Merge lp:~3v1n0/unity/massif-textures-sharing into lp:unity

[Marco Trevisan (Treviño)]

Unity: share textures whenever possible, optimize memory usage.

And some code improvements in TextureCache, PanelStyle, PanelView and unityshell

I've run unity under valgrind's massif, and I've noticed (as expected) that the most of the unity memory is used by textures. However, massif also underlined that we were allocating some resources many times (especially when in multi-monitor).

So, I've moved many components to use TextureCache, including PanelView, DashStyle, WindowButtons.

Improved a little the code of TextureCache that now has a default factory function to fetch textures from the default unity location.

Improvements in the PanelView background texture (that was used also by unityshell to paint the "fake" panel under the dash, in case of maximized windows): before we were generating real-size textures (and in case of unityshell big as the entire screen, a problem especially in case of multi-monitor), now we only generate 1x24 px texture that is repeated when drawing.

A not-scientific comparison of massif: http://ubuntuone.com/3NFLnQxLhIuBYziH0GKUfJ
In that tests I've ran unity for 5 minutes in my machine performing some basic unity operations using AP tests. It underlines ~5MB saving, it won't change the world but it's still a win! :)

[Brandon Schaefer (brandontschaefer)]

494 glib::Object<GtkStyleContext> _style_context;
495 glib::Object<GSettings> _gsettings;
496 + BaseTexturePtr _bg_texture;
497 std::string _theme_name;
498 nux::Color _text_color;

Someday the naming of these variables will have to be fixed :)

[Brandon Schaefer (brandontschaefer)]

Looks good to me, tests pass and I don't see any black textures anywhere :)

review: Approve

[PS Jenkins bot (ps-jenkins)]

review: Approve (continuous-integration)

=== modified file 'launcher/Launcher.cpp'
--- launcher/Launcher.cpp	2013-04-05 19:20:49 +0000
+++ launcher/Launcher.cpp	2013-04-09 01:09:21 +0000
@@ -198,12 +198,8 @@
   icon_renderer->SetTargetSize(_icon_size, _icon_image_size, _space_between_icons);
 
   TextureCache& cache = TextureCache::GetDefault();
-  TextureCache::CreateTextureCallback cb = [&](std::string const& name, int width, int height) {
-    return nux::CreateTexture2DFromFile((PKGDATADIR"/" + name + ".png").c_str(), -1, true);
-  };
-
-  launcher_sheen_ = cache.FindTexture("dash_sheen", 0, 0, cb);
-  launcher_pressure_effect_ = cache.FindTexture("launcher_pressure_effect", 0, 0, cb);
+  launcher_sheen_ = cache.FindTexture("dash_sheen.png");
+  launcher_pressure_effect_ = cache.FindTexture("launcher_pressure_effect.png");
 
   options.changed.connect(sigc::mem_fun(this, &Launcher::OnOptionsChanged));
   monitor.changed.connect(sigc::mem_fun(this, &Launcher::OnMonitorChanged));

=== modified file 'panel/PanelView.cpp'
--- panel/PanelView.cpp	2013-03-19 18:47:01 +0000
+++ panel/PanelView.cpp	2013-04-09 01:09:21 +0000
@@ -25,7 +25,6 @@
 #include <Nux/WindowCompositor.h>
 
 #include <NuxGraphics/CairoGraphics.h>
-#include <NuxGraphics/ImageSurface.h>
 #include <NuxCore/Logger.h>
 #include <UnityCore/GLibWrapper.h>
 
@@ -35,6 +34,7 @@
 #include <glib.h>
 
 #include "unity-shared/PanelStyle.h"
+#include "unity-shared/TextureCache.h"
 #include "unity-shared/WindowManager.h"
 #include "unity-shared/UBusMessages.h"
 #include <UnityCore/Variant.h>
@@ -128,9 +128,10 @@
   bg_effect_helper_.owner = this;
 
