Editor: Highlight automatically inserted text

Keep the highlight as long as the cursor is directly behind the closing
character and the editor is the focus widget.

Change-Id: Ic1d4bac263e9d2f395791dad7ecdceb9d69635c5
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

7 files changed, 79 insertions, 16 deletions

diff --git a/src/plugins/texteditor/codeassist/codeassistant.cpp b/src/plugins/texteditor/codeassist/codeassistant.cpp
index a21cf7c46c6..8af30428e07 100644
--- a/src/plugins/texteditor/codeassist/codeassistant.cpp
+++ b/src/plugins/texteditor/codeassist/codeassistant.cpp
@@ -307,6 +307,7 @@ void CodeAssistantPrivate::displayProposal(IAssistProposal *newProposal, AssistR
     if (m_proposal->isCorrective())
         m_proposal->makeCorrection(m_editorWidget);
 
+    m_editorWidget->keepAutoCompletionHighlight(true);
     basePosition = m_proposal->basePosition();
     m_proposalWidget = m_proposal->createWidget();
     connect(m_proposalWidget, &QObject::destroyed,
@@ -421,6 +422,7 @@ void CodeAssistantPrivate::destroyContext()
     if (isWaitingForProposal()) {
         cancelCurrentRequest();
     } else if (isDisplayingProposal()) {
+        m_editorWidget->keepAutoCompletionHighlight(false);
         m_proposalWidget->closeProposal();
         disconnect(m_proposalWidget, &QObject::destroyed,
                    this, &CodeAssistantPrivate::finalizeProposal);
diff --git a/src/plugins/texteditor/completionsettings.cpp b/src/plugins/texteditor/completionsettings.cpp
index 325b7580282..8bdcbded959 100644
--- a/src/plugins/texteditor/completionsettings.cpp
+++ b/src/plugins/texteditor/completionsettings.cpp
@@ -39,6 +39,7 @@ static const char partiallyCompleteKey[]        = "PartiallyComplete";
 static const char spaceAfterFunctionNameKey[]   = "SpaceAfterFunctionName";
 static const char autoSplitStringsKey[]         = "AutoSplitStrings";
 static const char animateAutoCompleteKey[]      = "AnimateAutoComplete";
+static const char highlightAutoCompleteKey[]    = "HighlightAutoComplete";
 
 using namespace TextEditor;
 
@@ -56,6 +57,7 @@ void CompletionSettings::toSettings(QSettings *s) const
     s->setValue(spaceAfterFunctionNameKey, m_spaceAfterFunctionName);
     s->setValue(autoSplitStringsKey, m_autoSplitStrings);
     s->setValue(animateAutoCompleteKey, m_animateAutoComplete);
+    s->setValue(highlightAutoCompleteKey, m_highlightAutoComplete);
     s->endGroup();
 }
 
@@ -86,6 +88,8 @@ void CompletionSettings::fromSettings(QSettings *s)
             s->value(autoSplitStringsKey, m_autoSplitStrings).toBool();
     m_animateAutoComplete =
             s->value(animateAutoCompleteKey, m_animateAutoComplete).toBool();
+    m_highlightAutoComplete =
+            s->value(highlightAutoCompleteKey, m_highlightAutoComplete).toBool();
     s->endGroup();
 }
 
@@ -102,5 +106,6 @@ bool CompletionSettings::equals(const CompletionSettings &cs) const
         && m_spaceAfterFunctionName         == cs.m_spaceAfterFunctionName
         && m_autoSplitStrings               == cs.m_autoSplitStrings
         && m_animateAutoComplete            == cs.m_animateAutoComplete
+        && m_highlightAutoComplete          == cs.m_highlightAutoComplete
         ;
 }
diff --git a/src/plugins/texteditor/completionsettings.h b/src/plugins/texteditor/completionsettings.h
index 5dfb172eb27..0b466718f97 100644
--- a/src/plugins/texteditor/completionsettings.h
+++ b/src/plugins/texteditor/completionsettings.h
@@ -67,6 +67,7 @@ public:
     bool m_spaceAfterFunctionName = false;
     bool m_autoSplitStrings = true;
     bool m_animateAutoComplete = true;
+    bool m_highlightAutoComplete = false;
 };
 
