图片旋转，压缩，保存，拷贝+dp2px

àì夳堔傛蜴生んèń 2022-06-17 14:25 109阅读 0赞

/** * 选择变换 * * @param origin 原图 * @param alpha 旋转角度，可正可负 * @return 旋转后的图片 */
        public Bitmap rotateBitmap(Bitmap origin, float alpha) {
            if (origin == null) {
                return null;
            }
            int width = origin.getWidth();
            int height = origin.getHeight();
            Matrix matrix = new Matrix();
            matrix.setRotate(alpha);
            // 围绕原地进行旋转
            Bitmap newBM = Bitmap.createBitmap(origin, 0, 0, width, height, matrix, false);
            if (newBM.equals(origin)) {
                return newBM;
            }
            origin.recycle();
            return newBM;
        }
    
     /** * 图片缩放 * * @param bitmap 原图 * @param rate 缩放比例，例如0.5--表示压缩为原图的1/2 * @return 缩放后图片 */
        private static Bitmap smallBitmap(Bitmap bitmap, float rate) {
            Matrix matrix = new Matrix();
            matrix.postScale(rate, rate); //长和宽放大缩小的比例
            Bitmap resizeBmp = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
            bitmap.recycle();
            bitmap = null;
            return resizeBmp;
        }
    
        private int i = 1;
        private String path = Environment.getExternalStorageDirectory().getAbsolutePath() + "/0Face/";
        private Calendar now = new GregorianCalendar();
        private SimpleDateFormat simpleDate = new SimpleDateFormat("yyyyMMddHHmmss", Locale.getDefault());
        private String fileName = simpleDate.format(now.getTime());
    
        public void saveBitmap(Bitmap mBitmap) {
            File dir = new File(path);
            if (!dir.exists()) dir.mkdirs();
            File f = new File(path + (fileName + "-" + i++) + ".jpg");
            FileOutputStream fOut = null;
            try {
                fOut = new FileOutputStream(f);
                mBitmap.compress(Bitmap.CompressFormat.JPEG, 100, fOut);
                fOut.flush();
                fOut.close();
            } catch (IOException e) {
                e.printStackTrace();
                Log.e("FFF", e.getMessage());
            }
        }
    
      /** * 根据原位图生成一个新的位图，并将原位图所占空间释放 * * @param srcBmp 原位图 * @return 新位图 */
        public static Bitmap copy(Bitmap srcBmp) {
            Bitmap destBmp = null;
            try {
                //创建一个临时文件
                File file = new File("/mnt/sdcard/temp/tmp.txt");
                file.getParentFile().mkdirs();
                RandomAccessFile randomAccessFile = new RandomAccessFile(file, "rw");
                int width = srcBmp.getWidth();
                int height = srcBmp.getHeight();
                FileChannel channel = randomAccessFile.getChannel();
                MappedByteBuffer map = channel.map(FileChannel.MapMode.READ_WRITE, 0, width * height * 4);
                //将位图信息写进buffer
                srcBmp.copyPixelsToBuffer(map);
                //释放原位图占用的空间
                srcBmp.recycle();
                //创建一个新的位图
                destBmp = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
                map.position(0);
                //从临时缓冲中拷贝位图信息
                destBmp.copyPixelsFromBuffer(map);
                channel.close();
                randomAccessFile.close();
            } catch (Exception ex) {
                destBmp = null;
            }
            return destBmp;
        }
    
        /** * 根据手机的分辨率从 dp 的单位 转成为 px(像素) */
        public static int dip2px(float dpValue) {
            final float scale = PhoneApplication.getApplication().getResources().getDisplayMetrics().density;
            return (int) (dpValue * scale + 0.5f);
        }
    
        /** * 根据手机的分辨率从 px(像素) 的单位 转成为 dp */
        public static int px2dip(float pxValue) {
            final float scale = PhoneApplication.getApplication().getResources().getDisplayMetrics().density;
            return (int) (pxValue / scale + 0.5f);
        }
    
        /** * 获得屏幕宽度 * * @return */
        public static int getScreenWidth() {
            WindowManager wm = (WindowManager) PhoneApplication.getApplication()
                    .getSystemService(Context.WINDOW_SERVICE);
            DisplayMetrics outMetrics = new DisplayMetrics();
            wm.getDefaultDisplay().getMetrics(outMetrics);
            return outMetrics.widthPixels;
        }
    
        /** * 获得屏幕高度 * * @return */
        public static int getScreenHeight() {
            WindowManager wm = (WindowManager) PhoneApplication.getApplication()
                    .getSystemService(Context.WINDOW_SERVICE);
            DisplayMetrics outMetrics = new DisplayMetrics();
            wm.getDefaultDisplay().getMetrics(outMetrics);
            return outMetrics.heightPixels;
        }