   //FIXME (gord)- replace with async loading
-  panel_sheen_.Adopt(nux::CreateTexture2DFromFile(PKGDATADIR"/dash_sheen.png", -1, true));
-  bg_refine_tex_.Adopt(nux::CreateTexture2DFromFile(PKGDATADIR"/refine_gradient_panel.png", -1, true));
-  bg_refine_single_column_tex_.Adopt(nux::CreateTexture2DFromFile(PKGDATADIR"/refine_gradient_panel_single_column.png", -1, true));
+  TextureCache& cache = TextureCache::GetDefault();
+  panel_sheen_ = cache.FindTexture("dash_sheen.png");
+  bg_refine_tex_ = cache.FindTexture("refine_gradient_panel.png");
+  bg_refine_single_column_tex_ = cache.FindTexture("refine_gradient_panel_single_column.png");
 
   rop.Blend = true;
   rop.SrcBlend = GL_ONE;
@@ -188,7 +189,8 @@
   bg_color_.blue = blue;
   bg_color_.alpha = alpha;
 
-  ForceUpdateBackground();
+  if (overlay_is_open_)
+    ForceUpdateBackground();
 }
 
 void PanelView::OnOverlayHidden(GVariant* data)
@@ -267,7 +269,7 @@
 
   GfxContext.PushClippingRectangle(geo);
 
-  if ((overlay_is_open_ || (opacity_ != 1.0f && opacity_ != 0.0f)))
+  if (IsTransparent())
   {
     nux::Geometry const& geo_absolute = GetAbsoluteGeometry();
     nux::Geometry blur_geo(geo_absolute.x, geo_absolute.y, geo.width, geo.height);
@@ -281,7 +283,7 @@
       bg_blur_texture_ = bg_effect_helper_.GetRegion(blur_geo);
     }
 
-    if (bg_blur_texture_.IsValid() && (overlay_is_open_ || opacity_ != 1.0f))
+    if (bg_blur_texture_.IsValid())
     {
       nux::TexCoordXForm texxform_blur_bg;
       texxform_blur_bg.flip_v_coord = true;
@@ -371,8 +373,7 @@
   GfxContext.GetRenderStates().SetBlend(true);
   GfxContext.GetRenderStates().SetPremultipliedBlend(nux::SRC_OVER);
 
-  if (bg_blur_texture_.IsValid() &&
-      (overlay_is_open_ || (opacity_ != 1.0f && opacity_ != 0.0f)))
+  if (bg_blur_texture_.IsValid() && IsTransparent())
   {
     nux::Geometry const& geo_absolute = GetAbsoluteGeometry();
     nux::TexCoordXForm texxform_blur_bg;
@@ -482,12 +483,9 @@
 void
 PanelView::UpdateBackground()
 {
-  nux::Geometry const& geo = GetGeometry();
-
-  if (!is_dirty_ && geo == last_geo_)
+  if (!is_dirty_)
     return;
 
-  last_geo_ = geo;
   is_dirty_ = false;
 
   nux::ROPConfig rop;
@@ -512,13 +510,13 @@
         opacity = 1.0f;
     }
 
-    auto tex = panel::Style::Instance().GetBackground(geo.width, geo.height, opacity);
+    auto const& tex = panel::Style::Instance().GetBackground();
     nux::TexCoordXForm texxform;
     texxform.SetTexCoordType(nux::TexCoordXForm::OFFSET_COORD);
-    texxform.SetWrap(nux::TEXWRAP_REPEAT, nux::TEXWRAP_REPEAT);
+    texxform.SetWrap(nux::TEXWRAP_REPEAT, nux::TEXWRAP_CLAMP);
 
     bg_layer_.reset(new nux::TextureLayer(tex->GetDeviceTexture(), texxform,
-                                          nux::color::White, true, rop));
+                                          nux::color::White * opacity, true, rop));
   }
 }
 
@@ -527,12 +525,6 @@
   is_dirty_ = true;
   UpdateBackground();
 
-  indicators_->QueueDraw();
-  tray_->QueueDraw();
-
-  if (!overlay_is_open_)
-    menu_view_->QueueDraw();
-
   QueueDraw();
 }
 
@@ -703,12 +695,17 @@
   if (opacity_ == opacity)
     return;
 
