3 files changed, 40 insertions, 8 deletions

diff --git a/ui/egl-helpers.c b/ui/egl-helpers.c
index 9cda2bbbee..5503a795e4 100644
--- a/ui/egl-helpers.c
+++ b/ui/egl-helpers.c
@@ -93,14 +93,18 @@ void egl_fb_destroy(egl_fb *fb)
 
     fb->width = 0;
     fb->height = 0;
+    fb->x = 0;
+    fb->y = 0;
     fb->texture = 0;
     fb->framebuffer = 0;
 }
 
-void egl_fb_setup_default(egl_fb *fb, int width, int height)
+void egl_fb_setup_default(egl_fb *fb, int width, int height, int x, int y)
 {
     fb->width = width;
     fb->height = height;
+    fb->x = x;
+    fb->y = y;
     fb->framebuffer = 0; /* default framebuffer */
 }
 
@@ -145,6 +149,7 @@ void egl_fb_blit(egl_fb *dst, egl_fb *src, bool flip)
     glBindFramebuffer(GL_READ_FRAMEBUFFER, src->framebuffer);
     glBindFramebuffer(GL_DRAW_FRAMEBUFFER, dst->framebuffer);
     glViewport(0, 0, dst->width, dst->height);
+    glClear(GL_COLOR_BUFFER_BIT);
 
     if (src->dmabuf) {
         x1 = qemu_dmabuf_get_x(src->dmabuf);
@@ -161,7 +166,8 @@ void egl_fb_blit(egl_fb *dst, egl_fb *src, bool flip)
     x2 = x1 + w;
 
     glBlitFramebuffer(x1, y1, x2, y2,
-                      0, 0, dst->width, dst->height,
+                      dst->x, dst->y,
+                      dst->x + dst->width, dst->y + dst->height,
                       GL_COLOR_BUFFER_BIT, GL_LINEAR);
 }
 
diff --git a/ui/gtk-egl.c b/ui/gtk-egl.c
index f8e4f4bc70..0b787bea25 100644
--- a/ui/gtk-egl.c
+++ b/ui/gtk-egl.c
@@ -340,7 +340,11 @@ void gd_egl_scanout_flush(DisplayChangeListener *dcl,
 {
     VirtualConsole *vc = container_of(dcl, VirtualConsole, gfx.dcl);
     GdkWindow *window;
-    int ww, wh, ws;
+    int px_offset, py_offset;
+    int gs;
+    int pw_widget, ph_widget, pw_surface, ph_surface;
+    int ww_widget, wh_widget, ww_surface, wh_surface;
+    int fbw, fbh;
 
     if (!vc->gfx.scanout_mode) {
         return;
@@ -353,10 +357,32 @@ void gd_egl_scanout_flush(DisplayChangeListener *dcl,
                    vc->gfx.esurface, vc->gfx.ectx);
 
     window = gtk_widget_get_window(vc->gfx.drawing_area);
-    ws = gdk_window_get_scale_factor(window);
-    ww = gdk_window_get_width(window) * ws;
-    wh = gdk_window_get_height(window) * ws;
-    egl_fb_setup_default(&vc->gfx.win_fb, ww, wh);
+    gs = gdk_window_get_scale_factor(window);
+    ww_widget = gdk_window_get_width(window);
+    wh_widget = gdk_window_get_height(window);
+    fbw = surface_width(vc->gfx.ds);
+    fbh = surface_height(vc->gfx.ds);
+
+    gd_update_scale(vc, ww_widget, wh_widget, fbw, fbh);
+
+    ww_surface = fbw * vc->gfx.scale_x;
+    wh_surface = fbh * vc->gfx.scale_y;
+    pw_widget = ww_widget * gs;
+    ph_widget = wh_widget * gs;
+    pw_surface = ww_surface * gs;
+    ph_surface = wh_surface * gs;
+
+    px_offset = 0;
+    py_offset = 0;
+    if (pw_widget > pw_surface) {
+        px_offset = (pw_widget - pw_surface) / 2;
+    }
+    if (ph_widget > ph_surface) {
+        py_offset = (ph_widget - ph_surface) / 2;
+    }
+
+    egl_fb_setup_default(&vc->gfx.win_fb, pw_surface, ph_surface,
+                         px_offset, py_offset);
     if (vc->gfx.cursor_fb.texture) {
         egl_texture_blit(vc->gfx.gls, &vc->gfx.win_fb, &vc->gfx.guest_fb,
                          vc->gfx.y0_top);
diff --git a/ui/sdl2-gl.c b/ui/sdl2-gl.c
index e01d9ab0c7..3be17d1079 100644
--- a/ui/sdl2-gl.c
+++ b/ui/sdl2-gl.c
@@ -241,7 +241,7 @@ void sdl2_gl_scanout_flush(DisplayChangeListener *dcl,
     SDL_GL_MakeCurrent(scon->real_window, scon->winctx);
 
     SDL_GetWindowSize(scon->real_window, &ww, &wh);
-    egl_fb_setup_default(&scon->win_fb, ww, wh);
+    egl_fb_setup_default(&scon->win_fb, ww, wh, 0, 0);
     egl_fb_blit(&scon->win_fb, &scon->guest_fb, !scon->y0_top);
 
     SDL_GL_SwapWindow(scon->real_window);