Re: Displaying a scaled pixmap

[Michael J M Thomson <mjmt internode on net>]

TheLonelyStar wrote:
> Hello dear community,
>
> I draw a pixmap on a Gtk::DrawingArea using render_to_drawable.
>
> What I have not found out is how to scale the pixmap while drawing!
> Any hints?
> Thanks!
>
> nathan

Cairo's perfect for that...

#include <gdk/gdkcairo.h>

...

// create a Cairo context that outputs to drawingarea's window
cairo_t* cairo = gdk_cairo_create(
	drawingarea.get_window()->gobj());
	// note above needs GdkWindow* from RefPtr<Gdk::Window>, hence gobj()

gdk_cairo_set_source_pixmap(cairo,
                            pixmap->gobj(), // function needs GdkPixmap*
                            0, 0);

cairo_scale(cairo, 2.0, 2.0);

cairo_rectangle(cairo, 0, 0, pixmap->get_width(), pixmap->get_height());
cairo_fill(cairo);

cairo_destroy(cairo);