android的照相图片压缩
16lz
2021-01-26
android的照相功能随着手机硬件的发展,变得越来越强大,能够找出很高分辨率的图片。
有些场景中,需要照相并且上传到服务,但是由于图片的大小太大,那么就上传就会很慢(在有些网络情况下),而且很耗流量,要想速度快,那么就需要减小图片的大小。减少图片的大小有两种方法,1. 照小图片; 2. 压缩大图片。 照相时获取小图片一般不太符合要求,因为,图片的清晰度会很差,但是这种情况有个好处就是应用速度会快些; 压缩图片,就是把大图片压缩小,降低图片的质量,在一定范围内,降低图片的大小,并且满足需求(图片仍就清晰)。下面组要是介绍图片的压缩:
- 照相请查看http://www.jb51.net/article/37760.htm ->想要保存图片到制定目录,启动Camera应用时,需要指定文件
- 压缩过程:
2.1 从图片路径中读取图片(图片很大,不能全部加在到内存中处理,要是全部加载到内存中会内存溢出)
[java]
复制代码 代码如下:
final BitmapFactory.Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeFile(filePath, options); // Calculate inSampleSize options.inSampleSize = calculateInSampleSize(options, 480, 800); // Decode bitmap with inSampleSize set options.inJustDecodeBounds = false; Bitmap bm = BitmapFactory.decodeFile(filePath, options); final BitmapFactory.Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeFile(filePath, options); // Calculate inSampleSize options.inSampleSize = calculateInSampleSize(options, 480, 800); // Decode bitmap with inSampleSize set options.inJustDecodeBounds = false; Bitmap bm = BitmapFactory.decodeFile(filePath, options); 2.2 处理图片旋转 [java]复制代码 代码如下:int degree = readPictureDegree(filePath); bm = rotateBitmap(bm,degree) ; int degree = readPictureDegree(filePath); bm = rotateBitmap(bm,degree) ;[java] view plaincopyprint?private static int readPictureDegree(String path) { int degree = 0; try { ExifInterface exifInterface = new ExifInterface(path); int orientation = exifInterface.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL); switch (orientation) { case ExifInterface.ORIENTATION_ROTATE_90: degree = 90; break; case ExifInterface.ORIENTATION_ROTATE_180: degree = 180; break; case ExifInterface.ORIENTATION_ROTATE_270: degree = 270; break; } } catch (IOException e) { e.printStackTrace(); } return degree; } private static int readPictureDegree(String path) { int degree = 0; try { ExifInterface exifInterface = new ExifInterface(path); int orientation = exifInterface.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL); switch (orientation) { case ExifInterface.ORIENTATION_ROTATE_90: degree = 90; break; case ExifInterface.ORIENTATION_ROTATE_180: degree = 180; break; case ExifInterface.ORIENTATION_ROTATE_270: degree = 270; break; } } catch (IOException e) { e.printStackTrace(); } return degree; }[java]
复制代码 代码如下:
view plaincopyprint?private static Bitmap rotateBitmap(Bitmap bitmap, int rotate){ if(bitmap == null) return null ; int w = bitmap.getWidth(); int h = bitmap.getHeight(); // Setting post rotate to 90 Matrix mtx = new Matrix(); mtx.postRotate(rotate); return Bitmap.createBitmap(bitmap, 0, 0, w, h, mtx, true); } private static Bitmap rotateBitmap(Bitmap bitmap, int rotate){ if(bitmap == null) return null ; int w = bitmap.getWidth(); int h = bitmap.getHeight(); // Setting post rotate to 90 Matrix mtx = new Matrix(); mtx.postRotate(rotate); return Bitmap.createBitmap(bitmap, 0, 0, w, h, mtx, true); }
2.3压缩图片
[java]
复制代码 代码如下:
bm.compress(Bitmap.CompressFormat.JPEG, 30, baos);//30 是压缩率,表示压缩70%; 如果不压缩是100,表示压缩率为0
bm.compress(Bitmap.CompressFormat.JPEG, 30, baos);//30 是压缩率,表示压缩70%; 如果不压缩是100,表示压缩率为0
完整的方法代码:
[java]
复制代码 代码如下:
public static Bitmap getSmallBitmap(String filePath) { final BitmapFactory.Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeFile(filePath, options); // Calculate inSampleSize options.inSampleSize = calculateInSampleSize(options, 480, 800); // Decode bitmap with inSampleSize set options.inJustDecodeBounds = false; Bitmap bm = BitmapFactory.decodeFile(filePath, options); if(bm == null){ return null; } int degree = readPictureDegree(filePath); bm = rotateBitmap(bm,degree) ; ByteArrayOutputStream baos = null ; try{ baos = new ByteArrayOutputStream(); bm.compress(Bitmap.CompressFormat.JPEG, 30, baos); }finally{ try { if(baos != null) baos.close() ; } catch (IOException e) { e.printStackTrace(); } } return bm ; } public static Bitmap getSmallBitmap(String filePath) { final BitmapFactory.Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeFile(filePath, options); // Calculate inSampleSize options.inSampleSize = calculateInSampleSize(options, 480, 800); // Decode bitmap with inSampleSize set options.inJustDecodeBounds = false; Bitmap bm = BitmapFactory.decodeFile(filePath, options); if(bm == null){ return null; } int degree = readPictureDegree(filePath); bm = rotateBitmap(bm,degree) ; ByteArrayOutputStream baos = null ; try{ baos = new ByteArrayOutputStream(); bm.compress(Bitmap.CompressFormat.JPEG, 30, baos); }finally{ try { if(baos != null) baos.close() ; } catch (IOException e) { e.printStackTrace(); } } return bm ; }
[java]
复制代码 代码如下:
view plaincopyprint?private static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) { // Raw height and width of image final int height = options.outHeight; final int width = options.outWidth; int inSampleSize = 1; if (height > reqHeight || width > reqWidth) { // Calculate ratios of height and width to requested height and // width final int heightRatio = Math.round((float) height / (float) reqHeight); final int widthRatio = Math.round((float) width / (float) reqWidth); // Choose the smallest ratio as inSampleSize value, this will // guarantee // a final image with both dimensions larger than or equal to the // requested height and width. inSampleSize = heightRatio < widthRatio ? widthRatio : heightRatio; } return inSampleSize; } private static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) { // Raw height and width of image final int height = options.outHeight; final int width = options.outWidth; int inSampleSize = 1; if (height > reqHeight || width > reqWidth) { // Calculate ratios of height and width to requested height and // width final int heightRatio = Math.round((float) height / (float) reqHeight); final int widthRatio = Math.round((float) width / (float) reqWidth); // Choose the smallest ratio as inSampleSize value, this will // guarantee // a final image with both dimensions larger than or equal to the // requested height and width. inSampleSize = heightRatio < widthRatio ? widthRatio : heightRatio; } return inSampleSize; }
更多相关文章
- Android中读取系统图库(包含相册)中的图片,显示图片与图片的路径
- 【移动开发】Android图片异步加载之Android-Universal-Image-Loa
- android 帧动画的替代方案
- Android(安卓)TextView自动换行文字排版参差不齐的原因及解决办
- android处理拍照旋转问题及带来的对内存占用的思考
- Android用AsyncTask来下载图片及用AsyncTask的好处
- 【Bugly干货分享】手把手教你逆向分析 Android(安卓)程序
- 【Android归纳】阿里笔试题之Android网络优化
- Android实现图片滚动控件,含页签功能,让你的应用像淘宝一样炫起来