android 圖片處理工具類

圖片工具類，可用於Bitmap, byte array, Drawable之間進行轉換以及圖片縮放，目前功能薄弱，後面會進行增強。如：
bitmapToDrawable(Bitmap b) bimap轉換為drawable
drawableToBitmap(Drawable d) drawable轉換為bitmap
drawableToByte(Drawable d) drawable轉換為byte

scaleImage(Bitmap org, float scaleWidth, float scaleHeight) 縮放圖片

package cn.trinea.android.common.util;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Map;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;

/**
 * ImageUtils
 * 

 * convert between Bitmap, byte array, Drawable
 * 
{@link #bitmapToByte(Bitmap)}
 * 
{@link #bitmapToDrawable(Bitmap)}
 * 
{@link #byteToBitmap(byte[])}
 * 
{@link #byteToDrawable(byte[])}
 * 
{@link #drawableToBitmap(Drawable)}
 * 
{@link #drawableToByte(Drawable)}
 * 
 * 

 * get image
 * 
{@link #getInputStreamFromUrl(String, int)}
 * 
{@link #getBitmapFromUrl(String, int)}
 * 
{@link #getDrawableFromUrl(String, int)}
 * 
 * 

 * scale image
 * 
{@link #scaleImageTo(Bitmap, int, int)}
 * 
{@link #scaleImage(Bitmap, float, float)}
 * 
 * 
 * @author Trinea 2012-6-27
 */
public class ImageUtils {

    private ImageUtils() {
        throw new AssertionError();
    }

    /**
     * convert Bitmap to byte array
     * 
     * @param b
     * @return
     */
    public static byte[] bitmapToByte(Bitmap b) {
        if (b == null) {
            return null;
        }

        ByteArrayOutputStream o = new ByteArrayOutputStream();
        b.compress(Bitmap.CompressFormat.PNG, 100, o);
        return o.toByteArray();
    }

    /**
     * convert byte array to Bitmap
     * 
     * @param b
     * @return
     */
    public static Bitmap byteToBitmap(byte[] b) {
        return (b == null || b.length == 0) ? null : BitmapFactory.decodeByteArray(b, 0, b.length);
    }

    /**
     * convert Drawable to Bitmap
     * 
     * @param d
     * @return
     */
    public static Bitmap drawableToBitmap(Drawable d) {
        return d == null ? null : ((BitmapDrawable)d).getBitmap();
    }

    /**
     * convert Bitmap to Drawable
     * 
     * @param b
     * @return
     */
    public static Drawable bitmapToDrawable(Bitmap b) {
        return b == null ? null : new BitmapDrawable(b);
    }

    /**
     * convert Drawable to byte array
     * 
     * @param d
     * @return
     */
    public static byte[] drawableToByte(Drawable d) {
        return bitmapToByte(drawableToBitmap(d));
    }

    /**
     * convert byte array to Drawable
     * 
     * @param b
     * @return
     */
    public static Drawable byteToDrawable(byte[] b) {
        return bitmapToDrawable(byteToBitmap(b));
    }

    /**
     * get input stream from network by imageurl, you need to close inputStream yourself
     * 
     * @param imageUrl
     * @param readTimeOutMillis
     * @return
     * @see ImageUtils#getInputStreamFromUrl(String, int, boolean)
     */
    public static InputStream getInputStreamFromUrl(String imageUrl, int readTimeOutMillis) {
        return getInputStreamFromUrl(imageUrl, readTimeOutMillis, null);
    }

    /**
     * get input stream from network by imageurl, you need to close inputStream yourself
     * 
     * @param imageUrl
     * @param readTimeOutMillis read time out, if less than 0, not set, in mills
     * @param requestProperties http request properties
     * @return
     * @throws MalformedURLException
     * @throws IOException
     */
    public static InputStream getInputStreamFromUrl(String imageUrl, int readTimeOutMillis,
            Map requestProperties) {
        InputStream stream = null;
        try {
            URL url = new URL(imageUrl);
            HttpURLConnection con = (HttpURLConnection)url.openConnection();
            HttpUtils.setURLConnection(requestProperties, con);
            if (readTimeOutMillis > 0) {
                con.setReadTimeout(readTimeOutMillis);
            }
            stream = con.getInputStream();
        } catch (MalformedURLException e) {
            closeInputStream(stream);
            throw new RuntimeException("MalformedURLException occurred. ", e);
        } catch (IOException e) {
            closeInputStream(stream);
            throw new RuntimeException("IOException occurred. ", e);
        }
        return stream;
    }

    /**
     * get drawable by imageUrl
     * 
     * @param imageUrl
     * @param readTimeOutMillis
     * @return
     * @see ImageUtils#getDrawableFromUrl(String, int, boolean)
     */
    public static Drawable getDrawableFromUrl(String imageUrl, int readTimeOutMillis) {
        return getDrawableFromUrl(imageUrl, readTimeOutMillis, null);
    }

    /**
     * get drawable by imageUrl
     * 
     * @param imageUrl
     * @param readTimeOutMillis read time out, if less than 0, not set, in mills
     * @param requestProperties http request properties
     * @return
     */
    public static Drawable getDrawableFromUrl(String imageUrl, int readTimeOutMillis,
            Map requestProperties) {
        InputStream stream = getInputStreamFromUrl(imageUrl, readTimeOutMillis, requestProperties);
        Drawable d = Drawable.createFromStream(stream, "src");
        closeInputStream(stream);
        return d;
    }

    /**
     * get Bitmap by imageUrl
     * 
     * @param imageUrl
     * @param readTimeOut
     * @return
     * @see ImageUtils#getBitmapFromUrl(String, int, boolean)
     */
    public static Bitmap getBitmapFromUrl(String imageUrl, int readTimeOut) {
        return getBitmapFromUrl(imageUrl, readTimeOut, null);
    }

    /**
     * get Bitmap by imageUrl
     * 
     * @param imageUrl
     * @param requestProperties http request properties
     * @return
     */
    public static Bitmap getBitmapFromUrl(String imageUrl, int readTimeOut, Map requestProperties) {
        InputStream stream = getInputStreamFromUrl(imageUrl, readTimeOut, requestProperties);
        Bitmap b = BitmapFactory.decodeStream(stream);
        closeInputStream(stream);
        return b;
    }

    /**
     * scale image
     * 
     * @param org
     * @param newWidth
     * @param newHeight
     * @return
     */
    public static Bitmap scaleImageTo(Bitmap org, int newWidth, int newHeight) {
        return scaleImage(org, (float)newWidth / org.getWidth(), (float)newHeight / org.getHeight());
    }

    /**
     * scale image
     * 
     * @param org
     * @param scaleWidth sacle of width
     * @param scaleHeight scale of height
     * @return
     */
    public static Bitmap scaleImage(Bitmap org, float scaleWidth, float scaleHeight) {
        if (org == null) {
            return null;
        }

        Matrix matrix = new Matrix();
        matrix.postScale(scaleWidth, scaleHeight);
        return Bitmap.createBitmap(org, 0, 0, org.getWidth(), org.getHeight(), matrix, true);
    }

    /**
     * close inputStream
     * 
     * @param s
     */
    private static void closeInputStream(InputStream s) {
        if (s == null) {
            return;
        }

        try {
            s.close();
        } catch (IOException e) {
            throw new RuntimeException("IOException occurred. ", e);
        }
    }
}