Resolves: rhbz#1373933 gtk 3.21 emits a lot more "style-set" signals

also deb#837356

since gtk3 commit of...

commit 0f116135f4a5033ce4e9dfa19f10624701fa615c
Author: Matthias Clasen <mclasen@redhat.com>
Date:   Fri May 6 10:12:14 2016 -0400

    Avoid emitting ::style-set by name

    GtkStyle is deprecated, but we still emit ::style-set quite
    a bit, so lets at least not be slow while doing it.

docs say...

'GtkWidget::style-set has been deprecated since version 3.0 and should not be
used in newly-written code.

Use the “style-updated” signal'

and this code just came over from gtk2 without any thought about it at the
time, so change it over to the "style-updated" which makes everything happy
again

gtk3 still emits a lot of style-updateds signals

so also don't throw away font settings every time, check if the font settings
changed and only emit FontChanged if they differ from the last seen settings.

(cherry picked from commit ef7abe81df10cb8a8c04afbb1fbe700f94e73f04)

Change-Id: I9e920d2fb2d820ff1b1b5a9ecb228484df3d6146
Reviewed-on: https://gerrit.libreoffice.org/28944
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>

5 files changed, 60 insertions, 15 deletions

diff --git a/vcl/inc/unx/gtk/gtkframe.hxx b/vcl/inc/unx/gtk/gtkframe.hxx
index 2b5dc5547c3f..1b48aa338978 100644
--- a/vcl/inc/unx/gtk/gtkframe.hxx
+++ b/vcl/inc/unx/gtk/gtkframe.hxx
@@ -242,7 +242,11 @@ class GtkSalFrame : public SalFrame
 
     // signals
     static gboolean     signalButton( GtkWidget*, GdkEventButton*, gpointer );
-    static void         signalStyleSet( GtkWidget*, GtkStyle* pPrevious, gpointer );
+#if GTK_CHECK_VERSION(3,0,0)
+    static void         signalStyleUpdated(GtkWidget*, gpointer);
+#else
+    static void         signalStyleSet(GtkWidget*, GtkStyle* pPrevious, gpointer);
+#endif
 #if GTK_CHECK_VERSION(3,0,0)
     static gboolean     signalDraw( GtkWidget*, cairo_t *cr, gpointer );
     static void         sizeAllocated(GtkWidget*, GdkRectangle *pAllocation, gpointer frame);
diff --git a/vcl/inc/unx/gtk/gtkinst.hxx b/vcl/inc/unx/gtk/gtkinst.hxx
index 6212d5dcccba..f1ee2732b1ae 100644
--- a/vcl/inc/unx/gtk/gtkinst.hxx
+++ b/vcl/inc/unx/gtk/gtkinst.hxx
@@ -239,6 +239,8 @@ public:
 #endif
 
     virtual const cairo_font_options_t* GetCairoFontOptions() override;
+            const cairo_font_options_t* GetLastSeenCairoFontOptions();
+                                   void ResetLastSeenCairoFontOptions();
 
     void                        RemoveTimer (SalTimer *pTimer);
 
@@ -248,6 +250,7 @@ private:
     std::vector<GtkSalTimer *>  m_aTimers;
     bool                        IsTimerExpired();
     bool                        bNeedsInit;
+    cairo_font_options_t*       m_pLastCairoFontOptions;
 
     mutable std::shared_ptr<vcl::unx::GtkPrintWrapper> m_xPrintWrapper;
 };
diff --git a/vcl/unx/gtk/gtkinst.cxx b/vcl/unx/gtk/gtkinst.cxx
index c138005a4c78..1aa17fd67671 100644
--- a/vcl/unx/gtk/gtkinst.cxx
+++ b/vcl/unx/gtk/gtkinst.cxx
@@ -157,6 +157,7 @@ GtkInstance::GtkInstance( SalYieldMutex* pMutex )
     : X11SalInstance( pMutex )
 #endif
     , bNeedsInit(true)
+    , m_pLastCairoFontOptions(nullptr)
 {
 }
 
@@ -202,6 +203,7 @@ GtkInstance::~GtkInstance()
     while( !m_aTimers.empty() )
         delete *m_aTimers.begin();
     DeInitAtkBridge();
+    ResetLastSeenCairoFontOptions();
 }
 
 SalFrame* GtkInstance::CreateFrame( SalFrame* pParent, SalFrameStyleFlags nStyle )
@@ -477,7 +479,24 @@ GtkInstance::getPrintWrapper() const
 
