---
title: "Using Skia's PDF Backend"
linkTitle: "Using Skia's PDF Backend"
---

Here is an example of using Skia's PDF backend (SkPDF) via the SkDocument and
SkCanvas APIs.





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## SkPDF Limitations

There are several corners of Skia's public API that SkPDF currently does not
handle because either no known client uses the feature or there is no simple
PDF-ish way to handle it.

In this document:

- **drop** means to draw nothing.

- **ignore** means to draw without the effect

- **expand** means to implement something in a non-PDF-ish way. This may mean to
  rasterize vector graphics, to expand paths with path effects into many
  individual paths, or to convert text to paths.



Effect
                  
text
   
images
 
everything
                                                                         else
SkMaskFilter
            
drop
   
ignore
 
ignore
SkPathEffect
            
ignore
 
n/a
    
expand
SkColorFilter
           
ignore
 
expand
 
ignore
SkImageFilter
           
expand
 
expand
 
expand
unsupported SkXferModes
 
ignore
 
ignore
 
ignore
non-gradient SkShader
   
expand
 
n/a
    
expand


Notes:

- _SkImageFilter_: When SkImageFilter is expanded, text-as-text is lost.

- _SkXferMode_: The following transfer modes are not natively supported by PDF:
  DstOver, SrcIn, DstIn, SrcOut, DstOut, SrcATop, DstATop, and Modulate.

Other limitations:

- _drawText with VerticalText_ — drop. No known clients seem to make use of the
  VerticalText flag.

- _drawTextOnPath_ — expand. (Text-as-text is lost.)

- _drawVertices_ — drop.

- _drawPatch_ — drop.

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