Diego A. Fons ?????:
[...]
Still I don't understand why can't get a context and store it in a
member variable.
[...]
Then look here:
this is Plot class definition:
class Plot
{
public:
Plot(Cairo::RefPtr<Cairo::Context>& context, Gdk::Rectangle& plotarea);
~Plot();
std::vector<Series*> series;
...
private:
*Cairo::RefPtr<Cairo::Context> plot_context;*
Gdk::Color background_color, foreground_color;
....
};
Plot constructor:
Plot::Plot(Cairo::RefPtr<Cairo::Context>& context, Gdk::Rectangle& pltarea)
{
plotarea = pltarea;
marginrect = Gdk::Rectangle(int(0.03*plotarea.get_width()),
int(0.03*plotarea.get_height()),
int(0.94*plotarea.get_width()), int(0.94*plotarea.get_height()));
plotrect = marginrect;
* plot_context = context;*
background_color = Gdk::Color("white");
...
}
Plot resizing:
void Plot::resize(Cairo::RefPtr<Cairo::Context>& context,
Gdk::Rectangle& pltarea)
{ // ??????????? ???????? ??? ????????? ???????
* plot_context = context;*
plotarea = pltarea;
plot_context->set_source_rgb(background_color.get_red(),
background_color.get_green(), background_color.get_blue());
...
}
And this is plot initialization from MainWindow:
void Mainwindow::plot_init(void)
{ // ????????? ????????? ???????
plotarea_win = drawingarea->get_window();
...
win_context->set_source_rgb(color.get_red(), color.get_green(),
color.get_blue());
//prepare a copy
plotareaCopy = Gdk::Pixmap::create(plotarea_win,
drawingarea->get_allocation().get_width(),
drawingarea->get_allocation().get_height(), -1);
gc = Gdk::GC::create(plotarea_win);//sorry...
* cairo = plotareaCopy->create_cairo_context();*
int pwidth, pheight;
plotareaCopy->get_size(pwidth, pheight);
Gdk::Rectangle plot_area = Gdk::Rectangle(0, 0, pwidth, pheight);
*plot = new Plot(cairo, plot_area);*
....
drawingarea->signal_expose_event().connect(
sigc::mem_fun(*this, &Mainwindow::on_drawingarea_expose_event));
}
This is an expose event - sorry, but for the sake of speed I use here
Gdk::GC approach
for simple copying of area from a background copy:
bool Mainwindow::on_drawingarea_expose_event(GdkEventExpose *event)
{
plotarea_win->draw_drawable(gc, plotareaCopy, event->area.x,
event->area.y,
event->area.x, event->area.y, event->area.width,
event->area.height);
...
return true;
}
And here is resizing of a plot:
bool Mainwindow::on_drawingarea_configure_event(GdkEventConfigure*)
{ // redefine demensions
plotareaCopy = Gdk::Pixmap::create(plotarea_win,
drawingarea->get_allocation().get_width(),
drawingarea->get_allocation().get_height(), -1);
if (plot)
{
*cairo = plotareaCopy->create_cairo_context();*
int pwidth, pheight;
plotareaCopy->get_size(pwidth, pheight);
Gdk::Rectangle plot_area = Gdk::Rectangle(0, 0, pwidth, pheight);
plot->resize(cairo, plot_area);
plot->drawplots();
}
return true;
}
When I need printing I just call Plot::resize(Cairo::RefPt...) with the
context and rectangle
taken from Gtk::PrintContext.
Hope it helps somewhat,
Igor Gorbounov
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