如何获取图片的倒映及剪切、放缩图片?

最近研究了一下获取图片倒映的算法及剪切、放缩图片，有点成就，现贡献给大家参考:

1. 获取图片倒映:

public Bitmap getReflectedImage(Bitmap originalImage) {final int reflectionGap = 0;int width = originalImage.getWidth();int height = originalImage.getHeight();Matrix matrix = new Matrix();matrix.preScale(1, -1);Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0,height / 2, width, height / 2, matrix, false);Bitmap bitmapWithReflection = Bitmap.createBitmap(width,(height + height / 2), Config.ARGB_8888);Canvas canvas = new Canvas(bitmapWithReflection);canvas.drawBitmap(originalImage, 0, 0, null);Paint defaultPaint = new Paint();canvas.drawRect(0, height, width, height + reflectionGap, defaultPaint);canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);Paint paint = new Paint();LinearGradient shader = new LinearGradient(0,originalImage.getHeight(), 0, bitmapWithReflection.getHeight()+ reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.CLAMP);paint.setShader(shader);paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()+ reflectionGap, paint); defaultPaint.setColor(Color.LTGRAY); width--; try { if (!originalImage.isRecycled()) originalImage.recycle(); } catch (Exception e) { Log.e(tag, e.getMessage(), e); }return bitmapWithReflection;}

 2. 剪切图片：

private Bitmap cutImage(Bitmap oldBitmap){Bitmap newBitmap = Bitmap.createBitmap(oldBitmap, 0, 0,oldBitmap.getHeight() / 2, oldBitmap.getWidth() / 2); return newBitmap;}

3. 放缩图片：

a. 指定大小放缩图片 

private Bitmap scaleImage(Bitmap bmSrc){ Matrix matrix=new Matrix(); matrix.postScale((float)0.5,(float)0.5); Bitmap bmTarget=Bitmap.createBitmap(bmSrc, 0, 0, bmSrc.getWidth(), bmSrc.getHeight(), matrix, true); return bmTarget; }

b. 指定大小范围放缩图片 

public Bitmap getImgBitmap(File f, int size){ //图片文件 FileInputStream fis1=null; Bitmap bm=null; try { fis1=new FileInputStream(f); //Decode image size BitmapFactory.Options o = new BitmapFactory.Options(); o.inJustDecodeBounds = true; BitmapFactory.decodeStream(fis1,null,o); //The new size we want to scale to final int REQUIRED_SIZE=size; //Find the correct scale value. It should be the power of 2. int width_tmp=o.outWidth, height_tmp=o.outHeight; if (width_tmp < size){ FileInputStream fis2=new FileInputStream(f); bm=BitmapFactory.decodeStream(fis2); fis2.close(); return bm; } int scale=1; while(true){ if(width_tmp/2<REQUIRED_SIZE || height_tmp/2<REQUIRED_SIZE) break; width_tmp/=2; height_tmp/=2; scale++; } //Decode with inSampleSize BitmapFactory.Options o2 = new BitmapFactory.Options(); o2.inSampleSize=scale; FileInputStream fis3=new FileInputStream(f); bm=BitmapFactory.decodeStream(fis3, null, o2); fis3.close(); return bm; } catch (Exception e) { Log.e(tag, e.getMessage(), e); return BitmapFactory.decodeResource(context.getResources(), R.drawable.icon); } finally{ try {fis1.close();} catch (IOException e) {Log.e(tag, e.getMessage(), e);} }}