图像裁剪后缩放到某个尺寸，不变形

                int bw = bitmap.getWidth();
                int bh = bitmap.getHeight();
                float radio = (outHeight / (float) outWidth);
                int tw = (int) (bh / radio);
                int th = (int) (bw * radio);
                int sw, sh, ow, oh;
                if (tw <= bw) {
                    sw = tw;
                    sh = (int) (tw * radio);
                    oh = 0;
                    ow = (bw - sw) / 2;
                } else {
                    sh = th;
                    sw = (int) (th / radio);
                    ow = 0;
                    oh = (bh - sh) / 2;
                }
                Matrix m = new Matrix();
                m.preScale(outWidth / (float) sw, outHeight / (float) sh);
                bitmap = Bitmap.createBitmap(bitmap, ow, oh, sw, sh, m, false);