Here is an example of using Skia's PDF backend (SkPDF) via the SkDocument and SkCanvas APIs.
#include "SkDocument.h" bool WritePDF(SkWStream* outputStream) { SkDocument::PDFMetadata metadata; metadata.fCreator = "creator...."; metadata.fTitle = "title..."; metadata.fAuthor = "author..."; metadata.fSubject = "subject..."; metadata.fKeywords = "keywords..."; metadata.fCreator = "creator..."; SkTime::DateTime now = get_current_date_and_time(); metadata.fCreation.fEnabled = true; metadata.fCreation.fDateTime = now; metadata.fModified.fEnabled = true; metadata.fModified.fDateTime = now; sk_sp<SkDocument> pdfDocument(SkDocument::MakePDF( outputStream, SK_ScalarDefaultRasterDPI, metadata, nullptr, true); assert(pdfDocument); int numberOfPages = ....; for (int page = 0; page < numberOfPages; ++page) { SkScalar pageWidth = ....; SkScalar pageHeight = ....; SkCanvas* pageCanvas = pdfDocument->beginPage(pageWidth, pageHeight); // ....insert canvas draw commands here.... pdfDocument->endPage(); } return pdfDocument->close(); }
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 mean 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.
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.