[Qemu-devel] [PATCH 6/9] gtk: add support for screen scaling and full screen (v5)

[Anthony Liguori]

Basic menu items to enter full screen mode and zoom in/out.  Unlike SDL, we
don't allow arbitrary scaling based on window resizing.  The current behavior
with SDL causes a lot of problems for me.

Sometimes I accidentally resize the window a tiny bit while trying to move it
(Ubuntu's 1-pixel window decorations don't help here).  After that, scaling is
now active and if the screen changes size again, badness ensues since the
aspect ratio is skewed.

Allowing zooming by 25% in and out should cover most use cases.  We can add a
more flexible scaling later but for now, I think this is a more friendly
behavior.

Signed-off-by: Anthony Liguori <address@hidden>
---
v1 -> v2
 - fix scaling (Paolo)
 - use ctrl-alt-+ instead of ctrl-alt-= for zoom
v2 -> v3
 - add a zoom to 100% menu (Stefan)
 - allow window to be resizable
v4 -> v5
 - keep window size when enabling zoom to fit (Kevin)
---
 ui/gtk.c | 254 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 237 insertions(+), 17 deletions(-)

diff --git a/ui/gtk.c b/ui/gtk.c
index 0c1ec4d..01a1777 100644
--- a/ui/gtk.c
+++ b/ui/gtk.c
@@ -80,6 +80,11 @@ typedef struct GtkDisplayState
 
     GtkWidget *view_menu_item;
     GtkWidget *view_menu;
+    GtkWidget *full_screen_item;
+    GtkWidget *zoom_in_item;
+    GtkWidget *zoom_out_item;
+    GtkWidget *zoom_fixed_item;
+    GtkWidget *zoom_fit_item;
     GtkWidget *grab_item;
     GtkWidget *grab_on_hover_item;
     GtkWidget *vga_item;
@@ -101,9 +106,11 @@ typedef struct GtkDisplayState
 
     double scale_x;
     double scale_y;
+    gboolean full_screen;
 
     GdkCursor *null_cursor;
     Notifier mouse_mode_notifier;
+    gboolean free_scale;
 } GtkDisplayState;
 
 static GtkDisplayState *global_state;
@@ -135,7 +142,7 @@ static void gd_update_cursor(GtkDisplayState *s, gboolean 
override)
     on_vga = gd_on_vga(s);
 
     if ((override || on_vga) &&
-        (kbd_mouse_is_absolute() || gd_is_grab_active(s))) {
+        (s->full_screen || kbd_mouse_is_absolute() || gd_is_grab_active(s))) {
         gdk_window_set_cursor(window, s->null_cursor);
     } else {
         gdk_window_set_cursor(window, NULL);
@@ -173,6 +180,9 @@ static void gd_update(DisplayState *ds, int x, int y, int 
w, int h)
 {
     GtkDisplayState *s = ds->opaque;
     int x1, x2, y1, y2;
+    int mx, my;
+    int fbw, fbh;
+    int ww, wh;
 
     DPRINTF("update(x=%d, y=%d, w=%d, h=%d)\n", x, y, w, h);
 
@@ -182,7 +192,20 @@ static void gd_update(DisplayState *ds, int x, int y, int 
w, int h)
     x2 = ceil(x * s->scale_x + w * s->scale_x);
     y2 = ceil(y * s->scale_y + h * s->scale_y);
 
-    gtk_widget_queue_draw_area(s->drawing_area, x1, y1, (x2 - x1), (y2 - y1));
+    fbw = ds_get_width(s->ds) * s->scale_x;
+    fbh = ds_get_height(s->ds) * s->scale_y;
+
+    gdk_drawable_get_size(gtk_widget_get_window(s->drawing_area), &ww, &wh);
+
+    mx = my = 0;
+    if (ww > fbw) {
+        mx = (ww - fbw) / 2;
+    }
+    if (wh > fbh) {
+        my = (wh - fbh) / 2;
+    }
+
+    gtk_widget_queue_draw_area(s->drawing_area, mx + x1, my + y1, (x2 - x1), 
(y2 - y1));
 }
 
 static void gd_refresh(DisplayState *ds)
@@ -227,9 +250,29 @@ static void gd_resize(DisplayState *ds)
                                                      ds_get_height(ds),
                                                      ds_get_linesize(ds));
 
