support completely styling a welded button

Change-Id: I6e45c711b406a3836dd230ceaa738c5a250ff846
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/107173
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>

4 files changed, 78 insertions, 1 deletions

diff --git a/vcl/inc/salvtables.hxx b/vcl/inc/salvtables.hxx
index 9fe7a6a5dac5..2fd7198a7b65 100644
--- a/vcl/inc/salvtables.hxx
+++ b/vcl/inc/salvtables.hxx
@@ -1007,6 +1007,8 @@ public:
 
     virtual void set_font(const vcl::Font& rFont) override;
 
+    virtual void set_custom_button(VirtualDevice* pDevice) override;
+
     virtual ~SalInstanceButton() override;
 };
 
diff --git a/vcl/source/app/salvtables.cxx b/vcl/source/app/salvtables.cxx
index 0daf586ebb89..ccc3757e6718 100644
--- a/vcl/source/app/salvtables.cxx
+++ b/vcl/source/app/salvtables.cxx
@@ -2488,6 +2488,15 @@ void SalInstanceButton::set_font(const vcl::Font& rFont)
     m_xButton->Invalidate();
 }
 
+void SalInstanceButton::set_custom_button(VirtualDevice* pDevice)
+{
+    if (pDevice)
+        m_xButton->SetCustomButtonImage(createImage(*pDevice));
+    else
+        m_xButton->SetCustomButtonImage(Image());
+    m_xButton->Invalidate();
+}
+
 OUString SalInstanceButton::get_label() const { return m_xButton->GetText(); }
 
 SalInstanceButton::~SalInstanceButton() { m_xButton->SetClickHdl(Link<::Button*, void>()); }
diff --git a/vcl/source/control/button.cxx b/vcl/source/control/button.cxx
index 66a399c15bbc..38b32d4f54af 100644
--- a/vcl/source/control/button.cxx
+++ b/vcl/source/control/button.cxx
@@ -83,12 +83,14 @@ public:
     ImageAlign      meImageAlign;
     SymbolAlign     meSymbolAlign;
 
+    Image           maCustomContentImage;
+
     /** StatusListener. Updates the button as the slot state changes */
     rtl::Reference<VclStatusListener<Button>> mpStatusListener;
 };
 
 ImplCommonButtonData::ImplCommonButtonData() : maFocusRect(), mnSeparatorX(0), mnButtonState(DrawButtonFlags::NONE),
-mbSmallSymbol(false), maImage(), meImageAlign(ImageAlign::Top), meSymbolAlign(SymbolAlign::LEFT)
+mbSmallSymbol(false), maImage(), meImageAlign(ImageAlign::Top), meSymbolAlign(SymbolAlign::LEFT), maCustomContentImage()
 {
 }
 
@@ -158,6 +160,20 @@ ImageAlign Button::GetImageAlign() const
     return mpButtonData->meImageAlign;
 }
 
+void Button::SetCustomButtonImage(const Image& rImage)
+{
+    if (rImage != mpButtonData->maCustomContentImage)
+    {
+        mpButtonData->maCustomContentImage = rImage;
+        StateChanged( StateChangedType::Data );
+    }
+}
+
+Image const & Button::GetCustomButtonImage() const
+{
+    return mpButtonData->maCustomContentImage;
+}
+
 tools::Long Button::ImplGetSeparatorX() const
 {
     return mpButtonData->mnSeparatorX;
@@ -1294,6 +1310,12 @@ void PushButton::FillLayoutData() const
 
 void PushButton::Paint(vcl::RenderContext& rRenderContext, const tools::Rectangle&)
 {
+    const Image& rCustomButtonImage = GetCustomButtonImage();
+    if (!!rCustomButtonImage)
+    {
+        rRenderContext.DrawImage(Point(0, 0), rCustomButtonImage);
+        return;
+    }
     ImplDrawPushButton(rRenderContext);
 }
 
