CGUITTFont.h

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/*
   CGUITTFont FreeType class for Irrlicht
   Copyright (c) 2009-2010 John Norman
   Copyright (c) 2016 Nathanaëlle Courant
   Copyright (c) 2023 Caleb Butler
   Copyright (c) 2024 Luanti contributors
 
   This software is provided 'as-is', without any express or implied
   warranty. In no event will the authors be held liable for any
   damages arising from the use of this software.
 
   Permission is granted to anyone to use this software for any
   purpose, including commercial applications, and to alter it and
   redistribute it freely, subject to the following restrictions:
 
   1. The origin of this software must not be misrepresented; you
      must not claim that you wrote the original software. If you use
      this software in a product, an acknowledgment in the product
      documentation would be appreciated but is not required.
 
   2. Altered source versions must be plainly marked as such, and
      must not be misrepresented as being the original software.
 
   3. This notice may not be removed or altered from any source
      distribution.
 
   The original version of this class can be located at:
   http://irrlicht.suckerfreegames.com/
 
   John Norman
   john@suckerfreegames.com
*/
 
#pragma once
 
#include <ft2build.h>
#include <freetype/freetype.h>
 
#include "irr_ptr.h"
#include "IGUIFont.h"
#include "irrArray.h"
#include "path.h"
 
namespace gui {
        class IGUIEnvironment;
}
 
namespace video {
        class IImage;
        class ITexture;
        class IVideoDriver;
}
 
class EnrichedString;
 
namespace gui
{
        class CGUITTFont;
        class CGUITTGlyphPage; // internal

        struct SGUITTGlyph
        {
                SGUITTGlyph() :
                        glyph_page(0),
                        source_rect(),
                        offset(),
                        advance()
                {}
                ~SGUITTGlyph() { unload(); }

                inline bool isLoaded() const {
                        return source_rect != core::recti();
                }

                void preload(u32 char_index, FT_Face face, CGUITTFont *parent, u32 font_size, const FT_Int32 loadFlags);

                void unload();

                video::IImage* createGlyphImage(const FT_Bitmap &bits, video::IVideoDriver *driver) const;

                u32 glyph_page;

                core::recti source_rect;

                core::vector2di offset;

                core::vector2di advance;
        };
 
        // Manages the FT_Face cache.
        struct SGUITTFace : public IReferenceCounted
        {
        private:
 
                static FT_Library freetype_library;
                static size_t n_faces;
 
                static FT_Library getFreeTypeLibrary();
 
                // This holds the font file data for this face.
                // Must not be deallocated until we are done with the face!
                std::string face_buffer;
 
        public:
                SGUITTFace(std::string &&buffer);
                ~SGUITTFace();
 
                FT_Face face;
 
                static SGUITTFace* createFace(std::string &&buffer);
 
                static SGUITTFace* loadFace(const io::path &filename);
        };

        class CGUITTFont final : public IGUIFont
        {
                public:
                        static CGUITTFont* createTTFont(IGUIEnvironment *env,
                                SGUITTFace *face, u32 size, bool antialias = true,
                                bool preload = true, u32 shadow = 0, u32 shadow_alpha = 255);

                        virtual ~CGUITTFont();

                        void setBatchLoadSize(u32 batch_size) { batch_load_size = batch_size; }

                        u32 getFontSize() const { return size; }

                        bool useAutoHinting() const { return use_auto_hinting; }

                        bool useHinting()        const { return use_hinting; }

                        bool useMonochrome()  const { return use_monochrome; }

                        void setMonochrome(const bool flag);

                        void setFontHinting(const bool enable, const bool enable_auto_hinting = true);

                        virtual void draw(const core::stringw& utext, const core::rect<s32>& position,
                                video::SColor color, bool hcenter=false, bool vcenter=false,
                                const core::rect<s32>* clip=0) override;
 
                        void draw(const EnrichedString& text, const core::rect<s32>& position,
                                bool hcenter=false, bool vcenter=false,
                                const core::rect<s32>* clip=0);

                        virtual core::dimension2du getDimension(const wchar_t* text) const override;

                        virtual s32 getCharacterFromPos(const wchar_t* text, s32 pixel_x) const override;

                        virtual void setKerningWidth(s32 kerning) override;

                        virtual void setKerningHeight(s32 kerning) override;

                        virtual core::vector2di getKerning(const wchar_t thisLetter, const wchar_t previousLetter) const override;

                        virtual void setInvisibleCharacters(const wchar_t *s) override;

                        CGUITTGlyphPage* getLastGlyphPage() const;

                        //should be better typed. fix later.
                        CGUITTGlyphPage* createGlyphPage(const u8 pixel_mode);

                        u32 getLastGlyphPageIndex() const { return Glyph_Pages.size() - 1; }

                        void setFallback(gui::IGUIFont *font);
 
                        inline s32 getAscender() const { return font_metrics.ascender; }
 
                protected:
                        bool use_monochrome;
                        bool use_hinting;
                        bool use_auto_hinting;
                        u32 size;
                        u32 batch_load_size;
 
                private:
                        // Helper functions for the same-named public member functions above
                        // (Since std::u32string is nicer to work with than wchar_t *)
                        core::dimension2d<u32> getDimension(const std::u32string& text) const;
                        s32 getCharacterFromPos(const std::u32string& text, s32 pixel_x) const;
 
                        // Helper function for the above helper functions :P
                        std::u32string convertWCharToU32String(const wchar_t* const) const;
 
                        CGUITTFont(IGUIEnvironment *env);
                        bool load(SGUITTFace *face, const u32 size, const bool antialias,
                                const bool transparency, const bool preload);
 
                        void reset_images();
                        void update_glyph_pages() const;
                        void update_load_flags()
                        {
                                // Set up our loading flags.
                                load_flags = FT_LOAD_DEFAULT | FT_LOAD_RENDER;
                                if (!useHinting())
                                        load_flags |= FT_LOAD_NO_HINTING;
                                if (!useAutoHinting())
                                        load_flags |= FT_LOAD_NO_AUTOHINT;
                                if (useMonochrome())
                                        load_flags |= FT_LOAD_MONOCHROME | FT_LOAD_TARGET_MONO;
                                else
                                        load_flags |= FT_LOAD_TARGET_NORMAL;
                        }

                        inline u32 getLineHeight() const { return font_metrics.height / 64 + 1; }
                        u32 getWidthFromCharacter(char32_t c) const;
                        u32 getHeightFromCharacter(char32_t c) const;
                        u32 getGlyphIndexByChar(char32_t c) const;
                        core::vector2di getKerning(const char32_t thisLetter, const char32_t previousLetter) const;
 
                        video::IVideoDriver* Driver = nullptr;
                        FT_Face tt_face;
                        FT_Size_Metrics font_metrics;
                        FT_Int32 load_flags;
 
                        mutable core::array<CGUITTGlyphPage*> Glyph_Pages;
                        mutable core::array<SGUITTGlyph> Glyphs;
 
                        s32 GlobalKerningWidth = 0;
                        s32 GlobalKerningHeight = 0;
                        std::u32string InvisibleChars;
                        u32 shadow_offset = 0;
                        u32 shadow_alpha = 0;
 
                        irr_ptr<gui::IGUIFont> fallback;
        };
 
} // end namespace gui