diff --git a/src/applications/calendar/query/PhabricatorCalendarEventSearchEngine.php b/src/applications/calendar/query/PhabricatorCalendarEventSearchEngine.php
--- a/src/applications/calendar/query/PhabricatorCalendarEventSearchEngine.php
+++ b/src/applications/calendar/query/PhabricatorCalendarEventSearchEngine.php
@@ -214,8 +214,9 @@
         ->setBarColor($color)
         ->addByline(pht('Creator: %s', $creator_handle->renderLink()))
         ->addAttribute(pht('From %s to %s', $from, $to))
-        ->addAttribute(
-            phutil_utf8_shorten($event->getDescription(), 64));
+        ->addAttribute(id(new PhutilUTF8StringTruncator())
+          ->setMaximumGlyphs(64)
+          ->truncateString($event->getDescription()));
 
       $list->addItem($item);
     }
diff --git a/src/applications/chatlog/controller/PhabricatorChatLogChannelLogController.php b/src/applications/chatlog/controller/PhabricatorChatLogChannelLogController.php
--- a/src/applications/chatlog/controller/PhabricatorChatLogChannelLogController.php
+++ b/src/applications/chatlog/controller/PhabricatorChatLogChannelLogController.php
@@ -108,7 +108,9 @@
     $out = array();
     foreach ($blocks as $block) {
       $author = $block['author'];
-      $author = phutil_utf8_shorten($author, 18);
+      $author = id(new PhutilUTF8StringTruncator())
+        ->setMaximumGlyphs(18)
+        ->truncateString($author);
       $author = phutil_tag('td', array('class' => 'author'), $author);
 
       $href = $uri->alter('at', $block['id']);
diff --git a/src/applications/conduit/method/ConduitConnectConduitAPIMethod.php b/src/applications/conduit/method/ConduitConnectConduitAPIMethod.php
--- a/src/applications/conduit/method/ConduitConnectConduitAPIMethod.php
+++ b/src/applications/conduit/method/ConduitConnectConduitAPIMethod.php
@@ -59,9 +59,9 @@
     $client = $request->getValue('client');
     $client_version = (int)$request->getValue('clientVersion');
     $client_description = (string)$request->getValue('clientDescription');
-    // TODO: This should be character-oriented, not display-oriented.
-    // See T3307.
-    $client_description = phutil_utf8_shorten($client_description, 255);
+    $client_description = id(new PhutilUTF8StringTruncator())
+      ->setMaximumCodepoints(255)
+      ->truncateString($client_description);
     $username = (string)$request->getValue('user');
 
     // Log the connection, regardless of the outcome of checks below.
diff --git a/src/applications/conpherence/view/ConpherenceFileWidgetView.php b/src/applications/conpherence/view/ConpherenceFileWidgetView.php
--- a/src/applications/conpherence/view/ConpherenceFileWidgetView.php
+++ b/src/applications/conpherence/view/ConpherenceFileWidgetView.php
@@ -20,7 +20,9 @@
         '');
       $file_view = id(new PhabricatorFileLinkView())
         ->setFilePHID($file->getPHID())
-        ->setFileName(phutil_utf8_shorten($file->getName(), 28))
+        ->setFileName(id(new PhutilUTF8StringTruncator())
+          ->setMaximumGlyphs(28)
+          ->truncateString($file->getName()))
         ->setFileViewable($file->isViewableImage())
         ->setFileViewURI($file->getBestURI())
         ->setCustomClass('file-title');
diff --git a/src/applications/differential/controller/DifferentialDiffViewController.php b/src/applications/differential/controller/DifferentialDiffViewController.php
--- a/src/applications/differential/controller/DifferentialDiffViewController.php
+++ b/src/applications/differential/controller/DifferentialDiffViewController.php
@@ -62,8 +62,10 @@
             array(
               'value' => $revision->getID(),
             ),
-            phutil_utf8_shorten(
-              'D'.$revision->getID().' '.$revision->getTitle(), 128));
+            id(new PhutilUTF8StringTruncator())
+            ->setMaximumGlyphs(128)
+            ->truncateString(
+              'D'.$revision->getID().' '.$revision->getTitle()));
         }
         $select[] = hsprintf('</optgroup>');
       }
diff --git a/src/applications/differential/event/DifferentialHovercardEventListener.php b/src/applications/differential/event/DifferentialHovercardEventListener.php
--- a/src/applications/differential/event/DifferentialHovercardEventListener.php
+++ b/src/applications/differential/event/DifferentialHovercardEventListener.php
@@ -69,7 +69,9 @@
 
     if ($rev->getSummary()) {
       $hovercard->addField(pht('Summary'),
-        phutil_utf8_shorten($rev->getSummary(), 120));
+        id(new PhutilUTF8StringTruncator())
+        ->setMaximumGlyphs(120)
+        ->truncateString($rev->getSummary()));
     }
 