-  opacity_ = opacity;
-  bg_effect_helper_.enabled = (opacity_ < 1.0f || overlay_is_open_);
+  opacity_ = (opacity <= 0.0f ? 0.0001f : opacity); // Not to get a black menu area
+  bg_effect_helper_.enabled = IsTransparent();
 
   ForceUpdateBackground();
 }
 
+bool PanelView::IsTransparent()
+{
+  return (opacity_ < 1.0f || overlay_is_open_);
+}
+
 void PanelView::SetMenuShowTimings(int fadein, int fadeout, int discovery,
                                    int discovery_fadein, int discovery_fadeout)
 {

=== modified file 'panel/PanelView.h'
--- panel/PanelView.h	2013-03-04 23:56:40 +0000
+++ panel/PanelView.h	2013-04-09 01:09:21 +0000
@@ -91,6 +91,7 @@
   void OnOverlayShown(GVariant *data);
   void OnOverlayHidden(GVariant *data);
 
+  bool IsTransparent();
   void UpdateBackground();
   void ForceUpdateBackground();
   bool TrackMenuPointer();
@@ -116,7 +117,6 @@
   BaseTexturePtr bg_refine_single_column_tex_;
   std::unique_ptr<nux::AbstractPaintLayer> bg_refine_single_column_layer_;
 
-  nux::Geometry last_geo_;
   nux::Color bg_color_;
   std::string active_overlay_;
   nux::Point  tracked_pointer_pos_;

=== modified file 'plugins/unityshell/src/unityshell.cpp'
--- plugins/unityshell/src/unityshell.cpp	2013-03-29 13:59:11 +0000
+++ plugins/unityshell/src/unityshell.cpp	2013-04-09 01:09:21 +0000
@@ -146,8 +146,7 @@
   , last_scroll_event_(0)
   , hud_keypress_time_(0)
   , first_menu_keypress_time_(0)
-  , panel_texture_has_changed_(true)
-  , paint_panel_(false)
+  , paint_panel_under_dash_(false)
   , scale_just_activated_(false)
   , big_tick_(0)
   , screen_introspection_(screen)
@@ -705,8 +704,6 @@
 
 void UnityScreen::OnPanelStyleChanged()
 {
-  panel_texture_has_changed_ = true;
-
   // Reload the windows themed textures
   UnityWindow::CleanupSharedTextures();
 
@@ -723,7 +720,7 @@
 {
   CompOutput *output = _last_output;
 
-  DrawTopPanelBackground();
+  DrawPanelUnderDash();
 
   auto gpu_device = nux::GetGraphicsDisplay()->GetGpuDevice();
 
@@ -809,45 +806,29 @@
   didShellRepaint = true;
 }
 
-void UnityScreen::DrawTopPanelBackground()
+void UnityScreen::DrawPanelUnderDash()
 {
+  if (!paint_panel_under_dash_ || !launcher_controller_->IsOverlayOpen())
+    return;
+
+  if (_last_output->id() != screen->currentOutputDev().id())
+    return;
+
   auto graphics_engine = nux::GetGraphicsDisplay()->GetGraphicsEngine();
 
