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/* Pixbufs
*
* A Gdk::Pixbuf represents an image, normally in RGB or RGBA format.
* Pixbufs are normally used to load files from disk and perform
* image scaling.
*
* This demo is not all that educational, but looks cool. It was written
* by Extreme Pixbuf Hacker Federico Mena Quintero. It also shows
* off how to use Gtk::DrawingArea to do a simple animation.
*
* Look at the Image demo for additional pixbuf usage examples.
*
*/
#include <gtkmm.h>
#include <cmath>
#include <algorithm>
namespace
{
const char* background_name = "background.jpg";
const char* image_names[] = {
"apple-red.png",
"gnome-applets.png",
"gnome-calendar.png",
"gnome-foot.png",
"gnome-gmush.png",
"gnome-gimp.png",
"gnome-gsame.png",
"gnu-keys.png"
};
const int n_images = G_N_ELEMENTS(image_names);
const gint64 cycle_time = 3000000; // microseconds
} // anonymous namespace
class Example_Pixbufs : public Gtk::Window
{
public:
Example_Pixbufs();
~Example_Pixbufs() override;
protected:
virtual void load_pixbufs();
// Signal handler:
bool on_drawingarea_draw(const Cairo::RefPtr<Cairo::Context>& cr);
// Callback:
bool on_tick(const Glib::RefPtr<Gdk::FrameClock>& frame_clock);
//Member widgets:
Glib::RefPtr<Gdk::Pixbuf> m_refPixbuf;
Glib::RefPtr<Gdk::Pixbuf> m_refPixbuf_Background;
Glib::RefPtr<Gdk::Pixbuf> m_images[n_images];
Gtk::DrawingArea m_DrawingArea;
guint m_tick_id = 0;
guint m_back_width = 0;
guint m_back_height = 0;
gint64 m_start_time = 0;
};
//Called by DemoWindow;
Gtk::Window* do_pixbufs()
{
return new Example_Pixbufs();
}
Example_Pixbufs::Example_Pixbufs()
{
set_title("Pixbufs");
set_resizable(false);
try
{
load_pixbufs();
set_size_request(m_back_width, m_back_height);
m_refPixbuf = Gdk::Pixbuf::create(Gdk::COLORSPACE_RGB, false, 8, m_back_width, m_back_height);
m_DrawingArea.signal_draw().connect(sigc::mem_fun(*this, &Example_Pixbufs::on_drawingarea_draw));
add(m_DrawingArea);
m_tick_id = m_DrawingArea.add_tick_callback(
sigc::mem_fun(*this, &Example_Pixbufs::on_tick));
}
catch (const Glib::Error& error)
{
Glib::ustring strMsg = "Failed to load an image: ";
strMsg += error.what();
Gtk::MessageDialog dialog(strMsg, false, Gtk::MESSAGE_ERROR, Gtk::BUTTONS_CLOSE);
dialog.run();
}
show_all();
}
Example_Pixbufs::~Example_Pixbufs()
{
m_DrawingArea.remove_tick_callback(m_tick_id); // Will probably happen anyway, in the destructor.
}
/* Loads the m_images for the demo and throws an exception if the operation failed */
void Example_Pixbufs::load_pixbufs()
{
if(m_refPixbuf_Background)
return; /* already loaded earlier */
auto resource_name_background = std::string("/pixbufs/") + background_name;
m_refPixbuf_Background = Gdk::Pixbuf::create_from_resource(resource_name_background);
m_back_width = m_refPixbuf_Background->get_width();
m_back_height = m_refPixbuf_Background->get_height();
for (int i = 0; i < n_images; ++i)
{
auto resource_name = std::string("/pixbufs/") + image_names[i];
auto pixbuf = Gdk::Pixbuf::create_from_resource(resource_name);
m_images[i] = pixbuf;
}
}
/* Draw callback for the drawing area */
bool Example_Pixbufs::on_drawingarea_draw(const Cairo::RefPtr<Cairo::Context>& cr)
{
Gdk::Cairo::set_source_pixbuf(cr, m_refPixbuf);
cr->paint();
return true;
}
/* Handler to regenerate the frame */
bool Example_Pixbufs::on_tick(const Glib::RefPtr<Gdk::FrameClock>& frame_clock)
{
m_refPixbuf_Background->copy_area(0, 0, m_back_width, m_back_height, m_refPixbuf, 0, 0);
if (m_start_time == 0)
m_start_time = frame_clock->get_frame_time();
const gint64 current_time = frame_clock->get_frame_time();
const double f = ((current_time - m_start_time) % cycle_time) / (double)cycle_time;
const double xmid = m_back_width / 2.0;
const double ymid = m_back_height / 2.0;
const double radius = std::min(xmid, ymid) / 2.0;
for (int i = 0; i < n_images; i++)
{
const double ang = 2.0 * G_PI * (double)i / n_images - f * 2.0 * G_PI;
const int iw = m_images[i]->get_width();
const int ih = m_images[i]->get_height();
const double r = radius + (radius / 3.0) * std::sin(f * 2.0 * G_PI);
const double xpos = std::floor(xmid + r * std::cos(ang) - iw / 2.0 + 0.5);
const double ypos = std::floor(ymid + r * std::sin(ang) - ih / 2.0 + 0.5);
double k = (i & 1) ? std::sin(f * 2.0 * G_PI) : std::cos(f * 2.0 * G_PI);
k = 2.0 * k * k;
k = std::max(0.25, k);
const Gdk::Rectangle r1((int)xpos, (int)ypos, (int)(iw * k), (int)(ih * k));
const Gdk::Rectangle r2(0, 0, m_back_width, m_back_height);
if (r1.intersects(r2))
{
Gdk::Rectangle dest = r1;
dest.intersect(r2);
m_images[i]->composite(m_refPixbuf,
dest.get_x(), dest.get_y(),
dest.get_width(), dest.get_height(),
xpos, ypos,
k, k,
Gdk::INTERP_NEAREST,
(int)((i & 1)
? std::max(127.0, std::fabs(255.0 * std::sin(f * 2.0 * G_PI)))
: std::max(127.0, std::fabs(255.0 * std::cos(f * 2.0 * G_PI)))));
}
}
m_DrawingArea.queue_draw();
return true;
}
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