 inline bool operator==(const CompletionSettings &t1, const CompletionSettings &t2) { return t1.equals(t2); }
diff --git a/src/plugins/texteditor/completionsettingspage.cpp b/src/plugins/texteditor/completionsettingspage.cpp
index b505eb65661..fce419b422d 100644
--- a/src/plugins/texteditor/completionsettingspage.cpp
+++ b/src/plugins/texteditor/completionsettingspage.cpp
@@ -103,6 +103,7 @@ QWidget *CompletionSettingsPage::widget()
         m_page->spaceAfterFunctionName->setChecked(m_completionSettings.m_spaceAfterFunctionName);
         m_page->autoSplitStrings->setChecked(m_completionSettings.m_autoSplitStrings);
         m_page->animateAutoComplete->setChecked(m_completionSettings.m_animateAutoComplete);
+        m_page->highlightAutoComplete->setChecked(m_completionSettings.m_highlightAutoComplete);
 
         m_page->enableDoxygenCheckBox->setChecked(m_commentsSettings.m_enableDoxygen);
         m_page->generateBriefCheckBox->setChecked(m_commentsSettings.m_generateBrief);
@@ -177,6 +178,7 @@ void CompletionSettingsPage::settingsFromUi(CompletionSettings &completion, Comm
     completion.m_spaceAfterFunctionName = m_page->spaceAfterFunctionName->isChecked();
     completion.m_autoSplitStrings = m_page->autoSplitStrings->isChecked();
     completion.m_animateAutoComplete = m_page->animateAutoComplete->isChecked();
+    completion.m_highlightAutoComplete = m_page->highlightAutoComplete->isChecked();
 
     comment.m_enableDoxygen = m_page->enableDoxygenCheckBox->isChecked();
     comment.m_generateBrief = m_page->generateBriefCheckBox->isChecked();
diff --git a/src/plugins/texteditor/completionsettingspage.ui b/src/plugins/texteditor/completionsettingspage.ui
index d91caeda947..23e61d22be4 100644
--- a/src/plugins/texteditor/completionsettingspage.ui
+++ b/src/plugins/texteditor/completionsettingspage.ui
@@ -7,7 +7,7 @@
     <x>0</x>
     <y>0</y>
     <width>511</width>
-    <height>420</height>
+    <height>437</height>
    </rect>
   </property>
   <layout class="QVBoxLayout" name="verticalLayout_2">
@@ -227,6 +227,13 @@ In addition, Shift+Enter inserts an escape character at the cursor position and
         </property>
        </widget>
       </item>
+      <item row="3" column="1">
+       <widget class="QCheckBox" name="highlightAutoComplete">
+        <property name="text">
+         <string>Highlight automatically inserted text</string>
+        </property>
+       </widget>
+      </item>
      </layout>
     </widget>
    </item>
@@ -316,6 +323,7 @@ In addition, Shift+Enter inserts an escape character at the cursor position and
   <tabstop>surroundQuotes</tabstop>
   <tabstop>spaceAfterFunctionName</tabstop>
   <tabstop>animateAutoComplete</tabstop>
+  <tabstop>highlightAutoComplete</tabstop>
   <tabstop>enableDoxygenCheckBox</tabstop>
   <tabstop>generateBriefCheckBox</tabstop>
   <tabstop>leadingAsterisksCheckBox</tabstop>
diff --git a/src/plugins/texteditor/texteditor.cpp b/src/plugins/texteditor/texteditor.cpp
index f2cb276008c..d5f50ec4b8a 100644
--- a/src/plugins/texteditor/texteditor.cpp
+++ b/src/plugins/texteditor/texteditor.cpp
@@ -329,7 +329,7 @@ public:
     // parentheses matcher
     void _q_matchParentheses();
     void _q_highlightBlocks();
-    void _q_autocompleterHighlight(const QTextCursor &cursor = QTextCursor());
+    void autocompleterHighlight(const QTextCursor &cursor = QTextCursor());
     void updateAnimator(QPointer<TextEditorAnimator> animator, QPainter &painter);
     void cancelCurrentAnimations();
     void slotSelectionChanged();
@@ -452,8 +452,14 @@ public:
     QList<BaseHoverHandler *> m_hoverHandlers; // Not owned
 
     QPointer<TextEditorAnimator> m_bracketsAnimator;
+
+    // Animation and highlighting of auto completed text
     QPointer<TextEditorAnimator> m_autocompleteAnimator;
     bool m_animateAutoComplete = true;
+    bool m_highlightAutoComplete = true;
+    bool m_keepAutoCompletionHighlight = false;
+    QTextCursor m_autoCompleteHighlightPos;
+
     int m_cursorBlockNumber;
     int m_blockCount;
 
