[PATCH v2 3/3] ui: Fix gtk/gl when the scaled virtual console does not fit the window

[Alexander Orzechowski <orzechowski.alexander@gmail.com>]

gtk/gl was incorrectly always rendering as if the 'Zoom to Fit' was
always checked even if it wasn't. This is now using logic closer
to what is being used for the existing cairo code paths.

Signed-off-by: Alexander Orzechowski <orzechowski.alexander@gmail.com>
---
 ui/gtk-gl-area.c | 34 +++++++++++++++++++++++++++++-----
 1 file changed, 29 insertions(+), 5 deletions(-)

diff --git a/ui/gtk-gl-area.c b/ui/gtk-gl-area.c
index 01e4e74ee3..f4f2dac882 100644
--- a/ui/gtk-gl-area.c
+++ b/ui/gtk-gl-area.c
@@ -41,16 +41,40 @@ void gd_gl_area_draw(VirtualConsole *vc)
 #ifdef CONFIG_GBM
     QemuDmaBuf *dmabuf = vc->gfx.guest_fb.dmabuf;
 #endif
+    GtkDisplayState *s = vc->s;
     int ww, wh, ws, y1, y2;
+    int mx, my;
+    int fbh, fbw;
 
     if (!vc->gfx.gls) {
         return;
     }
 
     gtk_gl_area_make_current(GTK_GL_AREA(vc->gfx.drawing_area));
+
+    fbw = surface_width(vc->gfx.ds);
+    fbh = surface_height(vc->gfx.ds);
+
     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;
+    ww = gtk_widget_get_allocated_width(vc->gfx.drawing_area);
+    wh = gtk_widget_get_allocated_height(vc->gfx.drawing_area);
+
+    if (s->full_screen) {
+        vc->gfx.scale_x = (double)ww / fbw;
+        vc->gfx.scale_y = (double)wh / fbh;
+    } else if (s->free_scale) {
+        double sx, sy;
+
+        sx = (double)ww / fbw;
+        sy = (double)wh / fbh;
+
+        vc->gfx.scale_x = vc->gfx.scale_y = MIN(sx, sy);
+    }
+
+    fbw *= vc->gfx.scale_x * ws;
+    fbh *= vc->gfx.scale_y * ws;
+    mx = (ww * ws - fbw) / 2;
+    my = (wh * ws - fbh) / 2;
 
     if (vc->gfx.scanout_mode) {
         if (!vc->gfx.guest_fb.framebuffer) {
@@ -70,11 +94,11 @@ 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);
+        glViewport(mx, my, fbw, fbh);
         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,
+                          mx, my, fbw + mx, fbh + my,
                           GL_COLOR_BUFFER_BIT, GL_NEAREST);
 #ifdef CONFIG_GBM
         if (dmabuf) {
@@ -98,7 +122,7 @@ 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);
+        glViewport(mx, my, fbw, fbh);
         surface_gl_render_texture(vc->gfx.gls, vc->gfx.ds);
     }
 
-- 
2.34.1