-  if (!graphics_engine->UsingGLSLCodePath() || !launcher_controller_->IsOverlayOpen() || !paint_panel_)
-   return;
-
-  if (TopPanelBackgroundTextureNeedsUpdate())
-    UpdateTopPanelBackgroundTexture();
-
-  if (panel_texture_.IsValid())
-  {
-    graphics_engine->ResetModelViewMatrixStack();
-    graphics_engine->Push2DTranslationModelViewMatrix(0.0f, 0.0f, 0.0f);
-    graphics_engine->ResetProjectionMatrix();
-    graphics_engine->SetOrthographicProjectionMatrix(screen->width (), screen->height());
-
-    nux::TexCoordXForm texxform;
-    int panel_height = panel_style_.panel_height;
-    graphics_engine->QRP_GLSL_1Tex(0, 0, screen->width (), panel_height, panel_texture_, texxform, nux::color::White);
-  }
-}
-
-bool UnityScreen::TopPanelBackgroundTextureNeedsUpdate() const
-{
-  return panel_texture_has_changed_ || !panel_texture_.IsValid();
-}
-
-void UnityScreen::UpdateTopPanelBackgroundTexture()
-{
-  auto &panel_style = panel::Style::Instance();
-
-  panel_texture_.Release();
-  auto texture = panel_style.GetBackground(screen->width(), screen->height(), 1.0f);
-
-  if (texture)
-    panel_texture_ = texture->GetDeviceTexture();
-
-  panel_texture_has_changed_ = false;
+  if (!graphics_engine->UsingGLSLCodePath())
+    return;
+
+  graphics_engine->ResetModelViewMatrixStack();
+  graphics_engine->Push2DTranslationModelViewMatrix(0.0f, 0.0f, 0.0f);
+  graphics_engine->ResetProjectionMatrix();
+  graphics_engine->SetOrthographicProjectionMatrix(screen->width(), screen->height());
+
+  nux::TexCoordXForm texxform;
+  texxform.SetWrap(nux::TEXWRAP_REPEAT, nux::TEXWRAP_CLAMP);
+  int panel_height = panel_style_.panel_height;
+  auto const& texture = panel_style_.GetBackground()->GetDeviceTexture();
+  graphics_engine->QRP_GLSL_1Tex(0, 0, screen->width(), panel_height, texture, texxform, nux::color::White);
 }
 
 bool UnityScreen::forcePaintOnTop ()
@@ -1256,7 +1237,7 @@
 
   allowWindowPaint = true;
   _last_output = output;
-  paint_panel_ = false;
+  paint_panel_under_dash_ = false;
 
   // CompRegion has no clear() method. So this is the fastest alternative.
   fullscreenRegion = CompRegion();
@@ -2597,19 +2578,17 @@
                          const CompRegion& region,
                          unsigned int mask)
 {
-  if (uScreen->doShellRepaint && !uScreen->paint_panel_ && window->type() == CompWindowTypeNormalMask)
+  if (uScreen->doShellRepaint && !uScreen->paint_panel_under_dash_ && window->type() == CompWindowTypeNormalMask)
   {
-    guint32 id = window->id();
-    bool maximized = WindowManager::Default().IsWindowMaximized(id);
-    bool on_current = window->onCurrentDesktop();
-    bool override_redirect = window->overrideRedirect();
-    bool managed = window->managed();
-    CompPoint viewport = window->defaultViewport();
-    int output = window->outputDevice();
-
-    if (maximized && on_current && !override_redirect && managed && viewport == uScreen->screen->vp() && output == (int)uScreen->screen->currentOutputDev().id())
+    if ((window->state() & MAXIMIZE_STATE) && window->onCurrentDesktop() && !window->overrideRedirect() && window->managed())
     {
-      uScreen->paint_panel_ = true;
+      CompPoint const& viewport = window->defaultViewport();
+      unsigned output = window->outputDevice();
+
+      if (viewport == uScreen->screen->vp() && output == uScreen->screen->currentOutputDev().id())
+      {
+        uScreen->paint_panel_under_dash_ = true;
+      }
     }
   }
 

=== modified file 'plugins/unityshell/src/unityshell.h'
--- plugins/unityshell/src/unityshell.h	2013-03-11 17:46:46 +0000
+++ plugins/unityshell/src/unityshell.h	2013-04-09 01:09:21 +0000
@@ -243,9 +243,7 @@
 
   void InitGesturesSupport();
 
-  void DrawTopPanelBackground();
-  bool TopPanelBackgroundTextureNeedsUpdate() const;
-  void UpdateTopPanelBackgroundTexture();
+  void DrawPanelUnderDash();
 
   unsigned CompizModifiersToNux(unsigned input) const;
   unsigned XModifiersToNux(unsigned input) const;
@@ -331,9 +329,7 @@
 
   GLMatrix panel_shadow_matrix_;
 
-  bool panel_texture_has_changed_;
-  bool paint_panel_;
-  nux::ObjectPtr<nux::IOpenGLBaseTexture> panel_texture_;
+  bool paint_panel_under_dash_;
   std::set<UnityWindow*> fake_decorated_windows_;
 
   bool scale_just_activated_;