     $hovercard->addTag(
diff --git a/src/applications/differential/parser/DifferentialCommitMessageParser.php b/src/applications/differential/parser/DifferentialCommitMessageParser.php
--- a/src/applications/differential/parser/DifferentialCommitMessageParser.php
+++ b/src/applications/differential/parser/DifferentialCommitMessageParser.php
@@ -141,7 +141,11 @@
     if (isset($fields[$key_title])) {
       $terminal = '...';
       $title = $fields[$key_title];
-      $short = phutil_utf8_shorten($title, 250, $terminal);
+      $short = id(new PhutilUTF8StringTruncator())
+        ->setMaximumGlyphs(250)
+        ->setTerminator($terminal)
+        ->truncateString($title);
+
       if ($short != $title) {
 
         // If we shortened the title, split the rest into the summary, so
diff --git a/src/applications/differential/view/DifferentialLocalCommitsView.php b/src/applications/differential/view/DifferentialLocalCommitsView.php
--- a/src/applications/differential/view/DifferentialLocalCommitsView.php
+++ b/src/applications/differential/view/DifferentialLocalCommitsView.php
@@ -77,7 +77,9 @@
       $message = idx($commit, 'message');
 
       $summary = idx($commit, 'summary');
-      $summary = phutil_utf8_shorten($summary, 80);
+      $summary = id(new PhutilUTF8StringTruncator())
+        ->setMaximumGlyphs(80)
+        ->truncateString($summary);
 
       $view = new AphrontMoreView();
       $view->setSome($summary);
diff --git a/src/applications/diffusion/controller/DiffusionBrowseFileController.php b/src/applications/diffusion/controller/DiffusionBrowseFileController.php
--- a/src/applications/diffusion/controller/DiffusionBrowseFileController.php
+++ b/src/applications/diffusion/controller/DiffusionBrowseFileController.php
@@ -684,7 +684,10 @@
                 'size'  => 600,
               ),
             ),
-            phutil_utf8_shorten($line['commit'], 9, ''));
+            id(new PhutilUTF8StringTruncator())
+            ->setMaximumGlyphs(9)
+            ->setTerminator('')
+            ->truncateString($line['commit']));
 
           $revision_id = null;
           if (idx($commits, $commit)) {
diff --git a/src/applications/feed/story/PhabricatorFeedStory.php b/src/applications/feed/story/PhabricatorFeedStory.php
--- a/src/applications/feed/story/PhabricatorFeedStory.php
+++ b/src/applications/feed/story/PhabricatorFeedStory.php
@@ -378,7 +378,9 @@
 
   final protected function renderSummary($text, $len = 128) {
     if ($len) {
-      $text = phutil_utf8_shorten($text, $len);
+      $text = id(new PhutilUTF8StringTruncator())
+        ->setMaximumGlyphs($len)
+        ->truncateString($text);
     }
     switch ($this->getRenderingTarget()) {
       case PhabricatorApplicationTransaction::TARGET_HTML:
diff --git a/src/applications/harbormaster/storage/build/HarbormasterBuild.php b/src/applications/harbormaster/storage/build/HarbormasterBuild.php
--- a/src/applications/harbormaster/storage/build/HarbormasterBuild.php
+++ b/src/applications/harbormaster/storage/build/HarbormasterBuild.php
@@ -196,7 +196,9 @@
     $log_source,
     $log_type) {
 
-    $log_source = phutil_utf8_shorten($log_source, 250);
+    $log_source = id(new PhutilUTF8StringTruncator())
+      ->setMaximumCodepoints(250)
+      ->truncateString($log_source);
 
