BitmapUtil（高效压缩不失真）

package com.changim.patient.app.utils;

import android.app.Activity;
import android.content.ContentResolver;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.net.Uri;
import android.provider.MediaStore;
import android.view.Gravity;
import android.widget.Toast;

import java.io.File;

/**
* Created by zzw on 2016/2/23 0023.
*/
public class ImageUtils {

/**
* 根据图片的Uri得到它的路径
*
* @param activity
* @param imageUri
* @return 返回null表示不能找到此图片
*/
public static String getImagePathFromImageUri(Activity activity, Uri imageUri) {

String[] filePathColumn = {MediaStore.Images.Media.DATA};
Cursor cursor = activity.getContentResolver().query(imageUri, filePathColumn, null, null, null);

if (cursor != null) {
cursor.moveToFirst();
int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
String imagePath = cursor.getString(columnIndex);
cursor.close();

if (imagePath == null || imagePath.equals("null")) {
Toast toast = Toast.makeText(activity, "不能发现图片", Toast.LENGTH_SHORT);
toast.setGravity(Gravity.CENTER, 0, 0);
toast.show();
return null;
}

return imagePath;
} else {
File file = new File(imageUri.getPath());
if (!file.exists()) {
Toast toast = Toast.makeText(activity, "不能发现图片", Toast.LENGTH_SHORT);
toast.setGravity(Gravity.CENTER, 0, 0);
toast.show();
return null;
}
return file.getAbsolutePath();
}
}

/**
* 根据图片的路径得到图片资源(压缩后)
* 如果targetW或者targetH为0就自动压缩
*
* @param path
* @param
* @return 压缩后的图片
*/
public static Bitmap getYaSuoBitmapFromImagePath(String path, int targetW, int targetH) {
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(path, options);
int height = options.outHeight;
int width = options.outWidth;
int inSampleSize = calculateInSampleSize(options);
options.inSampleSize = inSampleSize;
options.inJustDecodeBounds = false;
Bitmap src = BitmapFactory.decodeFile(path, options);

if (src == null) {
return null;
}
Bitmap bitmap = null;

if (targetH == 0 || targetW == 0) {
bitmap = Bitmap.createScaledBitmap(src, width / inSampleSize, height / inSampleSize, false);
} else {
bitmap = Bitmap.createScaledBitmap(src, targetW, targetH, false);
}

if (src != bitmap) {
src.recycle();
}

return bitmap;
}

/**
* 计算压缩比
*
* @param options
* @return
*/
public static int calculateInSampleSize(BitmapFactory.Options options) {
int height = options.outHeight;
int width = options.outWidth;

int min = height > width ? width : height;
int inSampleSize = min / 400;

if (inSampleSize == 0)

return 1;

return inSampleSize;
}

/**
* 根据图片的路径得到该图片在表中的ID
*
* @param cr
* @param fileName
* @return
*/
public static String getImageIdFromPath(ContentResolver cr, String fileName) {

//select condition.
String whereClause = MediaStore.Images.Media.DATA + " = '" + fileName + "'";

//colection of results.
Cursor cursor = cr.query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, new String[]{MediaStore.Images.Media._ID}, whereClause, null, null);
if (cursor == null || cursor.getCount() == 0) {
if (cursor != null)
cursor.close();
return null;
}
cursor.moveToFirst();
//imageView id in imageView table.
String imageId = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media._ID));
cursor.close();
if (imageId == null) {
return null;
}
return imageId;
}

/**
* 根据图片的ID得到缩略图
*
* @param cr
* @param imageId
* @return
*/
public static Bitmap getThumbnailsFromImageId(ContentResolver cr, String imageId) {
if (imageId == null || imageId.equals(""))
return null;

Bitmap bitmap = null;
BitmapFactory.Options options = new BitmapFactory.Options();
options.inDither = false;
options.inPreferredConfig = Bitmap.Config.ARGB_8888;

long imageIdLong = Long.parseLong(imageId);
//via imageid get the bimap type thumbnail in thumbnail table.
bitmap = MediaStore.Images.Thumbnails.getThumbnail(cr, imageIdLong, MediaStore.Images.Thumbnails.MINI_KIND, options);

return bitmap;
}

/**
* 获得圆角图片的方法
*
* @param bitmap 源Bitmap
* @param roundPx 圆角大小
* @return 期望Bitmap
*/
public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, float roundPx) {

Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
bitmap.getHeight(), Bitmap.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(PorterDuff.Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);

return output;
}
}