kmssink: Enforce pixel aspect ratio when we cannot scale

When we cannot scale, we need to enforce the pixel aspect ratio.
This was partly implemented in the previous patch. Doing this
simplify some of the code.

https://bugzilla.gnome.org/show_bug.cgi?id=784599

sys/kms/gstkmssink.c

@@ -99,48 +99,35 @@ gst_kms_sink_set_render_rectangle (GstVideoOverlay * overlay,
 {
   GstKMSSink *self = GST_KMS_SINK (overlay);
 
+  GST_DEBUG_OBJECT (self, "Setting render rectangle to (%d,%d) %dx%d", x, y,
+      width, height);
+
+  GST_OBJECT_LOCK (self);
+
   if (width == -1 && height == -1) {
     x = 0;
     y = 0;
     width = self->hdisplay;
     height = self->vdisplay;
   }
 
-  if (width <= 0 || height <= 0) {
-    return;
-  }
+  if (width <= 0 || height <= 0)
+    goto done;
 
-  GST_OBJECT_LOCK (self);
-  if (self->can_scale) {
-    self->render_rect.x = x;
-    self->render_rect.y = y;
-    self->render_rect.w = width;
-    self->render_rect.h = height;
-  } else {
-    GstVideoRectangle src = { 0, };
-    GstVideoRectangle dst = { 0, };
-    GstVideoRectangle result;
+  self->pending_rect.x = x;
+  self->pending_rect.y = y;
+  self->pending_rect.w = width;
+  self->pending_rect.h = height;
 
-    src.w = GST_VIDEO_INFO_WIDTH (&self->vinfo);
-    src.h = GST_VIDEO_INFO_HEIGHT (&self->vinfo);
-
-    dst.w = width;
-    dst.h = height;
-
-    if (src.w != dst.w || src.h != dst.h)
-      self->reconfigure = TRUE;
-
-    gst_video_sink_center_rect (src, dst, &result, TRUE);
-
-    self->pending_rect.x = x + result.x;
-    self->pending_rect.y = y + result.y;
-    self->pending_rect.w = result.w;
-    self->pending_rect.h = result.h;
-
-    GST_DEBUG_OBJECT (self, "pending resize to (%d,%d)-(%dx%d)",
-        self->pending_rect.x, self->pending_rect.y,
-        self->pending_rect.w, self->pending_rect.h);
+  if (self->can_scale ||
+      (self->render_rect.w == width && self->render_rect.h == height)) {
+    self->render_rect = self->pending_rect;
+  } else {
+    self->reconfigure = TRUE;
+    GST_DEBUG_OBJECT (self, "Waiting for new caps to apply render rectangle");
   }
+
+done:
   GST_OBJECT_UNLOCK (self);
 }
 
@@ -149,18 +136,23 @@ gst_kms_sink_expose (GstVideoOverlay * overlay)
 {
   GstKMSSink *self = GST_KMS_SINK (overlay);
 
+  GST_DEBUG_OBJECT (overlay, "Expose called by application");
+
   if (!self->can_scale) {
     GST_OBJECT_LOCK (self);
     if (self->reconfigure) {
       GST_OBJECT_UNLOCK (self);
+      GST_DEBUG_OBJECT (overlay, "Sending a reconfigure event");
       gst_pad_push_event (GST_BASE_SINK_PAD (self),
           gst_event_new_reconfigure ());
     } else {
+      GST_DEBUG_OBJECT (overlay, "Applying new render rectangle");
       /* size of the rectangle does not change, only the (x,y) position changes */
       self->render_rect = self->pending_rect;
       GST_OBJECT_UNLOCK (self);
     }
   }
+
   gst_kms_sink_show_frame (GST_VIDEO_SINK (self), NULL);
 }
 
@@ -659,12 +651,12 @@ gst_kms_sink_start (GstBaseSink * bsink)
   GST_INFO_OBJECT (self, "connector id = %d / crtc id = %d / plane id = %d",
       self->conn_id, self->crtc_id, self->plane_id);
 