@@ -629,6 +635,7 @@ static const char kTextBlockMimeType[] = "application/vnd.qtcreator.blocktext";
 Id TextEditorWidget::SnippetPlaceholderSelection("TextEdit.SnippetPlaceHolderSelection");
 Id TextEditorWidget::CurrentLineSelection("TextEdit.CurrentLineSelection");
 Id TextEditorWidget::ParenthesesMatchingSelection("TextEdit.ParenthesesMatchingSelection");
+Id TextEditorWidget::AutoCompleteSelection("TextEdit.AutoCompleteSelection");
 Id TextEditorWidget::CodeWarningsSelection("TextEdit.CodeWarningsSelection");
 Id TextEditorWidget::CodeSemanticsSelection("TextEdit.CodeSemanticsSelection");
 Id TextEditorWidget::UndefinedSymbolSelection("TextEdit.UndefinedSymbolSelection");
@@ -2156,12 +2163,12 @@ void TextEditorWidget::keyPressEvent(QKeyEvent *e)
                     d->m_document->autoIndent(ensureVisible);
                 else if (!previousIndentationString.isEmpty())
                     ensureVisible.insertText(previousIndentationString);
-                if (d->m_animateAutoComplete) {
+                if (d->m_animateAutoComplete || d->m_highlightAutoComplete) {
                     QTextCursor tc = ensureVisible;
                     tc.movePosition(QTextCursor::EndOfBlock);
                     tc.movePosition(QTextCursor::StartOfBlock, QTextCursor::KeepAnchor);
                     tc.movePosition(QTextCursor::NextWord, QTextCursor::KeepAnchor);
-                    d->_q_autocompleterHighlight(tc);
+                    d->autocompleterHighlight(tc);
                 }
             }
             setTextCursor(ensureVisible);
@@ -2422,9 +2429,10 @@ void TextEditorWidget::keyPressEvent(QKeyEvent *e)
         if (!autoText.isEmpty()) {
             int pos = cursor.position();
             cursor.insertText(autoText);
+            cursor.movePosition(QTextCursor::PreviousCharacter, QTextCursor::KeepAnchor);
+            d->autocompleterHighlight(cursor);
             //Select the inserted text, to be able to re-indent the inserted text
             cursor.setPosition(pos, QTextCursor::KeepAnchor);
-            d->_q_autocompleterHighlight(cursor);
         }
         if (!electricChar.isNull() && d->m_autoCompleter->contextAllowsElectricCharacters(cursor))
             d->m_document->autoIndent(cursor, electricChar);
@@ -4705,6 +4713,17 @@ void TextEditorWidgetPrivate::updateHighlights()
         }
     }
 
+    if (m_highlightAutoComplete && !m_autoCompleteHighlightPos.isNull()) {
+        QTimer::singleShot(0, this, [this](){
+            if ((!m_keepAutoCompletionHighlight && !q->hasFocus())
+                    || m_autoCompleteHighlightPos != q->textCursor()) {
+                q->setExtraSelections(TextEditorWidget::AutoCompleteSelection,
+                                      QList<QTextEdit::ExtraSelection>()); // clear
+                m_autoCompleteHighlightPos = QTextCursor();
+            }
+        });
+    }
+
     updateCurrentLineHighlight();
 
     if (m_displaySettings.m_highlightBlocks) {
@@ -6026,23 +6045,38 @@ void TextEditorWidgetPrivate::_q_highlightBlocks()
     }
 }
 
-void TextEditorWidgetPrivate::_q_autocompleterHighlight(const QTextCursor &cursor)
+void TextEditorWidgetPrivate::autocompleterHighlight(const QTextCursor &cursor)
 {
-    if (!m_animateAutoComplete || q->isReadOnly() || !cursor.hasSelection())
+    QList<QTextEdit::ExtraSelection> extraSelections;
+    if ((!m_animateAutoComplete && !m_highlightAutoComplete)
+            || q->isReadOnly() || !cursor.hasSelection()) {
+        q->setExtraSelections(TextEditorWidget::AutoCompleteSelection, extraSelections); // clear
         return;
+    }
 
     const QTextCharFormat &matchFormat
             = q->textDocument()->fontSettings().toTextCharFormat(C_AUTOCOMPLETE);
 
