PdfRenderer
class PdfRenderer : AutoCloseable
kotlin.Any | |
↳ | android.graphics.pdf.PdfRenderer |
This class enables rendering a PDF document. This class is not thread safe.
If you want to render a PDF, you create a renderer and for every page you want to render, you open the page, render it, and close the page. After you are done with rendering, you close the renderer. After the renderer is closed it should not be used anymore. Note that the pages are rendered one by one, i.e. you can have only a single page opened at any given time.
A typical use of the APIs to render a PDF looks like this:
// create a new renderer PdfRenderer renderer = new PdfRenderer(getSeekableFileDescriptor()); // let us just render all pages final int pageCount = renderer.getPageCount(); for (int i = 0; i < pageCount; i++) { Page page = renderer.openPage(i); // say we render for showing on the screen page.render(mBitmap, null, null, Page.RENDER_MODE_FOR_DISPLAY); // do stuff with the bitmap // close the page page.close(); } // close the renderer renderer.close();
Print preview and print output
If you are using this class to rasterize a PDF for printing or show a print preview, it is recommended that you respect the following contract in order to provide a consistent user experience when seeing a preview and printing, i.e. the user sees a preview that is the same as the printout.
- Respect the property whether the document would like to be scaled for printing as per
shouldScaleForPrinting()
. - When scaling a document for printing the aspect ratio should be preserved.
- Do not inset the content with any margins from the
android.print.PrintAttributes
as the application is responsible to render it such that the margins are respected. - If document page size is greater than the printed media size the content should be anchored to the upper left corner of the page for left-to-right locales and top right corner for right-to-left locales.
Summary
Nested classes | |
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This class represents a PDF document page for rendering. |
Public constructors | |
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PdfRenderer(input: ParcelFileDescriptor) Creates a new instance. |
Public methods | |
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Unit |
close() Closes this renderer. |
Int |
Gets the number of pages in the document. |
PdfRenderer.Page! |
Opens a page for rendering. |
Boolean |
Gets whether the document prefers to be scaled for printing. |
Protected methods | |
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Unit |
finalize() |
Public constructors
PdfRenderer
PdfRenderer(input: ParcelFileDescriptor)
Creates a new instance.
Note: The provided file descriptor must be seekable, i.e. its data being randomly accessed, e.g. pointing to a file.
Note: This class takes ownership of the passed in file descriptor and is responsible for closing it when the renderer is closed.
If the file is from an untrusted source it is recommended to run the renderer in a separate, isolated process with minimal permissions to limit the impact of security exploits.
Parameters | |
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input |
ParcelFileDescriptor: Seekable file descriptor to read from. This value cannot be null . |
Exceptions | |
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java.io.IOException |
If an error occurs while reading the file. |
java.lang.SecurityException |
If the file requires a password or the security scheme is not supported. |
Public methods
close
fun close(): Unit
Closes this renderer. You should not use this instance after this method is called.
Exceptions | |
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java.lang.Exception |
if this resource cannot be closed |
getPageCount
fun getPageCount(): Int
Gets the number of pages in the document.
Return | |
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Int |
The page count. |
openPage
fun openPage(index: Int): PdfRenderer.Page!
Opens a page for rendering.
Parameters | |
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index |
Int: The page index. |
Return | |
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PdfRenderer.Page! |
A page that can be rendered. |
shouldScaleForPrinting
fun shouldScaleForPrinting(): Boolean
Gets whether the document prefers to be scaled for printing. You should take this info account if the document is rendered for printing and the target media size differs from the page size.
Return | |
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Boolean |
If to scale the document. |
Protected methods
finalize
protected fun finalize(): Unit
Exceptions | |
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java.lang.Throwable |
the Exception raised by this method |