NullReferenceException thrown when invoking TextMeasurer.MeasureBounds

Prerequisites

• I have written a descriptive issue title
• I have verified that I am running the latest version of Fonts
• I have verified if the problem exist in both DEBUG and RELEASE mode
• I have searched open and closed issues to ensure it has not already been reported

Description

The method TextMeasurer.MeasureBounds throws a System.NullReferenceException when using the OpenSans font.

Steps to Reproduce

I downloaded the OpenSans font from Google Fonts

The following code demonstrates the issue:

using SixLabors.Fonts;

var fontCollection = new FontCollection();
FontFamily fontFamily = fontCollection.Add("./OpenSans/OpenSans-Regular.ttf");
Font font = new Font(fontFamily, 100, FontStyle.Regular);
var rendererOptions = new TextOptions(font)
{
	HorizontalAlignment = HorizontalAlignment.Left,
	VerticalAlignment = VerticalAlignment.Top,
};
FontRectangle bounds = TextMeasurer.MeasureBounds(
	"Hello World",
	rendererOptions
);

The call to MeasureBounds throws a NullReference exception. Here are the exception details:

System.NullReferenceException
  HResult=0x80004003
  Message=Object reference not set to an instance of an object.
  Source=SixLabors.Fonts
  StackTrace:
   at SixLabors.Fonts.Tables.AdvancedTypographic.GPosTable.GetFeatureLookups(Tag& stageFeature, ScriptClass script)
   at SixLabors.Fonts.Tables.AdvancedTypographic.GPosTable.TryUpdatePositions(FontMetrics fontMetrics, GlyphPositioningCollection collection, KerningMode kerningMode, Boolean& kerned)
   at SixLabors.Fonts.StreamFontMetrics.UpdatePositions(GlyphPositioningCollection collection, KerningMode kerningMode)
   at SixLabors.Fonts.FileFontMetrics.UpdatePositions(GlyphPositioningCollection collection, KerningMode kerningMode)
   at SixLabors.Fonts.TextLayout.ProcessText(ReadOnlySpan`1 text, TextOptions options)
   at SixLabors.Fonts.TextLayout.GenerateLayout(ReadOnlySpan`1 text, TextOptions options)
   at SixLabors.Fonts.TextMeasurer.TextMeasurerInt.MeasureBounds(ReadOnlySpan`1 text, TextOptions options)
   at SixLabors.Fonts.TextMeasurer.MeasureBounds(String text, TextOptions options)
   at Program.<Main>$(String[] args) in C:\Development\PlayArea\ImageSharp\MeasureBounds\MeasureBounds\Program.cs:line 11

System Configuration

• Fonts version: 1.0.0-beta 16 (I am not explicitly including it)
• Other Six Labors packages and versions:
  • SixLabors.ImageSharp version 2.1.2
  • SixLabors.ImageSharp.Drawing version 1.0.0-beta14
• Environment (Operating system, version and so on): Windows 10
• .NET Framework version: 6.0

[loraderon]

I do think #266 is a duplicate since it was reported against 1.0.0-beta17.

The fix hasn’t been released to nuget yet, I haven’t tested the myget beta17.8 (https://www.myget.org/feed/sixlabors/package/nuget/SixLabors.Fonts) but it would probably work since the fix was “obvious” 😄

[AndrewShepherd]

Here is the file OpenSans-Regular.ttf that my example code was loading:

OpenSans-Regular.zip