Client|UI: Added a basic implementation of NotificationWidget

This will act as a common notification area.

Also added changeRef() to aid in changing the value of a reference
counted pointer, and safe type casting for Widget-based classes.

doomsday/client/client.pro

@@ -346,6 +346,7 @@ DENG_HEADERS += \
     include/ui/widgets/lineeditwidget.h \
     include/ui/widgets/logwidget.h \
     include/ui/widgets/menuwidget.h \
+    include/ui/widgets/notificationwidget.h \
     include/ui/widgets/popupmenuwidget.h \
     include/ui/widgets/popupwidget.h \
     include/ui/widgets/scrollareawidget.h \
@@ -637,6 +638,7 @@ SOURCES += \
     src/ui/widgets/lineeditwidget.cpp \
     src/ui/widgets/logwidget.cpp \
     src/ui/widgets/menuwidget.cpp \
+    src/ui/widgets/notificationwidget.cpp \
     src/ui/widgets/popupmenuwidget.cpp \
     src/ui/widgets/popupwidget.cpp \
     src/ui/widgets/scrollareawidget.cpp \

doomsday/client/include/ui/widgets/notificationwidget.h

@@ -0,0 +1,53 @@
+/** @file notificationwidget.h  Notifiction area.
+ *
+ * @authors Copyright (c) 2013 Jaakko Keränen <jaakko.keranen@iki.fi>
+ *
+ * @par License
+ * GPL: http://www.gnu.org/licenses/gpl.html
+ *
+ * <small>This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version. This program is distributed in the hope that it
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details. You should have received a copy of the GNU
+ * General Public License along with this program; if not, see:
+ * http://www.gnu.org/licenses</small> 
+ */
+
+#ifndef DENG_CLIENT_NOTIFICATIONWIDGET_H
+#define DENG_CLIENT_NOTIFICATIONWIDGET_H
+
+#include "guiwidget.h"
+
+/**
+ * Notification area.
+ *
+ * Children the widget are expected to size themselves and allow unrestricted,
+ * automatical positioning inside the area. Children can be added and removed
+ * dynamically. The notification area is dismissed if there are no visible
+ * notifications.
+ *
+ * The client window owns an instance of NotificationWidget. Other widgets and
+ * subsystems are expected to give ownership of their notifications to the
+ * window's NotificationWidget.
+ */
+class NotificationWidget : public GuiWidget
+{
+public:
+    NotificationWidget(de::String const &name = "");
+
+    // Events.
+    void viewResized();
+    void drawContent();
+
+protected:
+    void glInit();
+    void glDeinit();
+
+private:
+    DENG2_PRIVATE(d)
+};
+
+#endif // DENG_CLIENT_NOTIFICATIONWIDGET_H