diff --git a/vcl/unx/gtk3/gtk3gtkinst.cxx b/vcl/unx/gtk3/gtk3gtkinst.cxx
index 1863076ddfcf..c4df0cca2855 100644
--- a/vcl/unx/gtk3/gtk3gtkinst.cxx
+++ b/vcl/unx/gtk3/gtk3gtkinst.cxx
@@ -6815,8 +6815,10 @@ class GtkInstanceButton : public GtkInstanceContainer, public virtual weld::Butt
 {
 private:
     GtkButton* m_pButton;
+    GtkCssProvider* m_pCustomCssProvider;
     gulong m_nSignalId;
     std::unique_ptr<vcl::Font> m_xFont;
+    std::unique_ptr<utl::TempFile> m_xCustomImage;
 
     static void signalClicked(GtkButton*, gpointer widget)
     {
@@ -6856,6 +6858,39 @@ private:
         return pChild;
     }
 
+    // See: https://developer.gnome.org/Buttons/
+    void use_custom_content(VirtualDevice* pDevice)
+    {
+        GtkStyleContext *pWidgetContext = gtk_widget_get_style_context(GTK_WIDGET(m_pButton));
+
+        if (m_pCustomCssProvider)
+        {
+            gtk_style_context_remove_provider(pWidgetContext, GTK_STYLE_PROVIDER(m_pCustomCssProvider));
+            m_pCustomCssProvider = nullptr;
+        }
+
+        m_xCustomImage.reset();
+
+        if (!pDevice)
+            return;
+
+        m_xCustomImage.reset(new utl::TempFile);
+        m_xCustomImage->EnableKillingFile(true);
+
+        cairo_surface_t* surface = get_underlying_cairo_surface(*pDevice);
+        Size aSize = pDevice->GetOutputSizePixel();
+        cairo_surface_write_to_png(surface, OUStringToOString(m_xCustomImage->GetFileName(), osl_getThreadTextEncoding()).getStr());
+
+        m_pCustomCssProvider = gtk_css_provider_new();
+        OUString aBuffer = "* { background-image: url(\"" + m_xCustomImage->GetURL() + "\"); "
+                           "background-size: " + OUString::number(aSize.Width()) + "px " + OUString::number(aSize.Height()) + "px; "
+                           "border-radius: 0; border-width: 0; }";
+        OString aResult = OUStringToOString(aBuffer, RTL_TEXTENCODING_UTF8);
+        gtk_css_provider_load_from_data(m_pCustomCssProvider, aResult.getStr(), aResult.getLength(), nullptr);
+        gtk_style_context_add_provider(pWidgetContext, GTK_STYLE_PROVIDER(m_pCustomCssProvider),
+                                       GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
+    }
+
 protected:
     GtkWidget* get_label_widget()
     {
@@ -6875,6 +6910,7 @@ public:
     GtkInstanceButton(GtkButton* pButton, GtkInstanceBuilder* pBuilder, bool bTakeOwnership)
         : GtkInstanceContainer(GTK_CONTAINER(pButton), pBuilder, bTakeOwnership)
         , m_pButton(pButton)
+        , m_pCustomCssProvider(nullptr)
         , m_nSignalId(g_signal_connect(pButton, "clicked", G_CALLBACK(signalClicked), this))
     {
         g_object_set_data(G_OBJECT(m_pButton), "g-lo-GtkInstanceButton", this);
@@ -6919,6 +6955,11 @@ public:
         }
     }
 
+    virtual void set_custom_button(VirtualDevice* pDevice) override
+    {
+        use_custom_content(pDevice);
+    }
+
     virtual OUString get_label() const override
     {
         return ::get_label(m_pButton);
@@ -6971,6 +7012,9 @@ public:
     {
         g_object_steal_data(G_OBJECT(m_pButton), "g-lo-GtkInstanceButton");
         g_signal_handler_disconnect(m_pButton, m_nSignalId);
+        if (m_pCustomCssProvider)
+            use_custom_content(nullptr);
+        assert(!m_pCustomCssProvider);
     }
 };