Added zoom support with keyboard and mouse wheel

1 files changed, 65 insertions, 8 deletions

diff --git a/main.c b/main.c
index 915d843..e293a07 100644
--- a/main.c
+++ b/main.c
@@ -1,5 +1,6 @@
 #include <gtk-3.0/gtk/gtk.h>
 #define TIMEOUT 20
+#define ZOOM_FACTOR 0.1
 
 GtkWidget *window;
 GtkWidget *image;
@@ -7,16 +8,69 @@ GdkPixbuf *pixbuf;
 GdkPixbuf *curr_pixbuf;
 int pixbuf_width, pixbuf_height;
 double aspect_ratio;
+double curr_zoom = 1.0;
 
-static gboolean key_press(GtkWindow *window, gpointer data)
+void zoom(int type)
 {
-	GdkEventKey *event = (GdkEventKey *)data;
-	if (event->keyval == GDK_KEY_q) {
+	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;
-	} else
+	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)
@@ -73,10 +127,13 @@ static void activate(GtkApplication *app, gpointer user_data)
 	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), "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",
@@ -91,12 +148,12 @@ static void activate(GtkApplication *app, gpointer user_data)
 	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);
+	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));
 }