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/****************************************************************************
*
* svgrenderer.h
*
* Interface for SVG Renderer Module (specification).
*
* Copyright (C) 2004-2019 by
* David Turner, Robert Wilhelm, Werner Lemberg and Moazin Khatti.
*
* This file is part of the FreeType project, and may only be used,
* modified, and distributed under the terms of the FreeType project
* license, LICENSE.TXT. By continuing to use, modify, or distribute
* this file you indicate that you have read the license and
* understand and accept it fully.
*
*/
#ifndef FTSVG_RENDERER_H_
#define FTSVG_RENDERER_H_
#include <ft2build.h>
#include FT_FREETYPE_H
#ifdef FREETYPE_H
#error "freetype.h of FreeType 1 has been loaded!"
#error "Please fix the directory search order for header files"
#error "so that freetype.h of FreeType 2 is found first."
#endif
FT_BEGIN_HEADER
/**************************************************************************
*
* @functype:
* SVG_Lib_Init_Func
*
* @description:
* A callback used to initiate the SVG Rendering port
*
* @input:
* library ::
* A instance of library. This is required to initialize the
* renderer's state which will be held in the library.
*
* @return:
* FreeType error code. 0 means success.
*/
typedef FT_Error
(*SVG_Lib_Init_Func)( FT_Library library );
/**************************************************************************
*
* @functype:
* SVG_Lib_Free_Func
*
* @description:
* A callback used to free the SVG Rendering port. Calling this callback
* shall do all cleanups that the SVG Rendering port wants to do.
*
* @input:
* library ::
* A instance of library. This is required to free the renderer's
* state which will be held in the library.
*/
typedef void
(*SVG_Lib_Free_Func)( FT_Library library );
/**************************************************************************
*
* @functype:
* SVG_Lib_Render_Func
*
* @description:
* A callback used to render the glyph loaded in the slot.
*
* @input:
* slot ::
* The whole glyph slot object.
*
* outline_bbox ::
* The bounding box of the glyph in font units. So that the renderer
* may not need to calculate it again.
*
* @return:
* FreeType error code. 0 means success.
*/
typedef FT_Error
(*SVG_Lib_Render_Func)( FT_GlyphSlot slot,
FT_BBox outline_bbox);
/**************************************************************************
*
* @functype:
* SVG_Lib_Get_Buffer_Size_Func
*
* @description:
* A callback which is called to get the size of the image buffer needed.
* This buffer will ultimately be populated by `SVG_Lib_Render_Func`
* hook.
*
* @input:
* slot ::
* The glyph slot which has the SVG document loaded as well as other
* info.
*
* bbox ::
* The bbox in font units. This is required for the rendering port to
* predict the final size of the image buffer.
*
* @return:
* Size of the state structure in bytes.
*/
typedef FT_ULong
(*SVG_Lib_Get_Buffer_Size_Func)( FT_GlyphSlot slot,
FT_BBox bbox );
typedef struct SVG_RendererHooks_
{
/* Api Hooks for OT-SVG Rendering */
SVG_Lib_Init_Func init_svg;
SVG_Lib_Free_Func free_svg;
SVG_Lib_Render_Func render_svg;
SVG_Lib_Get_Buffer_Size_Func get_buffer_size;
} SVG_RendererHooks;
/**************************************************************************
*
* @struct:
* FT_SVG_DocumentRec_
*
* @description:
* A structure that models one SVG document.
*
* @fields:
* svg_document ::
* A pointer to the SVG document string.
*
* svg_document_length ::
* The length of the SVG document string.
*
* metrics ::
* A metrics object storing the size information.
*
* units_per_EM ::
* The size of the EM square.
*
* start_glyph_id ::
* The starting glyph ID for the glyph range that this document has.
*
* end_glyph_id ::
* The ending glyph ID for the glyph range that this document has.
*
* @note:
* `metrics` and `units_per_EM` might look like repetitions since both
* fields are stored in face objects. However, the Glyph Management API
* requires an `FT_Glyph` to store all the information that completely
* describes a glyph. Outline glyphs are themselves scaled thus they
* don`t need this information. However, SVG documents do. The field
* of `units_per_EM` is needed because the SVG is to be scaled in case
* its viewbox size differs from `units_per_EM`. For more info, refer
* to the section `Coordinate Systems and Glyph Metrics` of the OpenType
* SVG specs.
*/
typedef struct FT_SVG_DocumentRec_
{
FT_Byte* svg_document;
FT_ULong svg_document_length;
FT_Size_Metrics metrics;
FT_UShort units_per_EM;
FT_UShort start_glyph_id;
FT_UShort end_glyph_id;
/* TODO: (OT-SVG) Not storing glyph_index here for now. Might need to
* at some point. Review this! */
} FT_SVG_DocumentRec;
/**************************************************************************
*
* @type:
* FT_SVG_Document
*
* @description:
* A handle to a FT_SVG_DocumentRec object.
*/
typedef struct FT_SVG_DocumentRec_* FT_SVG_Document;
FT_END_HEADER
#endif
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