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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 #include <memory>
     22 
     23 #include <minikin/FontFamily.h>
     24 #include <minikin/Hyphenator.h>
     25 
     26 // An abstraction for platform fonts, allowing Minikin to be used with
     27 // multiple actual implementations of fonts.
     28 
     29 namespace minikin {
     30 
     31 class MinikinFont;
     32 
     33 // Possibly move into own .h file?
     34 // Note: if you add a field here, either add it to LayoutCacheKey or to skipCache()
     35 struct MinikinPaint {
     36     MinikinPaint() : font(nullptr), size(0), scaleX(0), skewX(0), letterSpacing(0), wordSpacing(0),
     37             paintFlags(0), fakery(), hyphenEdit(), fontFeatureSettings() { }
     38 
     39     bool skipCache() const {
     40         return !fontFeatureSettings.empty();
     41     }
     42 
     43     MinikinFont *font;
     44     float size;
     45     float scaleX;
     46     float skewX;
     47     float letterSpacing;
     48     float wordSpacing;
     49     uint32_t paintFlags;
     50     FontFakery fakery;
     51     HyphenEdit hyphenEdit;
     52     std::string fontFeatureSettings;
     53 };
     54 
     55 // Only a few flags affect layout, but those that do should have values
     56 // consistent with Android's paint flags.
     57 enum MinikinPaintFlags {
     58     LinearTextFlag = 0x40,
     59 };
     60 
     61 struct MinikinRect {
     62     float mLeft, mTop, mRight, mBottom;
     63     bool isEmpty() const {
     64         return mLeft == mRight || mTop == mBottom;
     65     }
     66     void set(const MinikinRect& r) {
     67         mLeft = r.mLeft;
     68         mTop = r.mTop;
     69         mRight = r.mRight;
     70         mBottom = r.mBottom;
     71     }
     72     void offset(float dx, float dy) {
     73         mLeft += dx;
     74         mTop += dy;
     75         mRight += dx;
     76         mBottom += dy;
     77     }
     78     void setEmpty() {
     79         mLeft = mTop = mRight = mBottom = 0;
     80     }
     81     void join(const MinikinRect& r);
     82 };
     83 
     84 // Callback for freeing data
     85 typedef void (*MinikinDestroyFunc) (void* data);
     86 
     87 class MinikinFont {
     88 public:
     89     explicit MinikinFont(int32_t uniqueId) : mUniqueId(uniqueId) {}
     90 
     91     virtual ~MinikinFont();
     92 
     93     virtual float GetHorizontalAdvance(uint32_t glyph_id,
     94         const MinikinPaint &paint) const = 0;
     95 
     96     virtual void GetBounds(MinikinRect* bounds, uint32_t glyph_id,
     97         const MinikinPaint &paint) const = 0;
     98 
     99     // Override if font can provide access to raw data
    100     virtual const void* GetFontData() const {
    101         return nullptr;
    102     }
    103 
    104     // Override if font can provide access to raw data
    105     virtual size_t GetFontSize() const {
    106         return 0;
    107     }
    108 
    109     // Override if font can provide access to raw data.
    110     // Returns index within OpenType collection
    111     virtual int GetFontIndex() const {
    112         return 0;
    113     }
    114 
    115     virtual const std::vector<minikin::FontVariation>& GetAxes() const = 0;
    116 
    117     virtual std::shared_ptr<MinikinFont> createFontWithVariation(
    118             const std::vector<FontVariation>&) const {
    119         return nullptr;
    120     }
    121 
    122     static uint32_t MakeTag(char c1, char c2, char c3, char c4) {
    123         return ((uint32_t)c1 << 24) | ((uint32_t)c2 << 16) |
    124             ((uint32_t)c3 << 8) | (uint32_t)c4;
    125     }
    126 
    127     int32_t GetUniqueId() const { return mUniqueId; }
    128 private:
    129     const int32_t mUniqueId;
    130 };
    131 
    132 }  // namespace minikin
    133 
    134 #endif  // MINIKIN_FONT_H
    135