From dfd03f5feee9fd6aa1a6a7bfa2fb53bedf8ccdd8 Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Sun, 16 Jul 2017 02:29:49 +0200
Subject: [PATCH] Don't refresh wxStaticText if its label didn't really change

Optimize calling SetLabel() with the same label as the current one, this
seems to happen quite often in practice and results in flicker, so check
for it explicitly.
---
 interface/wx/stattext.h  | 12 ++++++++++++
 src/gtk/stattext.cpp     |  3 +++
 src/motif/stattext.cpp   |  3 +++
 src/msw/stattext.cpp     |  4 ++++
 src/osx/stattext_osx.cpp |  3 +++
 src/univ/stattext.cpp    |  3 +++
 6 files changed, 28 insertions(+)

diff --git a/interface/wx/stattext.h b/interface/wx/stattext.h
index 19525e0ae7..230a208d7d 100644
--- a/interface/wx/stattext.h
+++ b/interface/wx/stattext.h
@@ -99,6 +99,18 @@ public:
     */
     bool IsEllipsized() const;
 
+    /**
+        Change the label shown in the control.
+
+        Notice that since wxWidgets 3.1.1 this function is guaranteed not to do
+        anything if the label didn't really change, so there is no benefit to
+        checking if the new label is different from the current one in the
+        application code.
+
+        @see wxControl::SetLabel()
+     */
+    virtual void SetLabel(const wxString& label);
+
     /**
         This functions wraps the controls label so that each of its lines becomes at
         most @a width pixels wide if possible (the lines are broken at words
diff --git a/src/gtk/stattext.cpp b/src/gtk/stattext.cpp
index c560dcb4b1..b84ddd9073 100644
--- a/src/gtk/stattext.cpp
+++ b/src/gtk/stattext.cpp
@@ -144,6 +144,9 @@ void wxStaticText::GTKDoSetLabel(GTKLabelSetter setter, const wxString& label)
 
 void wxStaticText::SetLabel(const wxString& label)
 {
+    if ( label == m_labelOrig )
+        return;
+
     m_labelOrig = label;
 
     GTKDoSetLabel(&wxStaticText::GTKSetLabelForLabel, label);
diff --git a/src/motif/stattext.cpp b/src/motif/stattext.cpp
index 9920a4c82d..44822abbfe 100644
--- a/src/motif/stattext.cpp
+++ b/src/motif/stattext.cpp
@@ -71,6 +71,9 @@ bool wxStaticText::Create(wxWindow *parent, wxWindowID id,
 
 void wxStaticText::SetLabel(const wxString& label)
 {
+    if ( label == m_labelOrig )
+        return;
+
     m_labelOrig = label;       // save original label
 
     // Motif does not support ellipsized labels natively
diff --git a/src/msw/stattext.cpp b/src/msw/stattext.cpp
index 3d0d074023..62dd20512b 100644
--- a/src/msw/stattext.cpp
+++ b/src/msw/stattext.cpp
@@ -150,6 +150,10 @@ void wxStaticText::DoSetSize(int x, int y, int w, int h, int sizeFlags)
 
 void wxStaticText::SetLabel(const wxString& label)
 {
+    // If the label doesn't really change, avoid flicker by not doing anything.
+    if ( label == m_labelOrig )
+        return;
+
 #ifdef SS_ENDELLIPSIS
     long styleReal = ::GetWindowLong(GetHwnd(), GWL_STYLE);
     if ( HasFlag(wxST_ELLIPSIZE_END) )
diff --git a/src/osx/stattext_osx.cpp b/src/osx/stattext_osx.cpp
index 5a291af9f9..4176add134 100644
--- a/src/osx/stattext_osx.cpp
+++ b/src/osx/stattext_osx.cpp
@@ -58,6 +58,9 @@ bool wxStaticText::Create( wxWindow *parent,
 
 void wxStaticText::SetLabel(const wxString& label)
 {
+    if ( label == m_labelOrig )
+        return;
+
     m_labelOrig = label;
 
     // middle/end ellipsization is handled by the OS:
diff --git a/src/univ/stattext.cpp b/src/univ/stattext.cpp
index a34cf8ad17..08dfe84b4f 100644
--- a/src/univ/stattext.cpp
+++ b/src/univ/stattext.cpp
@@ -70,6 +70,9 @@ void wxStaticText::DoDraw(wxControlRenderer *renderer)
 
 void wxStaticText::SetLabel(const wxString& str)
 {
+    if ( label == m_labelOrig )
+        return;
+
     // save original label
     m_labelOrig = str;