tests/wayland/buffer-transform: Draw the buffer with the right size

This test currently only works because the monitor has the same width
and height. Generalize it to arbitrary monitor sizes by taking into
account that width and hight are swapped for some rotations.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3350>

src/tests/wayland-test-clients/buffer-transform.c

@@ -88,7 +88,7 @@ static const struct xdg_surface_listener xdg_surface_listener = {
 };
 
 static void
-draw_main (void)
+draw_main (gboolean rotated)
 {
   static uint32_t color0 = 0xffffffff;
   static uint32_t color1 = 0xff00ffff;
@@ -96,31 +96,36 @@ draw_main (void)
   static uint32_t color3 = 0xffffff00;
   WaylandBuffer *buffer;
   int x, y;
+  uint32_t width;
+  uint32_t height;
+
+  width = rotated ? window_height : window_width,
+  height = rotated ? window_width : window_height,
 
   buffer = wayland_buffer_create (display, NULL,
-                                  window_width, window_height,
+                                  width, height,
                                   DRM_FORMAT_XRGB8888,
                                   NULL, 0,
                                   GBM_BO_USE_LINEAR);
   if (!buffer)
     g_error ("Failed to create buffer");
 
-  for (y = 0; y < window_height; y++)
+  for (y = 0; y < height; y++)
     {
-      for (x = 0; x < window_width; x++)
+      for (x = 0; x < width; x++)
         {
           uint32_t current_color;
 
-          if (y < window_height / 2)
+          if (y < height / 2)
             {
-              if (x < window_width / 2)
+              if (x < width / 2)
                 current_color = color0;
               else
                 current_color = color1;
             }
           else
             {
-              if (x < window_width / 2)
+              if (x < width / 2)
                 current_color = color2;
               else
                 current_color = color3;
@@ -160,7 +165,7 @@ main (int    argc,
   wl_surface_commit (surface);
   wait_for_configure ();
 
-  draw_main ();
+  draw_main (FALSE);
   wl_surface_commit (surface);
   wait_for_effects_completed (display, surface);
 
@@ -168,27 +173,28 @@ main (int    argc,
   wl_surface_commit (surface);
   wait_for_view_verified (display, 0);
 
-  wl_surface_set_buffer_transform (surface, WL_OUTPUT_TRANSFORM_90);
+  wl_surface_set_buffer_transform (surface, WL_OUTPUT_TRANSFORM_180);
   wl_surface_commit (surface);
   wait_for_view_verified (display, 1);
 
-  wl_surface_set_buffer_transform (surface, WL_OUTPUT_TRANSFORM_180);
+  wl_surface_set_buffer_transform (surface, WL_OUTPUT_TRANSFORM_FLIPPED);
   wl_surface_commit (surface);
   wait_for_view_verified (display, 2);
 
-  wl_surface_set_buffer_transform (surface, WL_OUTPUT_TRANSFORM_270);
+  wl_surface_set_buffer_transform (surface, WL_OUTPUT_TRANSFORM_FLIPPED_180);
   wl_surface_commit (surface);
   wait_for_view_verified (display, 3);
 
-  wl_surface_set_buffer_transform (surface, WL_OUTPUT_TRANSFORM_FLIPPED);
+  draw_main (TRUE);
+  wl_surface_set_buffer_transform (surface, WL_OUTPUT_TRANSFORM_90);
   wl_surface_commit (surface);
   wait_for_view_verified (display, 4);
 
-  wl_surface_set_buffer_transform (surface, WL_OUTPUT_TRANSFORM_FLIPPED_90);
+  wl_surface_set_buffer_transform (surface, WL_OUTPUT_TRANSFORM_270);
   wl_surface_commit (surface);
   wait_for_view_verified (display, 5);
 
-  wl_surface_set_buffer_transform (surface, WL_OUTPUT_TRANSFORM_FLIPPED_180);
+  wl_surface_set_buffer_transform (surface, WL_OUTPUT_TRANSFORM_FLIPPED_90);
   wl_surface_commit (surface);
   wait_for_view_verified (display, 6);