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      1 /*
      2  * Copyright (C) 2013 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef MINIKIN_FONT_H
     18 #define MINIKIN_FONT_H
     19 
     20 #include <string>
     21 
     22 #include <minikin/MinikinRefCounted.h>
     23 #include <minikin/FontFamily.h>
     24 
     25 // An abstraction for platform fonts, allowing Minikin to be used with
     26 // multiple actual implementations of fonts.
     27 
     28 namespace android {
     29 
     30 // The hyphen edit represents an edit to the string when a word is
     31 // hyphenated. The most common hyphen edit is adding a "-" at the end
     32 // of a syllable, but nonstandard hyphenation allows for more choices.
     33 class HyphenEdit {
     34 public:
     35     HyphenEdit() : hyphen(0) { }
     36     HyphenEdit(uint32_t hyphenInt) : hyphen(hyphenInt) { }
     37     bool hasHyphen() const { return hyphen != 0; }
     38     bool operator==(const HyphenEdit &other) const { return hyphen == other.hyphen; }
     39 private:
     40     uint32_t hyphen;
     41 };
     42 
     43 class MinikinFont;
     44 
     45 // Possibly move into own .h file?
     46 // Note: if you add a field here, either add it to LayoutCacheKey or to skipCache()
     47 struct MinikinPaint {
     48     MinikinPaint() : font(0), size(0), scaleX(0), skewX(0), letterSpacing(0), paintFlags(0),
     49             fakery(), fontFeatureSettings() { }
     50 
     51     bool skipCache() const {
     52         return !fontFeatureSettings.empty();
     53     }
     54 
     55     MinikinFont *font;
     56     float size;
     57     float scaleX;
     58     float skewX;
     59     float letterSpacing;
     60     uint32_t paintFlags;
     61     FontFakery fakery;
     62     HyphenEdit hyphenEdit;
     63     std::string fontFeatureSettings;
     64 };
     65 
     66 // Only a few flags affect layout, but those that do should have values
     67 // consistent with Android's paint flags.
     68 enum MinikinPaintFlags {
     69     LinearTextFlag = 0x40,
     70 };
     71 
     72 struct MinikinRect {
     73     float mLeft, mTop, mRight, mBottom;
     74     bool isEmpty() const {
     75         return mLeft == mRight || mTop == mBottom;
     76     }
     77     void set(const MinikinRect& r) {
     78         mLeft = r.mLeft;
     79         mTop = r.mTop;
     80         mRight = r.mRight;
     81         mBottom = r.mBottom;
     82     }
     83     void offset(float dx, float dy) {
     84         mLeft += dx;
     85         mTop += dy;
     86         mRight += dx;
     87         mBottom += dy;
     88     }
     89     void setEmpty() {
     90         mLeft = mTop = mRight = mBottom = 0;
     91     }
     92     void join(const MinikinRect& r);
     93 };
     94 
     95 class MinikinFontFreeType;
     96 
     97 // Callback for freeing data
     98 typedef void (*MinikinDestroyFunc) (void* data);
     99 
    100 class MinikinFont : public MinikinRefCounted {
    101 public:
    102     MinikinFont(int32_t uniqueId) : mUniqueId(uniqueId) {}
    103 
    104     virtual ~MinikinFont();
    105 
    106     virtual float GetHorizontalAdvance(uint32_t glyph_id,
    107         const MinikinPaint &paint) const = 0;
    108 
    109     virtual void GetBounds(MinikinRect* bounds, uint32_t glyph_id,
    110         const MinikinPaint &paint) const = 0;
    111 
    112     virtual const void* GetTable(uint32_t tag, size_t* size, MinikinDestroyFunc* destroy) = 0;
    113 
    114     // Override if font can provide access to raw data
    115     virtual const void* GetFontData() const {
    116         return nullptr;
    117     }
    118 
    119     // Override if font can provide access to raw data
    120     virtual size_t GetFontSize() const {
    121         return 0;
    122     }
    123 
    124     // Override if font can provide access to raw data.
    125     // Returns index within OpenType collection
    126     virtual int GetFontIndex() const {
    127         return 0;
    128     }
    129 
    130     static uint32_t MakeTag(char c1, char c2, char c3, char c4) {
    131         return ((uint32_t)c1 << 24) | ((uint32_t)c2 << 16) |
    132             ((uint32_t)c3 << 8) | (uint32_t)c4;
    133     }
    134 
    135     int32_t GetUniqueId() const { return mUniqueId; }
    136 private:
    137     const int32_t mUniqueId;
    138 };
    139 
    140 }  // namespace android
    141 
    142 #endif  // MINIKIN_FONT_H
    143