Android中bitmap的相關處理

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載入大圖片Options options=new Options();options.inJustDecodeBounds=true;//不載入圖片，只負載檔案資訊//載入圖片，擷取到配置資訊BitmapFactory.decodeFile(Environment.getExternalStorageDirectory()+"/a.jpg",options);int width=options.outWidth;//擷取到圖片的真是寬度int height=options.outHeight;//擷取到圖片的真是的高度//擷取到手機螢幕顯示對象Display display = getWindowManager().getDefaultDisplay();int h = display.getHeight();//擷取螢幕的高度int w = display.getWidth();//擷取到平局的寬度//計算縮放的比率int scale=1;int scaley=width/w;int scalex=height/h;if(scalex<1 && scaley<1){}else{//如果縮放的寬，大於高，則安照寬的縮放比率，因為高的縮放比率小，那麼按照高的縮放比率的話，寬則超出了螢幕的寬scale=scalex>scaley?scalex:scaley;}options.inJustDecodeBounds=true;options.inSampleSize=scale;//指定縮放比率//根據配置資訊，重建有一個bitmap對象，這就得到的是縮放之後的圖片Bitmap bitmap = BitmapFactory.decodeFile(Environment.getExternalStorageDirectory()+"/a.jpg",options);img.setImageBitmap(bitmap);塗鴉        1、首先載入一個圖片Bitmap bitmap = BitmapFactory.decodeFile(Environment.getExternalStorageDirectory() + "/a.jpg");2.建立一個空的圖片，bit = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(),bitmap.getConfig());3.建立一個畫布，Canvas canvas=new Canvas(bit);4.建立一個畫筆 panint paint=new Paint(); paint.setcolor(Color.red);5.把載入的圖片畫到畫布上 canvas.drawBitmap(bitmap)6.在圖片上設定觸摸事件，根據按下和移動的位置開始畫線加浮水印和上面的一樣，只是加了一句canvas.drawText("餓哦我到底發生", 100,100, paint);
儲存圖片通知相簿掃描該圖片bit.compress(CompressFormat.JPEG, 100, new FileOutputStream(Environment.getExternalStorageDirectory()+"/hdksh.jpg"));Intent intent=new Intent();intent.setAction("android.intent.action.MEDIA_MOUNTED");intent.setData(Uri.fromFile(new File(Environment.getExternalStorageDirectory()+"hdksh.jpg")));sendBroadcast(intent);//發送廣播，通知相簿掃描
圖片的旋轉Bitmap bitmap=BitmapFactory.decodeFile(Environment.getExternalStorageDirectory()+"/mm.jpg");Bitmap bit = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), bitmap.getConfig());Canvas canvas=new Canvas(bit);Matrix matrix=new Matrix();matrix.setRotate(180, bitmap.getWidth()/2, bitmap.getHeight()/2);Paint paint=new Paint();paint.setColor(Color.RED);canvas.drawBitmap(bitmap, matrix, paint);img.setImageBitmap(bit)
鏡面效果Bitmap bitmap = BitmapFactory.decodeFile(Environment.getExternalStorageDirectory()+"/mm.jpg");Bitmap bit = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), bitmap.getConfig());Canvas canvas=new Canvas(bit);Paint paint=new Paint();Matrix matrix=new Matrix();matrix.setScale(-1, 1);//反轉matrix.postTranslate(bitmap.getWidth(), 0);//移動canvas.drawBitmap(bitmap, matrix, paint);img.setImageBitmap(bit);