1 files changed, 46 insertions, 7 deletions

diff --git a/ui/gtk-gl-area.c b/ui/gtk-gl-area.c
index 2c9a0db425..8151cc413c 100644
--- a/ui/gtk-gl-area.c
+++ b/ui/gtk-gl-area.c
@@ -42,16 +42,37 @@ void gd_gl_area_draw(VirtualConsole *vc)
 #ifdef CONFIG_GBM
     QemuDmaBuf *dmabuf = vc->gfx.guest_fb.dmabuf;
 #endif
-    int ww, wh, ws, y1, y2;
+    int pw, ph, gs, y1, y2;
+    int ww, wh;
+    int ww_surface, wh_surface;
+    int fbw, fbh;
+    int wx_offset, wy_offset;
 
     if (!vc->gfx.gls) {
         return;
     }
 
     gtk_gl_area_make_current(GTK_GL_AREA(vc->gfx.drawing_area));
-    ws = gdk_window_get_scale_factor(gtk_widget_get_window(vc->gfx.drawing_area));
-    ww = gtk_widget_get_allocated_width(vc->gfx.drawing_area) * ws;
-    wh = gtk_widget_get_allocated_height(vc->gfx.drawing_area) * ws;
+    gs = gdk_window_get_scale_factor(gtk_widget_get_window(vc->gfx.drawing_area));
+    fbw = surface_width(vc->gfx.ds);
+    fbh = surface_height(vc->gfx.ds);
+    ww = gtk_widget_get_allocated_width(vc->gfx.drawing_area);
+    wh = gtk_widget_get_allocated_height(vc->gfx.drawing_area);
+    pw = ww * gs;
+    ph = wh * gs;
+
+    gd_update_scale(vc, ww, wh, fbw, fbh);
+
+    ww_surface = fbw * vc->gfx.scale_x;
+    wh_surface = fbh * vc->gfx.scale_y;
+
+    wx_offset = wy_offset = 0;
+    if (ww > ww_surface) {
+        wx_offset = (ww - ww_surface) / 2;
+    }
+    if (wh > wh_surface) {
+        wy_offset = (wh - wh_surface) / 2;
+    }
 
     if (vc->gfx.scanout_mode) {
         if (!vc->gfx.guest_fb.framebuffer) {
@@ -71,11 +92,29 @@ void gd_gl_area_draw(VirtualConsole *vc)
         glBindFramebuffer(GL_READ_FRAMEBUFFER, vc->gfx.guest_fb.framebuffer);
         /* GtkGLArea sets GL_DRAW_FRAMEBUFFER for us */
 
-        glViewport(0, 0, ww, wh);
+        if (wx_offset > 0) {
+            glEnable(GL_SCISSOR_TEST);
+            glScissor(0, 0, wx_offset * gs, wh * gs);
+            glClear(GL_COLOR_BUFFER_BIT);
+            glScissor((ww - wx_offset) * gs, 0, wx_offset * gs, wh * gs);
+            glClear(GL_COLOR_BUFFER_BIT);
+            glDisable(GL_SCISSOR_TEST);
+        }
+        if (wy_offset > 0) {
+            glEnable(GL_SCISSOR_TEST);
+            glScissor(0, 0, ww * gs, wy_offset * gs);
+            glClear(GL_COLOR_BUFFER_BIT);
+            glScissor(0, (wh - wy_offset) * gs, ww * gs, wy_offset * gs);
+            glClear(GL_COLOR_BUFFER_BIT);
+            glDisable(GL_SCISSOR_TEST);
+        }
+
+        glViewport(0, 0, pw, ph);
         y1 = vc->gfx.y0_top ? 0 : vc->gfx.h;
         y2 = vc->gfx.y0_top ? vc->gfx.h : 0;
         glBlitFramebuffer(0, y1, vc->gfx.w, y2,
-                          0, 0, ww, wh,
+                          wx_offset * gs, wy_offset * gs,
+                          (ww - wx_offset) * gs, (wh - wy_offset) * gs,
                           GL_COLOR_BUFFER_BIT, GL_NEAREST);
 #ifdef CONFIG_GBM
         if (dmabuf) {
@@ -101,7 +140,7 @@ void gd_gl_area_draw(VirtualConsole *vc)
         }
         gtk_gl_area_make_current(GTK_GL_AREA(vc->gfx.drawing_area));
 
-        surface_gl_setup_viewport(vc->gfx.gls, vc->gfx.ds, ww, wh);
+        surface_gl_setup_viewport(vc->gfx.gls, vc->gfx.ds, pw, ph);
         surface_gl_render_texture(vc->gfx.gls, vc->gfx.ds);
     }
 }