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      1 /*
      2  * Copyright 2011 Google Inc. All Rights Reserved.
      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 SFNTLY_CPP_SRC_SFNTLY_TABLE_CORE_HORIZONTAL_METRICS_TABLE_H_
     18 #define SFNTLY_CPP_SRC_SFNTLY_TABLE_CORE_HORIZONTAL_METRICS_TABLE_H_
     19 
     20 #include "sfntly/table/table.h"
     21 #include "sfntly/table/table_based_table_builder.h"
     22 
     23 namespace sfntly {
     24 
     25 // A Horizontal Metrics table - 'hmtx'.
     26 class HorizontalMetricsTable : public Table,
     27                                public RefCounted<HorizontalMetricsTable> {
     28  public:
     29   // Builder for a Horizontal Metrics Table - 'hmtx'.
     30   class Builder : public TableBasedTableBuilder, public RefCounted<Builder> {
     31    public:
     32     // Constructor scope altered to public because C++ does not allow base
     33     // class to instantiate derived class with protected constructors.
     34     Builder(Header* header, WritableFontData* data);
     35     Builder(Header* header, ReadableFontData* data);
     36     virtual ~Builder();
     37 
     38     virtual CALLER_ATTACH FontDataTable* SubBuildTable(ReadableFontData* data);
     39     static CALLER_ATTACH Builder* CreateBuilder(Header* header,
     40                                                 WritableFontData* data);
     41 
     42     void SetNumberOfHMetrics(int32_t num_hmetrics);
     43     void SetNumGlyphs(int32_t num_glyphs);
     44 
     45    private:
     46     int32_t num_hmetrics_;
     47     int32_t num_glyphs_;
     48   };
     49 
     50   virtual ~HorizontalMetricsTable();
     51   int32_t NumberOfHMetrics();
     52   int32_t NumberOfLSBs();
     53   int32_t HMetricAdvanceWidth(int32_t entry);
     54   int32_t HMetricLSB(int32_t entry);
     55   int32_t LsbTableEntry(int32_t entry);
     56   int32_t AdvanceWidth(int32_t glyph_id);
     57   int32_t LeftSideBearing(int32_t glyph_id);
     58 
     59  private:
     60   struct Offset {
     61     enum {
     62       // hMetrics
     63       kHMetricsStart = 0,
     64       kHMetricsSize = 4,
     65 
     66       // Offset within an hMetric
     67       kHMetricsAdvanceWidth = 0,
     68       kHMetricsLeftSideBearing = 2,
     69 
     70       kLeftSideBearingSize = 2
     71     };
     72   };
     73 
     74   HorizontalMetricsTable(Header* header,
     75                          ReadableFontData* data,
     76                          int32_t num_hmetrics,
     77                          int32_t num_glyphs);
     78 
     79   int32_t num_hmetrics_;
     80   int32_t num_glyphs_;
     81 };
     82 typedef Ptr<HorizontalMetricsTable> HorizontalMetricsTablePtr;
     83 typedef Ptr<HorizontalMetricsTable::Builder> HorizontalMetricsTableBuilderPtr;
     84 
     85 }  // namespace sfntly
     86 
     87 #endif  // SFNTLY_CPP_SRC_SFNTLY_TABLE_CORE_HORIZONTAL_METRICS_TABLE_H_
     88