MosaicProcessor.java

package com.kaixin.android.utils;

import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Rect;

/**
 * mosaic processor
 * 
 * @author sky
 * 
 */
public class MosaicProcessor {

	public static final int min_mosaic_block_size = 4;

	private MosaicProcessor() {
	}

	/**
	 * 
	 * @param bitmap
	 * @param targetRect
	 * @param blockSize
	 *            {@link #min_mosaic_block_size}
	 * @return
	 * @throws Exception
	 */
	public static Bitmap makeMosaic(Bitmap bitmap, Rect targetRect,
			int blockSize) throws OutOfMemoryError {
		if (bitmap == null || bitmap.getWidth() == 0 || bitmap.getHeight() == 0
				|| bitmap.isRecycled()) {
			throw new RuntimeException("bad bitmap to add mosaic");
		}
		if (blockSize < min_mosaic_block_size) {
			blockSize = min_mosaic_block_size;
		}
		if (targetRect == null) {
			targetRect = new Rect();
		}
		int bw = bitmap.getWidth();
		int bh = bitmap.getHeight();
		if (targetRect.isEmpty()) {
			targetRect.set(0, 0, bw, bh);
		}
		//
		int rectW = targetRect.width();
		int rectH = targetRect.height();
		int[] bitmapPxs = new int[bw * bh];
		// fetch bitmap pxs
		bitmap.getPixels(bitmapPxs, 0, bw, 0, 0, bw, bh);
		//
		int rowCount = (int) Math.ceil((float) rectH / blockSize);
		int columnCount = (int) Math.ceil((float) rectW / blockSize);
		int maxX = bw;
		int maxY = bh;
		for (int r = 0; r < rowCount; r++) { // row loop
			for (int c = 0; c < columnCount; c++) {// column loop
				int startX = targetRect.left + c * blockSize + 1;
				int startY = targetRect.top + r * blockSize + 1;
				dimBlock(bitmapPxs, startX, startY, blockSize, maxX, maxY);
			}
		}
		return Bitmap.createBitmap(bitmapPxs, bw, bh, Config.ARGB_8888);
	}

	/**
	 * �ӿ���ȡ���Ŵ󣬴Ӷ�ﵽ����˵�ģ��Ч��
	 * 
	 * @param pxs
	 * @param startX
	 * @param startY
	 * @param blockSize
	 * @param maxX
	 * @param maxY
	 */
	private static void dimBlock(int[] pxs, int startX, int startY,
			int blockSize, int maxX, int maxY) {
		int stopX = startX + blockSize - 1;
		int stopY = startY + blockSize - 1;
		if (stopX > maxX) {
			stopX = maxX;
		}
		if (stopY > maxY) {
			stopY = maxY;
		}
		//
		int sampleColorX = startX + blockSize / 2;
		int sampleColorY = startY + blockSize / 2;
		//
		if (sampleColorX > maxX) {
			sampleColorX = maxX;
		}
		if (sampleColorY > maxY) {
			sampleColorY = maxY;
		}
		int colorLinePosition = (sampleColorY - 1) * maxX;
		int sampleColor = pxs[colorLinePosition + sampleColorX - 1];// ���ش�1��ʼ�����������0��ʼ
		for (int y = startY; y <= stopY; y++) {
			int p = (y - 1) * maxX;
			for (int x = startX; x <= stopX; x++) {
				// ���ش�1��ʼ�����������0��ʼ
				pxs[p + x - 1] = sampleColor;
			}
		}
	}

}