直接上代码：
public class BitmapTool { /**【给图片添加固定水印】**/ public static Bitmap addWatermark(Bitmap bitmap , Context context){ int width = bitmap.getWidth(); //长 int height = bitmap.getHeight(); //高 Bitmap icon = Bitmap.createBitmap(width , height , Bitmap.Config.ARGB_8888);//建立一个空的Bitmap Canvas canvas = new Canvas(icon); //初始化画布到绘制的图像icon上 Paint paint = new Paint(); //建立画笔 paint.setDither(true); //获取清晰的图像采样 paint.setFilterBitmap(true);//过滤一些 Rect src = new Rect(0 , 0 , width , height);//创建一个指定的新矩形坐标 Rect dst = new Rect(0 , 0 , width , height);//创建一个指定的新矩形坐标 canvas.drawBitmap(bitmap , src , dst , paint); //将bitmap缩小或者扩大到 dst使用的填充区paint Paint textPaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.DEV_KERN_TEXT_FLAG); textPaint.setTextSize(50.0f); //画笔字体大小 textPaint.setTypeface(Typeface.DEFAULT);//采用默认的宽度DEFAULT_BOLD textPaint.setColor(Color.RED); //采用的颜色 Resources resources = context.getResources(); Bitmap watermark = BitmapFactory.decodeResource(resources, R.drawable.mark); Bitmap mark = changeBitmapSize(watermark); String markText = "YouTu"; canvas.drawBitmap(mark , width - mark.getWidth()*2 , height - mark.getHeight() , null);//绘制图标 canvas.drawText(markText , width - mark.getWidth() ,height - mark.getHeight()/2 , textPaint);//绘制文字 canvas.save(Canvas.ALL_SAVE_FLAG); //保存 canvas.restore(); //储存 return icon; } /**【调整bitmap的尺寸大小】**/ public static Bitmap changeBitmapSize(Bitmap bitmap){ float markWidth = bitmap.getWidth() / 100; //图标缩放比例 float markHeight = bitmap.getHeight() / 100; //图标缩放比例 Matrix matrix = new Matrix(); // 取得想要缩放的matrix参数 matrix.postScale(markWidth , markHeight); Bitmap bitMap = Bitmap.createBitmap(bitmap , 0 , 0 ,bitmap.getWidth() ,bitmap.getHeight() ,matrix ,true); return bitMap; } /**【根据图片的Uri获取图片的绝对路径】**/ public static String getReadPathFromUri(Context context , Uri uri){ if (context == null || uri == null){ return null; } if (uri.getScheme().equalsIgnoreCase("file")){ /** * 针对图片URI格式为Uri:: file:///storage/emulated/0/DCIM/Camera/IMG_20170613_132837.jpg **/ String uriToString = uri.toString(); String filePath = uriToString.substring(uriToString.indexOf(":")+3); return filePath; }else if (uri.getScheme().equalsIgnoreCase("content")){ /** * 适配api11-api18,根据uri获取图片的绝对路径。 * 针对图片URI格式为Uri:: content://media/external/images/media/1028 **/ String filePath = ""; String [] projection = {MediaStore.Images.Media.DATA}; CursorLoader loader = new CursorLoader(context , uri , projection ,null ,null , null); Cursor cursor = loader.loadInBackground(); if (cursor != null && cursor.moveToFirst()){ filePath = cursor.getString(cursor.getColumnIndex(projection[0])); Log.e("filePath","filePath的值为"+filePath); cursor.close(); if (filePath!