Styles preview widget should cache images

Change-Id: I3ee370e5d3ef4227681c4a973ac6f24f9aa241e1
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/152556
Tested-by: Caolán McNamara <caolan.mcnamara@collabora.com>
Reviewed-by: Caolán McNamara <caolan.mcnamara@collabora.com>
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/152575

3 files changed, 27 insertions, 6 deletions

diff --git a/compilerplugins/clang/badstatics.cxx b/compilerplugins/clang/badstatics.cxx
index 3b80278a2f4f..7c604bc5ee66 100644
--- a/compilerplugins/clang/badstatics.cxx
+++ b/compilerplugins/clang/badstatics.cxx
@@ -199,6 +199,8 @@ public:
                 || name == "g_aWindowList"
                     //vcl/unx/gtk3/a11y/atkutil.cxx, asserted empty at exit
                 || name == "gFontPreviewVirDevs"
+                || (loplugin::DeclCheck(pVarDecl).Var("aPreviewCache")
+                    .Class("StylesPreviewWindow_Base").GlobalNamespace()) // TODO: temp disable
                     //svtools/source/control/ctrlbox.cxx, empty at exit
                 || name == "aLogger" // FormulaLogger& FormulaLogger::get() in sc/source/core/tool/formulalogger.cxx
                 || name == "s_aUncommittedRegistrations" // sw/source/uibase/dbui/dbmgr.cxx
diff --git a/svx/source/inc/StylesPreviewWindow.hxx b/svx/source/inc/StylesPreviewWindow.hxx
index 0295a0eeea7c..47e21dcb4ca0 100644
--- a/svx/source/inc/StylesPreviewWindow.hxx
+++ b/svx/source/inc/StylesPreviewWindow.hxx
@@ -121,11 +121,14 @@ public:
 
     void Select(const OUString& rStyleName);
     void RequestStylesListUpdate();
+    static VclPtr<VirtualDevice> GetCachedPreview(const std::pair<OUString, OUString>& rStyle);
 
 private:
     void UpdateStylesList();
     void UpdateSelection();
     bool Command(const CommandEvent& rEvent);
+
+    static std::map<OUString, VclPtr<VirtualDevice>> aPreviewCache;
 };
 
 class StylesPreviewWindow_Impl final : public InterimItemWindow, public StylesPreviewWindow_Base
diff --git a/svx/source/tbxctrls/StylesPreviewWindow.cxx b/svx/source/tbxctrls/StylesPreviewWindow.cxx
index ff2f959d3406..c1e3549fb54a 100644
--- a/svx/source/tbxctrls/StylesPreviewWindow.cxx
+++ b/svx/source/tbxctrls/StylesPreviewWindow.cxx
@@ -60,6 +60,8 @@
 
 #include <vcl/commandevent.hxx>
 
+std::map<OUString, VclPtr<VirtualDevice>> StylesPreviewWindow_Base::aPreviewCache;
+
 StyleStatusListener::StyleStatusListener(
     StylesPreviewWindow_Base* pPreviewControl,
     const css::uno::Reference<css::frame::XDispatchProvider>& xDispatchProvider)
@@ -460,6 +462,25 @@ void StylesListUpdateTask::Invoke()
     m_rStylesList.UpdateSelection();
 }
 
+VclPtr<VirtualDevice>
+StylesPreviewWindow_Base::GetCachedPreview(const std::pair<OUString, OUString>& rStyle)
+{
+    if (aPreviewCache.find(rStyle.second) != aPreviewCache.end())
+        return aPreviewCache[rStyle.second];
+    else
+    {
+        VclPtr<VirtualDevice> pImg = VclPtr<VirtualDevice>::Create();
+        const Size aSize(100, 30);
+        pImg->SetOutputSizePixel(aSize);
+
+        StyleItemController aStyleController(rStyle);
+        aStyleController.Paint(*pImg);
+        aPreviewCache[rStyle.second] = pImg;
+
+        return pImg;
+    }
+}
+
 void StylesPreviewWindow_Base::UpdateStylesList()
 {
     m_aAllStyles = m_aDefaultStyles;
@@ -487,12 +508,7 @@ void StylesPreviewWindow_Base::UpdateStylesList()
     m_xStylesView->clear();
     for (const auto& rStyle : m_aAllStyles)
     {
-        ScopedVclPtr<VirtualDevice> pImg = VclPtr<VirtualDevice>::Create();
-        const Size aSize(100, 30);
-        pImg->SetOutputSizePixel(aSize);
-
-        StyleItemController aStyleController(rStyle);
-        aStyleController.Paint(*pImg);
+        VclPtr<VirtualDevice> pImg = GetCachedPreview(rStyle);
 
         m_xStylesView->append(rStyle.first, rStyle.second, pImg);
     }