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Crash in SharpFont when trying to read the horizontal header of a TrueType font

Open wldevries opened this issue 2 years ago • 2 comments

Crash in Face when trying to read the horizontal header of a TrueType font.

var library = new Library();
Face face = new Face(library, "c:/windows/fonts/arial.ttf");
face.GetSfntTable(SfntTag.HorizontalHeader);

This results in the following error:

System.TypeLoadException: Cannot marshal field 'Reserved' of type 'SharpFont.TrueType.lnternal.HoriHeaderRec': This type can only be marshaled in restricted ways.
at System.Runtime.lnteropServices.Marshal.PtrToStructureHelper(lntPtr ptr, Object structure, Boolean allowValueClasses)
at System.Runtime.lnteropServices.Marshal.PtrToStructure(lntPtr ptr, Type structureType)
at SharpFont.PlnvokeHelper.PtrToStructure[T](lntPtr reference)
at SharpFont.TrueType.HoriHeader.set_Reference(lntPtr value)
at SharpFont.TrueType.HoriHeader..ctor(lntPtr reference)
at SharpFont.Face.GetSfntTable(SfntTag tag)

I'm trying to get to get access to the LineGap of a font which seems to be present only in the vertical and horizontal headers. The vertical header loads fine.

The SpaceWizards.SharpFont package combined with SharpFont.Dependencies loads the horizontal header just fine. https://github.com/Robmaister/SharpFont/issues/140

wldevries avatar Feb 15 '23 08:02 wldevries

The reason might be that the version in this repository might be 2.5.3 (?) and the official SharpFont lib is at 4.0.1 now.

wldevries avatar Feb 15 '23 09:02 wldevries

The OS/2 table has the same problem:

face.GetSfntTable(SfntTag.HorizontalHeader);

results in

System.TypeLoadException: Cannot marshal field 'panose' of type 'SharpFont.TrueType.lnternal.CS2Rec': This type can only be marshaled in restricted ways.
at System.Runtime.lnteropServices.MarshaI.PtrToStructureHelper(lntPtr ptr, Object structure, Boolean allowValueCIasses)
at System.Runtime.lnteropServices.MarshaI.PtrToStructure(lntPtr ptr, Type structureType)
at SharpFont. reference)
at value)
at SharpFont.TrueType.OS2..ctor(lntPtr reference)
at SharpFont. Face.GetSfntTäble(SfntTag tag)

wldevries avatar Feb 17 '23 15:02 wldevries