zoomedit: Improved scrolling, added zoom

3 files changed, 63 insertions, 29 deletions

diff --git a/ui.c b/ui.c
index da702ba..d0fc58b 100644
--- a/ui.c
+++ b/ui.c
@@ -26,7 +26,14 @@ static const gchar *uiData =
 "</ui>";
 
 
-
+static void handleAction(GtkAction *action, gpointer user_data) {
+  const gchar* name = gtk_action_get_name(action);
+  
+  if(!strcmp(name, "zoomIn"))
+    zoomInCentered(1.2);
+  else if(!strcmp(name, "zoomOut"))
+    zoomOutCentered(1.2);
+}
 
 static GtkActionGroup *createActions() {
   GtkActionGroup *actionGroup = gtk_action_group_new("actions");
@@ -51,11 +58,11 @@ static GtkActionGroup *createActions() {
   gtk_action_group_add_action(actionGroup, action);
   
   action = gtk_action_new("zoomIn", "Zoom _in", NULL, GTK_STOCK_ZOOM_IN);
-  g_signal_connect(G_OBJECT(action), "activate", G_CALLBACK(zoomIn), NULL);
+  g_signal_connect(G_OBJECT(action), "activate", G_CALLBACK(handleAction), NULL);
   gtk_action_group_add_action_with_accel(actionGroup, action, NULL);
   
   action = gtk_action_new("zoomOut", "Zoom _out", NULL, GTK_STOCK_ZOOM_OUT);
-  g_signal_connect(G_OBJECT(action), "activate", G_CALLBACK(zoomOut), NULL);
+  g_signal_connect(G_OBJECT(action), "activate", G_CALLBACK(handleAction), NULL);
   gtk_action_group_add_action_with_accel(actionGroup, action, NULL);
   
   action = gtk_action_new("quit", "_Quit", NULL, GTK_STOCK_QUIT);
diff --git a/window.c b/window.c
index 5dcbf20..b62ff77 100644
--- a/window.c
+++ b/window.c
@@ -8,10 +8,22 @@ static GtkWidget *drawingArea = NULL;
 static GtkAdjustment *hAdjustment = NULL, *vAdjustment = NULL;
 
 
-static gboolean delete_event(GtkWidget *widget, GdkEvent  *event, gpointer data) {
+static gboolean deleteEvent(GtkWidget *widget, GdkEvent  *event, gpointer data) {
   return FALSE;
 }
 
+static gboolean scrollEvent(GtkWidget *widget, GdkEventScroll *event, gpointer user_data) {
+  const gdouble x = event->x/widget->allocation.width, y = event->y/widget->allocation.height;
+  
+  switch(event->direction) {
+    case GDK_SCROLL_UP:
+      zoomIn(1.1, x, y);
+      break;
+    case GDK_SCROLL_DOWN:
+      zoomOut(1.1, x, y);
+  }
+}
+
 static void destroy(GtkWidget *widget, gpointer data) {
   gtk_main_quit();
 }
@@ -27,36 +39,44 @@ static void refreshScrolling() {
   else 
     setYTranslate(gtk_adjustment_get_value(vAdjustment));
   
-  gdk_window_invalidate_rect(drawingArea->window, NULL, FALSE);
+  gtk_widget_queue_draw(drawingArea);
 }
 
-static void updateScrollbars() {
+static void updateScrollbars(double x, double y) {
   const gdouble imageWidth = getImageWidth(), imageHeight = getImageHeight();
   const gdouble width = drawingArea->allocation.width, height = drawingArea->allocation.height;
   gdouble upper, pageSize, value;
   
+  gdk_window_freeze_updates(drawingArea->window);
+  
   g_object_get(G_OBJECT(hAdjustment), "upper", &upper, "page_size", &pageSize, NULL);
   g_object_set(G_OBJECT(hAdjustment), "upper", imageWidth, "page_size", width, NULL);
   gtk_adjustment_changed(hAdjustment);
   
-  if(pageSize > upper && width < imageWidth)
+  if((pageSize > upper && width < imageWidth) || upper == 0)
     value = (imageWidth-width)/2;
   else
-    value = MAX(MIN(gtk_adjustment_get_value(hAdjustment) - (width-pageSize)/2 + (imageWidth-upper)/2, imageWidth-width), 0);
-  gtk_adjustment_set_value(hAdjustment, value);
+    value = (gtk_adjustment_get_value(hAdjustment)+pageSize*x)/upper*imageWidth-width*x;
+  gtk_adjustment_set_value(hAdjustment, MAX(MIN(value, imageWidth-width), 0));
   
   g_object_get(G_OBJECT(vAdjustment), "upper", &upper, "page_size", &pageSize, NULL);
   g_object_set(G_OBJECT(vAdjustment), "upper", imageHeight, "page_size", height, NULL);
   