-    gtk_widget_set_size_request(s->drawing_area,
-                                ds_get_width(ds) * s->scale_x,
-                                ds_get_height(ds) * s->scale_y);
+    if (!s->full_screen) {
+        GtkRequisition req;
+        double sx, sy;
+
+        if (s->free_scale) {
+            sx = s->scale_x;
+            sy = s->scale_y;
+
+            s->scale_y = 1.0;
+            s->scale_x = 1.0;
+        } else {
+            sx = 1.0;
+            sy = 1.0;
+        }
+
+        gtk_widget_set_size_request(s->drawing_area,
+                                    ds_get_width(ds) * s->scale_x,
+                                    ds_get_height(ds) * s->scale_y);
+        gtk_widget_size_request(s->vbox, &req);
+
+        gtk_window_resize(GTK_WINDOW(s->window),
+                          req.width * sx, req.height * sy);
+    }
 }
 
 /** QEMU Events **/
@@ -266,29 +309,55 @@ static gboolean gd_window_close(GtkWidget *widget, 
GdkEvent *event,
 static gboolean gd_draw_event(GtkWidget *widget, cairo_t *cr, void *opaque)
 {
     GtkDisplayState *s = opaque;
+    int mx, my;
     int ww, wh;
     int fbw, fbh;
 
+    if (!gtk_widget_get_realized(widget)) {
+        return FALSE;
+    }
+
     fbw = ds_get_width(s->ds);
     fbh = ds_get_height(s->ds);
 
     gdk_drawable_get_size(gtk_widget_get_window(widget), &ww, &wh);
 
-    cairo_rectangle(cr, 0, 0, ww, wh);
-
-    if (ww != fbw || wh != fbh) {
+    if (s->full_screen) {
         s->scale_x = (double)ww / fbw;
         s->scale_y = (double)wh / fbh;
-        cairo_scale(cr, s->scale_x, s->scale_y);
-    } else {
-        s->scale_x = 1.0;
-        s->scale_y = 1.0;
+    } else if (s->free_scale) {
+        double sx, sy;
+
+        sx = (double)ww / fbw;
+        sy = (double)wh / fbh;
+
+        s->scale_x = s->scale_y = MIN(sx, sy);
     }
 
     fbw *= s->scale_x;
     fbh *= s->scale_y;
 
-    cairo_set_source_surface(cr, s->surface, 0, 0);
+    mx = my = 0;
+    if (ww > fbw) {
+        mx = (ww - fbw) / 2;
+    }
+    if (wh > fbh) {
+        my = (wh - fbh) / 2;
+    }
+
+    cairo_rectangle(cr, 0, 0, ww, wh);
+
+    /* Optionally cut out the inner area where the pixmap
+       will be drawn. This avoids 'flashing' since we're
+       not double-buffering. Note we're using the undocumented
+       behaviour of drawing the rectangle from right to left
+       to cut out the whole */
+    cairo_rectangle(cr, mx + fbw, my,
+                    -1 * fbw, fbh);
+    cairo_fill(cr);
+
+    cairo_scale(cr, s->scale_x, s->scale_y);
+    cairo_set_source_surface(cr, s->surface, mx / s->scale_x, my / s->scale_y);
     cairo_paint(cr);
 
     return TRUE;
@@ -321,9 +390,31 @@ static gboolean gd_motion_event(GtkWidget *widget, 
GdkEventMotion *motion,
     GtkDisplayState *s = opaque;
     int dx, dy;
     int x, y;
+    int mx, my;
+    int fbh, fbw;
+    int ww, wh;
+
+    fbw = ds_get_width(s->ds) * s->scale_x;
+    fbh = ds_get_height(s->ds) * s->scale_y;
 
-    x = motion->x / s->scale_x;
-    y = motion->y / s->scale_y;
+    gdk_drawable_get_size(gtk_widget_get_window(s->drawing_area), &ww, &wh);
+
+    mx = my = 0;
+    if (ww > fbw) {
+        mx = (ww - fbw) / 2;
+    }
+    if (wh > fbh) {
+        my = (wh - fbh) / 2;
+    }
+
+    x = (motion->x - mx) / s->scale_x;
+    y = (motion->y - my) / s->scale_y;
+
+    if (x < 0 || y < 0 ||
+        x >= ds_get_width(s->ds) ||
+        y >= ds_get_height(s->ds)) {
+        return TRUE;
+    }
 
     if (kbd_mouse_is_absolute()) {
         dx = x * 0x7FFF / (ds_get_width(s->ds) - 1);
@@ -492,6 +583,90 @@ static void gd_menu_show_tabs(GtkMenuItem *item, void 
*opaque)
     }
 }
 
