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      1 /*
      2  * Copyright 2013 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #include "SkFontMgr.h"
      9 #include "SkFontStyle.h"
     10 #include "SkFontConfigInterface.h"
     11 #include "SkFontConfigTypeface.h"
     12 #include "SkMath.h"
     13 #include "SkString.h"
     14 #include "SkTDArray.h"
     15 
     16 // for now we pull these in directly. eventually we will solely rely on the
     17 // SkFontConfigInterface instance.
     18 #include <fontconfig/fontconfig.h>
     19 #include <unistd.h>
     20 
     21 // borrow this global from SkFontHost_fontconfig. eventually that file should
     22 // go away, and be replaced with this one.
     23 extern SkFontConfigInterface* SkFontHost_fontconfig_ref_global();
     24 static SkFontConfigInterface* RefFCI() {
     25     return SkFontHost_fontconfig_ref_global();
     26 }
     27 
     28 // look for the last substring after a '/' and return that, or return null.
     29 static const char* find_just_name(const char* str) {
     30     const char* last = strrchr(str, '/');
     31     return last ? last + 1 : NULL;
     32 }
     33 
     34 static bool is_lower(char c) {
     35     return c >= 'a' && c <= 'z';
     36 }
     37 
     38 static int get_int(FcPattern* pattern, const char field[]) {
     39     int value;
     40     if (FcPatternGetInteger(pattern, field, 0, &value) != FcResultMatch) {
     41         value = SK_MinS32;
     42     }
     43     return value;
     44 }
     45 
     46 static const char* get_name(FcPattern* pattern, const char field[]) {
     47     const char* name;
     48     if (FcPatternGetString(pattern, field, 0, (FcChar8**)&name) != FcResultMatch) {
     49         name = "";
     50     }
     51     return name;
     52 }
     53 
     54 static bool valid_pattern(FcPattern* pattern) {
     55     FcBool is_scalable;
     56     if (FcPatternGetBool(pattern, FC_SCALABLE, 0, &is_scalable) != FcResultMatch || !is_scalable) {
     57         return false;
     58     }
     59 
     60     // fontconfig can also return fonts which are unreadable
     61     const char* c_filename = get_name(pattern, FC_FILE);
     62     if (0 == *c_filename) {
     63         return false;
     64     }
     65     if (access(c_filename, R_OK) != 0) {
     66         return false;
     67     }
     68     return true;
     69 }
     70 
     71 static bool match_name(FcPattern* pattern, const char family_name[]) {
     72     return !strcasecmp(family_name, get_name(pattern, FC_FAMILY));
     73 }
     74 
     75 static FcPattern** MatchFont(FcFontSet* font_set,
     76                              const char post_config_family[],
     77                              int* count) {
     78   // Older versions of fontconfig have a bug where they cannot select
     79   // only scalable fonts so we have to manually filter the results.
