Printing: Replace PdfiumViewer with native pdfium.dll binary

Elwig/Helpers/Printing/Pdf.cs

@@ -1,5 +1,4 @@
 using Elwig.Windows;
-using PdfiumViewer;
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
@@ -27,6 +26,7 @@ namespace Elwig.Helpers.Printing {
         public static bool IsReady => WinziPrintProc != null;
 
         public static async Task Init(Action? evtHandler = null) {
+            PdfiumNative.FPDF_InitLibrary();
             // NOTE: If the WinziPrint daemon is already running this will succeed, but the process will fail.
             //       Should be no problem, as long as the daemon is not closed
             var p = new Process() { StartInfo = new() {
@@ -47,6 +47,7 @@ namespace Elwig.Helpers.Printing {
         public static Task Cleanup() {
             WinziPrintProc?.Kill(true);
             WinziPrintProc?.Close();
+            PdfiumNative.FPDF_DestroyLibrary();
             return Task.CompletedTask;
         }
 
@@ -123,9 +124,9 @@ namespace Elwig.Helpers.Printing {
 
         public static Task Print(string path, PrinterSettings settings) {
             try {
-                using var doc = PdfDocument.Load(path);
-                using var printDoc = doc.CreatePrintDocument(PdfPrintMode.CutMargin);
-                printDoc.PrinterSettings = settings;
+                using var printDoc = new PdfPrintDocument(path) {
+                    PrinterSettings = settings,
+                };
                 printDoc.Print();
             } catch (Exception e) {
                 MessageBox.Show("Beim Drucken ist ein Fehler aufgetreten:\n\n" + e.Message, "Fehler beim Drucken", MessageBoxButton.OK, MessageBoxImage.Error);

Elwig/Helpers/Printing/PdfPrintDocument.cs

@@ -0,0 +1,102 @@
+using System;
+using System.Drawing;
+using System.Drawing.Imaging;
+using System.Drawing.Printing;
+using System.Runtime.InteropServices;
+
+namespace Elwig.Helpers.Printing {
+    public class PdfPrintDocument : PrintDocument {
+
+        private readonly IntPtr _handle;
+        private readonly int _pageCount;
+        private readonly double _dpi;
+
+        private int _currentPage;
+
+        public PdfPrintDocument(string path, string? password = null, double dpi = 300.0) :
+            base() {
+            _handle = PdfiumNative.FPDF_LoadDocument(path, password);
+            _pageCount = PdfiumNative.FPDF_GetPageCount(_handle);
+            _dpi = dpi;
+        }
+
+        protected override void Dispose(bool disposing) {
+            PdfiumNative.FPDF_CloseDocument(_handle);
+            base.Dispose(disposing);
+        }
+
+        protected override void OnBeginPrint(PrintEventArgs evt) {
+            _currentPage = (PrinterSettings.FromPage != 0) ? (PrinterSettings.FromPage - 1) : 0;
+            base.OnBeginPrint(evt);
+        }
+
+        protected override void OnPrintPage(PrintPageEventArgs evt) {
+            if (_currentPage < _pageCount) {
+                IntPtr page = PdfiumNative.FPDF_LoadPage(_handle, _currentPage);
+                double width = PdfiumNative.FPDF_GetPageWidth(page);
+                double height = PdfiumNative.FPDF_GetPageHeight(page);
+                int pixelWidth = (int)(width / 72.0 * _dpi);
+                int pixelHeight = (int)(height / 72.0 * _dpi);
+
+                IntPtr bitmap = PdfiumNative.FPDFBitmap_Create(pixelWidth, pixelHeight, 1);
+                PdfiumNative.FPDF_RenderPageBitmap(bitmap, page, 0, 0, pixelWidth, pixelHeight, 0, 0);
+
+                IntPtr buffer = PdfiumNative.FPDFBitmap_GetBuffer(bitmap);
+                int stride = PdfiumNative.FPDFBitmap_GetStride(bitmap);
+                using (var bmp = new Bitmap(pixelWidth, pixelHeight, stride, PixelFormat.Format32bppArgb, buffer)) {
+                    evt.Graphics?.DrawImage(bmp, evt.PageBounds);
+                }
+                _currentPage++;
+
+                PdfiumNative.FPDFBitmap_Destroy(bitmap);
+                PdfiumNative.FPDF_ClosePage(page);
+            }
+            evt.HasMorePages = _currentPage < ((PrinterSettings.ToPage == 0) ? _pageCount : Math.Min(PrinterSettings.ToPage, _pageCount));
+            base.OnPrintPage(evt);
+        }
+    }
+
+    internal partial class PdfiumNative {
+        [LibraryImport("pdfium.dll")]
+        public static partial void FPDF_InitLibrary();
+
+        [LibraryImport("pdfium.dll")]
+        public static partial void FPDF_DestroyLibrary();
+
+        [LibraryImport("pdfium.dll", StringMarshalling = StringMarshalling.Utf8)]
+        public static partial IntPtr FPDF_LoadDocument(string filePath, string? password);
+
+        [LibraryImport("pdfium.dll")]
+        public static partial void FPDF_CloseDocument(IntPtr document);
+
+        [LibraryImport("pdfium.dll")]
+        public static partial int FPDF_GetPageCount(IntPtr document);
+
+        [LibraryImport("pdfium.dll")]
+        public static partial IntPtr FPDF_LoadPage(IntPtr document, int pageIndex);
+
+        [LibraryImport("pdfium.dll")]
+        public static partial void FPDF_ClosePage(IntPtr page);
+
+        [LibraryImport("pdfium.dll")]
+        public static partial double FPDF_GetPageWidth(IntPtr page);
+
+        [LibraryImport("pdfium.dll")]
+        public static partial double FPDF_GetPageHeight(IntPtr page);
+
+        [LibraryImport("pdfium.dll")]
+        public static partial IntPtr FPDFBitmap_Create(int width, int height, int alpha);
+
+        [LibraryImport("pdfium.dll")]
+        public static partial void FPDFBitmap_Destroy(IntPtr bitmap);
+
+        [LibraryImport("pdfium.dll")]
+        public static partial IntPtr FPDFBitmap_GetBuffer(IntPtr bitmap);
+
+        [LibraryImport("pdfium.dll")]
+        public static partial int FPDFBitmap_GetStride(IntPtr bitmap);
+
+        [LibraryImport("pdfium.dll")]
+        public static partial void FPDF_RenderPageBitmap(IntPtr bitmap, IntPtr page, int start_x, int start_y, int size_x, int size_y, int rotate, int flags);
+    }
+}