-    cancelCurrentAnimations();// one animation is enough
-    m_autocompleteAnimator = new TextEditorAnimator(this);
-    m_autocompleteAnimator->setPosition(cursor.selectionStart());
-    QPalette pal;
-    pal.setBrush(QPalette::Text, matchFormat.foreground());
-    pal.setBrush(QPalette::Base, matchFormat.background());
-    m_autocompleteAnimator->setData(q->font(), pal, cursor.selectedText());
-    connect(m_autocompleteAnimator.data(), &TextEditorAnimator::updateRequest,
-            this, &TextEditorWidgetPrivate::_q_animateUpdate);
+    if (m_highlightAutoComplete) {
+        QTextEdit::ExtraSelection sel;
+        sel.cursor = cursor;
+        sel.format.setBackground(matchFormat.background());
+        extraSelections.append(sel);
+        m_autoCompleteHighlightPos = cursor;
+        m_autoCompleteHighlightPos.movePosition(QTextCursor::PreviousCharacter);
+    }
+    if (m_animateAutoComplete) {
+        cancelCurrentAnimations();// one animation is enough
+        m_autocompleteAnimator = new TextEditorAnimator(this);
+        m_autocompleteAnimator->setPosition(cursor.selectionStart());
+        QPalette pal;
+        pal.setBrush(QPalette::Text, matchFormat.foreground());
+        pal.setBrush(QPalette::Base, matchFormat.background());
+        m_autocompleteAnimator->setData(q->font(), pal, cursor.selectedText());
+        connect(m_autocompleteAnimator.data(), &TextEditorAnimator::updateRequest,
+                this, &TextEditorWidgetPrivate::_q_animateUpdate);
+    }
+    q->setExtraSelections(TextEditorWidget::AutoCompleteSelection, extraSelections);
 }
 
 void TextEditorWidgetPrivate::updateAnimator(QPointer<TextEditorAnimator> animator,
@@ -6089,6 +6123,7 @@ void TextEditorWidget::focusOutEvent(QFocusEvent *e)
     QPlainTextEdit::focusOutEvent(e);
     if (viewport()->cursor().shape() == Qt::BlankCursor)
         viewport()->setCursor(Qt::IBeamCursor);
+    d->updateHighlights();
 }
 
 
@@ -6542,6 +6577,7 @@ void TextEditorWidget::setCompletionSettings(const CompletionSettings &completio
     d->m_autoCompleter->setAutoInsertQuotesEnabled(completionSettings.m_autoInsertQuotes);
     d->m_autoCompleter->setSurroundWithQuotesEnabled(completionSettings.m_surroundingAutoQuotes);
     d->m_animateAutoComplete = completionSettings.m_animateAutoComplete;
+    d->m_highlightAutoComplete = completionSettings.m_highlightAutoComplete;
 }
 
 void TextEditorWidget::setExtraEncodingSettings(const ExtraEncodingSettings &extraEncodingSettings)
@@ -7003,6 +7039,11 @@ void TextEditorWidget::insertExtraToolBarWidget(TextEditorWidget::Side side,
         d->m_toolBar->insertWidget(d->m_toolBar->actions().first(), widget);
 }
 
+void TextEditorWidget::keepAutoCompletionHighlight(bool keepHighlight)
+{
+    d->m_keepAutoCompletionHighlight = keepHighlight;
+}
+
 int BaseTextEditor::currentLine() const
 {
     return editorWidget()->textCursor().blockNumber() + 1;
diff --git a/src/plugins/texteditor/texteditor.h b/src/plugins/texteditor/texteditor.h
index ce896250e1c..87182f18cf3 100644
--- a/src/plugins/texteditor/texteditor.h
+++ b/src/plugins/texteditor/texteditor.h
@@ -301,6 +301,7 @@ public:
     static Core::Id SnippetPlaceholderSelection;
     static Core::Id CurrentLineSelection;
     static Core::Id ParenthesesMatchingSelection;
+    static Core::Id AutoCompleteSelection;
     static Core::Id CodeWarningsSelection;
     static Core::Id CodeSemanticsSelection;
     static Core::Id UndefinedSymbolSelection;
@@ -323,6 +324,9 @@ public:
     enum Side { Left, Right };
     void insertExtraToolBarWidget(Side side, QWidget *widget);
 
+    // keep the auto completion even if the focus is lost
+    void keepAutoCompletionHighlight(bool keepHighlight);
+
     virtual void copy();
     virtual void paste();
     virtual void cut();