=null){ return filePath; }else{ return getReadFromUri_AboveAPI19(context,uri); } }else{ Log.e("cursor","cursor的值为null"); return filePath; } }else{ return getReadFromUri_AboveAPI19(context,uri); } } /** * 适配api19以上,根据uri获取图片的绝对路径 */ @SuppressLint("NewApi") private static String getReadFromUri_AboveAPI19(Context context , Uri uri){ String filePath = null; String wholeID = null; wholeID = DocumentsContract.getDocumentId(uri); // 使用':'分割 String id = wholeID.split(":")[1]; String[] projection = { MediaStore.Images.Media.DATA }; String selection = MediaStore.Images.Media._ID + "=?"; String[] selectionArgs = { id }; Cursor cursor = context.getContentResolver().query( MediaStore.Images.Media.EXTERNAL_CONTENT_URI, projection, selection, selectionArgs, null); int columnIndex = cursor.getColumnIndex(projection[0]); if (cursor.moveToFirst()) { filePath = cursor.getString(columnIndex); } cursor.close(); return filePath; } /**【图片旋转，每次旋转度数：rotate】**/ public static Bitmap bitmapRotate(Bitmap bitmap , int rotate){ Matrix matrix = new Matrix(); matrix.setRotate(rotate); //旋转 bitmap = Bitmap.createBitmap(bitmap,bitmap.getWidth()/10,0,bitmap.getHeight()*8/10, bitmap.getHeight(),matrix,true);//重新绘制bitmap return bitmap; } /**【图片怀旧效果】**/ public static Bitmap oldRemeber(Bitmap bitmap){ int width = bitmap.getWidth(); //长 int height = bitmap.getHeight();//高 Bitmap map = Bitmap.createBitmap(width , height , Bitmap.Config.RGB_565); int pixColor = 0; int pixR = 0; int pixG = 0; int pixB = 0; int newR = 0; int newG = 0; int newB = 0; int [] pixels = new int[width * height]; bitmap.getPixels(pixels,0,width,0,0,width,height); for (int i=0;i<height;i++){ for (int k=0;k<width;k++){ pixColor = pixels[width * i + k]; pixR = Color.red(pixColor); pixG = Color.red(pixColor); pixB = Color.red(pixColor); newR = (int)(0.393 * pixR + 0.769 * pixG + 0.189 * pixB); newG = (int)(0.349 * pixR + 0.686 * pixG + 0.168 * pixB); newB = (int)(0.272 * pixR + 0.534 * pixG + 0.131 * pixB); int newColor = Color.argb(255,newR > 255 ? 255 : newR ,newG > 255 ? 255 : newG ,newB > 255 ? 255 :newB); pixels[width * i + k ] = newColor; } } map.setPixels(pixels,0,width,0,0,width,height); return map; } /**【图片模糊效果】**/ public static Bitmap vagueBitmap(Bitmap bmp){ // 高斯矩阵 int[] gauss = new int[] { 1, 2, 1, 2, 4, 2, 1, 2, 1 }; int width = bmp.getWidth(); int height = bmp.getHeight(); Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565); int pixR = 0; int pixG = 0; int pixB = 0; int pixColor = 0; int newR = 0; int newG = 0; int newB = 0; int delta = 16; // 值越小图片会越亮，越大则越暗 int idx = 0; int[] pixels = new int[width * height]; bmp.getPixels(pixels, 0, width, 0, 0, width, height); for (int i = 1, length = height - 1; i < length; i++) { for (int k = 1, len = width - 1; k < len; k++) { idx = 0; for (int m = -1; m <= 1; m++) { for (int n = -1; n <= 1; n++) { pixColor = pixels[(i + m) * width + k + n]; pixR = Color.red(pixColor); pixG = Color.green(pixColor); pixB = Color.blue(pixColor); newR = newR + (int) (pixR * gauss[idx]); newG = newG + (int) (pixG * gauss[idx]); newB = newB + (int) (pixB * gauss[idx]); idx++; } } newR /= delta; newG /= delta; newB /= delta; newR = Math.min(255, Math.max(0, newR)); newG = Math.min(255, Math.max(0, newG)); newB = Math.min(255, Math.max(0, newB)); pixels[i * width + k] = Color.argb(255, newR, newG, newB); newR = 0; newG = 0; newB = 0; } } bitmap.setPixels(pixels, 0, width, 0, 0, width, height); return bitmap; } }