     80 
     81     FcPattern** iter = font_set->fonts;
     82     FcPattern** stop = iter + font_set->nfont;
     83     // find the first good match
     84     for (; iter < stop; ++iter) {
     85         if (valid_pattern(*iter)) {
     86             break;
     87         }
     88     }
     89 
     90     if (iter == stop || !match_name(*iter, post_config_family)) {
     91         return NULL;
     92     }
     93 
     94     FcPattern** firstIter = iter++;
     95     for (; iter < stop; ++iter) {
     96         if (!valid_pattern(*iter) || !match_name(*iter, post_config_family)) {
     97             break;
     98         }
     99     }
    100 
    101     *count = iter - firstIter;
    102     return firstIter;
    103 }
    104 
    105 class SkFontStyleSet_FC : public SkFontStyleSet {
    106 public:
    107     SkFontStyleSet_FC(FcPattern** matches, int count);
    108     virtual ~SkFontStyleSet_FC();
    109 
    110     virtual int count() SK_OVERRIDE { return fRecCount; }
    111     virtual void getStyle(int index, SkFontStyle*, SkString* style) SK_OVERRIDE;
    112     virtual SkTypeface* createTypeface(int index) SK_OVERRIDE;
    113     virtual SkTypeface* matchStyle(const SkFontStyle& pattern) SK_OVERRIDE;
    114 
    115 private:
    116     struct Rec {
    117         SkString    fStyleName;
    118         SkString    fFileName;
    119         SkFontStyle fStyle;
    120     };
    121     Rec* fRecs;
    122     int  fRecCount;
    123 };
    124 
    125 static int map_range(int value,
    126                      int old_min, int old_max, int new_min, int new_max) {
    127     SkASSERT(old_min < old_max);
    128     SkASSERT(new_min < new_max);
    129     return new_min + SkMulDiv(value - old_min,
    130                               new_max - new_min, old_max - old_min);
    131 }
    132 
    133 static SkFontStyle make_fontconfig_style(FcPattern* match) {
    134     int weight = get_int(match, FC_WEIGHT);
    135     int width = get_int(match, FC_WIDTH);
    136     int slant = get_int(match, FC_SLANT);
    137 //    SkDebugf("old weight %d new weight %d\n", weight, map_range(weight, 0, 80, 0, 400));
    138 
    139     // fontconfig weight seems to be 0..200 or so, so we remap it here
    140     weight = map_range(weight, 0, 80, 0, 400);
    141     width = map_range(width, 0, 200, 0, 9);
    142     return SkFontStyle(weight, width, slant > 0 ? SkFontStyle::kItalic_Slant
    143                                                 : SkFontStyle::kUpright_Slant);
    144 }
    145 
    146 SkFontStyleSet_FC::SkFontStyleSet_FC(FcPattern** matches, int count) {
    147     fRecCount = count;
    148     fRecs = SkNEW_ARRAY(Rec, count);
    149     for (int i = 0; i < count; ++i) {
    150         fRecs[i].fStyleName.set(get_name(matches[i], FC_STYLE));
    151         fRecs[i].fFileName.set(get_name(matches[i], FC_FILE));
    152         fRecs[i].fStyle = make_fontconfig_style(matches[i]);
    153     }
    154 }
    155 
    156 SkFontStyleSet_FC::~SkFontStyleSet_FC() {
    157     SkDELETE_ARRAY(fRecs);
    158 }
    159 
    160 void SkFontStyleSet_FC::getStyle(int index, SkFontStyle* style,
    161                                  SkString* styleName) {
    162     SkASSERT((unsigned)index < (unsigned)fRecCount);
    163     if (style) {
    164         *style = fRecs[index].fStyle;
    165     }
    166     if (styleName) {
    167         *styleName = fRecs[index].fStyleName;
    168     }
    169 }
    170 
    171 SkTypeface* SkFontStyleSet_FC::createTypeface(int index) {
    172     return NULL;
    173 }
    174 
    175 SkTypeface* SkFontStyleSet_FC::matchStyle(const SkFontStyle& pattern) {
    176     return NULL;
    177 }
    178 
    179 class SkFontMgr_fontconfig : public SkFontMgr {
    180     SkAutoTUnref<SkFontConfigInterface> fFCI;
    181     SkDataTable* fFamilyNames;
    182 
    183     void init() {
    184         if (!fFamilyNames) {
    185             fFamilyNames = fFCI->getFamilyNames();
    186         }
    187     }
    188 
    189 public:
    190     SkFontMgr_fontconfig(SkFontConfigInterface* fci)
    191         : fFCI(fci)
    192         , fFamilyNames(NULL) {}
    193 
    194     virtual ~SkFontMgr_fontconfig() {
