A final post about the problems with Gdk::Pixbuf::create() on OS X 10.7
using gtkmm-3.0...
I have not found a way to make this call work on the MAC.
I found a work-around. I needed to save the image drawn within a
Cairo::Context (cr). Rather than getting a pixbuf from the Gdk::Window
after rendering the image, I do a cr->push_group() before the cairo draw
instructions. After drawing the image I do a
Cairo::RefPtr<Cairo::Pattern> pattern_ = cr->pop_group(). This saves a
pointer to the image. I can then render the image with
cr->set_source(pattern_) and cr->paint(). Later, after placing some
additional features on the image I can revert to the original image in
pattern_ by wiping the context with cr->set_source_rgb( 0.9,0.9,0.9);
cr->paint(), and then restore the original image as above.
I am sure that most of my problems stem from a lack of familiarity with
cairo and cairomm. But for now, I seem to have solved my immediate
problems.
Sorry I could not be more helpful with the bug in the gtkmm/gtk
libraries on OS X.
jim...
On 12-07-14 05:08 PM, JIm Charlton wrote:
Further to my problem with a call to Gdk::Pixbuf::create(), I compiled
the gtk libraries with debugging support and ran my test program under
gdb. Here is the output from stepping into the Gdk library. Any
suggestions on where to go now? Exactly where do I file a bug with
bugzilla? Sorry about my ignorance! :-)
********************
(gdb) break 134
Breakpoint 1 at 0x1000021b9: file main-2.cc, line 134.
(gdb) run
Starting program: /Users/jim-2/pixbuf_test/bin/Debug/myprog
Reading symbols for shared libraries
++++++++++++++++++++++....................................................................................................................................................
done
Reading symbols for shared libraries . done
Reading symbols for shared libraries . done
Reading symbols for shared libraries . done
Reading symbols for shared libraries . done
Reading symbols for shared libraries . done
In Area::on_draw()...
In Area::on_draw()...
Realized 1
Breakpoint 1, PlotTest::on_test_clicked (this=0x7fff5fbfee98) at
main-2.cc:134
warning: Source file is more recent than executable.
134 Glib::RefPtr<Gdk::Pixbuf> pixbuf_ =
Gdk::Pixbuf::create(myarea.myarea_win_, 0,0,winw,winh);
(gdb) s
Gdk::Pixbuf::create (src=@0x7fff5fbfeee0, src_x=0, src_y=0, width=500,
height=300) at pixbuf.cc:381
381 return Glib::RefPtr<Pixbuf>( new Pixbuf(src, src_x, src_y,
width, height) );
(gdb) s
Gdk::Pixbuf::Pixbuf (this=0x102543b90, src=@0x7fff5fbfeee0, src_x=0,
src_y=0, width=500, height=300)
at pixbuf.cc:68
68 src->gobj(), src_x, src_y, width, height))
(gdb) s
Glib::ObjectBase::ObjectBase (this=0x102543ba0,
__vtt_parm=0x100a005a8) at objectbase.cc:49
49 cpp_destruction_in_progress_ (false)
(gdb) s
50 {}
(gdb) s
(myprog:38919): glibmm-CRITICAL **: Glib::Interface::Interface(const
Glib::Interface_Class&): assertion `gobject_ != 0' failed
(myprog:38919): GLib-GObject-CRITICAL **: g_object_unref: assertion
`G_IS_OBJECT (object)' failed
*********************
Here is the program
*********************
#include <gtkmm/main.h>
#include <gtkmm/box.h>
#include <gtkmm/window.h>
#include <gtkmm/separator.h>
#include <gtkmm/textview.h>
#include <gtkmm.h>
#include <gtkmm/drawingarea.h>
#include <gtkmm/image.h>
#include <gtkmm/stock.h>
#include <iostream>
#include <cairomm/context.h>
#include <gtkmm/button.h>
class Area : public Gtk::DrawingArea
{
public:
Area();
virtual ~Area();
Glib::RefPtr<Gdk::Window> myarea_win_;
protected:
virtual bool on_draw(const Cairo::RefPtr<Cairo::Context>& cr);
virtual void on_realize();
};
Area::Area()
{
}
Area::~Area()
{
}
bool Area::on_draw(const Cairo::RefPtr<Cairo::Context>& cr)
{
printf("In Area::on_draw()...\n");
return true;
}
void Area::on_realize()
{
// We need to call the base on_realize()
Gtk::DrawingArea::on_realize();
myarea_win_ = get_window();
}
class PlotTest : public Gtk::Window
{
public:
PlotTest();
virtual ~PlotTest();
protected:
Area myarea;
//Signal handlers:
void on_close_clicked();
void on_test_clicked();
//Child widgets:
Gtk::TextView t_view;
Gtk::Box m_Box_Top;
Gtk::Button m_Button_Close;
Gtk::Button m_Button_Test;
};
PlotTest::PlotTest() :
m_Box_Top(Gtk::ORIENTATION_VERTICAL),
m_Button_Close("Close"),
m_Button_Test("Test Pixbuf Code")
{
// Set title and border of the window
set_title("Cairo Test");
set_border_width(0);
add(m_Box_Top);
// Add myarea to m_Box3. myarea is an Area object (see myarea.h)
myarea.set_size_request(500, 300);
m_Box_Top.pack_start(myarea);
// Put Close button in Box2:
m_Box_Top.pack_start(m_Button_Close);
m_Box_Top.pack_start(m_Button_Test);
m_Button_Close.set_can_default();
m_Button_Close.grab_default();
// Connect the clicked signal of the button to
m_Button_Close.signal_clicked().connect(sigc::mem_fun(*this,
&PlotTest::on_close_clicked) );
m_Button_Test.signal_clicked().connect(sigc::mem_fun(*this,
&PlotTest::on_test_clicked) );
show_all();
}
PlotTest::~PlotTest()
{
}
void PlotTest::on_close_clicked()
{
hide(); //to close the application.
}
void PlotTest::on_test_clicked()
{
int winx, winy, winw, winh;
printf("Realized %i\n", myarea.get_realized());
myarea.get_window()->get_geometry(winx, winy, winw, winh);
Glib::RefPtr<Gdk::Pixbuf> pixbuf_ =
Gdk::Pixbuf::create(myarea.myarea_win_, 0,0,winw,winh);
}
int main(int argc, char *argv[])
{
Gtk::Main kit(argc, argv);
PlotTest Prog;
//Shows the window and returns when it is closed.
Gtk::Main::run(Prog);
return 0;
}
****************************
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