doomsday/client/src/ui/widgets/notificationwidget.cpp

@@ -0,0 +1,149 @@
+/** @file notificationwidget.cpp  Notification area.
+ *
+ * @authors Copyright (c) 2013 Jaakko Keränen <jaakko.keranen@iki.fi>
+ *
+ * @par License
+ * GPL: http://www.gnu.org/licenses/gpl.html
+ *
+ * <small>This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version. This program is distributed in the hope that it
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details. You should have received a copy of the GNU
+ * General Public License along with this program; if not, see:
+ * http://www.gnu.org/licenses</small> 
+ */
+
+#include "ui/widgets/notificationwidget.h"
+#include "ui/widgets/guirootwidget.h"
+
+#include <de/Drawable>
+#include <de/Matrix>
+
+using namespace de;
+
+DENG2_PIMPL(NotificationWidget)
+{
+    // GL objects:
+    typedef DefaultVertexBuf VertexBuf;
+    Drawable drawable;
+    GLUniform uMvpMatrix;
+    GLUniform uColor;
+
+    Instance(Public *i)
+        : Base(i),
+          uMvpMatrix("uMvpMatrix", GLUniform::Mat4),
+          uColor    ("uColor",     GLUniform::Vec4)
+    {
+        updateStyle();
+    }
+
+    void updateStyle()
+    {
+        self.set(Background(self.style().colors().colorf("background")));
+    }
+
+    void glInit()
+    {
+        drawable.addBuffer(new VertexBuf);
+
+        self.root().shaders().build(drawable.program(), "generic.color_ucolor")
+                << uMvpMatrix << uColor;
+    }
+
+    void glDeinit()
+    {
+        drawable.clear();
+    }
+
+    void updateGeometry()
+    {
+        Rectanglei pos;
+        if(self.hasChangedPlace(pos) || self.geometryRequested())
+        {
+            self.requestGeometry(false);
+
+            VertexBuf::Builder verts;
+            self.glMakeGeometry(verts);
+            drawable.buffer<VertexBuf>().setVertices(gl::TriangleStrip, verts, gl::Static);
+        }
+    }
+
+    void updateChildLayout()
+    {
+        Rule const &outer = self.style().rules().rule("gap");
+        Rule const &inner = self.style().rules().rule("unit");
+
+        Rule const *totalWidth = 0;
+        Rule const *totalHeight = 0;
+
+        WidgetList const children = self.Widget::children();
+        for(int i = 0; i < children.size(); ++i)
+        {
+            GuiWidget &w = children[i]->as<GuiWidget>();
+
+            // The children are laid out simply in a row from right to left.
+            w.rule().setInput(Rule::Top, self.rule().top() + outer);
+            if(i > 0)
+            {
+                w.rule().setInput(Rule::Right, children[i - 1]->as<GuiWidget>().rule().left() - inner);
+                changeRef(totalWidth, *totalWidth + inner + w.rule().width());
+            }
+            else
+            {
+                w.rule().setInput(Rule::Right, self.rule().right() - outer);
+                totalWidth = holdRef(w.rule().width());
+            }
+
+            if(!totalHeight)
+            {
+                totalHeight = holdRef(w.rule().height());
+            }
+            else
+            {
+                changeRef(totalHeight, OperatorRule::maximum(*totalHeight, w.rule().height()));
+            }
+        }
+
+        // Update the total size of the notification area.
+        self.rule()
+                .setInput(Rule::Width,  *totalWidth  + outer * 2)
+                .setInput(Rule::Height, *totalHeight + outer * 2);
+
+        releaseRef(totalWidth);
+        releaseRef(totalHeight);
+    }
+};
+
+NotificationWidget::NotificationWidget(String const &name) : d(new Instance(this))
+{
+    // Initially the widget is empty.
+    rule().setSize(Const(0), Const(0));
+    hide();
+}
+
+void NotificationWidget::viewResized()
+{
+    d->uMvpMatrix = root().projMatrix2D();
+}
+
+void NotificationWidget::drawContent()
+{
+    d->updateGeometry();
+
+    d->uColor = Vector4f(1, 1, 1, visibleOpacity());
+    d->drawable.draw();
+}
+
+void NotificationWidget::glInit()
+{
+    d->glInit();
+}
+
+void NotificationWidget::glDeinit()
+{
+    d->glDeinit();
+}
+

doomsday/libdeng2/include/de/data/counted.h

@@ -160,6 +160,20 @@ inline CountedType const *holdRef(CountedType const &counted) {
     return counted.template ref<CountedType>();
 }
 
+template <typename CountedType1, typename CountedType2>
+inline void changeRef(CountedType1 const *&counted, CountedType2 const *newRef) {
+    CountedType1 const *old = counted;
+    counted = holdRef(newRef);
+    releaseRef(old);
+}
+
+template <typename CountedType1, typename CountedType2>
+inline void changeRef(CountedType1 const *&counted, CountedType2 const &newRef) {
+    CountedType1 const *old = counted;
+    counted = holdRef(newRef);
+    releaseRef(old);
+}
+
 /**
  * Releases a reference to a Counted object. Afterwards, the pointer is cleared
  * to NULL.

doomsday/libdeng2/include/de/widgets/widget.h

@@ -85,6 +85,18 @@ class DENG2_PUBLIC Widget
     Widget(String const &name = "");
     virtual ~Widget();
 
+    template <typename Type>
+    Type &as() {
+        DENG2_ASSERT(dynamic_cast<Type *>(this) != 0);
+        return *static_cast<Type *>(this);
+    }
+
+    template <typename Type>
+    Type const &as() const {
+        DENG2_ASSERT(dynamic_cast<Type const *>(this) != 0);
+        return *static_cast<Type const *>(this);
+    }
+
     /**
      * Returns the automatically generated, unique identifier of the widget.
      */