+static void gd_menu_full_screen(GtkMenuItem *item, void *opaque)
+{
+    GtkDisplayState *s = opaque;
+
+    if 
(gtk_check_menu_item_get_active(GTK_CHECK_MENU_ITEM(s->full_screen_item))) {
+        gtk_notebook_set_show_tabs(GTK_NOTEBOOK(s->notebook), FALSE);
+        gtk_widget_set_size_request(s->menu_bar, 0, 0);
+        gtk_widget_set_size_request(s->drawing_area, -1, -1);
+        gtk_window_fullscreen(GTK_WINDOW(s->window));
+        if (gd_on_vga(s)) {
+            gtk_check_menu_item_set_active(GTK_CHECK_MENU_ITEM(s->grab_item), 
TRUE);
+        }
+        s->full_screen = TRUE;
+    } else {
+        gtk_window_unfullscreen(GTK_WINDOW(s->window));
+        gd_menu_show_tabs(GTK_MENU_ITEM(s->show_tabs_item), s);
+        gtk_widget_set_size_request(s->menu_bar, -1, -1);
+        gtk_widget_set_size_request(s->drawing_area,
+                                    ds_get_width(s->ds), ds_get_height(s->ds));
+        gtk_check_menu_item_set_active(GTK_CHECK_MENU_ITEM(s->grab_item), 
FALSE);
+        s->full_screen = FALSE;
+        s->scale_x = 1.0;
+        s->scale_y = 1.0;
+    }
+
+    gd_update_cursor(s, FALSE);
+}
+
+static void gd_menu_zoom_in(GtkMenuItem *item, void *opaque)
+{
+    GtkDisplayState *s = opaque;
+
+    gtk_check_menu_item_set_active(GTK_CHECK_MENU_ITEM(s->zoom_fit_item),
+                                   FALSE);
+
+    s->scale_x += .25;
+    s->scale_y += .25;
+
+    gd_resize(s->ds);
+}
+
+static void gd_menu_zoom_out(GtkMenuItem *item, void *opaque)
+{
+    GtkDisplayState *s = opaque;
+
+    gtk_check_menu_item_set_active(GTK_CHECK_MENU_ITEM(s->zoom_fit_item),
+                                   FALSE);
+
+    s->scale_x -= .25;
+    s->scale_y -= .25;
+
+    s->scale_x = MAX(s->scale_x, .25);
+    s->scale_y = MAX(s->scale_y, .25);
+
+    gd_resize(s->ds);
+}
+
+static void gd_menu_zoom_fixed(GtkMenuItem *item, void *opaque)
+{
+    GtkDisplayState *s = opaque;
+
+    s->scale_x = 1.0;
+    s->scale_y = 1.0;
+
+    gd_resize(s->ds);
+}
+
+static void gd_menu_zoom_fit(GtkMenuItem *item, void *opaque)
+{
+    GtkDisplayState *s = opaque;
+    int ww, wh;
+
+    if (gtk_check_menu_item_get_active(GTK_CHECK_MENU_ITEM(s->zoom_fit_item))) 
{
+        s->free_scale = TRUE;
+    } else {
+        s->free_scale = FALSE;
+    }
+
+    gd_resize(s->ds);
+
+    gdk_drawable_get_size(gtk_widget_get_window(s->drawing_area), &ww, &wh);
+    gtk_widget_queue_draw_area(s->drawing_area, 0, 0, ww, wh);
+}
+
 static void gd_grab_keyboard(GtkDisplayState *s)
 {
     gdk_keyboard_grab(gtk_widget_get_window(GTK_WIDGET(s->drawing_area)),
@@ -551,6 +726,9 @@ static void gd_change_page(GtkNotebook *nb, gpointer arg1, 
guint arg2,
     if (!on_vga) {
         gtk_check_menu_item_set_active(GTK_CHECK_MENU_ITEM(s->grab_item),
                                        FALSE);
+    } else if (s->full_screen) {
+        gtk_check_menu_item_set_active(GTK_CHECK_MENU_ITEM(s->grab_item),
+                                       TRUE);
     }
 
     if (arg2 == 0) {
@@ -739,6 +917,16 @@ static void gd_connect_signals(GtkDisplayState *s)
 
