锐客网

  1. 首页 > 睿知 > it技术 > >

Android 图片压缩，基于比例和质量压缩

IT知识android图片压缩

【Android 图片压缩，基于比例和质量压缩】与天地兮比寿，与日月兮齐光。这篇文章主要讲述Android 图片压缩，基于比例和质量压缩相关的知识，希望能为你提供帮助。

package cc.util.android.image; import java.io.ByteArrayOutputStream; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.math.BigDecimal; import java.math.RoundingMode; import java.nio.ByteBuffer; import java.nio.channels.Channels; import java.nio.channels.ReadableByteChannel; import android.content.Context; import android.content.res.Resources; import android.graphics.Bitmap; import android.graphics.Bitmap.CompressFormat; import android.graphics.BitmapFactory; import android.graphics.BitmapFactory.Options; import android.graphics.Matrix; import android.media.ExifInterface; import android.util.Log; /** * A class for helping deal the bitmap, *like: get the orientation of the bitmap, compress bitmap etc. * @author wangcccong * @version 1.140122 * crated at: 2014-03-22 * update at: 2014-06-26 */ public class BitmapHelper { /** * get the orientation of the bitmap {@link android.media.ExifInterface} * @param path * @return */ public final static int getDegress(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; }/** * rotate the bitmap * @param bitmap * @param degress * @return */ public static Bitmap rotateBitmap(Bitmap bitmap, int degress) { if (bitmap != null) { Matrix m = new Matrix(); m.postRotate(degress); bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), m, true); return bitmap; } return bitmap; }/** * caculate the bitmap sampleSize * @param path * @return */ public final static int caculateInSampleSize(BitmapFactory.Options options, int rqsW, int rqsH) { final int height = options.outHeight; final int width = options.outWidth; int inSampleSize = 1; if (rqsW == 0 || rqsH == 0) return 1; if (height > rqsH || width > rqsW) { final int heightRatio = Math.round((float) height/ (float) rqsH); final int widthRatio = Math.round((float) width / (float) rqsW); inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio; } return inSampleSize; }/** * 压缩指定路径的图片，并得到图片对象 * @param context * @param path bitmap source path * @return Bitmap {@link android.graphics.Bitmap} */ public final static Bitmap compressBitmap(String path, int rqsW, int rqsH) { final BitmapFactory.Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeFile(path, options); options.inSampleSize = caculateInSampleSize(options, rqsW, rqsH); options.inJustDecodeBounds = false; return BitmapFactory.decodeFile(path, options); }/** * 压缩指定路径图片，并将其保存在缓存目录中，通过isDelSrc判定是否删除源文件，并获取到缓存后的图片路径 * @param context * @param srcPath * @param rqsW * @param rqsH * @param isDelSrc * @return */ public final static String compressBitmap(Context context, String srcPath, int rqsW, int rqsH, boolean isDelSrc) { Bitmap bitmap = compressBitmap(srcPath, rqsW, rqsH); File srcFile = new File(srcPath); String desPath = getImageCacheDir(context) + srcFile.getName(); int degree = getDegress(srcPath); try { if (degree != 0) bitmap = rotateBitmap(bitmap, degree); File file = new File(desPath); FileOutputStreamfos = new FileOutputStream(file); bitmap.compress(Bitmap.CompressFormat.PNG, 70, fos); fos.close(); if (isDelSrc) srcFile.deleteOnExit(); } catch (Exception e) { // TODO: handle exception Log.e("BitmapHelper--> compressBitmap", e.getMessage()+""); } return desPath; }/** * 此方法过期，该方法可能造成OutOfMemoryError，使用不含isAdjust参数的方法 * @param is * @param reqsW * @param reqsH * @param isAdjust * @return */ @Deprecated public final static Bitmap compressBitmap(InputStream is, int reqsW, int reqsH, boolean isAdjust) { Bitmap bitmap = BitmapFactory.decodeStream(is); return compressBitmap(bitmap, reqsW, reqsH, isAdjust); }/** * 压缩某个输入流中的图片，可以解决网络输入流压缩问题，并得到图片对象 * @param context * @param path bitmap source path * @return Bitmap {@link android.graphics.Bitmap} */ public final static Bitmap compressBitmap(InputStream is, int reqsW, int reqsH) { try { ByteArrayOutputStream baos = new ByteArrayOutputStream(); ReadableByteChannel channel = Channels.newChannel(is); ByteBuffer buffer = ByteBuffer.allocate(1024); while (channel.read(buffer) != -1) { buffer.flip(); while (buffer.hasRemaining()) baos.write(buffer.get()); buffer.clear(); } byte[] bts = baos.toByteArray(); Bitmap bitmap = compressBitmap(bts, reqsW, reqsH); is.close(); channel.close(); baos.close(); return bitmap; } catch (Exception e) { // TODO: handle exception e.printStackTrace(); return