Removed usage of the Graphics.MeasureString and used TextRenderer.MeasureText instead (JohannBlais#61)

Author: JohannBlais

InfoBox/Form/InformationBoxForm.cs

@@ -74,11 +74,6 @@ internal partial class InformationBoxForm : Form
         /// </summary>
         private readonly string doNotShowAgainText;
 
-        /// <summary>
-        /// Contains the graphics used to measure the strings
-        /// </summary>
-        private readonly Graphics measureGraphics;
-
         /// <summary>
         /// Contains a reference to the active form
         /// </summary>
@@ -288,8 +283,6 @@ internal InformationBoxForm(string text,
                                     InformationBoxSound sound = InformationBoxSound.Default)
         {
             this.InitializeComponent();
-            this.measureGraphics = CreateGraphics();
-            this.measureGraphics.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;
 
             // Apply default font for message boxes
             this.Font = SystemFonts.MessageBoxFont;
@@ -1007,15 +1000,15 @@ private void SetLayout()
             #region Width
 
             // Caption width including button
-            int captionWidth = Convert.ToInt32(this.measureGraphics.MeasureString(Text, SystemFonts.CaptionFont).Width) + 30;
+            int captionWidth = TextRenderer.MeasureText(Text, SystemFonts.CaptionFont, Size.Empty, TextFormatFlags.NoPadding | TextFormatFlags.NoPrefix).Width + 30;
             if (this.titleStyle != InformationBoxTitleIconStyle.None)
             {
                 captionWidth += BorderPadding * 2;
             }
 
             // "Do not show this dialog again" width
             int checkBoxWidth = ((this.checkBox & InformationBoxCheckBox.Show) == InformationBoxCheckBox.Show)
-                                    ? (int)this.measureGraphics.MeasureString(this.chbDoNotShow.Text, this.chbDoNotShow.Font).Width + BorderPadding * 4
+                                    ? TextRenderer.MeasureText(this.chbDoNotShow.Text, this.chbDoNotShow.Font, Size.Empty, TextFormatFlags.NoPadding).Width + BorderPadding * 4
                                     : 0;
 
             // Width of the text and icon.
@@ -1273,7 +1266,7 @@ private void SetText()
                 if (this.autoSizeMode == InformationBoxAutoSizeMode.None)
                 {
                     this.messageText.WordWrap = true;
-                    this.messageText.Size = (this.measureGraphics.MeasureString(this.messageText.Text, this.messageText.Font, screenWidth / 2) + new SizeF(1, 0)).ToSize();
+                    this.messageText.Size = TextRenderer.MeasureText(this.messageText.Text, this.messageText.Font, new Size(screenWidth / 2, 0), TextFormatFlags.TextBoxControl | TextFormatFlags.WordBreak);
                 }
                 else
                 {
@@ -1290,7 +1283,7 @@ private void SetText()
 
                         foreach (Match sentence in sentences)
                         {
-                            int sentenceLength = (int)this.measureGraphics.MeasureString(sentence.Value, this.messageText.Font).Width;
+                            int sentenceLength = TextRenderer.MeasureText(sentence.Value, this.messageText.Font, Size.Empty, TextFormatFlags.TextBoxControl | TextFormatFlags.NoPadding).Width;
                             if (currentWidth != 0 && (sentenceLength + currentWidth) > (screenWidth - 50))
                             {
                                 formattedText.Append(Environment.NewLine);
@@ -1315,7 +1308,7 @@ private void SetText()
 
                     this.messageText.Text = this.internalText.ToString();
 
-                    this.messageText.Size = (this.measureGraphics.MeasureString(this.messageText.Text, this.messageText.Font) + new SizeF(1, 0)).ToSize();
+                    this.messageText.Size = TextRenderer.MeasureText(this.messageText.Text, this.messageText.Font, Size.Empty, TextFormatFlags.TextBoxControl);
                 }
             }
 
@@ -1426,7 +1419,7 @@ private void SetButtonsSize()
             // Measures the width of each button
             foreach (Control ctrl in this.pnlButtons.Controls)
             {
-                maxSize = Math.Max(Convert.ToInt32(this.measureGraphics.MeasureString(ctrl.Text, ctrl.Font).Width + 40), maxSize);
+                maxSize = Math.Max(TextRenderer.MeasureText(ctrl.Text, ctrl.Font, Size.Empty, TextFormatFlags.NoPadding | TextFormatFlags.NoPrefix).Width + 40, maxSize);
             }
 
             foreach (Control ctrl in this.pnlButtons.Controls)

InfoBox/InfoBox.nuspec

@@ -2,7 +2,7 @@
 <package xmlns="http://schemas.microsoft.com/packaging/2011/08/nuspec.xsd">
     <metadata>
         <id>InformationBox</id>
-        <version>1.0.0</version>
+        <version>1.4.0</version>
         <title>InformationBox</title>
         <authors>Johann Blais</authors>
         <owners>Johann Blais</owners>
@@ -15,10 +15,11 @@
 InformationBox is the simplest and easiest way to create personalized MessageBox.
 
 Stop wasting time developing your own custom MessageBox, everything you need is already available. Just customize your MessageBox using the visual designer and the code is automatically generated !</description>
-        <summary>InformationBox (.NET 4.0+) is a flexible alternative to the default MessageBox included in the System.Windows.Forms namespace</summary>
+        <summary>InformationBox (.NET 4.8+, dotnet core  8.0+) is a flexible alternative to the default MessageBox included in the System.Windows.Forms namespace</summary>
         <releaseNotes>
-            - Removed support for .NET 6.0 (Windows)
-            - Added support for .NET 10.0 (Windows)
+            - Improved text measurement accuracy by migrating from Graphics.MeasureString (GDI+) to TextRenderer.MeasureText (GDI)
+            - Removed Graphics dependency for better testability
+            - Text sizing now matches actual TextBox rendering more accurately
         </releaseNotes>
         <copyright>Copyright 2026</copyright>
         <language>en-US</language>

InfoBox/Properties/AssemblyInfo.cs

@@ -42,11 +42,11 @@
 // Version information for an assembly consists of the following four values:
 //
 //      Major Version
-//      Minor Version 
+//      Minor Version
 //      Build Number
 //      Revision
 //
-// You can specify all the values or you can default the Revision and Build Numbers 
+// You can specify all the values or you can default the Revision and Build Numbers
 // by using the '*' as shown below:
-[assembly: AssemblyVersion("1.3.0.0")]
-[assembly: AssemblyFileVersion("1.3.0.0")]
+[assembly: AssemblyVersion("1.4.0.0")]
+[assembly: AssemblyFileVersion("1.4.0.0")]