     g_signal_connect(s->quit_item, "activate",
                      G_CALLBACK(gd_menu_quit), s);
+    g_signal_connect(s->full_screen_item, "activate",
+                     G_CALLBACK(gd_menu_full_screen), s);
+    g_signal_connect(s->zoom_in_item, "activate",
+                     G_CALLBACK(gd_menu_zoom_in), s);
+    g_signal_connect(s->zoom_out_item, "activate",
+                     G_CALLBACK(gd_menu_zoom_out), s);
+    g_signal_connect(s->zoom_fixed_item, "activate",
+                     G_CALLBACK(gd_menu_zoom_fixed), s);
+    g_signal_connect(s->zoom_fit_item, "activate",
+                     G_CALLBACK(gd_menu_zoom_fit), s);
     g_signal_connect(s->vga_item, "activate",
                      G_CALLBACK(gd_menu_switch_vc), s);
     g_signal_connect(s->grab_item, "activate",
@@ -774,6 +962,39 @@ static void gd_create_menus(GtkDisplayState *s)
     gtk_menu_set_accel_group(GTK_MENU(s->view_menu), accel_group);
     s->view_menu_item = gtk_menu_item_new_with_mnemonic("_View");
 
+    s->full_screen_item = gtk_check_menu_item_new_with_mnemonic("_Full 
Screen");
+    gtk_menu_item_set_accel_path(GTK_MENU_ITEM(s->full_screen_item),
+                                 "<QEMU>/View/Full Screen");
+    gtk_accel_map_add_entry("<QEMU>/View/Full Screen", GDK_KEY_f, 
GDK_CONTROL_MASK | GDK_MOD1_MASK);
+    gtk_menu_append(GTK_MENU(s->view_menu), s->full_screen_item);
+
+    separator = gtk_separator_menu_item_new();
+    gtk_menu_append(GTK_MENU(s->view_menu), separator);
+
+    s->zoom_in_item = gtk_image_menu_item_new_from_stock(GTK_STOCK_ZOOM_IN, 
NULL);
+    gtk_menu_item_set_accel_path(GTK_MENU_ITEM(s->zoom_in_item),
+                                 "<QEMU>/View/Zoom In");
+    gtk_accel_map_add_entry("<QEMU>/View/Zoom In", GDK_KEY_plus, 
GDK_CONTROL_MASK | GDK_MOD1_MASK);
+    gtk_menu_append(GTK_MENU(s->view_menu), s->zoom_in_item);
+
+    s->zoom_out_item = gtk_image_menu_item_new_from_stock(GTK_STOCK_ZOOM_OUT, 
NULL);
+    gtk_menu_item_set_accel_path(GTK_MENU_ITEM(s->zoom_out_item),
+                                 "<QEMU>/View/Zoom Out");
+    gtk_accel_map_add_entry("<QEMU>/View/Zoom Out", GDK_KEY_minus, 
GDK_CONTROL_MASK | GDK_MOD1_MASK);
+    gtk_menu_append(GTK_MENU(s->view_menu), s->zoom_out_item);
+
+    s->zoom_fixed_item = 
gtk_image_menu_item_new_from_stock(GTK_STOCK_ZOOM_100, NULL);
+    gtk_menu_item_set_accel_path(GTK_MENU_ITEM(s->zoom_fixed_item),
+                                 "<QEMU>/View/Zoom Fixed");
+    gtk_accel_map_add_entry("<QEMU>/View/Zoom Fixed", GDK_KEY_0, 
GDK_CONTROL_MASK | GDK_MOD1_MASK);
+    gtk_menu_append(GTK_MENU(s->view_menu), s->zoom_fixed_item);
+
+    s->zoom_fit_item = gtk_check_menu_item_new_with_mnemonic("Zoom To _Fit");
+    gtk_menu_append(GTK_MENU(s->view_menu), s->zoom_fit_item);
+
+    separator = gtk_separator_menu_item_new();
+    gtk_menu_append(GTK_MENU(s->view_menu), separator);
+
     s->grab_on_hover_item = gtk_check_menu_item_new_with_mnemonic("Grab On 
_Hover");
     gtk_menu_append(GTK_MENU(s->view_menu), s->grab_on_hover_item);
 
@@ -837,6 +1058,7 @@ void gtk_display_init(DisplayState *ds)
 
     s->scale_x = 1.0;
     s->scale_y = 1.0;
+    s->free_scale = FALSE;
 
     s->null_cursor = gdk_cursor_new(GDK_BLANK_CURSOR);
 
@@ -865,8 +1087,6 @@ void gtk_display_init(DisplayState *ds)
     gtk_notebook_set_show_tabs(GTK_NOTEBOOK(s->notebook), FALSE);
     gtk_notebook_set_show_border(GTK_NOTEBOOK(s->notebook), FALSE);
 
-    gtk_window_set_resizable(GTK_WINDOW(s->window), FALSE);
-
     gd_update_caption(s);
 
     gtk_box_pack_start(GTK_BOX(s->vbox), s->menu_bar, FALSE, TRUE, 0);
-- 
1.8.0