Android實現圖片的倒影效果

最後更新：2018-12-05 來源：互聯網

上載者：User

創建阿里雲帳戶，並獲得超過 40 款產品的免費試用版；而企業帳戶則可以享有總值 $1200 的免費試用版。立即註冊！

public static Bitmap createReflectedImage(Bitmap originalImage) {    final int reflectionGap = 4;    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, 0×70ffffff, 0×00ffffff,             TileMode.MIRROR);    paint.setShader(shader);    paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));    canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()             + reflectionGap, paint);    return bitmapWithReflection; }

解釋一下：

Matrix matrix = new Matrix();
matrix.preScale(1, -1);

實現圖片的反轉，見Android利用Matrix簡單處理圖片。

Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0,
height / 2, width, height / 2, matrix, false);

建立反轉後的圖片Bitmap對象，圖片高是原圖的一半。

Bitmap bitmapWithReflection = Bitmap.createBitmap(width,
(height + height / 2), Config.ARGB_8888);

建立標準的Bitmap對象，寬和原圖一致，高是原圖的1.5倍。

Canvas canvas = new Canvas(bitmapWithReflection);

canvas.drawBitmap(originalImage, 0, 0, null);

建立畫布對象，將原圖畫於畫布，起點是原點位置。

Paint defaultPaint = new Paint();
canvas.drawRect(0, height, width, height + reflectionGap, defaultPaint);

canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);

將反轉後的圖片畫到畫布中。

LinearGradient shader = new LinearGradient(0,
            originalImage.getHeight(), 0, bitmapWithReflection.getHeight()
                    + reflectionGap, 0×70ffffff, 0×00ffffff,
            TileMode.MIRROR);

建立線性漸層LinearGradient 對象。

canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()
+ reflectionGap, paint);

畫布畫出反轉圖片大小地區，然後把漸層效果加到其中，就出現了圖片的倒影效果。

本文轉自：http://blog.csdn.net/ralfmonkey/article/details/6442395