// Created on: 2013-01-28
// Created by: Kirill GAVRILOV
// Copyright (c) 2013-2014 OPEN CASCADE SAS
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

#ifndef Font_FTFont_HeaderFile
#define Font_FTFont_HeaderFile

#include "Font_FontAspect.hxx"
#include "Font_Hinting.hxx"
#include "Font_Rect.hxx"
#include "Font_StrictLevel.hxx"
#include "Font_UnicodeSubset.hxx"
#include "Graphic3d_HorizontalTextAlignment.hxx"
#include "Graphic3d_VerticalTextAlignment.hxx"
#include "Image_PixMap.hxx"
#include "NCollection_String.hxx"
#include "TCollection_AsciiString.hxx"

// forward declarations to avoid including of FreeType headers
typedef struct FT_FaceRec_* FT_Face;
typedef struct FT_Vector_   FT_Vector;
typedef struct FT_Outline_  FT_Outline;
class Font_FTLibrary;

//! Font initialization parameters.
struct Font_FTFontParams
{
  unsigned int PointSize;  //!< face size in points (1/72 inch)
                           // clang-format off
  unsigned int Resolution;                 //!< resolution of the target device in dpi for FT_Set_Char_Size()
  Font_Hinting FontHinting;                //!< request hinting (exclude FT_LOAD_NO_HINTING flag), Font_Hinting_Off by default;
                                           //!  hinting improves readability of thin text on low-resolution screen,
                                           //!  but adds distortions to original font depending on font family and font library version
  bool         ToSynthesizeItalic;         //!< generate italic style (e.g. for font family having no italic style); FALSE by default
                           // clang-format on
  bool IsSingleStrokeFont; //!< single-stroke (one-line) font, FALSE by default

  //! Empty constructor.
  Font_FTFontParams()
      : PointSize(0),
        Resolution(72u),
        FontHinting(Font_Hinting_Off),
        ToSynthesizeItalic(false),
        IsSingleStrokeFont(false)
  {
  }

  //! Constructor.
  Font_FTFontParams(unsigned int thePointSize, unsigned int theResolution)
      : PointSize(thePointSize),
        Resolution(theResolution),
        FontHinting(Font_Hinting_Off),
        ToSynthesizeItalic(false),
        IsSingleStrokeFont(false)
  {
  }
};

//! Wrapper over FreeType font.
//! Notice that this class uses internal buffers for loaded glyphs
//! and it is absolutely UNSAFE to load/read glyph from concurrent threads!
class Font_FTFont : public Standard_Transient
{
  DEFINE_STANDARD_RTTIEXT(Font_FTFont, Standard_Transient)
public:
  //! Find the font Initialize the font.
  //! @param theFontName    the font name
  //! @param theFontAspect  the font style
  //! @param theParams      initialization parameters
  //! @param theStrictLevel search strict level for using aliases and fallback
  //! @return true on success
  Standard_EXPORT static occ::handle<Font_FTFont> FindAndCreate(
    const TCollection_AsciiString& theFontName,
    const Font_FontAspect          theFontAspect,
    const Font_FTFontParams&       theParams,
    const Font_StrictLevel         theStrictLevel = Font_StrictLevel_Any);

  //! Return TRUE if specified character is within subset of modern CJK characters.
  static bool IsCharFromCJK(char32_t theUChar)
  {
    return (theUChar >= 0x03400 && theUChar <= 0x04DFF)
           || (theUChar >= 0x04E00 && theUChar <= 0x09FFF)
           || (theUChar >= 0x0F900 && theUChar <= 0x0FAFF)
           || (theUChar >= 0x20000 && theUChar <= 0x2A6DF)
           || (theUChar >= 0x2F800 && theUChar <= 0x2FA1F)
           // Hiragana and Katakana (Japanese) are NOT part of CJK, but CJK fonts usually include
           // these symbols
           || IsCharFromHiragana(theUChar) || IsCharFromKatakana(theUChar);
  }

  //! Return TRUE if specified character is within subset of Hiragana (Japanese).
  static bool IsCharFromHiragana(char32_t theUChar)
  {
    return (theUChar >= 0x03040 && theUChar <= 0x0309F);
  }

