Improve text wrapping when multiple characters are combined into one …

…glyph.

#1923

src/modules/font/GenericShaper.cpp

@@ -151,8 +151,7 @@ int GenericShaper::computeWordWrapIndex(const ColoredCodepoints &codepoints, Ran
  float w = 0.0f;
  float outwidth = 0.0f;
  float widthbeforelastspace = 0.0f;
- int wrapindex = -1;
- int lastspaceindex = -1;
+ int firstindexafterspace = -1;
 
  for (int i = (int)range.getMin(); i <= (int)range.getMax(); i++)
  {
@@ -166,37 +165,48 @@ int GenericShaper::computeWordWrapIndex(const ColoredCodepoints &codepoints, Ran
 
  float newwidth = w + getKerning(prevglyph, g) + getGlyphAdvance(g);
 
- // Only wrap when there's a non-space character.
- if (newwidth > wraplimit && !isWhitespace(g))
- {
- // Rewind to the last seen space when wrapping.
- if (lastspaceindex != -1)
- {
- wrapindex = lastspaceindex;
- outwidth = widthbeforelastspace;
- }
- break;
- }
-
  // Don't count trailing spaces in the output width.
  if (isWhitespace(g))
  {
- lastspaceindex = i;
  if (!isWhitespace(prevglyph))
  widthbeforelastspace = w;
  }
  else
+ {
+ if (isWhitespace(prevglyph))
+ firstindexafterspace = i;
+
+ // Only wrap when there's a non-space character.
+ if (newwidth > wraplimit)
+ {
+ // If this is the first character, wrap from the next one instead of this one.
+ int wrapindex = i > (int)range.first ? i : (int)range.first + 1;
+
+ // Rewind to after the last seen space when wrapping.
+ if (firstindexafterspace != -1)
+ {
+ wrapindex = firstindexafterspace;
+ outwidth = widthbeforelastspace;
+ }
+
+ if (width)
+ *width = outwidth;
+
+ return wrapindex;
+ }
+
  outwidth = newwidth;
+ }
 
  w = newwidth;
  prevglyph = g;
- wrapindex = i;
  }
 
  if (width)
  *width = outwidth;
 
- return wrapindex;
+ // There wasn't any wrap in the middle of the range.
+ return range.last + 1;
 }
 
 } // font

src/modules/font/TextShaper.cpp

@@ -303,10 +303,10 @@ void TextShaper::getWrap(const ColoredCodepoints &codepoints, float wraplimit, s
  float width = 0.0f;
  int wrapindex = computeWordWrapIndex(codepoints, r, wraplimit, &width);
 
- if (wrapindex >= (int) i)
+ if (wrapindex > (int) i)
  {
- r = Range(i, (size_t) wrapindex + 1 - i);
- i = (size_t)wrapindex + 1;
+ r = Range(i, (size_t) wrapindex - i);
+ i = (size_t)wrapindex;
  }
  else
  {

src/modules/font/freetype/HarfbuzzShaper.cpp

@@ -335,8 +335,7 @@ int HarfbuzzShaper::computeWordWrapIndex(const ColoredCodepoints &codepoints, Ra
  float w = 0.0f;
  float outwidth = 0.0f;
  float widthbeforelastspace = 0.0f;
- int wrapindex = -1;
- int lastspaceindex = -1;
+ int firstindexafterspace = -1;
 
  uint32 prevcodepoint = 0;
 
@@ -376,38 +375,49 @@ int HarfbuzzShaper::computeWordWrapIndex(const ColoredCodepoints &codepoints, Ra
 
  float newwidth = w + floorf((glyphpos.x_advance >> 6) / dpiScales[0] + 0.5f);
 
- // Only wrap when there's a non-space character.
- if (newwidth > wraplimit && !isWhitespace(clustercodepoint))
- {
- // Rewind to the last seen space when wrapping.
- if (lastspaceindex != -1)
- {
- wrapindex = lastspaceindex;
- outwidth = widthbeforelastspace;
- }
- break;
- }
-
  // Don't count trailing spaces in the output width.
  if (isWhitespace(clustercodepoint))
  {
- lastspaceindex = info.cluster;
  if (!isWhitespace(prevcodepoint))
  widthbeforelastspace = w;
  }
  else
+ {
+ if (isWhitespace(prevcodepoint))
+ firstindexafterspace = info.cluster;
+
+ // Only wrap when there's a non-space character.
+ if (newwidth > wraplimit)
+ {
+ // If this is the first character, wrap from the next one instead of this one.
+ int wrapindex = info.cluster > (int) range.first ? info.cluster : (int) range.first + 1;
+
+ // Rewind to after the last seen space when wrapping.
+ if (firstindexafterspace != -1)
+ {
+ wrapindex = firstindexafterspace;
+ outwidth = widthbeforelastspace;
+ }
+
+ if (width)
+ *width = outwidth;
+
+ return wrapindex;
+ }
+
  outwidth = newwidth;
+ }
 
  w = newwidth;
  prevcodepoint = clustercodepoint;
- wrapindex = info.cluster;
  }
  }
 
  if (width)
  *width = outwidth;
 
- return wrapindex;
+ // There wasn't any wrap in the middle of the range.
+ return (int) range.last + 1;
 }
 
 } // freetype