SaBitmapUtils.java

package com.martin.simpledevelop.utils.bitmap;

import java.io.ByteArrayOutputStream;
import java.lang.ref.WeakReference;

import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.util.Base64;

/**
 * @Description  位图的工具类 <br>
 * @File SaBitmapUtils.java
 * @Package com.martin.simpledevelop.utils.bitmap
 * @Date 2015年6月25日下午11:31:04
 * @Author Donghongyu 1358506549@qq.com
 * @Version v1.0.0
 */
public class SaBitmapUtils {
	/**
	 * Log 输出标签
	 */
	public static String TAG = SaBitmapUtils.class.getName();

	/**
	 * 通过文件路径获取到bitmap
	 * 
	 * @param path
	 *            文件路径
	 * @param w
	 *            指定的宽
	 * @param h
	 *            指定的高
	 * @return
	 */
	public static Bitmap getBitmapFromPath(String path, int w, int h) {
		BitmapFactory.Options opts = new BitmapFactory.Options();
		// 设置为ture只获取图片大小
		opts.inJustDecodeBounds = true;
		opts.inPreferredConfig = Bitmap.Config.ARGB_8888;
		// 返回为空
		BitmapFactory.decodeFile(path, opts);
		int width = opts.outWidth;
		int height = opts.outHeight;
		float scaleWidth = 0.f, scaleHeight = 0.f;
		if (width > w || height > h) {
			// 缩放
			scaleWidth = ((float) width) / w;
			scaleHeight = ((float) height) / h;
		}
		opts.inJustDecodeBounds = false;
		float scale = Math.max(scaleWidth, scaleHeight);
		opts.inSampleSize = (int) scale;
		WeakReference<Bitmap> weak = new WeakReference<Bitmap>(
				BitmapFactory.decodeFile(path, opts));
		return Bitmap.createScaledBitmap(weak.get(), w, h, true);
	}

	/**
	 * 缩放/裁剪图片
	 * 
	 * @param bm
	 * @param newWidth
	 * @param newHeight
	 * @return
	 */
	public static Bitmap zoomImg(Bitmap bm, int newWidth, int newHeight) {
		// 获得图片的宽高
		int width = bm.getWidth();
		int height = bm.getHeight();
		// 计算缩放比例
		float scaleWidth = ((float) newWidth) / width;
		float scaleHeight = ((float) newHeight) / height;
		// 取得想要缩放的matrix参数
		Matrix matrix = new Matrix();
		matrix.postScale(scaleWidth, scaleHeight);
		// 得到新的图片
		Bitmap newbm = Bitmap.createBitmap(bm, 0, 0, width, height, matrix,
				true);
		return newbm;
	}

	/**
	 * 把bitmap转换成base64加密的字符串
	 * 
	 * @param bitmap
	 * @param bitmapQuality
	 *            压缩质量
	 * @return
	 */
	public static String getBase64FromBitmap(Bitmap bitmap, int bitmapQuality) {
		ByteArrayOutputStream bStream = new ByteArrayOutputStream();
		bitmap.compress(CompressFormat.PNG, bitmapQuality, bStream);
		byte[] bytes = bStream.toByteArray();
		return Base64.encodeToString(bytes, Base64.DEFAULT);
	}

	/**
	 * 把base64转换成bitmap
	 * 
	 * @param string
	 * @return
	 */
	public static Bitmap getBitmapFromBase64(String string) {
		byte[] bitmapArray = null;
		try {
			bitmapArray = Base64.decode(string, Base64.DEFAULT);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return BitmapFactory
				.decodeByteArray(bitmapArray, 0, bitmapArray.length);
	}
}