  //! Return TRUE if specified character is within subset of Katakana (Japanese).
  static bool IsCharFromKatakana(char32_t theUChar)
  {
    return (theUChar >= 0x030A0 && theUChar <= 0x030FF);
  }

  //! Return TRUE if specified character is within subset of modern Korean characters (Hangul).
  static bool IsCharFromKorean(char32_t theUChar)
  {
    return (theUChar >= 0x01100 && theUChar <= 0x011FF)
           || (theUChar >= 0x03130 && theUChar <= 0x0318F)
           || (theUChar >= 0x0AC00 && theUChar <= 0x0D7A3);
  }

  //! Return TRUE if specified character is within subset of Arabic characters.
  static bool IsCharFromArabic(char32_t theUChar)
  {
    return (theUChar >= 0x00600 && theUChar <= 0x006FF);
  }

  //! Return TRUE if specified character should be displayed in Right-to-Left order.
  static bool IsCharRightToLeft(char32_t theUChar) { return IsCharFromArabic(theUChar); }

  //! Determine Unicode subset for specified character
  static Font_UnicodeSubset CharSubset(char32_t theUChar)
  {
    if (IsCharFromCJK(theUChar))
    {
      return Font_UnicodeSubset_CJK;
    }
    else if (IsCharFromKorean(theUChar))
    {
      return Font_UnicodeSubset_Korean;
    }
    else if (IsCharFromArabic(theUChar))
    {
      return Font_UnicodeSubset_Arabic;
    }
    return Font_UnicodeSubset_Western;
  }

public:
  //! Create uninitialized instance.
  Standard_EXPORT Font_FTFont(
    const occ::handle<Font_FTLibrary>& theFTLib = occ::handle<Font_FTLibrary>());

  //! Destructor.
  Standard_EXPORT ~Font_FTFont() override;

  //! @return true if font is loaded
  inline bool IsValid() const { return myFTFace != nullptr; }

  //! @return image plane for currently rendered glyph
  inline const Image_PixMap& GlyphImage() const { return myGlyphImg; }

  //! Initialize the font from the given file path.
  //! @param theFontPath path to the font
  //! @param theParams   initialization parameters
  //! @param theFaceId   face id within the file (0 by default)
  //! @return true on success
  bool Init(const TCollection_AsciiString& theFontPath,
            const Font_FTFontParams&       theParams,
            const int                      theFaceId = 0)
  {
    return Init(occ::handle<NCollection_Buffer>(), theFontPath, theParams, theFaceId);
  }

  //! Initialize the font from the given file path or memory buffer.
  //! @param theData     memory to read from, should NOT be freed after initialization!
  //!                    when NULL, function will attempt to open theFileName file
  //! @param theFileName optional path to the font
  //! @param theParams   initialization parameters
  //! @param theFaceId   face id within the file (0 by default)
  //! @return true on success
  Standard_EXPORT bool Init(const occ::handle<NCollection_Buffer>& theData,
                            const TCollection_AsciiString&         theFileName,
                            const Font_FTFontParams&               theParams,
                            const int                              theFaceId = 0);

  //! Find (using Font_FontMgr) and initialize the font from the given name.
  //! @param theFontName    the font name
  //! @param theFontAspect  the font style
  //! @param theParams      initialization parameters
  //! @param theStrictLevel search strict level for using aliases and fallback
  //! @return true on success
  Standard_EXPORT bool FindAndInit(const TCollection_AsciiString& theFontName,
                                   Font_FontAspect                theFontAspect,
                                   const Font_FTFontParams&       theParams,
                                   Font_StrictLevel theStrictLevel = Font_StrictLevel_Any);

  //! Return flag to use fallback fonts in case if used font does not include symbols from specific
  //! Unicode subset; TRUE by default.
  //! @sa Font_FontMgr::ToUseUnicodeSubsetFallback()
  bool ToUseUnicodeSubsetFallback() const { return myToUseUnicodeSubsetFallback; }

  //! Set if fallback fonts should be used in case if used font does not include symbols from
  //! specific Unicode subset.
  void SetUseUnicodeSubsetFallback(bool theToFallback)
  {
    myToUseUnicodeSubsetFallback = theToFallback;
  }

