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C1.Util.DX.DirectWrite.FontFace.TryGetFontTable

TryGetFontTable Method

TryGetFontTable(int, out DataPointer, out IntPtr)

Finds the specified OpenType font table if it exists and returns a reference to it. The function accesses the underlying font data through the C1.Win.DX.DirectWrite.FontFileStream interface implemented by the font file loader.

Declaration
public bool TryGetFontTable(int openTypeTableTag, out DataPointer tableData, out IntPtr tableContext)
Parameters
Type Name Description
int openTypeTableTag

The four-character tag of a OpenType font table to find. Use the DWRITE_MAKE_OPENTYPE_TAG macro to create it as an UINT32. Unlike GDI, it does not support the special TTCF and null tags to access the whole font.

DataPointer tableData

When this method returns, contains the address of a reference to the base of the table in memory. The reference is valid only as long as the font face used to get the font table still exists; (not any other font face, even if it actually refers to the same physical font).

IntPtr tableContext

When this method returns, the address of a reference to the opaque context, which must be freed by calling {{ReleaseFontTable}}. The context actually comes from the lower-level C1.Win.DX.DirectWrite.FontFileStream, which may be implemented by the application or DWrite itself. It is possible for a NULL tableContext to be returned, especially if the implementation performs direct memory mapping on the whole file. Nevertheless, always release it later, and do not use it as a test for function success. The same table can be queried multiple times, but because each returned context can be different, you must release each context separately.

Returns
Type Description
bool

TRUE if the font table exists; otherwise, FALSE.

Remarks

The context for the same tag may be different for each call, so each one must be held and released separately.

TryGetFontTable(int, IntPtr, out int, out IntPtr)

HRESULT IDWriteFontFace::TryGetFontTable([In] unsigned int openTypeTableTag,[Out, Buffer] const void** tableData,[Out] unsigned int* tableSize,[Out] void** tableContext,[Out] BOOL* exists)

Declaration
public bool TryGetFontTable(int openTypeTableTag, IntPtr tableData, out int tableSize, out IntPtr tableContext)
Parameters
Type Name Description
int openTypeTableTag
IntPtr tableData
int tableSize
IntPtr tableContext
Returns
Type Description
bool