Fix text cutoff

Signed-off-by: x7z4w <x7z4w@noreply.codeberg.org>

base/string_utils.cpp

@@ -5,6 +5,7 @@
 
 #include <algorithm>
 #include <cmath>
+#include <cstddef>
 #include <iomanip>
 #include <iterator>
 
@@ -269,6 +270,48 @@ void Trim(std::string & s, std::string_view anyOf)
   boost::trim_if(s, boost::is_any_of(anyOf));
 }
 
+bool Truncate(std::string & utf8, size_t const maxTextLengthPlus1)
+{
+  size_t codePoints = 0;
+
+  for (size_t i = 0; i < utf8.length(); ++i)
+  {
+    if ((utf8[i] & 0xC0) != 0x80)
+    {
+      ++codePoints;
+
+      if (codePoints == maxTextLengthPlus1)
+      {
+        --i;
+
+        unsigned char byte = utf8[i];
+        uint8_t bytesInCodepoint = 1;
+
+        if ((byte & 0x80) == 0x00)
+        {
+          bytesInCodepoint = 1;
+        }
+        else if ((byte & 0xE0) == 0xC0)
+        {
+          bytesInCodepoint = 2;
+        }
+        else if ((byte & 0xF0) == 0xE0)
+        {
+          bytesInCodepoint = 3;
+        }
+        else if ((byte & 0xF8) == 0xF0)
+        {
+          bytesInCodepoint = 4;
+        }
+
+        utf8.resize(i + bytesInCodepoint);
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
 bool ReplaceFirst(std::string & str, std::string const & from, std::string const & to)
 {
   auto const pos = str.find(from);

base/string_utils.hpp

@@ -114,6 +114,8 @@ void Trim(std::string_view & sv);
 void Trim(std::string_view & s, std::string_view anyOf);
 void Trim(std::string & s, std::string_view anyOf);
 
+bool Truncate(std::string & utf8, size_t const maxTextLengthPlus1);
+
 // Replace the first match of the search substring in the input with the format string.
 // str - An input string
 // from - A substring to be searched for

drape_frontend/stylist.cpp

@@ -6,6 +6,8 @@
 #include "indexer/feature_visibility.hpp"
 #include "indexer/scales.hpp"
 
+#include "base/string_utils.hpp"
+
 #include <algorithm>
 #include <limits>
 
@@ -72,10 +74,10 @@ void CaptionDescription::Init(FeatureType & f, int8_t deviceLang, int zoomLevel,
     return;
   }
 
-  // Set max text size to avoid VB/IB overflow in rendering.
-  size_t constexpr kMaxTextSize = 200;
-  if (m_mainText.size() > kMaxTextSize)
-    m_mainText = m_mainText.substr(0, kMaxTextSize) + "...";
+  // Set max text length to avoid VB/IB overflow in rendering.
+  size_t constexpr kMaxTextLength = 65; 
+  if (strings::Truncate(&m_mainText, kMaxTextLength))
+    m_mainText += "…";
 
   // TODO(pastk) : its better to determine housenumbers minZoom once upon drules load and cache it,
   // but it'd mean a lot of housenumbers-specific logic in otherwise generic RulesHolder..