  //! Return TRUE if this is single-stroke (one-line) font, FALSE by default.
  //! Such fonts define single-line glyphs instead of closed contours, so that they are rendered
  //! incorrectly by normal software.
  bool IsSingleStrokeFont() const { return myFontParams.IsSingleStrokeFont; }

  //! Set if this font should be rendered as single-stroke (one-line).
  void SetSingleStrokeFont(bool theIsSingleLine)
  {
    myFontParams.IsSingleStrokeFont = theIsSingleLine;
  }

  //! Return TRUE if italic style should be synthesized; FALSE by default.
  bool ToSynthesizeItalic() const { return myFontParams.ToSynthesizeItalic; }

  //! Release currently loaded font.
  Standard_EXPORT virtual void Release();

  //! Render specified glyph into internal buffer (bitmap).
  Standard_EXPORT bool RenderGlyph(const char32_t theChar);

  //! @return maximal glyph width in pixels (rendered to bitmap).
  Standard_EXPORT unsigned int GlyphMaxSizeX(bool theToIncludeFallback = false) const;

  //! @return maximal glyph height in pixels (rendered to bitmap).
  Standard_EXPORT unsigned int GlyphMaxSizeY(bool theToIncludeFallback = false) const;

  //! @return vertical distance from the horizontal baseline to the highest character coordinate.
  Standard_EXPORT float Ascender() const;

  //! @return vertical distance from the horizontal baseline to the lowest character coordinate.
  Standard_EXPORT float Descender() const;

  //! @return default line spacing (the baseline-to-baseline distance).
  Standard_EXPORT float LineSpacing() const;

  //! Configured point size
  unsigned int PointSize() const { return myFontParams.PointSize; }

  //! Return glyph scaling along X-axis.
  float WidthScaling() const { return myWidthScaling; }

  //! Setup glyph scaling along X-axis.
  //! By default glyphs are not scaled (scaling factor = 1.0)
  void SetWidthScaling(const float theScaleFactor) { myWidthScaling = theScaleFactor; }

  //! Return TRUE if font contains specified symbol (excluding fallback list).
  Standard_EXPORT bool HasSymbol(char32_t theUChar) const;

  //! Compute horizontal advance to the next character with kerning applied when applicable.
  //! Assuming text rendered horizontally.
  //! @param theUCharNext the next character to compute advance from current one
  Standard_EXPORT float AdvanceX(char32_t theUCharNext) const;

  //! Compute horizontal advance to the next character with kerning applied when applicable.
  //! Assuming text rendered horizontally.
  //! @param theUChar     the character to be loaded as current one
  //! @param theUCharNext the next character to compute advance from current one
  Standard_EXPORT float AdvanceX(char32_t theUChar, char32_t theUCharNext);

  //! Compute vertical advance to the next character with kerning applied when applicable.
  //! Assuming text rendered vertically.
  //! @param theUCharNext the next character to compute advance from current one
  Standard_EXPORT float AdvanceY(char32_t theUCharNext) const;

  //! Compute vertical advance to the next character with kerning applied when applicable.
  //! Assuming text rendered vertically.
  //! @param theUChar     the character to be loaded as current one
  //! @param theUCharNext the next character to compute advance from current one
  Standard_EXPORT float AdvanceY(char32_t theUChar, char32_t theUCharNext);

  //! Return glyphs number in this font.
  //! @param theToIncludeFallback if TRUE then the number will include fallback list
  Standard_EXPORT int GlyphsNumber(bool theToIncludeFallback = false) const;

  //! Retrieve glyph bitmap rectangle
  Standard_EXPORT void GlyphRect(Font_Rect& theRect) const;