null; } }/** * 压缩指定byte[]图片，并得到压缩后的图像 * @param bts * @param reqsW * @param reqsH * @return */ public final static Bitmap compressBitmap(byte[] bts, int reqsW, int reqsH) { final Options options = new Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeByteArray(bts, 0, bts.length, options); options.inSampleSize = caculateInSampleSize(options, reqsW, reqsH); options.inJustDecodeBounds = false; return BitmapFactory.decodeByteArray(bts, 0, bts.length, options); }/** * 此方法已过期，该方法可能造成OutOfMemoryError，使用不含isAdjust参数的方法 * @param bitmap * @param reqsW * @param reqsH * @return */ @Deprecated public final static Bitmap compressBitmap(Bitmap bitmap, int reqsW, int reqsH, boolean isAdjust) { if (bitmap == null || reqsW == 0 || reqsH == 0) return bitmap; if (bitmap.getWidth() > reqsW || bitmap.getHeight() > reqsH) { float scaleX = new BigDecimal(reqsW).divide(new BigDecimal(bitmap.getWidth()), 4, RoundingMode.DOWN).floatValue(); float scaleY = new BigDecimal(reqsH).divide(new BigDecimal(bitmap.getHeight()), 4, RoundingMode.DOWN).floatValue(); if (isAdjust) { scaleX = scaleX < scaleY ? scaleX : scaleY; scaleY = scaleX; } Matrix matrix = new Matrix(); matrix.postScale(scaleX, scaleY); bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true); } return bitmap; }/** * 压缩已存在的图片对象，并返回压缩后的图片 * @param bitmap * @param reqsW * @param reqsH * @return */ public final static Bitmap compressBitmap(Bitmap bitmap, int reqsW, int reqsH) { try { ByteArrayOutputStream baos = new ByteArrayOutputStream(); bitmap.compress(CompressFormat.PNG, 100, baos); byte[] bts = baos.toByteArray(); Bitmap res = compressBitmap(bts, reqsW, reqsH); baos.close(); return res; } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); return bitmap; } }/** * 此方法过期，该方法可能造成OutOfMemoryError，使用不含isAdjust参数的方法 * get bitmap form resource dictory, and then compress bitmap according to reqsW and reqsH * @param res {@link android.content.res.Resources} * @param resID * @param reqsW * @param reqsH * @return */ @Deprecated public final static Bitmap compressBitmap(Resources res, int resID, int reqsW, int reqsH, boolean isAdjust) { Bitmap bitmap = BitmapFactory.decodeResource(res, resID); return compressBitmap(bitmap, reqsW, reqsH, isAdjust); }/** * 压缩资源图片，并返回图片对象 * @param res {@link android.content.res.Resources} * @param resID * @param reqsW * @param reqsH * @return */ public final static Bitmap compressBitmap(Resources res, int resID, int reqsW, int reqsH) { final Options options = new Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeResource(res, resID, options); options.inSampleSize = caculateInSampleSize(options, reqsW, reqsH); options.inJustDecodeBounds = false; return BitmapFactory.decodeResource(res, resID, options); }/** * 基于质量的压缩算法， 此方法未 解决压缩后图像失真问题 * < br> 可先调用比例压缩适当压缩图片后，再调用此方法可解决上述问题 * @param bts * @param maxBytes 压缩后的图像最大大小 单位为byte * @return */ public final static Bitmap compressBitmap(Bitmap bitmap, long maxBytes) { try { ByteArrayOutputStream baos = new ByteArrayOutputStream(); bitmap.compress(CompressFormat.PNG, 100, baos); int options = 90; while (baos.toByteArray().length > maxBytes) { baos.reset(); bitmap.compress(CompressFormat.PNG, options, baos); options -= 10; } byte[] bts = baos.toByteArray(); Bitmap bmp = BitmapFactory.decodeByteArray(bts, 0, bts.length); baos.close(); return bmp; } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); return null; } }//public final static Bitmap compressBitmap(InputStream is, long maxBytes) { //try { //ByteArrayOutputStream baos = new ByteArrayOutputStream(); //byte[] bts = new byte[1024]; //while (is.read(bts) != -1) baos.write(bts, 0, bts.length); //is.close(); //int options = 100; //while (baos.toByteArray().length > maxBytes) { // //} //} catch (Exception e) { //// TODO: handle exception //} //}/** * 得到指定路径图片的options * @param srcPath * @return Options {@link android.graphics.BitmapFactory.Options} */ public final static Options getBitmapOptions(String srcPath) { BitmapFactory.Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeFile(srcPath, options); return options; }/** * 获取图片缓存路径 * @param context * @return */ private static String getImageCacheDir(Context context) { String dir = FileHelper.getCacheDir(context) + "Image" + File.separator; File file = new File(dir); if (!file.exists()) file.mkdirs(); return dir; } }

 

    推荐阅读


    上一篇：android 比较靠谱的图片压缩

    下一篇：Android系统源代码目录结构 “Android源代码”“目录结构”