-  if(pageSize > upper && height < imageHeight)
+  if((pageSize > upper && height < imageHeight) || upper == 0)
     value = (imageHeight-height)/2;
   else
-    value = MAX(MIN(gtk_adjustment_get_value(vAdjustment) - (height-pageSize)/2 + (imageHeight-upper)/2, imageHeight-height), 0);
-  gtk_adjustment_set_value(vAdjustment, value);
+    value = (gtk_adjustment_get_value(vAdjustment)+pageSize*y)/upper*imageHeight-height*y;
+  gtk_adjustment_set_value(vAdjustment, MAX(MIN(value, imageHeight-height), 0));
+  
+  gdk_window_thaw_updates(drawingArea->window);
   
   refreshScrolling();
 }
 
+static void updateScrollbarsCentered() {
+  updateScrollbars(0.5, 0.5);
+}
+
 GtkWidget* createMainWindow() {
   GtkWidget *window, *vbox, *menubar, *toolbar, *table, *vScroll, *hScroll;
   GdkColor color = {0, 0, 0, 0};
@@ -64,7 +84,7 @@ GtkWidget* createMainWindow() {
   
   window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
   gtk_window_set_default_size(GTK_WINDOW(window), 640, 480);
-  g_signal_connect(G_OBJECT(window), "delete_event", G_CALLBACK(delete_event), NULL);
+  g_signal_connect(G_OBJECT(window), "delete-event", G_CALLBACK(deleteEvent), NULL);
   g_signal_connect(G_OBJECT(window), "destroy", G_CALLBACK(destroy), NULL);
   
   vbox = gtk_vbox_new(FALSE, 0);
@@ -72,11 +92,9 @@ GtkWidget* createMainWindow() {
   
   menubar = getMenu();
   gtk_box_pack_start(GTK_BOX(vbox), menubar, FALSE, FALSE, 0);
-  gtk_widget_show(menubar);
   
   toolbar = getToolbar();
   gtk_box_pack_start(GTK_BOX(vbox), toolbar, FALSE, FALSE, 0);
-  gtk_widget_show(toolbar);
   
   gtk_window_add_accel_group(GTK_WINDOW(window), getAccels());
   
@@ -85,35 +103,41 @@ GtkWidget* createMainWindow() {
   
   drawingArea = gtk_drawing_area_new();
   gtk_widget_modify_bg(drawingArea, GTK_WIDGET_STATE(drawingArea), &color);
-  g_signal_connect(G_OBJECT(drawingArea), "configure-event", G_CALLBACK(updateScrollbars), NULL);
+  g_signal_connect(G_OBJECT(drawingArea), "configure-event", G_CALLBACK(updateScrollbarsCentered), NULL);
   g_signal_connect(G_OBJECT(drawingArea), "expose-event", G_CALLBACK(drawTopView), NULL);
+  g_signal_connect(G_OBJECT(drawingArea), "scroll-event", G_CALLBACK(scrollEvent), NULL);
+  gtk_widget_add_events(drawingArea, GDK_SCROLL_MASK);
   gtk_table_attach(GTK_TABLE(table), drawingArea, 0, 1, 0, 1, GTK_FILL|GTK_EXPAND|GTK_SHRINK, GTK_FILL|GTK_EXPAND|GTK_SHRINK, 0, 0);
-  gtk_widget_show(drawingArea);
   
   hAdjustment = GTK_ADJUSTMENT(gtk_adjustment_new(0, 0, 0, 10, 100, 100));
   hScroll = gtk_hscrollbar_new(hAdjustment);
   g_signal_connect(G_OBJECT(hScroll), "value-changed", G_CALLBACK(refreshScrolling), NULL);
   gtk_table_attach(GTK_TABLE(table), hScroll, 0, 1, 1, 2, GTK_FILL|GTK_EXPAND|GTK_SHRINK, 0, 0, 0);
-  gtk_widget_show(hScroll);
   
   vAdjustment = GTK_ADJUSTMENT(gtk_adjustment_new(0, 0, 0, 10, 100, 100));
   vScroll = gtk_vscrollbar_new(vAdjustment);
   g_signal_connect(G_OBJECT(vScroll), "value-changed", G_CALLBACK(refreshScrolling), NULL);
   gtk_table_attach(GTK_TABLE(table), vScroll, 1, 2, 0, 1, 0, GTK_FILL|GTK_EXPAND|GTK_SHRINK, 0, 0);
-  gtk_widget_show(vScroll);
   
-  gtk_widget_show(table);
-  gtk_widget_show(vbox);
+  gtk_widget_show_all(vbox);
   
   return window;
 }
 
-void zoomIn() {
-  setScale(getScale()*1.5);
-  updateScrollbars();
+void zoomIn(double factor, double x, double y) {
+  setScale(getScale()*factor);
+  updateScrollbars(x, y);
+}
+
+void zoomOut(double factor, double x, double y) {
+  setScale(getScale()/factor);
+  updateScrollbars(x, y);
+}
+
+void zoomInCentered(double factor) {
+  zoomIn(factor, 0.5, 0.5);
 }
 
-void zoomOut() {
-  setScale(getScale()/1.5);
-  updateScrollbars();
+void zoomOutCentered(double factor) {
+  zoomOut(factor, 0.5, 0.5);
 }
diff --git a/window.h b/window.h
index 4d99224..01c377d 100644
--- a/window.h
+++ b/window.h
@@ -5,7 +5,10 @@
 
 
 GtkWidget* createMainWindow();
-void zoomIn();
-void zoomOut();
+
+void zoomIn(double factor, double x, double y);
+void zoomOut(double factor, double x, double y);
+void zoomInCentered(double factor);
+void zoomOutCentered(double factor);
 
 #endif /*WINDOW_H_*/