  //! Computes bounding box of the given text using plain-text formatter (Font_TextFormatter).
  //! Note that bounding box takes into account the text alignment options.
  //! Its corners are relative to the text alignment anchor point, their coordinates can be
  //! negative.
  Standard_EXPORT Font_Rect BoundingBox(const NCollection_String&               theString,
                                        const Graphic3d_HorizontalTextAlignment theAlignX,
                                        const Graphic3d_VerticalTextAlignment   theAlignY);

public:
  //! Computes outline contour for the symbol.
  //! @param[in] theUChar     the character to be loaded as current one
  //! @param[out] theOutline   outline contour
  //! @return true on success
  Standard_EXPORT const FT_Outline* renderGlyphOutline(const char32_t theChar);

public:
  //! Initialize the font.
  //! @param theFontPath   path to the font
  //! @param thePointSize  the face size in points (1/72 inch)
  //! @param theResolution the resolution of the target device in dpi
  //! @return true on success
  Standard_DEPRECATED("Deprecated method, Font_FTFontParams should be used for passing "
                      "parameters")
  bool Init(const NCollection_String& theFontPath,
            unsigned int              thePointSize,
            unsigned int              theResolution)
  {
    Font_FTFontParams aParams;
    aParams.PointSize  = thePointSize;
    aParams.Resolution = theResolution;
    return Init(theFontPath.ToCString(), aParams, 0);
  }

  //! Initialize the font.
  //! @param theFontName   the font name
  //! @param theFontAspect the font style
  //! @param thePointSize  the face size in points (1/72 inch)
  //! @param theResolution the resolution of the target device in dpi
  //! @return true on success
  Standard_DEPRECATED("Deprecated method, Font_FTFontParams should be used for passing "
                      "parameters")
  bool Init(const NCollection_String& theFontName,
            Font_FontAspect           theFontAspect,
            unsigned int              thePointSize,
            unsigned int              theResolution)
  {
    Font_FTFontParams aParams;
    aParams.PointSize  = thePointSize;
    aParams.Resolution = theResolution;
    return FindAndInit(theFontName.ToCString(), theFontAspect, aParams);
  }

protected:
  //! Convert value to 26.6 fixed-point format for FT library API.
  template <typename theInput_t>
  int32_t toFTPoints(const theInput_t thePointSize) const
  {
    return (int32_t)thePointSize * 64;
  }

  //! Convert value from 26.6 fixed-point format for FT library API.
  template <typename theReturn_t, typename theFTUnits_t>
  inline theReturn_t fromFTPoints(const theFTUnits_t theFTUnits) const
  {
    return (theReturn_t)theFTUnits / 64.0f;
  }

protected:
  //! Load glyph without rendering it.
  Standard_EXPORT bool loadGlyph(const char32_t theUChar);

  //! Wrapper for FT_Get_Kerning - retrieve kerning values.
  Standard_EXPORT bool getKerning(FT_Vector& theKern,
                                  char32_t   theUCharCurr,
                                  char32_t   theUCharNext) const;

  //! Initialize fallback font.
  Standard_EXPORT bool findAndInitFallback(Font_UnicodeSubset theSubset);

  //! Enable/disable load flag.
  void setLoadFlag(int32_t theFlag, bool theToEnable)
  {
    if (theToEnable)
    {
      myLoadFlags |= theFlag;
    }
    else
    {
      myLoadFlags &= ~theFlag;
    }
  }

protected:
  occ::handle<Font_FTLibrary>     myFTLib;  //!< handle to the FT library object
  occ::handle<NCollection_Buffer> myBuffer; //!< memory buffer
  occ::handle<Font_FTFont>        myFallbackFaces[Font_UnicodeSubset_NB]; //!< fallback fonts
  FT_Face                         myFTFace;                               //!< FT face object
  FT_Face                         myActiveFTFace; //!< active FT face object (the main of fallback)
  TCollection_AsciiString         myFontPath;     //!< font path
  Font_FTFontParams               myFontParams;   //!< font initialization parameters
  Font_FontAspect                 myFontAspect;   //!< font initialization aspect
  float                           myWidthScaling; //!< scale glyphs along X-axis
  int32_t                         myLoadFlags;    //!< default load flags

  Image_PixMap myGlyphImg; //!< cached glyph plane
  char32_t     myUChar;    //!< currently loaded unicode character
  // clang-format off
  bool           myToUseUnicodeSubsetFallback; //!< use default fallback fonts for extended Unicode sub-sets (Korean, CJK, etc.)
  // clang-format on
};

#endif // _Font_FTFont_H__