     $log = HarbormasterBuildLog::initializeNewBuildLog($build_target)
       ->setLogSource($log_source)
diff --git a/src/applications/herald/storage/transcript/HeraldObjectTranscript.php b/src/applications/herald/storage/transcript/HeraldObjectTranscript.php
--- a/src/applications/herald/storage/transcript/HeraldObjectTranscript.php
+++ b/src/applications/herald/storage/transcript/HeraldObjectTranscript.php
@@ -52,7 +52,7 @@
       if (strlen($value) <= $length) {
         return $value;
       } else {
-        // NOTE: phutil_utf8_shorten() has huge runtime for giant strings.
+        // NOTE: huge runtime for giant strings.
         return phutil_utf8ize(substr($value, 0, $length)."\n<...>");
       }
     } else if (is_array($value)) {
diff --git a/src/applications/maniphest/export/ManiphestExcelDefaultFormat.php b/src/applications/maniphest/export/ManiphestExcelDefaultFormat.php
--- a/src/applications/maniphest/export/ManiphestExcelDefaultFormat.php
+++ b/src/applications/maniphest/export/ManiphestExcelDefaultFormat.php
@@ -104,7 +104,9 @@
         $task->getTitle(),
         $projects,
         PhabricatorEnv::getProductionURI('/T'.$task->getID()),
-        phutil_utf8_shorten($task->getDescription(), 512),
+        id(new PhutilUTF8StringTruncator())
+        ->setMaximumBytes(512)
+        ->truncateString($task->getDescription()),
       );
     }
 
diff --git a/src/applications/metamta/storage/PhabricatorMetaMTAMail.php b/src/applications/metamta/storage/PhabricatorMetaMTAMail.php
--- a/src/applications/metamta/storage/PhabricatorMetaMTAMail.php
+++ b/src/applications/metamta/storage/PhabricatorMetaMTAMail.php
@@ -563,7 +563,9 @@
       $body = idx($params, 'body', '');
       $max = PhabricatorEnv::getEnvConfig('metamta.email-body-limit');
       if (strlen($body) > $max) {
-        $body = phutil_utf8_shorten($body, $max);
+        $body = id(new PhutilUTF8StringTruncator())
+          ->setMaximumBytes($max)
+          ->truncateString($body);
         $body .= "\n";
         $body .= pht('(This email was truncated at %d bytes.)', $max);
       }
diff --git a/src/applications/people/event/PhabricatorPeopleHovercardEventListener.php b/src/applications/people/event/PhabricatorPeopleHovercardEventListener.php
--- a/src/applications/people/event/PhabricatorPeopleHovercardEventListener.php
+++ b/src/applications/people/event/PhabricatorPeopleHovercardEventListener.php
@@ -59,7 +59,9 @@
 
     if ($profile->getBlurb()) {
       $hovercard->addField(pht('Blurb'),
-        phutil_utf8_shorten($profile->getBlurb(), 120));
+        id(new PhutilUTF8StringTruncator())
+        ->setMaximumGlyphs(120)
+        ->truncateString($profile->getBlurb()));
     }
 
     $event->setValue('hovercard', $hovercard);
diff --git a/src/applications/phame/conduit/PhameCreatePostConduitAPIMethod.php b/src/applications/phame/conduit/PhameCreatePostConduitAPIMethod.php
--- a/src/applications/phame/conduit/PhameCreatePostConduitAPIMethod.php
+++ b/src/applications/phame/conduit/PhameCreatePostConduitAPIMethod.php
@@ -90,7 +90,9 @@
     $post->setTitle($title);
     $phame_title = $request->getValue(
       'phameTitle',
-      phutil_utf8_shorten($title, 64));
+      id(new PhutilUTF8StringTruncator())
+      ->setMaximumCodepoints(64)
+      ->truncateString($title));
     $post->setPhameTitle(PhabricatorSlug::normalize($phame_title));
     $post->setBody($body);
     $post->save();
diff --git a/src/applications/pholio/storage/PholioTransaction.php b/src/applications/pholio/storage/PholioTransaction.php
--- a/src/applications/pholio/storage/PholioTransaction.php
+++ b/src/applications/pholio/storage/PholioTransaction.php
@@ -297,7 +297,9 @@
 
     if ($text) {
       return phutil_escape_html_newlines(
-        phutil_utf8_shorten($text, 128));
+        id(new PhutilUTF8StringTruncator())
+        ->setMaximumGlyphs(128)
+        ->truncateString($text));
     }
 
     return parent::getBodyForFeed($story);
diff --git a/src/applications/phriction/editor/PhrictionDocumentEditor.php b/src/applications/phriction/editor/PhrictionDocumentEditor.php
--- a/src/applications/phriction/editor/PhrictionDocumentEditor.php
+++ b/src/applications/phriction/editor/PhrictionDocumentEditor.php
@@ -264,6 +264,9 @@
     }
 
