PdfPrintDocument

gistfile1.cs

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Printing;
using System.Text;

namespace PdfiumViewer
{
    internal class PdfPrintDocument : PrintDocument
    {
        private readonly PdfDocument _document;
        private readonly PdfPrintMode _printMode;
        private int _currentPage;

        public PdfPrintDocument(PdfDocument document, PdfPrintMode printMode)
        {
            if (document == null)
                throw new ArgumentNullException("document");

            _document = document;
            _printMode = printMode;
        }

        protected override void OnBeginPrint(PrintEventArgs e)
        {
            _currentPage = PrinterSettings.FromPage == 0 ? 0 : PrinterSettings.FromPage - 1;
        }

        protected override void OnQueryPageSettings(QueryPageSettingsEventArgs e)
        {
            if (_currentPage < _document.PageCount)
                e.PageSettings.Landscape = GetOrientation(_document.PageSizes[_currentPage]) == Orientation.Landscape;
        }

        protected override void OnPrintPage(PrintPageEventArgs e)
        {
            if (_currentPage < _document.PageCount)
            {
                var pageSize = _document.PageSizes[_currentPage];

                var pageOrientation = GetOrientation(pageSize);
                var printOrientation = GetOrientation(e.PageBounds.Size);

                float scaleX = e.Graphics.VisibleClipBounds.Width / pageSize.Width;
                float scaleY = e.Graphics.VisibleClipBounds.Height / pageSize.Height;

                float scale = Math.Min(scaleX, scaleY);

                var dpiX = e.Graphics.DpiX * scale;
                var dpiY = e.Graphics.DpiY * scale;

                _document.Render(
                    _currentPage++,
                    e.Graphics,
                    dpiX,
                    dpiY,
                    new Rectangle(
                        AdjustDpi(dpiX, e.Graphics.VisibleClipBounds.X),
                        AdjustDpi(dpiY, e.Graphics.VisibleClipBounds.Y),
                        AdjustDpi(dpiX, e.Graphics.VisibleClipBounds.Width),
                        AdjustDpi(dpiY, e.Graphics.VisibleClipBounds.Height)
                    ),
                    true
                );
            }

            int pageCount =
                PrinterSettings.ToPage == 0
                ? _document.PageCount
                : Math.Min(PrinterSettings.ToPage, _document.PageCount);

            e.HasMorePages = _currentPage < pageCount;
        }

        private static int AdjustDpi(double value, double dpi)
        {
            return (int)((value / 96.0) * dpi);
        }

        private Orientation GetOrientation(SizeF pageSize)
        {
            if (pageSize.Height > pageSize.Width)
                return Orientation.Portrait;
            return Orientation.Landscape;
        }

        private enum Orientation
        {
            Portrait,
            Landscape
        }
    }
}