Text element: improved the default sizing behavior for the Text eleme…

…nt. Now, when the text is empty, it works more consistently by taking up zero width while still reserving vertical space based on the font size.
QuestPDF · Jun 13, 2024 · 32e2b1e · 32e2b1e
1 parent 64867b0
commit 32e2b1e
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Showing 3 changed files with 44 additions and 5 deletions.
diff --git a/Source/QuestPDF/Elements/Text/TextBlock.cs b/Source/QuestPDF/Elements/Text/TextBlock.cs
@@ -4,7 +4,6 @@
 using QuestPDF.Drawing;
 using QuestPDF.Drawing.Exceptions;
 using QuestPDF.Elements.Text.Items;
-using QuestPDF.Helpers;
 using QuestPDF.Infrastructure;
 using QuestPDF.Skia;
 using QuestPDF.Skia.Text;
@@ -37,6 +36,7 @@ internal sealed class TextBlock : Element, IStateResettable, IContentDirectionAw
         private float MaximumWidth { get; set; }
 
         private bool IsRendered { get; set; }
+        private bool? ContainsOnlyWhiteSpace { get; set; }
         private int CurrentLineIndex { get; set; }
         private float CurrentTopOffset { get; set; }
 
@@ -61,6 +61,13 @@ internal override SpacePlan Measure(Size availableSpace)
 
             if (IsRendered)
                 return SpacePlan.Empty();
+
+            // if the text block does not contain any items, or all items are null, return SpacePlan.Empty
+            // but if the text block contains only whitespace, return SpacePlan.FullRender with zero width and font-based height
+            ContainsOnlyWhiteSpace ??= Items.All(x => x is TextBlockSpan textBlockSpan && string.IsNullOrWhiteSpace(textBlockSpan.Text));
+
+            if (ContainsOnlyWhiteSpace == true)
+                return SpacePlan.FullRender(0, MeasureHeightOfParagraphContainingOnlyWhiteSpace());
 
             Initialize();
 
@@ -108,6 +115,9 @@ internal override void Draw(Size availableSpace)
             if (IsRendered)
                 return;
 
+            if (ContainsOnlyWhiteSpace == true)
+                return;
+
             CalculateParagraphMetrics(availableSpace);
 
             if (MaximumWidth == 0)
@@ -501,5 +511,30 @@ private void CheckUnresolvedGlyphs()
                 $"You can disable this check by setting the 'Settings.CheckIfAllTextGlyphsAreAvailable' option to 'false'. \n" +
                 $"However, this may result with text glyphs being incorrectly rendered without any warning.");
         }
+
+        private float MeasureHeightOfParagraphContainingOnlyWhiteSpace()
+        {
+            var paragraphStyle = new ParagraphStyleConfiguration
+            {
+                Alignment = ParagraphStyleConfiguration.TextAlign.Start,
+                Direction = ParagraphStyleConfiguration.TextDirection.Ltr
+            };
+
+            var builder = SkParagraphBuilderPoolManager.Get(paragraphStyle);
+
+            try
+            {
+                foreach (var textBlockSpan in Items.OfType<TextBlockSpan>())
+                    builder.AddText("\u00A0", textBlockSpan.Style.GetSkTextStyle()); // non-breaking space
+
+                var paragraph = builder.CreateParagraph();
+                paragraph.PlanLayout(1000);
+                return paragraph.GetLineMetrics().First().Height;
+            }
+            finally
+            {
+                SkParagraphBuilderPoolManager.Return(builder);
+            }
+        }
     }
 }
diff --git a/Source/QuestPDF/Fluent/TextExtensions.cs b/Source/QuestPDF/Fluent/TextExtensions.cs
@@ -237,7 +237,7 @@ public void Span(string? text, TextStyle style)
         /// <include file='../Resources/Documentation.xml' path='documentation/doc[@for="text.returns.spanDescriptor"]/*' />
         public TextSpanDescriptor Span(string? text)
         {
-            if (IsNullOrEmpty(text))
+            if (text == null)
                 return new TextSpanDescriptor(new TextBlockSpan());
 
             var textSpan = new TextBlockSpan() { Text = text };
@@ -352,7 +352,7 @@ public TextSpanDescriptor SectionLink(string? text, string sectionName)
             if (IsNullOrEmpty(sectionName))
                 throw new ArgumentException("Section name cannot be null or empty", nameof(sectionName));
 
-            if (IsNullOrEmpty(text))
+            if (text == null)
                 return new TextSpanDescriptor(new TextBlockSpan());
 
             var textBlockItem = new TextBlockSectionLink
@@ -381,7 +381,7 @@ public TextSpanDescriptor Hyperlink(string? text, string url)
             if (IsNullOrEmpty(url))
                 throw new ArgumentException("Url cannot be null or empty", nameof(url));
 
-            if (IsNullOrEmpty(text))
+            if (text == null)
                 return new TextSpanDescriptor(new TextBlockSpan());
 
             var textBlockItem = new TextBlockHyperlink
@@ -478,7 +478,7 @@ public static TextSpanDescriptor Text(this IContainer element, object? text)
         /// <include file='../Resources/Documentation.xml' path='documentation/doc[@for="text.returns.spanDescriptor"]/*' />
         public static TextBlockDescriptor Text(this IContainer container, string? text)
         {
-            if (IsNullOrEmpty(text))
+            if (text == null)
                 return new TextBlockDescriptor(new TextBlock(), new TextBlockSpan());
 
             var textBlock = new TextBlock();

diff --git a/Source/QuestPDF/Resources/ReleaseNotes.txt b/Source/QuestPDF/Resources/ReleaseNotes.txt
@@ -20,3 +20,7 @@ Bug Fixes:
 - Column Element: Resolved instability issues in nested layouts with spacing and zero-sized elements.
 - JPEG Quality: Disabled JPEG image downsampling/downscaling to maintain the highest quality levels.
 - Image Compression: Disabled additional image compression performed by Skia.
+
+
+Version 2024.6.1
+- Text element: improved the default sizing behavior for the Text element. Now, when the text is empty, it works more consistently by taking up zero width while still reserving vertical space based on the font size.