裁剪微信分享缩略图片(长缩略图取中裁剪)

有时分享出去的图片如果过长，就会导致缩略图的正方形图片呈现的效果是被压缩的，一般才用居中裁剪的方式，将裁剪后的图作为缩略图即可

本文后面将举微信分享到朋友圈和好友到例子，在分享出去到图片中，若为长图，则截取中间部分作为缩略图标，先放实现的代码。例子作为代码的复习笔记使用

实现图片居中裁剪代码如下：

//其中bitmap为老的Bitmap对象，将会被裁剪

Bitmap withSizeBitmap = null;//该withSizeBitmap是取过长宽的
Bitmap thumbBmp = null;//将上面的withSizeBitmap再次压缩否分享出去                  
if (bitmap.getWidth() < bitmap.getHeight()) {//如果是竖长图或正方形
     //居中裁剪创建一个带有宽高的bitmap
     withSizeBitmap = Bitmap.createBitmap(bitmap, 0, ((bitmap.getHeight() - bitmap.getWidth()) / 2), bitmap.getWidth(), bitmap.getWidth());
     //压缩
     thumbBmp = Bitmap.createScaledBitmap(withSizeBitmap, WX_THUMB_SIZE, WX_THUMB_SIZE, true);                 
}else if (bitmap.getWidth() >= bitmap.getHeight()){//如果是横长图
     withSizeBitmap = Bitmap.createBitmap(bitmap, ((bitmap.getWidth() - bitmap.getHeight()) / 2), 0, bitmap.getHeight(), bitmap.getHeight());
     thumbBmp = Bitmap.createScaledBitmap(withSizeBitmap, WX_THUMB_SIZE, WX_THUMB_SIZE, true);
}

分享朋友圈的方法：

/**
* 分享朋友圈
* @param url             链接
* @param title           标题
* @param content         内容简介
* @param imgPath         缩略图图片地址（本地）
* @param titleOrContent  分享出去的文字是标题还是简介
*/

public static void shareMoments(final String url, final String title, final String 
       content, final String imgPath, final boolean titleOrContent) {

     final int IMAGE_SIZE = 32768;
     new Thread(new Runnable() {
         @Override
         public void run() {
             WXWebpageObject textObj = new WXWebpageObject();
             textObj.webpageUrl = url;      
             WXMediaMessage msg = new WXMediaMessage();         
             if (titleOrContent){//标题还是描述都传过来，但是需要哪个根据此字段决定，
                msg.title = title;
             }else {
                msg.title = content;
             }
            final int WX_THUMB_SIZE = 120;
            try {
                Bitmap bitmap = BitmapFactory.decodeFile(imgPath);
                ByteArrayOutputStream output = new ByteArrayOutputStream();         
                bitmap.compress(Bitmap.CompressFormat.JPEG, 100, output);
                int options = 100;
                while (output.toByteArray().length > IMAGE_SIZE && options != 10) {
                    output.reset(); //清空baos
                    bitmap.compress(Bitmap.CompressFormat.JPEG, options, output);//这里压缩options%，把压缩后的数据存放到baos中
                    options -= 10;
                }
                //这就是上面的裁剪的方法
                Bitmap withSizeBitmap = null;
                Bitmap thumbBmp = null;
                if (bitmap.getWidth() < bitmap.getHeight()) {
                    withSizeBitmap = Bitmap.createBitmap(bitmap, 0, ((bitmap.getHeight() - bitmap.getWidth()) / 2), bitmap.getWidth(), bitmap.getWidth());
                    thumbBmp = Bitmap.createScaledBitmap(withSizeBitmap, WX_THUMB_SIZE, WX_THUMB_SIZE, true);
                }else if (bitmap.getWidth() >= bitmap.getHeight()){
                    //创建一个带有宽高的bitmap
                    withSizeBitmap = Bitmap.createBitmap(bitmap, ((bitmap.getWidth() - bitmap.getHeight()) / 2), 0, bitmap.getHeight(), bitmap.getHeight());
                    //压缩
                    thumbBmp = Bitmap.createScaledBitmap(withSizeBitmap, WX_THUMB_SIZE, WX_THUMB_SIZE, true);
                }
                msg.thumbData = WXUtil.bmpToByteArray(thumbBmp, true);

                bitmap.recycle();
                withSizeBitmap.recycle();
                thumbBmp.recycle();
                msg.mediaObject = textObj;
                SendMessageToWX.Req req = new SendMessageToWX.Req()

                // req.transaction = content;
                req.message = msg;
                req.scene = SendMessageToWX.Req.WXSceneTimeline;
                api.sendReq(req);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }).start();
}

分享到微信好友到方法：

/**
 * 分享微信好友
 * @param url     网址
 * @param title   标题
 * @param content 简介 
 * @param imgPath 图片地址(本地)
*/

public static void shareWX(final String url, final String title, final String 
       content, final String imgPath) {

      final int IMAGE_SIZE = 32768;
      new Thread(new Runnable() {
              @Override
              public void run() {
                   final WXWebpageObject textObj = new WXWebpageObject();
                   textObj.webpageUrl = url;
                   final WXMediaMessage msg = new WXMediaMessage();
                   msg.title = title;//标题
                   msg.description = content;//描述
                   final int WX_THUMB_SIZE = 120;
                   //开始把图片路径转成bitmap
                   try {
                        Bitmap bitmap = BitmapFactory.decodeFile(imgPath);
                        ByteArrayOutputStream output = new ByteArrayOutputStream();
                        bitmap.compress(Bitmap.CompressFormat.JPEG, 100, output);
                        int options = 100;
                        while (output.toByteArray().length > IMAGE_SIZE && options != 10) {//后面（options != 10）的条件判断必须加（vivo x7不加不行）
                            output.reset(); //清空baos
                            bitmap.compress(Bitmap.CompressFormat.JPEG, options, output);//这里压缩options%，把压缩后的数据存放到baos中
                                  options -= 10;
                        }
                        Bitmap withSizeBitmap = null;
                        Bitmap thumbBmp = null;
                        if (bitmap.getWidth() < bitmap.getHeight()) {//竖图
                             withSizeBitmap = Bitmap.createBitmap(bitmap, 0, ((bitmap.getHeight() - bitmap.getWidth()) / 2), bitmap.getWidth(), bitmap.getWidth());
                             thumbBmp = Bitmap.createScale dBitmap(withSizeBitmap, WX_THUMB_SIZE, WX_THUMB_SIZE, true);
                        }else if (bitmap.getWidth() >= bitmap.getHeight()){//横图
                             withSizeBitmap = Bitmap.createBitmap(bitmap, ((bitmap.getWidth() - bitmap.getHeight()) / 2), 0, bitmap.getHeight(), bitmap.getHeight());
                             thumbBmp = Bitmap.createScaledBitmap(withSizeBitmap, WX_THUMB_SIZE, WX_THUMB_SIZE, true);
                        }
                        msg.thumbData = WXUtil.bmpToByteArray(thumbBmp, true);

                        //回收
                        bitmap.recycle();
                        withSizeBitmap.recycle();
                        thumbBmp.recycle();
                        //bitmap到此结束

                        msg.mediaObject = textObj;

                        SendMessageToWX.Req req = new SendMessageToWX.Req();
                        req.transaction = title;
                        req.message = msg;
                        req.scene = SendMessageToWX.Req.WXSceneSession;

                        api.sendReq(req);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
       }
    }).start();
 }

结束。