    195         SkSafeUnref(fFamilyNames);
    196     }
    197 
    198 protected:
    199     virtual int onCountFamilies() {
    200         this->init();
    201         return fFamilyNames->count();
    202     }
    203 
    204     virtual void onGetFamilyName(int index, SkString* familyName) {
    205         this->init();
    206         familyName->set(fFamilyNames->atStr(index));
    207     }
    208 
    209     virtual SkFontStyleSet* onCreateStyleSet(int index) {
    210         this->init();
    211         return this->onMatchFamily(fFamilyNames->atStr(index));
    212     }
    213 
    214     virtual SkFontStyleSet* onMatchFamily(const char familyName[]) {
    215         this->init();
    216 
    217         FcPattern* pattern = FcPatternCreate();
    218 
    219         FcPatternAddString(pattern, FC_FAMILY, (FcChar8*)familyName);
    220 #if 0
    221         FcPatternAddBool(pattern, FC_SCALABLE, FcTrue);
    222 #endif
    223         FcConfigSubstitute(NULL, pattern, FcMatchPattern);
    224         FcDefaultSubstitute(pattern);
    225 
    226         const char* post_config_family = get_name(pattern, FC_FAMILY);
    227 
    228         FcResult result;
    229         FcFontSet* font_set = FcFontSort(0, pattern, 0, 0, &result);
    230         if (!font_set) {
    231             FcPatternDestroy(pattern);
    232             return NULL;
    233         }
    234 
    235         int count;
    236         FcPattern** match = MatchFont(font_set, post_config_family, &count);
    237         if (!match) {
    238             FcPatternDestroy(pattern);
    239             FcFontSetDestroy(font_set);
    240             return NULL;
    241         }
    242 
    243         FcPatternDestroy(pattern);
    244 
    245         SkTDArray<FcPattern*> trimmedMatches;
    246         for (int i = 0; i < count; ++i) {
    247             const char* justName = find_just_name(get_name(match[i], FC_FILE));
    248             if (!is_lower(*justName)) {
    249                 *trimmedMatches.append() = match[i];
    250             }
    251         }
    252 
    253         SkFontStyleSet_FC* sset = SkNEW_ARGS(SkFontStyleSet_FC,
    254                                              (trimmedMatches.begin(),
    255                                               trimmedMatches.count()));
    256         return sset;
    257     }
    258 
    259     virtual SkTypeface* onMatchFamilyStyle(const char familyName[],
    260                                            const SkFontStyle&) { return NULL; }
    261     virtual SkTypeface* onMatchFaceStyle(const SkTypeface*,
    262                                          const SkFontStyle&) { return NULL; }
    263 
    264     virtual SkTypeface* onCreateFromData(SkData*, int ttcIndex) { return NULL; }
    265 
    266     virtual SkTypeface* onCreateFromStream(SkStream* stream, int ttcIndex) {
    267         const size_t length = stream->getLength();
    268         if (!length) {
    269             return NULL;
    270         }
    271         if (length >= 1024 * 1024 * 1024) {
    272             return NULL;  // don't accept too large fonts (>= 1GB) for safety.
    273         }
    274 
    275         // TODO should the caller give us the style?
    276         SkTypeface::Style style = SkTypeface::kNormal;
    277         SkTypeface* face = SkNEW_ARGS(FontConfigTypeface, (style, stream));
    278         return face;
    279     }
    280 
    281     virtual SkTypeface* onCreateFromFile(const char path[], int ttcIndex) {
    282         SkAutoTUnref<SkStream> stream(SkStream::NewFromFile(path));
    283         return stream.get() ? this->createFromStream(stream, ttcIndex) : NULL;
    284     }
    285 
    286     virtual SkTypeface* onLegacyCreateTypeface(const char familyName[],
    287                                                unsigned styleBits) SK_OVERRIDE {
    288         return FontConfigTypeface::LegacyCreateTypeface(NULL, familyName,
    289                                                   (SkTypeface::Style)styleBits);
    290     }
    291 };
    292 
    293 SkFontMgr* SkFontMgr::Factory() {
    294     SkFontConfigInterface* fci = RefFCI();
    295     return fci ? SkNEW_ARGS(SkFontMgr_fontconfig, (fci)) : NULL;
    296 }
    297