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      1 /*
      2  * Copyright 2009, The Android Open Source Project
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  *  * Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  *  * Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     14  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     15  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     16  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
     17  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     19  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
     20  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     21  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     22  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     23  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     24  * SUCH DAMAGE.
     25  */
     26 
     27 #ifndef android_EmojiFont_DEFINED
     28 #define android_EmojiFont_DEFINED
     29 
     30 #include "SkScalar.h"
     31 #include "SkUtils.h"
     32 
     33 class SkCanvas;
     34 class SkPaint;
     35 
     36 namespace android {
     37 
     38     class EmojiFont {
     39     public:
     40         /** Returns true if the underlying emoji font mechanism is available.
     41          */
     42         static bool IsAvailable();
     43 
     44         /** Returns index for the corresponding index to the emoji table, or 0
     45             if there is no matching emoji form.
     46          */
     47         static uint16_t UnicharToGlyph(int32_t unichar);
     48 
     49         /** Returns true if the specified glyph is in the emoji range, i.e. was
     50             returned by UnicharToGlyph or UTF16ToGlyph.
     51          */
     52         static bool IsEmojiGlyph(uint16_t index) {
     53             return index >= kGlyphBase;
     54         }
     55 
     56         /** Returns the advance width for the specified emoji form.
     57          */
     58         static SkScalar GetAdvanceWidth(uint16_t index, const SkPaint& paint);
     59 
     60         /** Draw the specified emoji form, given the x,y origin of the text
     61             version. The paint is the one associated with the text that has
     62             the emoji in it.
     63          */
     64         static void Draw(SkCanvas*, uint16_t index, SkScalar x, SkScalar y,
     65                          const SkPaint& paint);
     66 
     67         /** Returns the conver name for Shift_JIS (one of Japanese charset)
     68          */
     69         static const char* GetShiftJisConverterName();
     70     private:
     71         enum {
     72             /*  this is our internal trick to embedded private emoji glyph IDs
     73                 along side normal glyphs IDs that come from real fonts. The
     74                 assumption is that normal fonts never will report a glyph ID
     75                 above 20K or 30K, so 64000 should always be a safe starting
     76                 index. We also assume the the number of emoji will not overflow
     77                 16bits starting at 64000 i.e. 65535 - 64000 > total emoji count
     78              */
     79             kGlyphBase = 64000
     80         };
     81     };
     82 }
     83 
     84 #endif
     85