=== modified file 'tests/test_texture_cache.cpp'
--- tests/test_texture_cache.cpp	2011-09-02 02:24:56 +0000
+++ tests/test_texture_cache.cpp	2013-04-09 01:09:21 +0000
@@ -50,7 +50,7 @@
   }
 };
 
-TEST(TestTextureCache, DISABLED_TestCallsCreateTextureCallback)
+TEST(TestTextureCache, TestCallsCreateTextureCallback)
 {
   // Another lambda issue.  If the lambda takes a reference to any other
   // variables, it seems incapable of assigning the function to the
@@ -80,7 +80,7 @@
   }
 };
 
-TEST(TestTextureCache, DISABLED_TestCallbackOnlyCalledOnce)
+TEST(TestTextureCache, TestCallbackOnlyCalledOnce)
 {
   TextureCallbackCounter counter;
   TextureCache::CreateTextureCallback callback(sigc::mem_fun(counter, &TextureCallbackCounter::callback));
@@ -95,7 +95,7 @@
   EXPECT_TRUE(t1 == t2);
 }
 
-TEST(TestTextureCache, DISABLED_TestCacheRemovesDeletedObject)
+TEST(TestTextureCache, TestCacheRemovesDeletedObject)
 {
   // Note for others, if just using the lambda function, the return value is
   // lost in the type deduction that sigc uses.  So we have the typedef

=== modified file 'unity-shared/DashStyle.cpp'
--- unity-shared/DashStyle.cpp	2013-03-11 22:18:58 +0000
+++ unity-shared/DashStyle.cpp	2013-04-09 01:09:21 +0000
@@ -42,6 +42,7 @@
 
 #include "CairoTexture.h"
 #include "JSONParser.h"
+#include "TextureCache.h"
 #include "UnitySettings.h"
 #include "config.h"
 
@@ -2547,19 +2548,8 @@
 
 void LazyLoadTexture::LoadTexture()
 {
-  std::string full_path = PKGDATADIR + filename_;
-  glib::Object<GdkPixbuf> pixbuf;
-  glib::Error error;
-
-  pixbuf = ::gdk_pixbuf_new_from_file_at_size(full_path.c_str(), size_, size_, &error);
-  if (error)
-  {
-    LOG_WARN(logger) << "Unable to texture " << full_path << ": " << error;
-  }
-  else
-  {
-    texture_.Adopt(nux::CreateTexture2DFromPixbuf(pixbuf, true));
-  }
+  TextureCache& cache = TextureCache::GetDefault();
+  texture_ = cache.FindTexture(filename_, size_, size_);
 }
 
 } // anon namespace

=== modified file 'unity-shared/PanelStyle.cpp'
--- unity-shared/PanelStyle.cpp	2012-12-14 15:17:24 +0000
+++ unity-shared/PanelStyle.cpp	2013-04-09 01:09:21 +0000
@@ -34,6 +34,7 @@
 #include "PanelStyle.h"
 
 #include <UnityCore/GLibWrapper.h>
+#include "unity-shared/TextureCache.h"
 #include "unity-shared/UnitySettings.h"
 
 namespace unity
@@ -138,7 +139,7 @@
   GdkRGBA rgba_text_color;
   glib::String theme_name;
   bool updated = false;
-  
+
   GtkSettings* settings = gtk_settings_get_default();
   g_object_get(settings, "gtk-theme-name", &theme_name, nullptr);
 
@@ -159,7 +160,10 @@
   }
 
   if (updated)
+  {
+    _bg_texture.Release();
     changed.emit();
+  }
 }
 
 GtkStyleContext* Style::GetStyleContext()
@@ -167,8 +171,14 @@
   return _style_context;
 }
 
-BaseTexturePtr Style::GetBackground(int width, int height, float opacity)
+BaseTexturePtr Style::GetBackground()
 {
+  if (_bg_texture)
+    return _bg_texture;
+
+  int width = 1;
+  int height = panel_height();
+
   nux::CairoGraphics context(CAIRO_FORMAT_ARGB32, width, height);
 
