Render to Skia Surface

Starting with version 4.0, we use the Skia 2D graphics library to render PDF pages. Methods Page.Save and Document.ConvertToTiff can be used to render pages or documents directly to single- or multipage raster images. It is however also possible to render to a Skia surface. This is demonstrated by the following code samples.

Open PDF and select the first page

var pdf = new Document(new FileStream(path, FileMode.Open, FileAccess.Read));
var page = pdf.Pages[0];

Calculate the size of the image

const float cScale = 1.0f; // 72 dpi
var pageBox = page.CropBox ?? page.MediaBox;
int width = (int)Math.Round(pageBox.Width * cScale);
int height = (int)Math.Round(pageBox.Height * cScale);
if (pdfPage.Rotation % 180 != 0)
{
  int tmp = width;
  width = height;
  height = tmp;
}

Render page into Skia surface

using (var surface = SKSurface.Create(info))
{
  page.Draw(surface, info, cScale);
  // ...
}

Save rendering buffer to raster image

using (var pixmap = surface.PeekPixels())
using (var stream = new SKFileWStream(imgFile))
{
  pixmap.Encode(stream, SKEncodedImageFormat.Jpeg, 90);
  stream.Flush();
}