TouchImageView leaves trails

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http://stackoverflow.com – I am using TouchImageView to get the Zoom in/out feature on my ImageView. Though it works, when i zoom out it is not clearing previous zoomed-in causing trails around the image, like in the image shown below. Please see the wavy at top and bottom that occurred when i zoomed out leaving trails of zoomed image. I tried invaldiate() before matrix.postTranslate, but that didn't solve this. Anyway to get this zoom out work without leaving the trail. Thank you. (HowTos)