itext pdfimage library

2024-03-01 16:00:16 +01:00
parent 4cbbee5147
commit 0c24ec1cbb
9 changed files with 502 additions and 400 deletions
@@ -0,0 +1,140 @@
+using iText.Kernel.Pdf;
+using iText.Kernel.Pdf.Canvas.Parser;
+using iText.Kernel.Pdf.Canvas.Parser.Listener;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using itext.pdfimage.Models;
+using itext.pdfimage.Extensions;
+using System.Threading;
+
+using System.Drawing;
+using System.Drawing.Drawing2D;
+using System.Drawing.Imaging;
+using System.Drawing.Text;
+
+
+namespace itext.pdfimage
+{
+    public class PdfToImageConverter
+    {
+        private static int counter;
+
+        public IEnumerable<Bitmap> ConvertToBitmaps(PdfDocument pdfDocument)
+        {
+            counter = 0;
+
+            var numberOfPages = pdfDocument.GetNumberOfPages();
+
+            for (var i = 1; i <= numberOfPages; i++)
+            {
+                var currentPage = pdfDocument.GetPage(i);
+
+                yield return ConvertToBitmap(currentPage);
+            }
+        }
+
+        public IEnumerable<Stream> ConvertToJpgStreams(PdfDocument pdfDocument)
+        {
+            foreach (var bmp in ConvertToBitmaps(pdfDocument))
+            {
+                using (var ms = new MemoryStream())
+                {
+                    bmp.Save(ms, ImageFormat.Jpeg);
+                    yield return ms;
+                }
+                bmp.Dispose();
+            }
+        }
+
+        public Bitmap ConvertToBitmap(PdfPage pdfPage)
+        {
+            var rotation = pdfPage.GetRotation();
+
+            var chunkDictionairy = new SortedDictionary<float, IChunk>();
+
+            FilteredEventListener listener = new FilteredEventListener();
+            listener.AttachEventListener(new TextListener(chunkDictionairy, IncreaseCounter));
+            listener.AttachEventListener(new ImageListener(chunkDictionairy, IncreaseCounter));
+            PdfCanvasProcessor processor = new PdfCanvasProcessor(listener);
+            processor.ProcessPageContent(pdfPage);
+
+            //var size = currentPage.GetPageSizeWithRotation();
+            var size = pdfPage.GetPageSize();
+
+            var width = size.GetWidth().PointsToPixels();
+            var height = size.GetHeight().PointsToPixels();
+
+            Bitmap bmp = new Bitmap(width, height);
+            using (Graphics g = Graphics.FromImage(bmp))
+            {
+                g.FillRectangle(Brushes.White, 0, 0, bmp.Width, bmp.Height);
+
+                g.SmoothingMode = SmoothingMode.AntiAlias;
+                g.InterpolationMode = InterpolationMode.HighQualityBicubic;
+                g.PixelOffsetMode = PixelOffsetMode.HighQuality;
+                g.TextRenderingHint = TextRenderingHint.SingleBitPerPixelGridFit;
+
+                foreach (var chunk in chunkDictionairy)
+                {
+                    g.ResetTransform();
+
+                    g.RotateTransform(-rotation);
+
+                    if (chunk.Value is Models.ImageChunk imageChunk)
+                    {
+                        var imgW = imageChunk.W.PointsToPixels();
+                        var imgH = imageChunk.H.PointsToPixels();
+                        var imgX = imageChunk.X.PointsToPixels();
+                        var imgY = (size.GetHeight() - imageChunk.Y - imageChunk.H).PointsToPixels();
+
+                        g.TranslateTransform(imgX, imgY, MatrixOrder.Append);
+                        g.DrawImage(imageChunk.Image, 0, 0, imgW, imgH);
+                        imageChunk.Image.Dispose();
+                    }
+                    else if (chunk.Value is Models.TextChunk textChunk)
+                    {
+                        var chunkX = textChunk.Rect.GetX().PointsToPixels();
+                        var chunkY = bmp.Height - textChunk.Rect.GetY().PointsToPixels();
+
+                        var fontSize = textChunk.FontSize.PointsToPixels();
+
+                        Font font;
+                        try
+                        {
+                            font = new Font(textChunk.FontFamily, fontSize, textChunk.FontStyle, GraphicsUnit.Pixel);
+                        }
+                        catch (Exception ex)
+                        {
+                            //log error
+
+                            font = new Font("Calibri", 11, textChunk.FontStyle, GraphicsUnit.Pixel);
+                        }
+
+                        g.TranslateTransform(chunkX, chunkY, MatrixOrder.Append);
+
+                        //g.DrawString(textChunk.Text, font, new SolidBrush(textChunk.Color), chunkX, chunkY);
+                        g.DrawString(textChunk.Text, font, new SolidBrush(textChunk.Color), 0, 0);
+                    }
+                }
+
+                g.Flush();
+            }
+
+            return bmp;
+        }
+
+        public Stream ConvertToJpgStream(PdfPage pdfPage)
+        {
+            var bmp = ConvertToBitmap(pdfPage);
+            var ms = new MemoryStream();
+            
+            bmp.Save(ms, ImageFormat.Jpeg);
+            bmp.Dispose();
+            return ms;
+            
+        }
+
+        private Func<float> IncreaseCounter = () => counter = Interlocked.Increment(ref counter);
+    }
+}