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一個Android實現圖片的倒影效果的代碼示例
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);
創建反轉後的圖片Bitmap對象，圖片高是原圖的一半。
Bitmap bitmapWithReflection = Bitmap.createBitmap(width,
(height + height / 2), Config.ARGB_8888);
創建標準的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);
創建畫布對象，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,
創建線性漸變LinearGradient 對象。
canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()
+ reflectionGap, paint);
畫布畫出反轉圖片大小區域，然後把漸變效果加到其中，就出現了圖片的倒影效果。
最後更新：2017-04-02 17:51:23