     if ($feed_action) {
+      $content = id(new PhutilUTF8StringTruncator())
+        ->setMaximumGlyphs(140)
+        ->truncateString($new_content->getContent());
       id(new PhabricatorFeedStoryPublisher())
         ->setRelatedPHIDs($related_phids)
         ->setStoryAuthorPHID($this->getActor()->getPHID())
@@ -273,7 +276,7 @@
           array(
             'phid'      => $document->getPHID(),
             'action'    => $feed_action,
-            'content'   => phutil_utf8_shorten($new_content->getContent(), 140),
+            'content'   => $content,
             'project'   => $project_phid,
             'movedFromPHID' => $this->fromDocumentPHID,
           ))
diff --git a/src/applications/ponder/storage/PonderAnswerTransaction.php b/src/applications/ponder/storage/PonderAnswerTransaction.php
--- a/src/applications/ponder/storage/PonderAnswerTransaction.php
+++ b/src/applications/ponder/storage/PonderAnswerTransaction.php
@@ -71,7 +71,9 @@
     switch ($this->getTransactionType()) {
       case self::TYPE_CONTENT:
         return phutil_escape_html_newlines(
-          phutil_utf8_shorten($new, 128));
+          id(new PhutilUTF8StringTruncator())
+          ->setMaximumGlyphs(128)
+          ->truncateString($new));
         break;
     }
     return parent::getBodyForFeed($story);
diff --git a/src/applications/ponder/storage/PonderQuestionTransaction.php b/src/applications/ponder/storage/PonderQuestionTransaction.php
--- a/src/applications/ponder/storage/PonderQuestionTransaction.php
+++ b/src/applications/ponder/storage/PonderQuestionTransaction.php
@@ -252,14 +252,18 @@
         if ($old === null) {
           $question = $story->getObject($this->getObjectPHID());
           return phutil_escape_html_newlines(
-            phutil_utf8_shorten($question->getContent(), 128));
+            id(new PhutilUTF8StringTruncator())
+            ->setMaximumGlyphs(128)
+            ->truncateString($question->getContent()));
         }
         break;
       case self::TYPE_ANSWERS:
         $answer = $this->getNewAnswerObject($story);
         if ($answer) {
           return phutil_escape_html_newlines(
-            phutil_utf8_shorten($answer->getContent(), 128));
+            id(new PhutilUTF8StringTruncator())
+            ->setMaximumGlyphs(128)
+            ->truncateString($answer->getContent()));
         }
         break;
     }
diff --git a/src/applications/repository/storage/PhabricatorRepositoryCommitData.php b/src/applications/repository/storage/PhabricatorRepositoryCommitData.php
--- a/src/applications/repository/storage/PhabricatorRepositoryCommitData.php
+++ b/src/applications/repository/storage/PhabricatorRepositoryCommitData.php
@@ -30,7 +30,9 @@
   public static function summarizeCommitMessage($message) {
     $summary = phutil_split_lines($message, $retain_endings = false);
     $summary = head($summary);
-    $summary = phutil_utf8_shorten($summary, self::SUMMARY_MAX_LENGTH);
+    $summary = id(new PhutilUTF8StringTruncator())
+      ->setMaximumCodepoints(self::SUMMARY_MAX_LENGTH)
+      ->truncateString($summary);
 
     return $summary;
   }
diff --git a/src/applications/slowvote/query/PhabricatorSlowvoteSearchEngine.php b/src/applications/slowvote/query/PhabricatorSlowvoteSearchEngine.php
--- a/src/applications/slowvote/query/PhabricatorSlowvoteSearchEngine.php
+++ b/src/applications/slowvote/query/PhabricatorSlowvoteSearchEngine.php
@@ -155,7 +155,9 @@
 
       $description = $poll->getDescription();
       if (strlen($description)) {
-        $item->addAttribute(phutil_utf8_shorten($poll->getDescription(), 120));
+        $item->addAttribute(id(new PhutilUTF8StringTruncator())
+          ->setMaximumGlyphs(120)
+          ->truncateString($poll->getDescription()));
       }
 
       if ($author) {
diff --git a/src/view/form/control/AphrontFormPolicyControl.php b/src/view/form/control/AphrontFormPolicyControl.php
--- a/src/view/form/control/AphrontFormPolicyControl.php
+++ b/src/view/form/control/AphrontFormPolicyControl.php
@@ -58,9 +58,12 @@
           continue;
         }
       }
+      $policy_short_name = id(new PhutilUTF8StringTruncator())
+        ->setMaximumGlyphs(28)
+        ->truncateString($policy->getName());
 
       $options[$policy->getType()][$policy->getPHID()] = array(
-        'name' => phutil_utf8_shorten($policy->getName(), 28),
+        'name' => $policy_short_name,
         'full' => $policy->getName(),
         'icon' => $policy->getIcon(),
       );