         return 1;
134     }
135     if((ret = WriteJPEGImage(fileNameDst, (void*)jpeginfo, quality)) == 1) {
136         free(jpeginfo);
137         return 1;
138     }
139     free(jpeginfo);
140     return 0;
141 }
142 
143 void initStructInfo(void** ppret, void* msg, int height, int width, int isRGB) {
144     unsigned char* imgMsg = (unsigned char*)msg;
145     FILE* tt;
146     JPEGINFO* pJPEGINFO = (JPEGINFO*)malloc(sizeof(JPEGINFO));
147     memset(pJPEGINFO, 0, sizeof(JPEGINFO));
148     pJPEGINFO->height = height;
149     pJPEGINFO->width = width;
150     pJPEGINFO->msg = imgMsg;
151     if(isRGB) pJPEGINFO->isRBG = 1;
152     else pJPEGINFO->isRBG = 0;
153     *ppret = pJPEGINFO;
154 }
155 
156 void freeStructInfo(void* pret) {
157     free((JPEGINFO*)pret);
158 }

 1 package Function
 2 
 3 /*
 4 #cgo LDFLAGS: -L /opt/libjpeg-turbo/lib64 -ljpeg
 5 #cgo LDFLAGS: -L ../Clib -lcompress
 6 #include "../Clib/CompressImage_C.h"
 7 */
 8 import "C"
 9 import (
10     "unsafe"
11 )
12 
13 func CompressImageByName(fileNameSrc, fileNameDst string, height, quality int) int {
14     fileNameSrcTmp := C.CString(fileNameSrc)
15     fileNameDstTmp := C.CString(fileNameDst)
16     heightTmp := C.int(height)
17     qualityTmp := C.int(quality)
18     ret := C.CompressImageByName(fileNameSrcTmp, fileNameDstTmp, heightTmp, qualityTmp)
19     C.free(unsafe.Pointer(fileNameDstTmp))
20     C.free(unsafe.Pointer(fileNameSrcTmp))
21     if ret == 0 {
22         return 0
23     } else {
24         return 1
25     }
26 }
27 
28 func CompressImageByByte(fileNameDst string, imgMsg *byte, height, width, quality int, isRGB bool) int {
29     fileNameDstTmp := C.CString(fileNameDst)
30     var ptr unsafe.Pointer
31     heightTmp, widthTmp, qualityTmp := C.int(height), C.int(width), C.int(quality)
32     msg := unsafe.Pointer(imgMsg)
33     inColor := 0
34     if isRGB == true {
35         inColor = 1
36     }
37     C.initStructInfo(&ptr, msg, heightTmp, widthTmp, C.int(inColor))
38     ret := C.WriteJPEGImage(fileNameDstTmp, ptr, qualityTmp)
39     C.freeStructInfo(ptr)
40     if ret == 0 {
41         return 0
42     } else {
43         return 1
44     }
45     return 0
46 }