Backport: Bug [#1548]. Implement calltips on Qt.

Backport of changeset 7237:a82b87a88556 and 7238:ba336ac439f0.

3 files changed, 33 insertions, 3 deletions

diff --git a/doc/ScintillaDoc.html b/doc/ScintillaDoc.html
index fdf1e36c0..e897060ae 100644
--- a/doc/ScintillaDoc.html
+++ b/doc/ScintillaDoc.html
@@ -4975,8 +4975,6 @@ struct Sci_TextToFind {
     There is some interaction between call tips and autocompletion lists in that showing a
     call tip cancels any active autocompletion list, and vice versa.</p>
 
-    <p>Call tips are not implemented on Qt.</p>
-
     <p>Call tips can highlight part of the text within them. You could use this to highlight the
     current argument to a function by counting the number of commas (or whatever separator your
     language uses). See <code>SciTEBase::CharAdded()</code> in <code>SciTEBase.cxx</code> for an
diff --git a/doc/ScintillaHistory.html b/doc/ScintillaHistory.html
index bf31ff711..7ede2b761 100644
--- a/doc/ScintillaHistory.html
+++ b/doc/ScintillaHistory.html
@@ -530,6 +530,7 @@
 	<td>Gokul Krishnan</td>
       </tr><tr>
 	<td>Jad Altahan</td>
+	<td>Andrea Ricchi</td>
     </tr>
     </table>
     <p>
@@ -548,6 +549,10 @@
 	<li>
 	Released 10 January 2019.
 	</li>
+	<li>
+	Calltips implemented on Qt.
+	<a href="https://sourceforge.net/p/scintilla/bugs/1548/">Bug #1548</a>.
+	</li>
  	<li>
 	The C++ lexer, with styling.within.preprocessor on, now interprets "(" in preprocessor "#if("
 	as an operator instead of part of the directive. This improves folding as well which could become
diff --git a/qt/ScintillaEditBase/ScintillaQt.cpp b/qt/ScintillaEditBase/ScintillaQt.cpp
index 804cd2dc0..98a8000fa 100644
--- a/qt/ScintillaEditBase/ScintillaQt.cpp
+++ b/qt/ScintillaEditBase/ScintillaQt.cpp
@@ -613,11 +613,38 @@ void ScintillaQt::StartDrag()
 	SetDragPosition(SelectionPosition(Sci::invalidPosition));
 }
 
+class CallTipImpl : public QWidget {
+public:
+	CallTipImpl(CallTip *pct_)
+		: QWidget(nullptr, Qt::ToolTip),
+		  pct(pct_)
+	{
+#if QT_VERSION >= QT_VERSION_CHECK(5, 9, 0)
+		setWindowFlag(Qt::WindowTransparentForInput);
+#endif
+	}
+
+	void paintEvent(QPaintEvent *) override
+	{
+		if (pct->inCallTipMode) {
+			Surface *surfaceWindow = Surface::Allocate(0);
+			surfaceWindow->Init(this);
+			surfaceWindow->SetUnicodeMode(SC_CP_UTF8 == pct->codePage);
+			surfaceWindow->SetDBCSMode(pct->codePage);
+			pct->PaintCT(surfaceWindow);
+			delete surfaceWindow;
+		}
+	}
+
+private:
+	CallTip *pct;
+};
+
 void ScintillaQt::CreateCallTipWindow(PRectangle rc)
 {
 
 	if (!ct.wCallTip.Created()) {
-		QWidget *pCallTip =  new QWidget(0, Qt::ToolTip);
+		QWidget *pCallTip = new CallTipImpl(&ct);
 		ct.wCallTip = pCallTip;
 		pCallTip->move(rc.left, rc.top);
 		pCallTip->resize(rc.Width(), rc.Height());