FreeType初探---获取字体文本度量信息

     FT_Library library;
     FT_Error error = FT_Init_FreeType( &library );
     if ( error )
     {
         ;
     }
     FT_Face face;
     error = FT_New_Face( library, "C:\\Windows\\Fonts\\simsun.ttc", 0, &face );
     if ( error == FT_Err_Unknown_File_Format)
     {
         ;
     }
    //遍历字符集
     int iCharMapCnt = face->num_charmaps;
     FT_CharMap* pCharMaps = face->charmaps;
     for ( int i = 0; i < iCharMapCnt; i ++)
     {
         FT_CharMapRec aCharMap = *(pCharMaps[i]);
         FT_Encoding enconding = aCharMap.encoding;
         int platform_id = aCharMap.platform_id;
         int encoding_id = aCharMap.encoding_id;
     }

     //字体全局的东西、用字体单元来度量的。
     int iGlyphsCnt = face->num_glyphs;
     int iFaceNo = face->face_index;
     int iFace_Flags = face->face_flags;
     int iUints_Per_EM = face->units_per_EM;
     int ascender = (face->ascender );
     int descender = (face->descender);
     int height = (face->height);
     int max_advance_width = (face->max_advance_width);
     int max_advance_height = (face->max_advance_width);


     //通过每英寸72个点、使用多少个点来设置字的大小。
     FT_Set_Char_Size(face,0,16 * 64,720, 720);//每英寸720像素、那么每个点10像素、16点则160像素。
     FT_Size pSize = face->size;
     FT_Size_Metrics_ font_Size_Metrics = pSize->metrics;  //整个字体的数据。按字体单元换算而来。
     int iX_PPEM = font_Size_Metrics.x_ppem;
     int iY_PPEM = font_Size_Metrics.y_ppem;
     int iX_Scale = (font_Size_Metrics.x_scale + 63)>>6;
     int iY_Scale = (font_Size_Metrics.y_scale + 63)>>6;
     int iAscender = (font_Size_Metrics.ascender + 63)>>6;
     int iDescender = (font_Size_Metrics.descender + 63)>>6;
     int iHeight = (font_Size_Metrics.height + 63)>>6;
     int iMax_advance = (font_Size_Metrics.max_advance + 63)>>6;




     //直接通过像素来设置点的大小
     FT_Set_Pixel_Sizes(face,160,160);
     bool bScale = FT_IS_SCALABLE(face);
     pSize = face->size;
     font_Size_Metrics = pSize->metrics;
     iX_PPEM = font_Size_Metrics.x_ppem;
     iY_PPEM = font_Size_Metrics.y_ppem;
     iX_Scale = (font_Size_Metrics.x_scale + 63)>>6;
     iY_Scale = (font_Size_Metrics.y_scale + 63)>>6;
     iAscender = (font_Size_Metrics.ascender + 63)>>6;
     iDescender = (font_Size_Metrics.descender + 63)>>6;
     iHeight = (font_Size_Metrics.height + 63)>>6;
     iMax_advance = (font_Size_Metrics.max_advance + 63)>>6;

     //轮廓索引
     int iGlyphIndex = FT_Get_Char_Index(face,'A');
     FT_Int32 loadflags = FT_LOAD_DEFAULT|FT_LOAD_NO_BITMAP;
     error = FT_Load_Glyph(face,1105/*iGlyphIndex*/,loadflags);
     if(error)
     {
         ;
     }
     //字槽、即对单个字的描述
     FT_GlyphSlot pGlyphSlot = face->glyph;
     FT_Glyph_Metrics glphy_Metrics = pGlyphSlot->metrics;//单个字的数据。
     int iWordW = (glphy_Metrics.width + 63)>>6;
     int iWordH = (glphy_Metrics.height + 63)>>6;
     int iWordHBearingX = (glphy_Metrics.horiBearingX + 63)>>6;
     int iWordHBearingY = (glphy_Metrics.horiBearingY + 63)>>6;
     int iWordHAdd = (glphy_Metrics.horiAdvance + 63) >> 6;
     int iWordVBearingX = (glphy_Metrics.vertBearingX + 63)>>6;
     int iWordVBearingY = (glphy_Metrics.vertBearingY + 63)>>6;
     int iWordVAdd = (glphy_Metrics.vertAdvance + 63) >> 6;