why scale bitmap larger than original picture?there is waste too mush native memory

ForMy Test: exactScaleFactor will >1 when original picture < view ,then the bitmap size will be larger than original picture, there is waste too mush native memory. why ?

For example:
My picture is 750x1733,but bitmap decode is 1176x2091,transform centerCrop will be 1080x2091。
At last: there is create two bitmap, and all larger than picture。
My device screen: 1080 x 2091

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`Glide.with(MainActivity.this).load("xxx").into(imageView);`

DownsampleStrategy| imageView scaleType | case1：original picture > View , original picture750x1733, view180x300 | case2:View > original ,picture original picture 750x1733, view1080x2091.
-- | -- | -- | --
AtLeast | 无 | 0.25 | 1.0
AtMost | 无 | 0.125 | 1.0
FitCenter | 默认，fitStart,fitEnd,fitCenter | 0.22505626 | 1.44
CenterInside | fitXY,centerInside | 0.22505626 | 1.0
CenterOntside | center,centerCrop | 0.24 | 1.5686421
None | 无 | 1.0 | 1.0