Add Zoom Level

Author: mstancombe

Source/Demos/HtmlRenderer.Demo.Console/PdfSharpCoreConverter.cs

@@ -15,7 +15,7 @@ public PdfSharpCoreConverter(string sampleRunIdentifier, string basePath) : base
         {
         }
 
-        public async Task GenerateSampleAsync(HtmlSample sample)
+        public async Task GenerateSampleAsync(HtmlSample sample, double zoomLevel = 1)
         {
             var config = new PdfGenerateConfig();
 
@@ -25,6 +25,8 @@ public async Task GenerateSampleAsync(HtmlSample sample)
             config.MarginTop = 0;
             config.MarginBottom = 0;
 
+            config.ZoomLevel = zoomLevel;
+
             var pdf = await PdfGenerator.GeneratePdfAsync(sample.Html, config, imageLoad: OnImageLoaded);
             pdf.Save(GetSamplePath(sample));
         }

Source/Demos/HtmlRenderer.Demo.Console/Program.cs

@@ -24,11 +24,12 @@
 foreach (var htmlSample in samples)
 {
     ////Just doing one test here.  Comment this for all of them.
-    if (!htmlSample.FullName.Contains("40")) continue;
+    if (!htmlSample.FullName.Contains("10")) continue;
 
     //await skia.GenerateSampleAsync(htmlSample);
     //await svgSkia.GenerateSampleAsync(htmlSample);
     await pdfSharp.GenerateSampleAsync(htmlSample);
+    //await pdfSharp.GenerateSampleAsync(htmlSample, .5);
 }
 
 

Source/HtmlRenderer.PdfSharp/PdfGenerateConfig.cs

@@ -37,6 +37,11 @@ public sealed class PdfGenerateConfig
         /// </summary>
         private PageOrientation _pageOrientation;
 
+        /// <summary>
+        /// the zoom level for the page.
+        /// </summary>
+        private double _zoomLevel;
+
         /// <summary>
         /// the top margin between the page start and the text
         /// </summary>
@@ -86,6 +91,19 @@ public PageOrientation PageOrientation
             set { _pageOrientation = value; }
         }
 
+        /// <summary>
+        /// The zoom level for the page as a percent, defaults to 1 (100%).
+        /// </summary>
+        public double ZoomLevel
+        {
+            get { return _zoomLevel; }
+            set
+            {
+                if (value > 0)
+                    _zoomLevel = value;
+            }
+        }
+
         /// <summary>
         /// the top margin between the page start and the text
         /// </summary>

Source/HtmlRenderer.PdfSharp/PdfGenerator.cs

@@ -140,6 +140,15 @@ public static async Task AddPdfPagesAsync(PdfDocument document, string html, Pdf
                 orgPageSize = new XSize(orgPageSize.Height, orgPageSize.Width);
             }
 
+            var pdfPageSize = orgPageSize;
+
+            if (config.ZoomLevel != 1)
+            {
+                // let the layout engine render onto a smaller page, as we'll scale it up when we
+                // render it to the PDF.
+                orgPageSize = new XSize(orgPageSize.Width / config.ZoomLevel, orgPageSize.Height / config.ZoomLevel);
+            }
+
             var pageSize = new XSize(orgPageSize.Width - config.MarginLeft - config.MarginRight, orgPageSize.Height - config.MarginTop - config.MarginBottom);
 
             if (!string.IsNullOrEmpty(html))
@@ -171,22 +180,25 @@ public static async Task AddPdfPagesAsync(PdfDocument document, string html, Pdf
                     while (scrollOffset > -container.ActualSize.Height)
                     {
                         var page = document.AddPage();
-                        page.Height = orgPageSize.Height;
-                        page.Width = orgPageSize.Width;
+                        page.Height = pdfPageSize.Height;
+                        page.Width = pdfPageSize.Width;
 
                         using (var g = XGraphics.FromPdfPage(page))
                         {
                             //g.IntersectClip(new XRect(config.MarginLeft, config.MarginTop, pageSize.Width, pageSize.Height));
                             g.IntersectClip(new XRect(0, 0, page.Width, page.Height));
 
+                            if (config.ZoomLevel != 1)
+                                g.ScaleTransform(config.ZoomLevel);
+
                             container.ScrollOffset = new XPoint(0, scrollOffset);
                             await container.PerformPaintAsync(g);
                         }
                         scrollOffset -= pageSize.Height;
                     }
 
                     // add web links and anchors
-                    HandleLinks(document, container, orgPageSize, pageSize);
+                    HandleLinks(document, container, pdfPageSize, pageSize, config.ZoomLevel);
                 }
             }
         }
@@ -198,17 +210,25 @@ public static async Task AddPdfPagesAsync(PdfDocument document, string html, Pdf
         /// <summary>
         /// Handle HTML links by create PDF Documents link either to external URL or to another page in the document.
         /// </summary>
-        private static void HandleLinks(PdfDocument document, HtmlContainer container, XSize orgPageSize, XSize pageSize)
+        private static void HandleLinks(PdfDocument document, HtmlContainer container, XSize pdfPageSize, XSize pageSize, double zoomLevel)
         {
             foreach (var link in container.GetLinks())
             {
                 int i = (int)(link.Rectangle.Top / pageSize.Height);
                 for (; i < document.Pages.Count && pageSize.Height * i < link.Rectangle.Bottom; i++)
                 {
-                    var offset = pageSize.Height * i;
+                    //Zoom as required.
+                    var offset = pageSize.Height * i * zoomLevel;
+                    var linkRect = new XRect
+                    {
+                        X = link.Rectangle.Left * zoomLevel,
+                        Y = link.Rectangle.Top * zoomLevel,
+                        Width = link.Rectangle.Width * zoomLevel,
+                        Height = link.Rectangle.Height * zoomLevel
+                    };
 
                     // fucking position is from the bottom of the page
-                    var xRect = new XRect(link.Rectangle.Left, orgPageSize.Height - (link.Rectangle.Height + link.Rectangle.Top - offset), link.Rectangle.Width, link.Rectangle.Height);
+                    var xRect = new XRect(linkRect.Left, pdfPageSize.Height - (linkRect.Height + linkRect.Top - offset), linkRect.Width, linkRect.Height);
 
                     if (link.IsAnchor)
                     {