ImageView.ScaleType 属性值

ImageView.ScaleType属性值：

CENTER Center the image in the view, but perform no scaling.

 按图片的原来size居中显示，当图片长/宽超过View的长/宽，则截取图片的居中部分显示

CENTER_CROP Scale the image uniformly (maintain the image's aspect ratio) so that both dimensions (width and height) of the image will be equal to or larger than the corresponding dimension of the view (minus padding).

按比例扩大图片的size居中显示，使得图片长(宽)等于或大于View的长(宽)

CENTER_INSIDE Scale the image uniformly (maintain the image's aspect ratio) so that both dimensions (width and height) of the image will be equal to or less than the corresponding dimension of the view (minus padding).

将图片的内容完整居中显示，通过按比例缩小或原来的size使得图片长/宽等于或小于View的长/宽

FIT_CENTER Scale the image using CENTER.

 把图片按比例扩大/缩小到View的宽度，居中显示

FIT_END Scale the image using END.

 把图片按比例扩大/缩小到View的宽度，底部显示

FIT_START Scale the image using START.

 把图片按比例扩大/缩小到View的宽度，顶部显示

FIT_XY Scale the image using FILL.

 不按比例缩放图片，目标是把图片塞满整个View。

MATRIX Scale using the image matrix when drawing.

   当绘画的时候使用，使用矩阵。

Bitmap常用：

http://www.cnblogs.com/fighter/archive/2012/02/20/android-bitmap-drawable.html