   // Use the internal context as we know it is good and shiny new.
@@ -177,9 +187,11 @@
   gtk_render_background(_style_context, cr, 0, 0, width, height);
   gtk_render_frame(_style_context, cr, 0, 0, width, height);
   cairo_pop_group_to_source(cr);
-  cairo_paint_with_alpha(cr, opacity);
-
-  return texture_ptr_from_cairo_graphics(context);
+  cairo_paint(cr);
+
+  _bg_texture = texture_ptr_from_cairo_graphics(context);
+
+  return _bg_texture;
 }
 
 /*!
@@ -222,20 +234,30 @@
 
 BaseTexturePtr Style::GetWindowButton(WindowButtonType type, WindowState state)
 {
-  BaseTexturePtr texture;
-
-  for (auto const& file : GetWindowButtonFileNames(type, state))
-  {
-    texture.Adopt(nux::CreateTexture2DFromFile(file.c_str(), -1, true));
-
-    if (texture)
-      break;
-  }
-
-  if (!texture)
-    texture = GetFallbackWindowButton(type, state);
-
-  return texture;
+  auto texture_factory = [this, type, state] (std::string const&, int, int) {
+    nux::BaseTexture* texture = nullptr;
+
+    for (auto const& file : GetWindowButtonFileNames(type, state))
+    {
+      texture = nux::CreateTexture2DFromFile(file.c_str(), -1, true);
+
+      if (texture)
+        return texture;
+    }
+
+    auto const& fallback = GetFallbackWindowButton(type, state);
+    texture = fallback.GetPointer();
+    texture->Reference();
+
+    return texture;
+  };
+
+  auto& cache = TextureCache::GetDefault();
+  std::string texture_id = "window-button-";
+  texture_id += std::to_string(static_cast<int>(type));
+  texture_id += std::to_string(static_cast<int>(state));
+
+  return cache.FindTexture(texture_id, 0, 0, texture_factory);
 }
 
 BaseTexturePtr Style::GetFallbackWindowButton(WindowButtonType type,

=== modified file 'unity-shared/PanelStyle.h'
--- unity-shared/PanelStyle.h	2012-12-14 14:41:16 +0000
+++ unity-shared/PanelStyle.h	2013-04-09 01:09:21 +0000
@@ -71,7 +71,7 @@
   typedef nux::ObjectPtr<nux::BaseTexture> BaseTexturePtr;
 
   GtkStyleContext* GetStyleContext();
-  BaseTexturePtr GetBackground(int width, int height, float opacity);
+  BaseTexturePtr GetBackground();
   BaseTexturePtr GetWindowButton(WindowButtonType type, WindowState state);
   BaseTexturePtr GetFallbackWindowButton(WindowButtonType type, WindowState state);
   std::vector<std::string> GetWindowButtonFileNames(WindowButtonType type, WindowState state);
@@ -88,6 +88,7 @@
 
   glib::Object<GtkStyleContext> _style_context;
   glib::Object<GSettings> _gsettings;
+  BaseTexturePtr _bg_texture;
   std::string _theme_name;
   nux::Color _text_color;
 

=== modified file 'unity-shared/TextureCache.cpp'
--- unity-shared/TextureCache.cpp	2012-10-29 09:34:54 +0000
+++ unity-shared/TextureCache.cpp	2013-04-09 01:09:21 +0000
@@ -22,25 +22,23 @@
 
 #include <sstream>
 #include <NuxCore/Logger.h>
+#include "config.h"
 
 namespace unity
 {
 DECLARE_LOGGER(logger, "unity.internal.texturecache");
 
-TextureCache::TextureCache()
-{
-}
-
-TextureCache::~TextureCache()
-{
-}
-
 TextureCache& TextureCache::GetDefault()
 {
   static TextureCache instance;
   return instance;
 }
 
+nux::BaseTexture* TextureCache::DefaultTexturesLoader(std::string const& name, int w, int h)
+{
+  return nux::CreateTexture2DFromFile((PKGDATADIR"/" + name).c_str(), -1, true);
+}
+
 std::string TextureCache::Hash(std::string const& id, int width, int height)
 {
   std::ostringstream sout;
@@ -50,17 +48,22 @@
 
