From 6ad465b9fad160b992ce4cd44a494fdf3d946ea9 Mon Sep 17 00:00:00 2001
From: MarcinZiabek <marcin@ziabek.com>
Date: Sun, 16 Apr 2023 11:42:38 +0200
Subject: [PATCH] Fix(#499): inconsistent text height when using multiple lines

---
 Source/QuestPDF.Examples/TextExamples.cs | 30 ++++++++++++++++++++++++
 Source/QuestPDF/Fluent/TextExtensions.cs | 14 ++++++++++-
 2 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/Source/QuestPDF.Examples/TextExamples.cs b/Source/QuestPDF.Examples/TextExamples.cs
index 4b42021..3aa3df3 100644
--- a/Source/QuestPDF.Examples/TextExamples.cs
+++ b/Source/QuestPDF.Examples/TextExamples.cs
@@ -974,5 +974,35 @@ namespace QuestPDF.Examples
                         });
                 });
         }
+        
+        [Test]
+        public void InconsistentLineHeightWhenUsingNewLineTest()
+        {
+            RenderingTest
+                .Create()
+                .PageSize(PageSizes.A4)
+                .ProduceImages()
+                .ShowResults()
+                .Render(container =>
+                {
+                    container
+                        .Padding(20)
+                        .Background(Colors.Grey.Lighten4)
+                        .Text(text =>
+                        {
+                            text.DefaultTextStyle(x => x.FontSize(16));
+                            
+                            text.Line(Placeholders.Paragraph());
+                            text.Line("");
+                            text.Line(Placeholders.Paragraph());
+                            
+                            text.Line(Placeholders.Label()).FontSize(48);
+                            
+                            text.Line(Placeholders.Paragraph());
+                            text.Line("");
+                            text.Line(Placeholders.Paragraph());
+                        });
+                });
+        }
     }
 }
\ No newline at end of file
diff --git a/Source/QuestPDF/Fluent/TextExtensions.cs b/Source/QuestPDF/Fluent/TextExtensions.cs
index 61fd331..c39bba8 100644
--- a/Source/QuestPDF/Fluent/TextExtensions.cs
+++ b/Source/QuestPDF/Fluent/TextExtensions.cs
@@ -88,7 +88,19 @@ namespace QuestPDF.Fluent
             if (!TextBlocks.Any())
                 TextBlocks.Add(new TextBlock());
             
-            TextBlocks.Last().Items.Add(item);
+            var lastTextBlock = TextBlocks.Last();
+
+            // TextBlock with only one Span with empty text is a special case.
+            // It represents an empty line with a given text style (e.g. text height).
+            // When more content is put to text block, the first items should be ignored (removed in this case).
+            // This change fixes inconsistent line height problem.
+            if (lastTextBlock.Items.Count == 1 && lastTextBlock.Items[0] is TextBlockSpan { Text: "" })
+            {
+                lastTextBlock.Items[0] = item;
+                return;
+            }
+            
+            lastTextBlock.Items.Add(item);
         }
         
         [Obsolete("This element has been renamed since version 2022.3. Please use the overload that returns a TextSpanDescriptor object which allows to specify text style.")]