Error when using TextMeasure.measure on some fonts

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

Error when using TextMeasure.Measure feauture

• Fonts version: 1.0.0-beta17

• Other Six Labors packages and versions:

• Environment (Operating system, version and so on): Windows 7

• .NET Framework version: .net core 3.1

• Additional information:

I recently upgraded SixLabors.Fonts from 1.0.0-beta0009 to 1.0.0-beta17, also I upgraded the imagesharp and imageSharp.Drawing to latest versions and I see that some of the fonts are failing with the following exception

"Invalid value for ‘subTableFormat’ 7294. Should be ‘1’

These were working before I did the upgrade. Following code is throwing the error. And also this is not happening with all the fonts… only few fonts.

AllFontCollection = new FontCollection(); AllFontCollection.Add(@“Fonts/font1.ttf”); AllFontCollection.Add(@“Fonts/font2.ttf”); if (fontCollectionService.AllFontCollection.TryGet(layer.Font.FontName, out FontFamily family)) { // family will not be null here font = family.CreateFont((float)(layer.Font.FontSize * 4), fontStyle); } var textOptions = new TextOptions(font) { WrappingLength = targetWidth };

var textSize = TextMeasurer.Measure(text, textOptions ); //this line throws exception

am I missing anything?

I would really appreciate any direction on this…

Thanks in advance…

fonts.zip

[loraderon]

I’ll update my poc to use the same sort of tests to verify this specific font an create a pr today with these changes.

[brianpopow]

By returning null and handle nulls with if (subTable?.TrySubstitution(fontMetrics, table, collection, feature, index, count) == true) also “works”.

I think that should work, I am in favor of this solution. @JimBobSquarePants what do you think, should we go this route?

Maybe the setting could be called HereBeDragonsUnsafeLookupTablesFallbackDoNotReportIssues 😆

I like you creativity with naming, but I think we need another name 😄

Also something we should consider is using the checksum in the table header. We should be able to determine such errors with it.

@loraderon before you start working on this let’s wait what @JimBobSquarePants thinks about it.