Re: Goocanvasmm

[Gennaro Bellizio <genbell tiscali it>]

>----Messaggio originale----
>Da: jonathon quotidian org
>Data: 20/02/2008 16.54
>A: "Gennaro Bellizio"<genbell tiscali it>
>Cc: <gtkmm-list gnome org>
>Ogg: Re: Goocanvasmm
>

>I'm afraid I don't really understand exactly what the problem is.
>Could you provide a small code example that shows the issue that
>you're having?
>
>-- 
>jonner
>

Let's consider the coordinates example. When I run the application no 
rectangle is displayed onto the canvas. Nevertheless if I click some 
button the item bounds labels are updated correctly. By applying the 
following patch to window.h

Index: window.h
===================================================================
--- window.h	(revisione 1357)
+++ window.h	(copia locale)
@@ -29,7 +29,7 @@
   void update_label();
 
   Goocanvas::Canvas m_canvas;
-  Glib::RefPtr<Goocanvas::Rect> m_rect;
+  Glib::RefPtr<Goocanvas::RectModel> m_rect;
 
   Gtk::VBox m_box;
   Gtk::HBox m_button_box;

and the following to window.cc

Index: window.cc
===================================================================
--- window.cc	(revisione 1357)
+++ window.cc	(copia locale)
@@ -34,8 +34,9 @@
   m_canvas.set_size_request(640, 480);
   m_canvas.set_bounds(0, 0, 1000, 1000);
 
-  Glib::RefPtr<Goocanvas::Item> root = m_canvas.get_root_item();
-  m_rect = Goocanvas::Rect::create(10, 10, 60, 60);
+  Glib::RefPtr<Goocanvas::ItemModel> root = Goocanvas::GroupModel::
create() ;
+  m_canvas->set_root_item_model(root) ;
+  m_rect = Goocanvas::RectModel::create(10, 10, 60, 60);
   root->add_child(m_rect);
   m_rect->property_line_width().set_value(10.0);
   m_rect->property_stroke_color().set_value("yellow");
@@ -74,6 +75,7 @@
          ", width=" << m_rect->property_width() << ",  height=" << 
m_rect->property_height() << 
          ", line_width=" << m_rect->property_line_width() << std::
endl;
 
+  // No bounds are available now, so the following will not compile
   Goocanvas::Bounds bounds = m_rect->get_bounds();
   str << "Item bounds: x1=" << bounds.get_x1() << ", y1=" << bounds.
get_y1() << ", x2=" << bounds.get_x2() << ", y2=" << bounds.get_y2() << 
std::endl;

the rectangle is displayed but now its bounds aren't available because 
the *Model classes do not provide the get_bounds() method. The same 
happens for the Goocanvas::Ellipse instances.

Goocanvas::Text instances, instead, are displayed correctly like it 
can be seen by applying the following patch

Index: window.h
===================================================================
--- window.h	(revisione 1357)
+++ window.h	(copia locale)
@@ -29,7 +29,7 @@
   void update_label();
 
   Goocanvas::Canvas m_canvas;
-  Glib::RefPtr<Goocanvas::Rect> m_rect;
+  Glib::RefPtr<Goocanvas::Text> m_text;
 
   Gtk::VBox m_box;
   Gtk::HBox m_button_box;

Index: window.cc
===================================================================
--- window.cc	(revisione 1357)
+++ window.cc	(copia locale)
@@ -35,11 +35,9 @@
   m_canvas.set_bounds(0, 0, 1000, 1000);
 
   Glib::RefPtr<Goocanvas::Item> root = m_canvas.get_root_item();
-  m_rect = Goocanvas::Rect::create(10, 10, 60, 60);
-  root->add_child(m_rect);
-  m_rect->property_line_width().set_value(10.0);
-  m_rect->property_stroke_color().set_value("yellow");
-  m_rect->property_fill_color().set_value("gray");
+  m_text = Goocanvas::Text::create("This is displayed\nand bounds are 
available");
+  root->add_child(m_text);
+  m_text->property_fill_color().set_value("blue");
 
 
   Gtk::ScrolledWindow* sw = Gtk::manage(new Gtk::ScrolledWindow());
@@ -70,11 +68,11 @@
 void ExampleWindow::update_label()
 {
   std::stringstream str;
-  str << "Rect: x=" << m_rect->property_x() << ", y=" << m_rect-
>property_y() << 
-         ", width=" << m_rect->property_width() << ",  height=" << 
m_rect->property_height() << 
-         ", line_width=" << m_rect->property_line_width() << std::
endl;
+  str << "Rect: x=" << m_text->property_x() << ", y=" << m_text-
>property_y() << 
+         ", width=" << m_text->property_width() <<
+         ", line_width=" << m_text->property_line_width() << std::
endl;
 
-  Goocanvas::Bounds bounds = m_rect->get_bounds();
+  Goocanvas::Bounds bounds = m_text->get_bounds();
   str << "Item bounds: x1=" << bounds.get_x1() << ", y1=" << bounds.
get_y1() << ", x2=" << bounds.get_x2() << ", y2=" << bounds.get_y2() << 
std::endl;
 
   
@@ -84,21 +82,21 @@
 
 void ExampleWindow::on_button_translate()
 {
-  m_rect->translate(20, 20);
+  m_text->translate(20, 20);
   update_label();
 }
 
 void ExampleWindow::on_button_setxy()
 {
-  m_rect->property_x() = 50;
-  m_rect->property_y() = 50;
+  m_text->property_x() = 50;
+  m_text->property_y() = 50;
   update_label();
 }
 
 
 void ExampleWindow::on_button_scale()
 {
-  m_rect->scale(1.2, 1.2);
+  m_text->scale(1.2, 1.2);
   update_label();
 }

In my application I used a Goocanvas::GroupModel for stacking a 
Goocanvas::EllipseModel and a Goocanvas::TextModel in order to draw a 
graph node with a text-label. My problem is to get the text-label 
bounds in order to correctly center it into the node.

I hope I have been more clear this time. :-)

Thanks in advance.


Gennaro Bellizio



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