 const cairo_font_options_t* GtkInstance::GetCairoFontOptions()
 {
-    return gdk_screen_get_font_options(gdk_screen_get_default());
+    const cairo_font_options_t* pCairoFontOptions = gdk_screen_get_font_options(gdk_screen_get_default());
+    if (!m_pLastCairoFontOptions && pCairoFontOptions)
+        m_pLastCairoFontOptions = cairo_font_options_copy(pCairoFontOptions);
+    return pCairoFontOptions;
+}
+
+const cairo_font_options_t* GtkInstance::GetLastSeenCairoFontOptions()
+{
+    return m_pLastCairoFontOptions;
+}
+
+void GtkInstance::ResetLastSeenCairoFontOptions()
+{
+    if (m_pLastCairoFontOptions)
+    {
+        cairo_font_options_destroy(m_pLastCairoFontOptions);
+        m_pLastCairoFontOptions = nullptr;
+    }
 }
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/vcl/unx/gtk/gtksalframe.cxx b/vcl/unx/gtk/gtksalframe.cxx
index 031170bec092..c8c38698eb00 100644
--- a/vcl/unx/gtk/gtksalframe.cxx
+++ b/vcl/unx/gtk/gtksalframe.cxx
@@ -3274,7 +3274,21 @@ void GtkSalFrame::signalStyleSet( GtkWidget*, GtkStyle* pPrevious, gpointer fram
         // so post user event to safely dispatch the SalEvent::SettingsChanged
         // note: settings changed for multiple frames is avoided in winproc.cxx ImplHandleSettings
         GtkSalFrame::getDisplay()->SendInternalEvent( pThis, nullptr, SalEvent::SettingsChanged );
-        GtkSalFrame::getDisplay()->SendInternalEvent( pThis, nullptr, SalEvent::FontChanged );
+
+        // fire off font-changed when the system cairo font hints change
+        GtkInstance *pInstance = static_cast<GtkInstance*>(GetSalData()->m_pInstance);
+        const cairo_font_options_t* pLastCairoFontOptions = pInstance->GetLastSeenCairoFontOptions();
+        const cairo_font_options_t* pCurrentCairoFontOptions = gdk_screen_get_font_options(gdk_screen_get_default());
+        bool bFontSettingsChanged = true;
+        if (pLastCairoFontOptions && pCurrentCairoFontOptions)
+            bFontSettingsChanged = !cairo_font_options_equal(pLastCairoFontOptions, pCurrentCairoFontOptions);
+        else if (!pLastCairoFontOptions && !pCurrentCairoFontOptions)
+            bFontSettingsChanged = false;
+        if (bFontSettingsChanged)
+        {
+            pInstance->ResetLastSeenCairoFontOptions();
+            GtkSalFrame::getDisplay()->SendInternalEvent( pThis, nullptr, SalEvent::FontChanged );
+        }
     }
 
     /* #i64117# gtk sets a nice background pixmap
diff --git a/vcl/unx/gtk3/gtk3gtkframe.cxx b/vcl/unx/gtk3/gtk3gtkframe.cxx
index 9ea6237eb2e3..931ed03febb7 100644
--- a/vcl/unx/gtk3/gtk3gtkframe.cxx
+++ b/vcl/unx/gtk3/gtk3gtkframe.cxx
@@ -993,7 +993,7 @@ void GtkSalFrame::InitCommon()
 
 
     // connect signals
-    g_signal_connect( G_OBJECT(m_pWindow), "style-set", G_CALLBACK(signalStyleSet), this );
+    g_signal_connect( G_OBJECT(m_pWindow), "style-updated", G_CALLBACK(signalStyleUpdated), this );
     gtk_widget_set_has_tooltip(pEventWidget, true);
     m_aMouseSignalIds.push_back(g_signal_connect( G_OBJECT(pEventWidget), "query-tooltip", G_CALLBACK(signalTooltipQuery), this ));
     m_aMouseSignalIds.push_back(g_signal_connect( G_OBJECT(pEventWidget), "button-press-event", G_CALLBACK(signalButton), this ));
@@ -3145,20 +3145,25 @@ gboolean GtkSalFrame::signalDelete( GtkWidget*, GdkEvent*, gpointer frame )
     return true;
 }
 
-void GtkSalFrame::signalStyleSet( GtkWidget*, GtkStyle* pPrevious, gpointer frame )
+void GtkSalFrame::signalStyleUpdated(GtkWidget*, gpointer frame)
 {
     GtkSalFrame* pThis = static_cast<GtkSalFrame*>(frame);
 
-    // every frame gets an initial style set on creation
-    // do not post these as the whole application tends to
-    // redraw itself to adjust to the new style
-    // where there IS no new style resulting in tremendous unnecessary flickering
-    if( pPrevious != nullptr )
-    {
-        // signalStyleSet does NOT usually have the gdk lock
-        // so post user event to safely dispatch the SalEvent::SettingsChanged
-        // note: settings changed for multiple frames is avoided in winproc.cxx ImplHandleSettings
-        GtkSalFrame::getDisplay()->SendInternalEvent( pThis, nullptr, SalEvent::SettingsChanged );
+    // note: settings changed for multiple frames is avoided in winproc.cxx ImplHandleSettings
+    GtkSalFrame::getDisplay()->SendInternalEvent( pThis, nullptr, SalEvent::SettingsChanged );
+
+    // fire off font-changed when the system cairo font hints change
+    GtkInstance *pInstance = static_cast<GtkInstance*>(GetSalData()->m_pInstance);
+    const cairo_font_options_t* pLastCairoFontOptions = pInstance->GetLastSeenCairoFontOptions();
+    const cairo_font_options_t* pCurrentCairoFontOptions = gdk_screen_get_font_options(gdk_screen_get_default());
+    bool bFontSettingsChanged = true;
+    if (pLastCairoFontOptions && pCurrentCairoFontOptions)
+        bFontSettingsChanged = !cairo_font_options_equal(pLastCairoFontOptions, pCurrentCairoFontOptions);
+    else if (!pLastCairoFontOptions && !pCurrentCairoFontOptions)
+        bFontSettingsChanged = false;
+    if (bFontSettingsChanged)
+    {
+        pInstance->ResetLastSeenCairoFontOptions();
         GtkSalFrame::getDisplay()->SendInternalEvent( pThis, nullptr, SalEvent::FontChanged );
     }
 }