获取分享到微信的缩略图 thumbData

来源：互联网发布：java 首字母大写方法编辑：程序博客网时间：2024/06/05 03:04

获取微信的缩略图供三步

1 获取一个较小的缩略图

public static Bitmap extractThumbNail(final String path, final int height, final int width, final boolean crop) {        Assert.assertTrue(path != null && !path.equals("") && height > 0 && width > 0);        BitmapFactory.Options options = new BitmapFactory.Options();        try {            options.inJustDecodeBounds = true;            Bitmap tmp = BitmapFactory.decodeFile(path, options);            if (tmp != null) {                tmp.recycle();                tmp = null;            }            Log.d(TAG, "extractThumbNail: round=" + width + "x" + height + ", crop=" + crop);            final double beY = options.outHeight * 1.0 / height;            final double beX = options.outWidth * 1.0 / width;            Log.d(TAG, "extractThumbNail: extract beX = " + beX + ", beY = " + beY);            options.inSampleSize = (int) (crop ? (beY > beX ? beX : beY) : (beY < beX ? beX : beY));            if (options.inSampleSize <= 1) {                options.inSampleSize = 1;            }            // NOTE: out of memory error            while (options.outHeight * options.outWidth / options.inSampleSize > MAX_DECODE_PICTURE_SIZE) {                options.inSampleSize++;            }            int newHeight = height;            int newWidth = width;            if (crop) {                if (beY > beX) {                    newHeight = (int) (newWidth * 1.0 * options.outHeight / options.outWidth);                } else {                    newWidth = (int) (newHeight * 1.0 * options.outWidth / options.outHeight);                }            } else {                if (beY < beX) {                    newHeight = (int) (newWidth * 1.0 * options.outHeight / options.outWidth);                } else {                    newWidth = (int) (newHeight * 1.0 * options.outWidth / options.outHeight);                }            }            options.inJustDecodeBounds = false;            Log.i(TAG, "bitmap required size=" + newWidth + "x" + newHeight + ", orig=" + options.outWidth + "x" + options.outHeight + ", sample=" + options.inSampleSize);            Bitmap bm = BitmapFactory.decodeFile(path, options);            if (bm == null) {                Log.e(TAG, "bitmap decode failed");                return null;            }            Log.i(TAG, "bitmap decoded size=" + bm.getWidth() + "x" + bm.getHeight());            final Bitmap scale = Bitmap.createScaledBitmap(bm, newWidth, newHeight, true);            if (scale != null) {                bm.recycle();                bm = scale;            }            if (crop) {                final Bitmap cropped = Bitmap.createBitmap(bm, (bm.getWidth() - width) >> 1, (bm.getHeight() - height) >> 1, width, height);                if (cropped == null) {                    return bm;                }                bm.recycle();                bm = cropped;                Log.i(TAG, "bitmap croped size=" + bm.getWidth() + "x" + bm.getHeight());            }            return bm;        } catch (final OutOfMemoryError e) {            Log.e(TAG, "decode bitmap failed: " + e.getMessage());            options = null;        }        return null;    }

调用方法

thumbBmp = Util.extractThumbNail(thumbUrl, 300, 300, false);

2 裁剪该缩略图，防止是那种长图

public static Bitmap checkImageSize(Bitmap bitmap) {        //防止超长图文件大小超过微信限制，需要进行截取，暂定比例上限为5        final int MAX_RATIO = 5;        Bitmap result = bitmap;        if (bitmap != null) {            int width = bitmap.getWidth();            int height = bitmap.getHeight();            float ratio = width > height ? width*1.0f / height : height*1.0f / width;            if (ratio > MAX_RATIO) {                int size = Math.min(width, height);                result = Bitmap.createBitmap(bitmap, 0, 0, size, size);            }        }        return result;    }

3 压缩图片使其在32k以下

public static byte[] compressBitmapToData(Bitmap bmp,float size) {        ByteArrayOutputStream output = new ByteArrayOutputStream();        byte[] result;        try {            bmp.compress(Bitmap.CompressFormat.JPEG, 100, output);//质量压缩方法，这里100表示不压缩，把压缩后的数据存放到baos中            int options = 100;            while ( output.toByteArray().length / 1024 >= size) {  //循环判断如果压缩后图片是否大于size kb,大于继续压缩                output.reset();//重置baos即清空baos                bmp.compress(Bitmap.CompressFormat.JPEG, options, output);//这里压缩options%，把压缩后的数据存放到baos中                if(options==1){                    break;                }                options -= 10;//每次都减少20                if(options<=0){                    options=1;                }            }            result = output.toByteArray();            Methods.log("compressBitmap return length = " + result.length);            return result;        } catch (Exception e) {            e.printStackTrace();            return null;        }finally {            try {                output.close();            } catch (IOException e) {                e.printStackTrace();            }        }    }

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