dali-toolkit/internal/text/glyph-metrics-helper.cpp

   1
   2 /*
   3  * Copyright (c) 2022 Samsung Electronics Co., Ltd.
   4  *
   5  * Licensed under the Apache License, Version 2.0 (the "License");
   6  * you may not use this file except in compliance with the License.
   7  * You may obtain a copy of the License at
   8  *
   9  * http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing, software
  12  * distributed under the License is distributed on an "AS IS" BASIS,
  13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14  * See the License for the specific language governing permissions and
  15  * limitations under the License.
  16  *
  17  */
  18
  19 // FILE HEADER
  20 #include <dali-toolkit/internal/text/glyph-metrics-helper.h>
  21
  22 namespace Dali
  23 {
  24 namespace Toolkit
  25 {
  26 namespace Text
  27 {
  28 Length GetNumberOfGlyphsOfGroup(GlyphIndex          glyphIndex,
  29                                 GlyphIndex          lastGlyphPlusOne,
  30                                 const Length* const charactersPerGlyphBuffer)
  31 {
  32   Length numberOfGLyphsInGroup = 1u;
  33
  34   for(GlyphIndex index = glyphIndex; index < lastGlyphPlusOne; ++index)
  35   {
  36     if(0u == *(charactersPerGlyphBuffer + index))
  37     {
  38       ++numberOfGLyphsInGroup;
  39     }
  40     else
  41     {
  42       break;
  43     }
  44   }
  45
  46   return numberOfGLyphsInGroup;
  47 }
  48
  49 void GetGlyphsMetrics(GlyphIndex             glyphIndex,
  50                       Length                 numberOfGlyphs,
  51                       GlyphMetrics&          glyphMetrics,
  52                       const GlyphInfo* const glyphsBuffer,
  53                       MetricsPtr&            metrics,
  54                       float                  calculatedAdvance)
  55 {
  56   const GlyphInfo& firstGlyph = *(glyphsBuffer + glyphIndex);
  57
  58   Text::FontMetrics fontMetrics;
  59   if(0u != firstGlyph.fontId)
  60   {
  61     metrics->GetFontMetrics(firstGlyph.fontId, fontMetrics);
  62   }
  63   else if(0u != firstGlyph.index)
  64   {
  65     // It may be an embedded image.
  66     fontMetrics.ascender  = firstGlyph.height;
  67     fontMetrics.descender = 0.f;
  68     fontMetrics.height    = fontMetrics.ascender;
  69   }
  70
  71   const bool isItalicFont = metrics->HasItalicStyle(firstGlyph.fontId);
  72
  73   glyphMetrics.fontId     = firstGlyph.fontId;
  74   glyphMetrics.fontHeight = fontMetrics.height;
  75   glyphMetrics.width      = firstGlyph.width;
  76   glyphMetrics.advance    = calculatedAdvance;
  77   glyphMetrics.ascender   = fontMetrics.ascender;
  78   glyphMetrics.xBearing   = firstGlyph.xBearing;
  79
  80   if(1u < numberOfGlyphs)
  81   {
  82     float maxWidthEdge = firstGlyph.xBearing + firstGlyph.width;
  83
  84     for(unsigned int i = 1u; i < numberOfGlyphs; ++i)
  85     {
  86       const GlyphInfo& glyphInfo = *(glyphsBuffer + glyphIndex + i);
  87
  88       // update the initial xBearing if smaller.
  89       glyphMetrics.xBearing = std::min(glyphMetrics.xBearing, glyphMetrics.advance + glyphInfo.xBearing);
  90
  91       // update the max width edge if bigger.
  92       const float currentMaxGlyphWidthEdge = glyphMetrics.advance + glyphInfo.xBearing + glyphInfo.width;
  93       maxWidthEdge                         = std::max(maxWidthEdge, currentMaxGlyphWidthEdge);
  94
  95       glyphMetrics.advance += (glyphInfo.advance);
  96     }
  97
  98     glyphMetrics.width = maxWidthEdge - glyphMetrics.xBearing;
  99   }
 100
 101   glyphMetrics.width += (firstGlyph.isItalicRequired && !isItalicFont) ? TextAbstraction::FontClient::DEFAULT_ITALIC_ANGLE * firstGlyph.height : 0.f;
 102 }
 103
 104 void GetGlyphMetricsFromCharacterIndex(CharacterIndex         index,
 105                                        const VisualModelPtr&  visualModel,
 106                                        const LogicalModelPtr& logicalModel,
 107                                        MetricsPtr&            metrics,
 108                                        GlyphMetrics&          glyphMetrics,
 109                                        GlyphIndex&            glyphIndex,
 110                                        Length&                numberOfGlyphs)
 111 {
 112   const GlyphIndex* const charactersToGlyphBuffer   = visualModel->mCharactersToGlyph.Begin();
 113   const Length* const     glyphsPerCharacterBuffer  = visualModel->mGlyphsPerCharacter.Begin();
 114   const GlyphInfo* const  glyphInfoBuffer           = visualModel->mGlyphs.Begin();
 115   Vector<CharacterIndex>& glyphToCharacterMap       = visualModel->mGlyphsToCharacters;
 116   const CharacterIndex*   glyphToCharacterMapBuffer = glyphToCharacterMap.Begin();
 117   const float             characterSpacing          = visualModel->GetCharacterSpacing();
 118
 119   //Takes the character index, obtains the glyph index (and the number of Glyphs) from it and finally gets the glyph metrics.
 120   glyphIndex     = *(charactersToGlyphBuffer + index);
 121   numberOfGlyphs = *(glyphsPerCharacterBuffer + index);
 122
 123   float calculatedAdvance = 0.f;
 124
 125   calculatedAdvance = GetCalculatedAdvance(*(logicalModel->mText.Begin() + (*(glyphToCharacterMapBuffer + glyphIndex))), characterSpacing, (*(visualModel->mGlyphs.Begin() + glyphIndex)).advance);
 126
 127   // Get the metrics for the group of glyphs.
 128   GetGlyphsMetrics(glyphIndex,
 129                    numberOfGlyphs,
 130                    glyphMetrics,
 131                    glyphInfoBuffer,
 132                    metrics,
 133                    calculatedAdvance);
 134 }
 135
 136 float GetCalculatedAdvance(unsigned int character, float characterSpacing, float advance)
 137 {
 138   //Gets the final advance value by adding the CharacterSpacing value to it
 139   //In some cases the CharacterSpacing should not be added. Ex: when the glyph is a ZWSP (Zero Width Space)
 140   return (TextAbstraction::IsZeroWidthNonJoiner(character) || TextAbstraction::IsZeroWidthJoiner(character) ||
 141           TextAbstraction::IsZeroWidthSpace(character) || TextAbstraction::IsNewParagraph(character) ||
 142           TextAbstraction::IsLeftToRightMark(character) || TextAbstraction::IsRightToLeftMark(character))
 143            ? advance
 144            : advance + characterSpacing;
 145 }
 146
 147 } // namespace Text
 148
 149 } // namespace Toolkit
 150
 151 } // namespace Dali