+  GST_OBJECT_LOCK (self);
   self->render_rect.x = 0;
   self->render_rect.y = 0;
-
-  GST_OBJECT_LOCK (self);
   self->hdisplay = self->render_rect.w = crtc->mode.hdisplay;
   self->vdisplay = self->render_rect.h = crtc->mode.vdisplay;
+  self->pending_rect = self->render_rect;
   GST_OBJECT_UNLOCK (self);
 
   self->buffer_id = crtc->buffer_id;
@@ -797,6 +789,11 @@ gst_kms_sink_stop (GstBaseSink * bsink)
   GST_OBJECT_LOCK (bsink);
   self->hdisplay = 0;
   self->vdisplay = 0;
+  self->pending_rect.x = 0;
+  self->pending_rect.y = 0;
+  self->pending_rect.w = 0;
+  self->pending_rect.h = 0;
+  self->render_rect = self->pending_rect;
   GST_OBJECT_UNLOCK (bsink);
 
   g_object_notify_by_pspec (G_OBJECT (self), g_properties[PROP_DISPLAY_WIDTH]);
@@ -818,35 +815,50 @@ gst_kms_sink_get_caps (GstBaseSink * bsink, GstCaps * filter)
 {
   GstKMSSink *self;
   GstCaps *caps, *out_caps;
+  GstStructure *s;
+  guint dpy_par_n, dpy_par_d;
 
   self = GST_KMS_SINK (bsink);
 
   caps = gst_kms_sink_get_allowed_caps (self);
+  if (!caps)
+    return NULL;
 
   GST_OBJECT_LOCK (self);
-  if (caps && self->reconfigure) {
-    GstStructure *s0, *s1;
-    guint dpy_par_n, dpy_par_d;
 
+  if (!self->can_scale) {
+    out_caps = gst_caps_new_empty ();
     gst_video_calculate_device_ratio (self->hdisplay, self->vdisplay,
         self->mm_width, self->mm_height, &dpy_par_n, &dpy_par_d);
 
-    caps = gst_caps_make_writable (caps);
-    s0 = gst_caps_get_structure (caps, 0);
-    s1 = gst_structure_copy (gst_caps_get_structure (caps, 0));
+    s = gst_structure_copy (gst_caps_get_structure (caps, 0));
+    gst_structure_set (s, "width", G_TYPE_INT, self->pending_rect.w,
+        "height", G_TYPE_INT, self->pending_rect.h,
+        "pixel-aspect-ratio", GST_TYPE_FRACTION, dpy_par_n, dpy_par_d, NULL);
+
+    gst_caps_append_structure (out_caps, s);
 
-    gst_structure_set (s0, "width", G_TYPE_INT, self->pending_rect.w,
-        "height", G_TYPE_INT, self->pending_rect.h, NULL);
-    gst_caps_append_structure (caps, s1);
+    out_caps = gst_caps_merge (out_caps, caps);
+    caps = NULL;
+
+    /* enforce our display aspect ratio */
+    gst_caps_set_simple (out_caps, "pixel-aspect-ratio", GST_TYPE_FRACTION,
+        dpy_par_n, dpy_par_d, NULL);
+  } else {
+    out_caps = gst_caps_make_writable (caps);
+    caps = NULL;
   }
+
   GST_OBJECT_UNLOCK (self);
 
-  if (caps && filter) {
+  GST_DEBUG_OBJECT (self, "Proposing caps %" GST_PTR_FORMAT, out_caps);
+
+  if (filter) {
+    caps = out_caps;
     out_caps = gst_caps_intersect_full (caps, filter, GST_CAPS_INTERSECT_FIRST);
     gst_caps_unref (caps);
-  } else {
-    out_caps = caps;
   }
+
   return out_caps;
 }