安卓NDK开发-实现图片的高效压缩

1、将Android的bitmap解码并转换为RGB数据 
2、为JPEG对象分配空间并初始化 
3、指定压缩数据源 
4、获取文件信息 
5、为压缩设定参数，包括图像大小，颜色空间 
6、开始压缩 
7、压缩完毕 
8、释放资源

#include <string.h>#include <android/bitmap.h>#include <android/log.h>#include <jni.h>#include <stdio.h>#include <setjmp.h>#include <math.h>#include <stdint.h>#include <time.h>#include "jpeglib.h"#include "cdjpeg.h"     /* Common decls for cjpeg/djpeg applications */#include "jversion.h"       /* for version message */#include "config.h"#define LOG_TAG "jni"#define LOGW(...)  __android_log_write(ANDROID_LOG_WARN,LOG_TAG,__VA_ARGS__)#define LOGI(...) __android_log_print(ANDROID_LOG_INFO,LOG_TAG,__VA_ARGS__)#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__)#define true 1#define false 0typedef uint8_t BYTE;char *error;struct my_error_mgr {  struct jpeg_error_mgr pub;  jmp_buf setjmp_buffer;};typedef struct my_error_mgr * my_error_ptr;METHODDEF(void)my_error_exit (j_common_ptr cinfo){  my_error_ptr myerr = (my_error_ptr) cinfo->err;  (*cinfo->err->output_message) (cinfo);  error=myerr->pub.jpeg_message_table[myerr->pub.msg_code];  LOGE("jpeg_message_table[%d]:%s", myerr->pub.msg_code,myerr->pub.jpeg_message_table[myerr->pub.msg_code]); // LOGE("addon_message_table:%s", myerr->pub.addon_message_table);//  LOGE("SIZEOF:%d",myerr->pub.msg_parm.i[0]);//  LOGE("sizeof:%d",myerr->pub.msg_parm.i[1]);  longjmp(myerr->setjmp_buffer, 1);}//图片压缩方法int generateJPEG(BYTE* data, int w, int h, int quality,        const char* outfilename, jboolean optimize) {    int nComponent = 3;    struct jpeg_compress_struct jcs;    struct my_error_mgr jem;    jcs.err = jpeg_std_error(&jem.pub);    jem.pub.error_exit = my_error_exit;        if (setjmp(jem.setjmp_buffer)) {            return 0;         }     //为JPEG对象分配空间并初始化    jpeg_create_compress(&jcs);    //获取文件信息    FILE* f = fopen(outfilename, "wb");    if (f == NULL) {        return 0;    }    //指定压缩数据源    jpeg_stdio_dest(&jcs, f);    jcs.image_width = w;    jcs.image_height = h;    if (optimize) {        LOGI("optimize==ture");    } else {        LOGI("optimize==false");    }    jcs.arith_code = false;    jcs.input_components = nComponent;    if (nComponent == 1)        jcs.in_color_space = JCS_GRAYSCALE;    else        jcs.in_color_space = JCS_RGB;    jpeg_set_defaults(&jcs);    jcs.optimize_coding = optimize;    //为压缩设定参数，包括图像大小，颜色空间    jpeg_set_quality(&jcs, quality, true);    //开始压缩    jpeg_start_compress(&jcs, TRUE);    JSAMPROW row_pointer[1];    int row_stride;    row_stride = jcs.image_width * nComponent;    while (jcs.next_scanline < jcs.image_height) {        row_pointer[0] = &data[jcs.next_scanline * row_stride];        //写入数据        jpeg_write_scanlines(&jcs, row_pointer, 1);    }    if (jcs.optimize_coding) {            LOGI("optimize==ture");        } else {            LOGI("optimize==false");        }    //压缩完毕    jpeg_finish_compress(&jcs);    //释放资源    jpeg_destroy_compress(&jcs);    fclose(f);    return 1;}typedef struct {    uint8_t r;    uint8_t g;    uint8_t b;} rgb;//将java string转换为char*char* jstrinTostring(JNIEnv* env, jbyteArray barr) {    char* rtn = NULL;    jsize alen = (*env)->GetArrayLength(env, barr);    jbyte* ba = (*env)->GetByteArrayElements(env, barr, 0);    if (alen > 0) {        rtn = (char*) malloc(alen + 1);        memcpy(rtn, ba, alen);        rtn[alen] = 0;    }    (*env)->ReleaseByteArrayElements(env, barr, ba, 0);    return rtn;}//jni方法入口jstring Java_net_bither_util_NativeUtil_compressBitmap(JNIEnv* env,        jobject thiz, jobject bitmapcolor, int w, int h, int quality,        jbyteArray fileNameStr, jboolean optimize) {    AndroidBitmapInfo infocolor;    BYTE* pixelscolor;    int ret;    BYTE * data;    BYTE *tmpdata;    char * fileName = jstrinTostring(env, fileNameStr);    //解码Android bitmap信息，并存储值infocolor中    if ((ret = AndroidBitmap_getInfo(env, bitmapcolor, &infocolor)) < 0) {        LOGE("AndroidBitmap_getInfo() failed ! error=%d", ret);        return (*env)->NewStringUTF(env, "0");;    }    if ((ret = AndroidBitmap_lockPixels(env, bitmapcolor, &pixelscolor)) < 0) {        LOGE("AndroidBitmap_lockPixels() failed ! error=%d", ret);    }    BYTE r, g, b;    data = NULL;    data = malloc(w * h * 3);    tmpdata = data;    int j = 0, i = 0;    int color;    //将bitmap转换为rgb数据    for (i = 0; i < h; i++) {        for (j = 0; j < w; j++) {            color = *((int *) pixelscolor);            r = ((color & 0x00FF0000) >> 16);            g = ((color & 0x0000FF00) >> 8);            b = color & 0x000000FF;            *data = b;            *(data + 1) = g;            *(data + 2) = r;            data = data + 3;            pixelscolor += 4;        }    }    AndroidBitmap_unlockPixels(env, bitmapcolor);    //进行压缩    int resultCode= generateJPEG(tmpdata, w, h, quality, fileName, optimize);    free(tmpdata);    if(resultCode==0){        jstring result=(*env)->NewStringUTF(env, error);        error=NULL;        return result;    }    return (*env)->NewStringUTF(env, "1"); //success}