FontCache Class Reference

Cached font glyphs. The class is designed to contain multiple font glyphs. For every font glyph, The caller should provide a hash code. More...

#include <font_cache.h>

Public Member Functions
	~FontCache ()
void	remove_smallest ()
void	clear ()
FT_BitmapGlyph	get_glyph (FT_Face face, const unsigned int hash_code, int ch)
Static Public Member Functions
static FontCache &	instance ()

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Detailed Description

Cached font glyphs. The class is designed to contain multiple font glyphs. For every font glyph, The caller should provide a hash code.

Copyright (C) 2008 iRex Technologies B.V. All rights reserved.

Definition at line 46 of file font_cache.h.

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Constructor & Destructor Documentation

FontCache::~FontCache

(

void

)

Definition at line 40 of file font_cache.cpp.

References clear().

{
    clear();
}

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Member Function Documentation

void FontCache::clear

(

)

Definition at line 80 of file font_cache.cpp.

Referenced by text::TextView::set_font_size(), and ~FontCache().

{
    for(FontIter it = cache.begin(); it != cache.end(); ++it)
    {
        for(GlyphIter t = it->second.begin(); t != it->second.end(); ++t)
        {
            FT_Done_Glyph(t->second);
        }
        it->second.clear();
    }
    cache.clear();

}

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FT_BitmapGlyph FontCache::get_glyph	(	FT_Face	face,
		const unsigned int	hash_code,
		int	ch
	)

Definition at line 94 of file font_cache.cpp.

References ERRORPRINTF.

Referenced by render_single_line().

{
    FT_UInt index = ch; 
    
    // check hash code at first
    CodeIter ci = codes.find(hash_code);
    if (ci == codes.end())
    {
        codes[hash_code] = 0;
    }

    // search 
    FontIter iter = cache.find(hash_code);
    if (iter != cache.end())
    {
        GlyphIter t = iter->second.find(index);
        if (t != iter->second.end())
        {
            return reinterpret_cast<FT_BitmapGlyph>(t->second);
        }
    }
    ++codes[hash_code];

    // load glyph 
    if (FT_Load_Glyph(face, index, FT_LOAD_DEFAULT))
    {
        // ERRORPRINTF("Unable to load glyph!");
        return 0;
    }    

    // get glyph
    FT_Glyph glyph;
    if (FT_Get_Glyph(face->glyph, &glyph))
    {
        // ERRORPRINTF("Unable to copy glyph!");
        return 0;
    }
    
    // convert to bitmap
    if (glyph->format != FT_GLYPH_FORMAT_BITMAP)
    {
        if (FT_Glyph_To_Bitmap(&glyph, FT_RENDER_MODE_NORMAL, 0, 1))
        {
            ERRORPRINTF("Unable to render glyph!");
            return 0;
        }
    }

    // cache it
    cache[hash_code][index] = glyph;

    return (FT_BitmapGlyph)glyph;
}

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static FontCache& FontCache::instance

(

)

[inline, static]

Definition at line 50 of file font_cache.h.

Referenced by render_single_line(), and text::TextView::set_font_size().

    {
        static FontCache _instance;
        return _instance;
    }

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void FontCache::remove_smallest

(

)

Definition at line 45 of file font_cache.cpp.

{
    // it's necessary to maintain at least one kind of glyph
    if (codes.size() <= 1)
    {
        return;
    }

    // get smallest one
    UINT32 count = (UINT32)-1;
    CodeIter smallest = codes.begin();
    for(CodeIter ci = codes.begin(); ci != codes.end(); ++ci)
    {
        if (count > ci->second)
        {
            smallest = ci;
            count = ci->second;
        }
    }
    UINT32 code = smallest->first;
    codes.erase(smallest);

    // release them
    FontIter it = cache.find(code);
    if (it != cache.end())
    {
        for(GlyphIter t = it->second.begin(); t != it->second.end(); ++t)
        {
            FT_Done_Glyph(t->second);
        }
        it->second.clear();
        cache.erase(it);
    }
}

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The documentation for this class was generated from the following files:

• font_cache.h
• font_cache.cpp