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// SPDX-License-Identifier: GPL-2.0-or-later
/** @file
* The data describing a single loaded font.
*//*
* Authors: see git history
*
* Copyright (C) 2022 Authors
* Released under GNU GPL v2+, read the file 'COPYING' for more information.
*/
#ifndef LIBNRTYPE_FONT_INSTANCE_H
#define LIBNRTYPE_FONT_INSTANCE_H
#include <map>
#include <vector>
#include <optional>
#include <unordered_map>
#include <2geom/pathvector.h>
#include <pango/pango-types.h>
#include <pango/pango-font.h>
#include "font-glyph.h"
#include "OpenTypeUtil.h"
#include "style-enums.h"
namespace Inkscape {
class Pixbuf;
} // namespace Inkscape
/**
* FontInstance provides metrics, OpenType data, and glyph curves/pixbufs for a font.
*
* Most data is loaded upon construction. Some rarely-used OpenType tables are lazy-loaded,
* as are the curves/pixbufs for each glyph.
*
* Although FontInstance can be used on its own, in practice it is always obtained through
* a FontFactory.
*
* Note: The font size is a scale factor in the transform matrix of the style.
*/
class FontInstance
{
public:
/// Constructor; takes ownership of both arguments, which must be non-null. Throws CtorException on failure.
FontInstance(PangoFont *p_font, PangoFontDescription *descr);
/// Exception thrown if construction fails.
struct CtorException : std::runtime_error
{
template <typename... Args>
CtorException(Args&&... args) : std::runtime_error(std::forward<Args>(args)...) {}
};
~FontInstance();
int MapUnicodeChar(gunichar c) const; // calls the relevant unicode->glyph index function
// Loads the given glyph's info. Glyphs are lazy-loaded, but never unloaded or modified
// as long as the FontInstance still exists. Pointers to FontGlyphs also remain valid.
FontGlyph const *LoadGlyph(int glyph_id);
// nota: all coordinates returned by these functions are on a [0..1] scale; you need to multiply
// by the fontsize to get the real sizes
// Return 2geom pathvector for glyph. Deallocated when font instance dies.
Geom::PathVector const *PathVector(int glyph_id);
// Return font has SVG OpenType enties.
bool FontHasSVG() const { return data->openTypeSVGGlyphs.size() > 0; };
auto const &get_opentype_varaxes() const { return data->openTypeVarAxes; }
// Return the font's OpenType tables, possibly loading them on-demand.
std::map<Glib::ustring, OTSubstitution> const &get_opentype_tables();
// Return pixbuf of SVG glyph or nullptr if no SVG glyph exists. As with glyphs, pixbufs
// are lazy-loaded but immutable once loaded. They are guaranteed to be in Cairo pixel format.
Inkscape::Pixbuf const *PixBuf(int glyph_id);
// Horizontal advance if 'vertical' is false, vertical advance if true.
double Advance(int glyph_id, bool vertical);
// Return a shared pointer that will keep alive the pathvector and pixbuf data, but nothing else.
std::shared_ptr<void const> share_data() const { return data; }
double GetTypoAscent() const { return _ascent; }
double GetTypoDescent() const { return _descent; }
double GetXHeight() const { return _xheight; }
double GetMaxAscent() const { return _ascent_max; }
double GetMaxDescent() const { return _descent_max; }
const double* GetBaselines() const { return _baselines; }
int GetDesignUnits() const { return _design_units; }
bool FontMetrics(double &ascent, double &descent, double &leading) const;
bool FontDecoration(double &underline_position, double &underline_thickness,
double &linethrough_position, double &linethrough_thickness) const;
bool FontSlope(double &run, double &rise) const; // for generating slanted cursors for oblique fonts
Geom::OptRect BBox(int glyph_id);
bool IsOutlineFont() const { return FT_IS_SCALABLE(face); }
bool has_vertical() const { return FT_HAS_VERTICAL(face); }
auto get_descr() const { return descr; }
auto get_font() const { return p_font; }
private:
void acquire(PangoFont *p_font, PangoFontDescription *descr);
void release();
void init_face();
void find_font_metrics(); // Find ascent, descent, x-height, and baselines.
/*
* Resources
*/
// The font's fingerprint; this particular PangoFontDescription gives the key at which this font instance
// resides in the font cache. It may differ from the PangoFontDescription belonging to p_font.
PangoFontDescription *descr;
// The real source of the font
PangoFont *p_font;
// we need to keep around an rw copy of the (read-only) hb font to extract the freetype face
hb_font_t *hb_font_copy;
// it's a pointer in fact; no worries to ref/unref it, pango does its magic
// as long as p_font is valid, face is too
FT_Face face;
/*
* Metrics
*/
// Font metrics in em-box units
double _ascent; // Typographic ascent.
double _descent; // Typographic descent.
double _xheight; // x-height of font.
double _ascent_max; // Maximum ascent of all glyphs in font.
double _descent_max; // Maximum descent of all glyphs in font.
int _design_units; // Design units, (units per em, typically 1000 or 2048).
// Baselines
double _baselines[SP_CSS_BASELINE_SIZE];
struct Data
{
/*
* Tables
*/
// Map of SVG in OpenType glyphs
std::map<int, SVGTableEntry> openTypeSVGGlyphs;
// Maps for font variations.
std::map<Glib::ustring, OTVarAxis> openTypeVarAxes; // Axes with ranges
// Map of OpenType tables found in font. Transparently lazy-loaded.
std::optional<std::map<Glib::ustring, OTSubstitution>> openTypeTables;
/*
* Glyphs
*/
// Lookup table mapping pango glyph ids to glyphs.
std::unordered_map<int, std::unique_ptr<FontGlyph const>> glyphs;
};
std::shared_ptr<Data> data;
};
#endif // LIBNRTYPE_FONT_INSTANCE_H
/*
Local Variables:
mode:c++
c-file-style:"stroustrup"
c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
indent-tabs-mode:nil
fill-column:99
End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :
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