问题
I'm working on a project where I need to display PDF content inside our application. I'm trying to use PdfRenderer of Android API. For now, I'm able to show a pdf page as bitmap and move between all other pages.
But I don't understand how to implement zoom on a page. I mean I know how to zoom an image, but for pdf it needs to be recalculated at every zoom level (such as tile ?). On zoom I need to recalculate Bitmap with correct Rect and Matrix I guess, that's the point I'm missing.
Does some one has already done this or similar ?
PS: I want to make it by my own but feel free to send me opensource library thanks
来源：https://stackoverflow.com/questions/47869508/pdfrendering-zoom-on-page