internal static IEnumerable <byte[]> GenerateImages(IDocument document)
{
var content = ElementExtensions.Create(document.Compose);
var metadata = document.GetMetadata();
var totalPages = 1;
while (true)
{
var spacePlan = content.Measure(metadata.Size);
byte[] result;
try
{
result = RenderPage(content);
}
catch (Exception exception)
{
throw new DocumentDrawingException("An exception occured during document drawing.", exception);
}
yield return(result);
if (totalPages >= metadata.DocumentLayoutExceptionThreshold)
{
throw new DocumentLayoutException("Composed layout generates infinite document.");
}
if (spacePlan is FullRender)
{
break;
}
totalPages++;
}
byte[] RenderPage(Element element)
{
// scale the result so it is more readable
var scalingFactor = metadata.RasterDpi / (float)PageSizes.PointsPerInch;
var imageInfo = new SKImageInfo((int)(metadata.Size.Width * scalingFactor), (int)(metadata.Size.Height * scalingFactor));
using var surface = SKSurface.Create(imageInfo);
surface.Canvas.Scale(scalingFactor);
var canvas = new Canvas(surface.Canvas);
element?.Draw(canvas, metadata.Size);
surface.Canvas.Save();
return(surface.Snapshot().Encode(SKEncodedImageFormat.Png, 100).ToArray());
}
}
internal static void GeneratePdf(Stream stream, IDocument document)
{
var content = ElementExtensions.Create(document.Compose);
var metadata = document.GetMetadata();
using var pdf = SKDocument.CreatePdf(stream, MapMetadata(metadata));
var totalPages = 1;
while (true)
{
var spacePlan = content.Measure(metadata.Size);
using var skiaCanvas = pdf.BeginPage(metadata.Size.Width, metadata.Size.Height);
var canvas = new Canvas(skiaCanvas);
try
{
content.Draw(canvas, metadata.Size);
}
catch (Exception exception)
{
pdf.Close();
stream.Close();
throw new DocumentDrawingException("An exception occured during document drawing.", exception);
}
pdf.EndPage();
if (totalPages >= metadata.DocumentLayoutExceptionThreshold)
{
pdf.Close();
stream.Close();
throw new DocumentLayoutException("Composed layout generates infinite document.");
}
if (spacePlan is FullRender)
{
break;
}
totalPages++;
}
pdf.Close();
stream.Dispose();
}
