赵雅智_运用Bitmap和Canvas实现图片显示，缩小，旋转，水印

上一篇已经介绍了Android种Bitmap和Canvas的使用，下面我们来写一个具体实例

http://blog.csdn.net/zhaoyazhi2129/article/details/32136179

运行效果：

主要代码

package com.example.guaguale;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.os.Bundle;
import android.util.Log;
import android.view.View;

public class CanvaDemoActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);

		setContentView(new CustomView(this));

	}

	/**
	 * 使用内部类 自定义一个简单的View
	 * 
	 * @author zhaoyazhi
	 * 
	 *         2014-6-18
	 */
	class CustomView extends View {

		public CustomView(Context context) {
			super(context);

		}

		// 在这里我们将测试canvas提供的绘制图形方法
		@Override
		protected void onDraw(Canvas canvas) {
			drawBitmap(canvas);
			drawBitmapPostScale(canvas);
			drapBitmapPostRotate(canvas);
			shuiyinBitmap(canvas);
		}

		/**
		 * 在canvas放置图片
		 * 
		 * @param canvas
		 */
		private void drawBitmap(Canvas canvas) {
			// 获取图片资源
			Bitmap bmp = BitmapFactory.decodeResource(getResources(),
					R.drawable.e);
			// 将图片添加到canvas
			canvas.drawBitmap(bmp, 0, 0, null);
		}

		/**
		 * 缩放图片
		 * 
		 * @param canvas
		 */
		private void drawBitmapPostScale(Canvas canvas) {
			// 获取图片资源
			Bitmap bmp1 = BitmapFactory.decodeResource(getResources(),
					R.drawable.e);
			// Matrix类进行图片处理（缩小或者旋转）
			Matrix matrix = new Matrix();
			// 缩小一倍
			matrix.postScale(0.5f, 0.5f);
			// 生成新的图片
			Bitmap dstbmp = Bitmap.createBitmap(bmp1, 0, 0, bmp1.getWidth(),
					bmp1.getHeight(), matrix, true);
			// 添加到canvas
			canvas.drawBitmap(dstbmp, 200, 0, null);
		}

		/**
		 * 旋转图片
		 * 
		 * @param canvas
		 */
		private void drapBitmapPostRotate(Canvas canvas) {
			// 获取图片资源
			Bitmap bmp2 = BitmapFactory.decodeResource(getResources(),
					R.drawable.e);
			// Matrix类进行图片处理（缩小或者旋转）
			Matrix matrix1 = new Matrix();
			// 缩小
			matrix1.postScale(0.8f, 0.8f);
			// 旋转
			matrix1.postRotate(45);
			// 生成新的图片
			Bitmap dstbmp1 = Bitmap.createBitmap(bmp2, 0, 0, bmp2.getWidth(),
					bmp2.getHeight(), matrix1, true);
			// 添加到canvas
			canvas.drawBitmap(dstbmp1, 130, 100, null);
		}

		/**
		 * 加水印图片
		 * 
		 * @param canvas
		 */
		private void shuiyinBitmap(Canvas canvas) {
			Bitmap bmp = createBitmap(
					BitmapFactory.decodeResource(getResources(), R.drawable.e),
					BitmapFactory.decodeResource(getResources(), R.drawable.c));
			canvas.drawBitmap(bmp, 10, 200, null);
		}

		// 图片添加水印处理
		private Bitmap createBitmap(Bitmap src, Bitmap watermark) {
			String tag = "createBitmap";
			Log.d(tag, "create a new bitmap");
			if (src == null) {
				return null;
			}

			int w = src.getWidth();
			int h = src.getHeight();
			int ww = watermark.getWidth();
			int wh = watermark.getHeight();
			// create the new blank bitmap
			Bitmap newb = Bitmap.createBitmap(w, h, Config.ARGB_8888);// 创建一个新的和SRC长度宽度一样的位图
			Canvas cv = new Canvas(newb);
			// draw src into
			cv.drawBitmap(src, 0, 0, null);// 在 0，0坐标开始画入src
			// draw watermark into
			cv.drawBitmap(watermark, w - ww + 5, h - wh + 5, null);// 在src的右下角画入水印
			// save all clip
			cv.save(Canvas.ALL_SAVE_FLAG);// 保存
			// store
			cv.restore();// 存储
			return newb;
		}
	}

}

赵雅智_运用Bitmap和Canvas实现图片显示，缩小，旋转，水印,,

赵雅智_运用Bitmap和Canvas实现图片显示，缩小，旋转，水印