减少一个位图的大小来Android中指定的尺寸 [英] Reduce the size of a bitmap to a specified size in Android

问题描述

欲减少一个位图的大小恰好200KB。我从SD卡，COM preSS得到它的形象，它用不同的名称再次保存到SD卡到不同的目录中。 COM pression工作正常（3 MB象图像为com pressed为100 KB左右）。我写的codeS以下行此​​：

 字符串镜像文件=/ SD卡/ DCIM / 100ANDRO / DSC_0530.jpg
位图BM = ShrinkBitmap（镜像文件，300，300）;//此方法COM presses图像并保存到SD卡中的位置
    位图ShrinkBitmap（字符串的文件，诠释的宽度，高度INT）{         BitmapFactory.Options bmpFactoryOptions =新BitmapFactory.Options（）;
            bmpFactoryOptions.inJustDe codeBounds = TRUE;
            位图位图= BitmapFactory.de codeFILE（文件，bmpFactoryOptions）;            INT heightRatio =（int）的Math.ceil（bmpFactoryOptions.outHeight /（浮点）高度）;
            INT widthRatio =（int）的Math.ceil（bmpFactoryOptions.outWidth /（浮点）宽度）;            如果（heightRatio→1 || widthRatio→1）
            {
             如果（heightRatio＆GT; widthRatio）
             {
              bmpFactoryOptions.inSampleSize = heightRatio;
             }其他{
              bmpFactoryOptions.inSampleSize = widthRatio;
             }
            }            bmpFactoryOptions.inJustDe codeBounds = FALSE;
            位= BitmapFactory.de codeFILE（文件，bmpFactoryOptions）;            ByteArrayOutputStream流=新ByteArrayOutputStream（）;
            bitmap.com preSS（Bitmap.Com pressFormat.JPEG，100，流）;
            字节[] = imageInByte stream.toByteArray（）;
            //这给了以KB为COM pressed图像的大小
            长lengthbmp = imageInByte.length / 1024;            尝试{
                bitmap.com preSS（比较pressFormat.JPEG，100，新的FileOutputStream（/ SD卡/ mediaAppPhotos / COM pressed_new.jpg））;
            }赶上（FileNotFoundException异常五）{
                // TODO自动生成catch块
                e.printStackTrace（）;
            }
         返回位图;
        }
 

解决方案

我发现，完美的作品对我的回答是：

  / **
     *减小了图像的大小
     * @参数图片
     * @参数MAXSIZE
     * @返回
     * /
    公共位图getResizedBitmap（位图图像​​，诠释MAXSIZE）{
        INT宽度= image.getWidth（）;
        INT高度= image.getHeight（）;        浮动bitmapRatio =（浮点）宽/（浮点）高度;
        如果（bitmapRatio大于0）{
            宽度= MAXSIZE;
            高度=（int）的（宽度/ bitmapRatio）;
        }其他{
            高度= MAXSIZE;
            宽度=（INT）（高* bitmapRatio）;
        }
        返回Bitmap.createScaledBitmap（图像，宽度，高度，真）;
    }
 

调用方法：

 位图converetdImage = getResizedBitmap（照片，500）;
 

• 照片是你的位图

I want to reduce the size of a bitmap to 200kb exactly. I get an image from the sdcard, compress it and save it to the sdcard again with a different name into a different directory. Compression works fine (3 mb like image is compressed to around 100 kb). I wrote the following lines of codes for this:

String imagefile ="/sdcard/DCIM/100ANDRO/DSC_0530.jpg";
Bitmap bm = ShrinkBitmap(imagefile, 300, 300);

//this method compresses the image and saves into a location in sdcard
    Bitmap ShrinkBitmap(String file, int width, int height){

         BitmapFactory.Options bmpFactoryOptions = new BitmapFactory.Options();
            bmpFactoryOptions.inJustDecodeBounds = true;
            Bitmap bitmap = BitmapFactory.decodeFile(file, bmpFactoryOptions);

            int heightRatio = (int)Math.ceil(bmpFactoryOptions.outHeight/(float)height);
            int widthRatio = (int)Math.ceil(bmpFactoryOptions.outWidth/(float)width);

            if (heightRatio > 1 || widthRatio > 1)
            {
             if (heightRatio > widthRatio)
             {
              bmpFactoryOptions.inSampleSize = heightRatio;
             } else {
              bmpFactoryOptions.inSampleSize = widthRatio; 
             }
            }

            bmpFactoryOptions.inJustDecodeBounds = false;
            bitmap = BitmapFactory.decodeFile(file, bmpFactoryOptions);

            ByteArrayOutputStream stream = new ByteArrayOutputStream();   
            bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream);   
            byte[] imageInByte = stream.toByteArray(); 
            //this gives the size of the compressed image in kb
            long lengthbmp = imageInByte.length / 1024; 

            try {
                bitmap.compress(CompressFormat.JPEG, 100, new FileOutputStream("/sdcard/mediaAppPhotos/compressed_new.jpg"));
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }


         return bitmap;
        }

解决方案

I found an answer that works perfectly for me:

/**
     * reduces the size of the image
     * @param image
     * @param maxSize
     * @return
     */
    public Bitmap getResizedBitmap(Bitmap image, int maxSize) {
        int width = image.getWidth();
        int height = image.getHeight();

        float bitmapRatio = (float)width / (float) height;
        if (bitmapRatio > 0) {
            width = maxSize;
            height = (int) (width / bitmapRatio);
        } else {
            height = maxSize;
            width = (int) (height * bitmapRatio);
        }
        return Bitmap.createScaledBitmap(image, width, height, true);
    }

calling the method:

Bitmap converetdImage = getResizedBitmap(photo, 500);

• photo is your bitmap

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