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#include <gtk-3.0/gtk/gtk.h>
#define TIMEOUT 20
#define ZOOM_FACTOR 0.1
GtkWidget *window;
GtkWidget *image;
GdkPixbuf *pixbuf;
GdkPixbuf *curr_pixbuf;
int pixbuf_width, pixbuf_height;
double aspect_ratio;
double curr_zoom = 1.0;
void zoom(int type)
{
if (type == 0) {
if (curr_zoom == 1.0)
return;
curr_zoom = (double)1.0;
} else if (type < 0) {
if (curr_zoom < 0.2)
return;
curr_zoom -= (double)ZOOM_FACTOR;
} else if (type > 0) {
if (curr_zoom > 2)
return;
curr_zoom += (double)ZOOM_FACTOR;
}
if (curr_pixbuf != NULL)
g_object_unref(curr_pixbuf);
curr_pixbuf = gdk_pixbuf_scale_simple(
GDK_PIXBUF(pixbuf), pixbuf_width * curr_zoom,
pixbuf_height * curr_zoom, GDK_INTERP_BILINEAR);
gtk_image_set_from_pixbuf(GTK_IMAGE(image), GDK_PIXBUF(curr_pixbuf));
}
static gboolean key_press(GtkWindow *window, GdkEvent *event, gpointer data)
{
switch (event->key.keyval) {
case GDK_KEY_q:
g_application_quit(G_APPLICATION(
gtk_window_get_application(GTK_WINDOW(window))));
return FALSE;
case GDK_KEY_plus:
case GDK_KEY_ScrollUp:
zoom(1);
return FALSE;
case GDK_KEY_minus:
case GDK_KEY_ScrollDown:
zoom(-1);
return FALSE;
case GDK_KEY_equal:
case GDK_KEY_ScrollClick:
zoom(0);
return FALSE;
default:
return TRUE;
}
}
gboolean scroll_callback(GtkWindow *window, GdkEvent *event, gpointer data)
{
GdkModifierType state;
gdk_event_get_state(event, &state);
if (state & GDK_CONTROL_MASK &&
event->scroll.direction == GDK_SCROLL_UP) {
zoom(1);
return FALSE;
} else if (state & GDK_CONTROL_MASK &&
event->scroll.direction == GDK_SCROLL_DOWN) {
zoom(-1);
return FALSE;
}
return TRUE;
}
gboolean resize_done(gpointer data)
{
guint *id = data;
*id = 0;
gint win_width, win_height;
gint new_pixbuf_width, new_pixbuf_height;
gtk_window_get_size(GTK_WINDOW(window), &win_width, &win_height);
if (win_width < pixbuf_width && win_height > pixbuf_height) {
new_pixbuf_width = win_width;
new_pixbuf_height = (double)new_pixbuf_width / aspect_ratio;
} else if (win_width > pixbuf_width && win_height < pixbuf_height) {
new_pixbuf_height = win_height;
new_pixbuf_width = (double)new_pixbuf_height * aspect_ratio;
} else if (win_width < pixbuf_width && win_height < pixbuf_height) {
if (((double)win_width / (double)win_height) > aspect_ratio) {
new_pixbuf_height = win_height;
new_pixbuf_width =
((double)new_pixbuf_height * aspect_ratio);
} else {
new_pixbuf_width = win_width;
new_pixbuf_height =
(double)new_pixbuf_width / aspect_ratio;
}
} else {
new_pixbuf_width = pixbuf_width;
new_pixbuf_height = pixbuf_height;
}
if (curr_pixbuf != NULL)
g_object_unref(curr_pixbuf);
curr_pixbuf =
gdk_pixbuf_scale_simple(GDK_PIXBUF(pixbuf), new_pixbuf_width,
new_pixbuf_height, GDK_INTERP_BILINEAR);
gtk_image_set_from_pixbuf(GTK_IMAGE(image), GDK_PIXBUF(curr_pixbuf));
return FALSE;
}
gboolean configure_callback(GtkWindow *window, GdkEvent *event, gpointer data)
{
static guint id = 0;
if (id)
g_source_remove(id);
id = g_timeout_add(TIMEOUT, resize_done, &id);
return FALSE;
}
static void activate(GtkApplication *app, gpointer user_data)
{
GError *error = NULL;
window = gtk_application_window_new(app);
gtk_window_set_title(GTK_WINDOW(window), "qwe");
gtk_window_set_default_size(GTK_WINDOW(window), 300, 300);
/* g_signal_connect(G_OBJECT(window), "configure-event", */
/* G_CALLBACK(configure_callback), NULL); */
g_signal_connect(G_OBJECT(window), "key-press-event",
G_CALLBACK(key_press), NULL);
gtk_widget_add_events(GTK_WIDGET(window), GDK_SCROLL_MASK);
g_signal_connect(G_OBJECT(window), "scroll-event",
G_CALLBACK(scroll_callback), NULL);
pixbuf = gdk_pixbuf_new_from_file(
"/home/nirav/Downloads/Saved Pictures/bash help shortcuts.png",
&error);
if (error) {
g_warning("gdk_pixbuf_new_from_file() failed with error: %s\n",
error->message);
g_clear_error(&error);
return;
}
image = gtk_image_new_from_pixbuf(GDK_PIXBUF(pixbuf));
pixbuf_width = gdk_pixbuf_get_width(GDK_PIXBUF(pixbuf));
pixbuf_height = gdk_pixbuf_get_height(GDK_PIXBUF(pixbuf));
aspect_ratio = (double)pixbuf_width / (double)pixbuf_height;
GtkWidget *scrolled_window = gtk_scrolled_window_new(NULL, NULL);
gtk_scrolled_window_set_policy(GTK_SCROLLED_WINDOW(scrolled_window),
GTK_POLICY_AUTOMATIC,
GTK_POLICY_AUTOMATIC);
gtk_container_add(GTK_CONTAINER(scrolled_window), GTK_WIDGET(image));
gtk_container_add(GTK_CONTAINER(window), GTK_WIDGET(scrolled_window));
gtk_widget_show_all(GTK_WIDGET(window));
}
int main(int argc, char *argv[])
{
GtkApplication *app;
int status;
app = gtk_application_new("org.gtk.qwe", G_APPLICATION_FLAGS_NONE);
g_signal_connect(app, "activate", G_CALLBACK(activate), NULL);
status = g_application_run(G_APPLICATION(app), argc, argv);
g_object_unref(app);
return status;
}
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