Android 性能优化系列之bitmap图片优化

  
public static void compress(Bitmap.CompressFORMat format, int quality) {
    File sdFile = Environment.getExternalStorageDirectory();
    File originFile = new File(sdFile, "originImg.jpg");
    Bitmap originBitmap = BitmapFactory.decodeFile(originFile.getAbsolutePath());
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    originBitmap.compress(format, quality, bos);
    try {
        FileOutputStream fos = new FileOutputStream(new File(sdFile, "resultImg.jpg"));
        fos.write(bos.toByteArray());
        fos.flush();
        fos.close();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

public static void compress(int inSampleSize) {
    File sdFile = Environment.getExternalStorageDirectory();
    File originFile = new File(sdFile, "originImg.jpg");
    BitmapFactory.Options options = new BitmapFactory.Options();
    //设置此参数是仅仅读取图片的宽高到options中，不会将整张图片读到内存中，防止oom
    options.inJustDecodeBounds = true;
    Bitmap emptyBitmap = BitmapFactory.decodeFile(originFile.getAbsolutePath(), options);

    options.inJustDecodeBounds = false;
    options.inSampleSize = inSampleSize;
    Bitmap resultBitmap = BitmapFactory.decodeFile(originFile.getAbsolutePath(), options);
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    resultBitmap.compress(Bitmap.CompressFormat.JPEG, 100, bos);
    try {
        FileOutputStream fos = new FileOutputStream(new File(sdFile, "resultImg.jpg"));
        fos.write(bos.toByteArray());
        fos.flush();
        fos.close();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

 
    public static Bitmap resizeBitmap(Context context,int id,int maxW,int maxH,boolean hasAlpha,Bitmap reusable){
        Resources resources = context.getResources();
        BitmapFactory.Options options = new BitmapFactory.Options();
        // 只解码出 outxxx参数 比如 宽、高
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeResource(resources,id,options);
        //根据宽、高进行缩放
        int w = options.outWidth;
        int h = options.outHeight;
        //设置缩放系数
        options.inSampleSize = calcuteInSampleSize(w,h,maxW,maxH);
        if (!hasAlpha){
            options.inPreferredConfig = Bitmap.Config.RGB_565;
        }
        options.inJustDecodeBounds = false;
        //设置成能复用
        options.inMutable=true;
        options.inBitmap=reusable;
        return BitmapFactory.decodeResource(resources,id,options);
    }

    
    private static int calcuteInSampleSize(int w,int h,int maxW,int maxH) {
        int inSampleSize = 1;
        if (w > maxW && h > maxH){
            inSampleSize = 2;
            //循环 使宽、高小于 最大的宽、高
            while (w /inSampleSize > maxW && h / inSampleSize > maxH){
                inSampleSize *= 2;
            }
        }
        return inSampleSize;
    }
}

void write_JPEG_file(uint8_t *data, int w, int h, jint q, const char *path) {
//    3.1、创建jpeg压缩对象
    jpeg_compress_struct jcs;
    //错误回调
    jpeg_error_mgr error;
    jcs.err = jpeg_std_error(&error);
    //创建压缩对象
    jpeg_create_compress(&jcs);
//    3.2、指定存储文件  write binary
    FILE *f = fopen(path, "wb");
    jpeg_stdio_dest(&jcs, f);
//    3.3、设置压缩参数
    jcs.image_width = w;
    jcs.image_height = h;
    //bgr
    jcs.input_components = 3;
    jcs.in_color_space = JCS_RGB;
    jpeg_set_defaults(&jcs);
    //开启哈夫曼功能
    jcs.optimize_coding = true;
    jpeg_set_quality(&jcs, q, 1);
//    3.4、开始压缩
    jpeg_start_compress(&jcs, 1);
//    3.5、循环写入每一行数据
    int row_stride = w * 3;//一行的字节数
    jsAMPROW row[1];
    while (jcs.next_scanline < jcs.image_height) {
        //取一行数据
        uint8_t *pixels = data + jcs.next_scanline * row_stride;
        row[0]=pixels;
        jpeg_write_scanlines(&jcs,row,1);
    }
//    3.6、压缩完成
    jpeg_finish_compress(&jcs);
//    3.7、释放jpeg对象
    fclose(f);
    jpeg_destroy_compress(&jcs);
}

   BitmapFactory.Options options = new BitmapFactory.Options();
        // 只解码出 outxxx参数 比如 宽、高
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeResource(resources,id,options);
        //根据宽、高进行缩放
        int w = options.outWidth;
        int h = options.outHeight;
        //设置缩放系数
        options.inSampleSize = calcuteInSampleSize(w,h,maxW,maxH);
        if (!hasAlpha){
            options.inPreferredConfig = Bitmap.Config.RGB_565;
        }
        options.inJustDecodeBounds = false;
        //设置成能复用
        options.inMutable=true;
        options.inBitmap=reusable;