Vars: Support functions and add FunctionButton widget for activating …

…closures etc.

examples/SimpleDisplay/main.cpp

@@ -30,9 +30,9 @@ std::istream& operator>> (std::istream& is, CustomType& o){
   return is;
 }
 
-void GlobalKeyHook()
+void SampleMethod()
 {
-    cout << "You pushed ctrl-r" << endl;
+    cout << "You typed ctrl-r or pushed reset" << endl;
 }
 
 int main( int /*argc*/, char* argv[] )
@@ -68,12 +68,6 @@ int main( int /*argc*/, char* argv[] )
   pangolin::CreatePanel("ui")
       .SetBounds(0.0, 1.0, 0.0, Attach::Pix(UI_WIDTH));
 
-  // Demonstration of how we can register a keyboard hook to alter a Var
-  pangolin::RegisterKeyPressCallback( PANGO_CTRL + 'b', SetVarFunctor<double>("ui.A Double", 3.5) );
-
-  // Demonstration of how we can register a keyboard hook to trigger a method
-  pangolin::RegisterKeyPressCallback( PANGO_CTRL + 'r', GlobalKeyHook );
-
   // Safe and efficient binding of named variables.
   // Specialisations mean no conversions take place for exact types
   // and conversions between scalar types are cheap.
@@ -90,6 +84,16 @@ int main( int /*argc*/, char* argv[] )
 
   Var<bool> record_teapot("ui.Record Teapot",false,false);
 
+  // boost::function / std::function objects can be used for Var's too.
+  // In C++11, these work great with closures.
+  Var<boostd::function<void(void)> > reset("ui.Reset", SampleMethod);
+
+  // Demonstration of how we can register a keyboard hook to alter a Var
+  pangolin::RegisterKeyPressCallback(PANGO_CTRL + 'b', SetVarFunctor<double>("ui.A Double", 3.5));
+
+  // Demonstration of how we can register a keyboard hook to trigger a method
+  pangolin::RegisterKeyPressCallback(PANGO_CTRL + 'r', SampleMethod);
+
   // Default hooks for exiting (Esc) and fullscreen (tab).
   while( !pangolin::ShouldQuit() )
   {

include/pangolin/type_convert.h

@@ -31,6 +31,7 @@
 #include <iostream>
 #include <sstream>
 
+#include <pangolin/compat/function.h>
 #include <pangolin/compat/type_traits.h>
 
 namespace pangolin
@@ -40,6 +41,27 @@ struct BadInputException : std::exception {
     char const* what() const throw() { return "Failed to serialise type"; }
 };
 
+// Dummy methods to serialise functions / functors / lambdas etc
+#ifdef CALLEE_HAS_CPP11
+template<typename Ret, typename... Args>
+std::istream& operator>>(std::istream& is, std::function<Ret(Args...)>& f) {
+    throw BadInputException();
+}
+template<typename Ret, typename... Args>
+std::ostream& operator<<(std::ostream& os, const std::function<Ret(Args...)>& f) {
+    throw BadInputException();
+}
+#else
+template<typename Ret, typename Arg>
+std::istream& operator>>(std::istream& is, boostd::function<Ret(Args...)>& f) {
+    throw BadInputException();
+}
+template<typename Ret, typename Args>
+std::ostream& operator<<(std::ostream& os, const boostd::function<Ret(Args...)>& f) {
+    throw BadInputException();
+}
+#endif
+
 template<typename T, typename S, typename Enable=void>
 struct Convert;
 

include/pangolin/widgets.h

@@ -31,6 +31,7 @@
 #include <pangolin/view.h>
 #include <pangolin/var/var.h>
 #include <pangolin/handler.h>
+#include <pangolin/compat/function.h>
 
 namespace pangolin
 {
@@ -76,6 +77,20 @@ struct PANGOLIN_EXPORT Button : public Widget<bool>
     bool down;
 };
 
+struct PANGOLIN_EXPORT FunctionButton : public Widget<boostd::function<void(void)> >
+{
+    FunctionButton(std::string title, VarValueGeneric& tv);
+    void Mouse(View&, MouseButton button, int x, int y, bool pressed, int mouse_state);
+    void Render();
+
+    //Cache params on resize
+    void ResizeChildren();
+    int text_width;
+    GLfloat raster[2];
+    Viewport vinside;
+    bool down;
+};
+
 struct PANGOLIN_EXPORT Checkbox : public Widget<bool>
 {
     Checkbox(std::string title, VarValueGeneric& tv);

src/widgets.cpp

@@ -161,8 +161,10 @@ void Panel::AddVariable(void* data, const std::string& name, VarValueGeneric& va
         View* nv = NULL;
         if( !strcmp(reg_type_name, typeid(bool).name()) ) {
             nv = var.Meta().flags ? (View*)new Checkbox(title,var) : (View*)new Button(title,var);
-        }else if( !strcmp(reg_type_name, typeid(double).name()) || !strcmp(reg_type_name, typeid(float).name()) || !strcmp(reg_type_name, typeid(int).name()) || !strcmp(reg_type_name, typeid(unsigned int).name()) ) {
-            nv = new Slider(title,var);
+        } else if (!strcmp(reg_type_name, typeid(double).name()) || !strcmp(reg_type_name, typeid(float).name()) || !strcmp(reg_type_name, typeid(int).name()) || !strcmp(reg_type_name, typeid(unsigned int).name())) {
+            nv = new Slider(title, var);
+        } else if (!strcmp(reg_type_name, typeid(boostd::function<void(void)>).name() ) ) {
+            nv = (View*)new FunctionButton(title, var);
         }else{
             nv = new TextInput(title,var);
         }
@@ -261,6 +263,45 @@ void Button::ResizeChildren()
     vinside = v.Inset(border);
 }
 
+FunctionButton::FunctionButton(string title, VarValueGeneric& tv)
+    : Widget<boostd::function<void(void)> >(title, tv), down(false)
+{
+    top = 1.0; bottom = Attach::Pix(-tab_h);
+    left = 0.0; right = 1.0;
+    hlock = LockLeft;
+    vlock = LockBottom;
+    text_width = glutBitmapLength(font, (unsigned char*)title.c_str());
+}
+
+void FunctionButton::Mouse(View&, MouseButton button, int x, int y, bool pressed, int mouse_state)
+{
+    if (button == MouseButtonLeft)
+    {
+        down = pressed;
+        if (!pressed) {
+            var->Get()();
+            GuiVarChanged(*this);
+        }
+    }
+}
+
+void FunctionButton::Render()
+{
+    glColor4fv(colour_fg);
+    glRect(v);
+    glColor4fv(colour_tx);
+    glRasterPos2f(raster[0], raster[1] - down);
+    glutBitmapString(font, (unsigned char*)title.c_str());
+    DrawShadowRect(v, down);
+}
+
+void FunctionButton::ResizeChildren()
+{
+    raster[0] = v.l + (v.w - text_width) / 2.0f;
+    raster[1] = v.b + (v.h - text_height) / 2.0f;
+    vinside = v.Inset(border);
+}
+
 Checkbox::Checkbox(std::string title, VarValueGeneric& tv)
     : Widget<bool>(title,tv)
 {