Font Generation

Namespace: FontGeneration Language: C++ Type: Defold C++ File: fontgen.h Source: engine/font/src/fontgen.h Include: engine/font/src/fontgen.h

Asynchronously generates glyphs and hands them to a caller-owned cache. Glyph insertion and completion callbacks run on the job context owner, or on the caller of FontGenUpdateGlyphs for a batch started with FontGenStartGlyphs. Cache lookup runs while preparing the batch. The caller context must remain valid until the completion callback has run or the job has been cancelled.

API

FFontGenAddGlyph

Type: TYPEDEF Returning FONT_RESULT_OK transfers ownership of the glyph to the callback. For every other result, font_gen retains ownership and frees the glyph.

FFontGenComplete

Type: TYPEDEF Reports completion of a glyph generation batch.

FFontGenIsGlyphCached

Type: TYPEDEF Looks up a glyph in the caller-owned cache.

FontGenCreateJobData

Type: FUNCTION Allocates scratch data for one generation batch.

Parameters

• params (FontGenParams*) - Generation settings and callbacks. The values are copied.
• num_glyphs (uint32_t) - Maximum number of glyphs in the batch.

Returns

• job_data (FontGenJobData*) - Job data, or null when unsupported.

FontGenDestroyJobData

Type: FUNCTION Batches started with FontGenStartGlyphs cancel and wait for their own jobs. Other batches must already have finished or been canceled by the caller.

Parameters

• jobdata (FontGenJobData*) - Batch to release.

FontGenIsSupported

Type: FUNCTION Tests whether runtime glyph generation is linked into the engine.

Returns

• supported (bool) - True when the full font_gen library is linked.

FontGenParams

Type: STRUCT Runtime glyph generation parameters.

Members

• m_UserContext (void*) - Opaque context passed to all callbacks.
• m_IsGlyphCached (FFontGenIsGlyphCached) - Cache lookup callback.
• m_AddGlyph (FFontGenAddGlyph) - Glyph insertion callback.
• m_Complete (FFontGenComplete) - Batch completion callback.
• m_Jobs (HJobContext) - Job system used for asynchronous generation.
• m_Size (float) - Glyph generation size in pixels.
• m_OutlineWidth (float) - Outline width in pixels.
• m_ShadowBlur (float) - Shadow blur spread in pixels.
• m_IsSdf (uint8_t) - Non-zero when SDF output is requested.
• m_IsVector (uint8_t) - Non-zero when Vector glyph output is requested.
• m_BitmapEffects (uint8_t) - Generate RGB vector effect bitmaps on the CPU.
• m_HasOutline (uint8_t) - Include the authored outline in the effect bitmaps.
• m_HasShadow (uint8_t) - Generate the authored shadow bitmap.

FontGenStartGlyphs

Type: FUNCTION Worker jobs generate glyphs without invoking callbacks. Call FontGenUpdateGlyphs on the resource’s creation thread to install the results. That update can take over queued glyphs, including when the caller occupies the last worker. With no workers it generates all glyphs. The job context must outlive the batch.

Parameters

• jobdata (FontGenJobData*) - Fresh batch; keep alive until completion or destruction.
• glyphs (::TextGlyph*) - Input glyphs, copied during this call.
• num_glyphs (uint32_t) - Number of input glyphs.

Returns

• started (bool) - False when runtime generation is unsupported.

FontGenUpdateGlyphs

Type: FUNCTION Generates queued glyphs or consumes finished results without dispatching other jobs or callbacks. Running jobs keep ownership until they finish. The completion callback may destroy the batch. Calls for one batch must be serialized by its owner.

Parameters

• jobdata (FontGenJobData*) - Batch to advance.
• time_limit (uint64_t) - Soft time limit in microseconds; 0 processes at most one glyph.

Returns

• complete (bool) - True once all glyphs and the completion callback have been processed.