Allow using a figure as a widget

Author: rapgenic

include/xeus-octave/plotstream.hpp

@@ -22,11 +22,27 @@
 
 #include <octave/graphics.h>
 
+#include <xwidgets/ximage.hpp>
+
 namespace xeus_octave
 {
 
 template <class T> inline T getPlotStream(octave::graphics_object const& o);
 
+/**
+ * Retrieve from the graphics object the plot_stream property
+ */
+template <> inline xw::image* getPlotStream<xw::image*>(octave::graphics_object const& o)
+{
+  octave_value ps =
+    dynamic_cast<octave::figure::properties const&>(o.get_ancestor("figure").get_properties()).get___plot_stream__();
+
+  if (ps.isnumeric() && ps.is_scalar_type())
+    return reinterpret_cast<xw::image*>(ps.long_value());
+  else
+    return nullptr;
+}
+
 /**
  * Retrieve from the graphics object the plot_stream property
  */
@@ -41,6 +57,18 @@ template <> inline std::string getPlotStream<std::string>(octave::graphics_objec
     return "";
 }
 
+/**
+ * Set in the graphics object the plot_stream propert
+ */
+inline void setPlotStream(octave::graphics_object& o, xw::image* p)
+{
+  if (o.isa("figure"))
+  {
+    auto& fp = dynamic_cast<octave::figure::properties&>(o.get_properties());
+    fp.set___plot_stream__(reinterpret_cast<intptr_t>(p));
+  }
+}
+
 /**
  * Set in the graphics object the plot_stream propert
  */
@@ -53,6 +81,16 @@ inline void setPlotStream(octave::graphics_object& o, std::string p)
   }
 }
 
+/**
+ * Set in the graphics object the plot_stream propert (const version)
+ */
+inline void setPlotStream(octave::graphics_object const& o, xw::image* p)
+{
+  // deCONSTify the graphics_object
+  auto _go = o;
+  setPlotStream(_go, p);
+}
+
 /**
  * Set in the graphics object the plot_stream propert (const version)
  */

include/xeus-octave/tk_notebook.hpp

@@ -64,6 +64,29 @@ class notebook_graphics_toolkit : public glfw_graphics_toolkit
   void show_figure(octave::graphics_object const&) const override;
 };
 
+/**
+ * Toolkit that uses a ximage as output region, updating its contents on each
+ * redraw. When a figure is added to a widget container (e.g. xvbox or xhbox)
+ * its toolkit is automatically converted to this one.
+ * Does not display anything on its own, it MUST be included in a container
+ * widget.
+ *
+ * Should not be used by users
+ */
+class widget_graphics_toolkit : public glfw_graphics_toolkit
+{
+public:
+
+  widget_graphics_toolkit() : glfw_graphics_toolkit("__widget") {}
+
+  bool is_valid() const override { return true; }
+
+  bool initialize(octave::graphics_object const&) override;
+  void send_figure(octave::graphics_object const&, std::vector<char> const&, int, int, double) const override;
+  void show_figure(octave::graphics_object const&) const override;
+  void finalize(octave::graphics_object const&) override;
+};
+
 void register_all(octave::interpreter& interpreter);
 
 }  // namespace xeus_octave::tk::notebook

include/xeus-octave/utils.hpp

@@ -110,6 +110,26 @@ inline void from_ov(octave_value const& from, xw::xholder& to, octave::interpret
     from_ov(ret(0), id, interpreter);
     to = xw::make_id_holder(id);
   }
+  // This is a figure handle
+  else if (from.is_real_scalar())
+  {
+    // Get the handle
+    graphics_handle gh = interpreter.get_gh_manager().lookup(from);
+
+    if (gh.ok())
+    {
+      // Get the object
+      octave::graphics_object go = interpreter.get_gh_manager().get_object(gh);
+      // Change the graphics_toolkit to widget
+      auto& figureProperties = dynamic_cast<octave::figure::properties&>(go.get_properties());
+      figureProperties.set___graphics_toolkit__("__widget");
+      auto* figure = getPlotStream<xw::image*>(go);
+
+      assert(figure != nullptr);
+
+      to = xw::make_id_holder(figure->id());
+    }
+  }
 }
 
 /**

notebooks/xeus-octave.ipynb

@@ -42,6 +42,7 @@
 #include <octave/ov.h>
 #include <png.h>
 #include <xtl/xbase64.hpp>
+#include <xwidgets/ximage.hpp>
 
 #include "xeus-octave/plotstream.hpp"
 #include "xeus-octave/tk_notebook.hpp"
@@ -323,11 +324,50 @@ void notebook_graphics_toolkit::send_figure(
   dynamic_cast<xoctave_interpreter&>(xeus::get_interpreter()).update_display_data(data, meta, tran);
 }
 
+bool widget_graphics_toolkit::initialize(oc::graphics_object const& go)
+{
+  bool ret = glfw_graphics_toolkit::initialize(go);
+
+  if (go.isa("figure"))
+  {
+    // Create a new object id and store it in the figure
+    setPlotStream(go, new xw::image());
+
+    return true;
+  }
+
+  return ret;
+}
+
+void widget_graphics_toolkit::show_figure(oc::graphics_object const&) const {}
+
+void widget_graphics_toolkit::send_figure(
+  octave::graphics_object const& go, std::vector<char> const& img, int width, int height, double dpr
+) const
+{
+  // Retrieve the figure id
+  xw::image* figure = getPlotStream<xw::image*>(go);
+
+  // TODO check value is changed before setting
+  figure->width = std::to_string(width / dpr);
+  figure->height = std::to_string(height / dpr);
+  figure->value = img;
+}
+
+void widget_graphics_toolkit::finalize(octave::graphics_object const& go)
+{
+  xw::image* figure = getPlotStream<xw::image*>(go);
+
+  delete figure;
+}
+
 void register_all(octave::interpreter& interpreter)
 {
   // Install the toolkit into the interpreter
   interpreter.get_gtk_manager().register_toolkit("notebook");
   interpreter.get_gtk_manager().load_toolkit(octave::graphics_toolkit(new notebook_graphics_toolkit()));
+  interpreter.get_gtk_manager().register_toolkit("__widget");
+  interpreter.get_gtk_manager().load_toolkit(octave::graphics_toolkit(new widget_graphics_toolkit()));
 }
 
 }  // namespace xeus_octave::tk::notebook