 TextureCache::BaseTexturePtr TextureCache::FindTexture(std::string const& texture_id,
                                                        int width, int height,
-                                                       CreateTextureCallback slot)
+                                                       CreateTextureCallback factory)
 {
-  if (!slot)
+  if (!factory)
     return BaseTexturePtr();
 
-  std::string key = Hash(texture_id, width, height);
-  BaseTexturePtr texture(cache_[key]);
+  std::string const& key = Hash(texture_id, width, height);
+  auto texture_it = cache_.find(key);
+
+  BaseTexturePtr texture(texture_it != cache_.end() ? texture_it->second : nullptr);
 
   if (!texture)
   {
-    texture = slot(texture_id, width, height);
+    texture.Adopt(factory(texture_id, width, height));
+
+    if (!texture)
+      return texture;
 
     // Now here is the magic.
     //
@@ -79,10 +82,6 @@
     // are destroyed first, then the sigc::trackable disconnects all methods
     // created using mem_fun.
 
-    // Reduce the internal reference count of the texture, so the smart
-    // pointer is the sole owner of the object.
-    texture->UnReference();
-
     cache_[key] = texture.GetPointer();
 
     auto on_destroy = sigc::mem_fun(this, &TextureCache::OnDestroyNotify);
@@ -92,7 +91,7 @@
   return texture;
 }
 
-void TextureCache::OnDestroyNotify(nux::Trackable* Object, std::string key)
+void TextureCache::OnDestroyNotify(nux::Trackable* Object, std::string const& key)
 {
   cache_.erase(key);
 }

=== modified file 'unity-shared/TextureCache.h'
--- unity-shared/TextureCache.h	2012-07-16 11:03:32 +0000
+++ unity-shared/TextureCache.h	2013-04-09 01:09:21 +0000
@@ -40,24 +40,26 @@
 public:
   typedef nux::ObjectPtr<nux::BaseTexture> BaseTexturePtr;
 
+  ~TextureCache() = default;
+
   // id, width, height -> texture
   typedef std::function<nux::BaseTexture*(std::string const&, int, int)> CreateTextureCallback;
 
   static TextureCache& GetDefault();
+  static nux::BaseTexture* DefaultTexturesLoader(std::string const&, int, int);
 
-  BaseTexturePtr FindTexture(std::string const& texture_id, int width, int height, CreateTextureCallback callback);
+  BaseTexturePtr FindTexture(std::string const& texture_id, int width = 0, int height = 0, CreateTextureCallback callback = DefaultTexturesLoader);
 
   // Return the current size of the cache.
   std::size_t Size() const;
 
 private:
-  TextureCache();
-  ~TextureCache();
+  TextureCache() = default;
 
   std::string Hash(std::string const& , int width, int height);
   // Have the key passed by value not referece, as the key will be a bound
   // parameter in the slot passed to the texture on_destroy signal.
-  void OnDestroyNotify(nux::Trackable* Object, std::string key);
+  void OnDestroyNotify(nux::Trackable* Object, std::string const& key);
 
   std::map<std::string, nux::BaseTexture*> cache_;
 };

=== modified file 'unity-shared/WindowButtons.cpp'
--- unity-shared/WindowButtons.cpp	2013-03-19 18:47:01 +0000
+++ unity-shared/WindowButtons.cpp	2013-04-09 01:09:21 +0000
@@ -29,6 +29,7 @@
 #include "WindowButtons.h"
 #include "WindowButtonPriv.h"
 
+#include "unity-shared/TextureCache.h"
 #include "unity-shared/UBusMessages.h"
 #include "unity-shared/WindowManager.h"
 
@@ -176,8 +177,8 @@
 
   std::string subpath = names[static_cast<int>(type)] + states[static_cast<int>(state)] + ".png";
 
-  glib::String filename(g_build_filename(PKGDATADIR, subpath.c_str(), NULL));
-  texture.Adopt(nux::CreateTexture2DFromFile(filename, -1, true));
+  auto& cache = TextureCache::GetDefault();
+  texture = cache.FindTexture(subpath);
 
   if (!texture)
     texture = panel::Style::Instance().GetFallbackWindowButton(type, state);