Android 图像处理（类型转换，比例缩放，倒影，圆角）

推荐安卓开发神器（里面有各种UI特效和android代码库实例）

/**
	 * 1.放大缩小图片
	 * 
	 * @param bitmap
	 * @param w
	 * @param h
	 * @return
	 */
	public static Bitmap zoomBitmap(Bitmap bitmap, int w, int h) {
		int width = bitmap.getWidth();
		int height = bitmap.getHeight();
		Matrix matrix = new Matrix();
		float scaleWidht = ((float) w / width);
		float scaleHeight = ((float) h / height);
		matrix.postScale(scaleWidht, scaleHeight);
		Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, width, height,
				matrix, true);
		return newbmp;
	}

	/**
	 * 2.获得圆角图片的方法
	 * 
	 * @param bitmap
	 * @param roundPx
	 * @return
	 */
	public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, float roundPx) {
		Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap
				.getHeight(), Config.ARGB_8888);
		Canvas canvas = new Canvas(output);
		final int color = 0xff424242;
		final Paint paint = new Paint();
		final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
		final RectF rectF = new RectF(rect);
		paint.setAntiAlias(true);
		canvas.drawARGB(0, 0, 0, 0);
		paint.setColor(color);
		canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
		paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
		canvas.drawBitmap(bitmap, rect, rect, paint);
		return output;
	}

	/**
	 * 3.获得带倒影的图片方法
	 * 
	 * @param bitmap
	 * @return
	 */
	public static Bitmap createReflectionImageWithOrigin(Bitmap bitmap) {
		final int reflectionGap = 4;
		int width = bitmap.getWidth();
		int height = bitmap.getHeight();
		Matrix matrix = new Matrix();
		matrix.preScale(1, -1);
		Bitmap reflectionImage = Bitmap.createBitmap(bitmap, 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(bitmap, 0, 0, null);
		Paint deafalutPaint = new Paint();
		canvas
				.drawRect(0, height, width, height + reflectionGap,
						deafalutPaint);
		canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);
		Paint paint = new Paint();
		LinearGradient shader = new LinearGradient(0, bitmap.getHeight(), 0,
				bitmapWithReflection.getHeight() + reflectionGap, 0x70ffffff,
				0x00ffffff, TileMode.CLAMP);
		paint.setShader(shader);
		// Set the Transfer mode to be porter duff and destination in
		paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
		// Draw a rectangle using the paint with our linear gradient
		canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()
				+ reflectionGap, paint);
		return bitmapWithReflection;
	}

	/**
	 * 4.将Drawable转化为Bitmap
	 * 
	 * @param drawable
	 * @return
	 */
	public static Bitmap drawableToBitmap(Drawable drawable) {
		int width = drawable.getIntrinsicWidth();
		int height = drawable.getIntrinsicHeight();
		Bitmap bitmap = Bitmap.createBitmap(width, height, drawable
				.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
				: Bitmap.Config.RGB_565);
		Canvas canvas = new Canvas(bitmap);
		drawable.setBounds(0, 0, width, height);
		drawable.draw(canvas);
		return bitmap;
	}