GUACAMOLE-176: Support layer location and opacity for guac_common_surface.

src/common/common/surface.h

@@ -118,6 +118,40 @@ typedef struct guac_common_surface {
      */
     guac_socket* socket;
 
+    /**
+     * The X coordinate of the upper-left corner of this layer, in pixels,
+     * relative to its parent layer. This is only applicable to visible
+     * (non-buffer) layers which are not the default layer.
+     */
+    int x;
+
+    /**
+     * The Y coordinate of the upper-left corner of this layer, in pixels,
+     * relative to its parent layer. This is only applicable to visible
+     * (non-buffer) layers which are not the default layer.
+     */
+    int y;
+
+    /**
+     * The Z-order of this layer, relative to sibling layers. This is only
+     * applicable to visible (non-buffer) layers which are not the default
+     * layer.
+     */
+    int z;
+
+    /**
+     * The level of opacity applied to this layer. Fully opaque is 255, while
+     * fully transparent is 0. This is only applicable to visible (non-buffer)
+     * layers which are not the default layer.
+     */
+    int opacity;
+
+    /**
+     * The layer which contains this layer. This is only applicable to visible
+     * (non-buffer) layers which are not the default layer.
+     */
+    const guac_layer* parent;
+
     /**
      * The width of this layer, in pixels.
      */
@@ -138,6 +172,18 @@ typedef struct guac_common_surface {
      */
     unsigned char* buffer;
 
+    /**
+     * Non-zero if the location or parent layer of this surface has been
+     * changed and needs to be flushed, 0 otherwise.
+     */
+    int location_dirty;
+
+    /**
+     * Non-zero if the opacity of this surface has been changed and needs to be
+     * flushed, 0 otherwise.
+     */
+    int opacity_dirty;
+
     /**
      * Non-zero if this surface is dirty and needs to be flushed, 0 otherwise.
      */
@@ -317,10 +363,77 @@ void guac_common_surface_clip(guac_common_surface* surface, int x, int y, int w,
 void guac_common_surface_reset_clip(guac_common_surface* surface);
 
 /**
- * Flushes the given surface, drawing any pending operations on the remote
+ * Changes the location of the surface relative to its parent layer. If the
- * display.
+ * surface does not represent a non-default visible layer, then this function
+ * has no effect.
  *
- * @param surface The surface to flush.
+ * @param surface
+ *     The surface to move relative to its parent layer.
+ *
+ * @param x
+ *     The new X coordinate for the upper-left corner of the layer, in pixels.
+ *
+ * @param y
+ *     The new Y coordinate for the upper-left corner of the layer, in pixels.
+ */
+void guac_common_surface_move(guac_common_surface* surface, int x, int y);
+
+/**
+ * Changes the stacking order of the surface relative to other surfaces within
+ * the same parent layer. If the surface does not represent a non-default
+ * visible layer, then this function has no effect.
+ *
+ * @param surface
+ *     The surface to reorder relative to sibling layers.
+ *
+ * @param z
+ *     The new Z-order for this layer, relative to sibling layers.
+ */
+void guac_common_surface_stack(guac_common_surface* surface, int z);
+
+/**
+ * Changes the parent layer of ths given surface. By default, layers will be
+ * children of the default layer. If the surface does not represent a
+ * non-default visible layer, then this function has no effect.
+ *
+ * @param surface
+ *     The surface whose parent layer should be changed.
+ *
+ * @param parent
+ *     The layer which should be set as the new parent of the given surface.
+ */
+void guac_common_surface_set_parent(guac_common_surface* surface,
+        const guac_layer* parent);
+
+/**
+ * Sets the opacity of the surface. If the surface does not represent a
+ * non-default visible layer, then this function has no effect.
+ *
+ * @param surface
+ *     The surface whose opacity should be changed.
+ *
+ * @param opacity
+ *     The level of opacity applied to this surface, where fully opaque is 255,
+ *     and fully transparent is 0.
+ */
+void guac_common_surface_set_opacity(guac_common_surface* surface, int opacity);
+
+/**
+ * Flushes only the properties of the given surface, such as layer location or
+ * opacity. Image state is not flushed. If the surface represents a buffer or
+ * the default layer, this function has no effect.
+ *
+ * @param surface
+ *     The surface to flush.
+ */
+void guac_common_surface_flush_properties(guac_common_surface* surface);
+
+/**
+ * Flushes the given surface, including any applicable properties, drawing any
+ * pending operations on the remote display.
+ *
+ * @param surface
+ *     The surface to flush.
  */
 void guac_common_surface_flush(guac_common_surface* surface);
 

src/common/display.c

@@ -155,7 +155,17 @@ void guac_common_display_dup(guac_common_display* display, guac_user* user,
 }
 
 void guac_common_display_flush(guac_common_display* display) {
+
+    guac_common_display_layer* current = display->layers;
+
+    /* Flush all surfaces */
+    while (current != NULL) {
+        guac_common_surface_flush(current->surface);
+        current = current->next;
+    }
+
     guac_common_surface_flush(display->default_surface);
+
 }
 
 /**

src/common/surface.c

@@ -116,6 +116,29 @@
  */
 #define GUAC_SURFACE_WEBP_BLOCK_SIZE 8
 
+void guac_common_surface_move(guac_common_surface* surface, int x, int y) {
+    surface->x = x;
+    surface->y = y;
+    surface->location_dirty = 1;
+}
+
+void guac_common_surface_stack(guac_common_surface* surface, int z) {
+    surface->z = z;
+    surface->location_dirty = 1;
+}
+
+void guac_common_surface_set_parent(guac_common_surface* surface,
+        const guac_layer* parent) {
+    surface->parent = parent;
+    surface->location_dirty = 1;
+}
+
+void guac_common_surface_set_opacity(guac_common_surface* surface,
+        int opacity) {
+    surface->opacity = opacity;
+    surface->opacity_dirty = 1;
+}
+
 /**
  * Updates the coordinates of the given rectangle to be within the bounds of
  * the given surface.
@@ -990,6 +1013,7 @@ guac_common_surface* guac_common_surface_alloc(guac_client* client,
     surface->client = client;
     surface->socket = socket;
     surface->layer = layer;
+    surface->parent = GUAC_DEFAULT_LAYER;
     surface->width = w;
     surface->height = h;
 
@@ -1443,6 +1467,29 @@ static int __guac_common_surface_bitmap_rect_compare(const void* a, const void*
 
 }
 
+void guac_common_surface_flush_properties(guac_common_surface* surface) {
+
+    guac_socket* socket = surface->socket;
+
+    /* Only applicable to non-default visible layers */
+    if (surface->layer->index <= 0)
+        return;
+
+    /* Flush opacity */
+    if (surface->opacity_dirty) {
+        guac_protocol_send_shade(socket, surface->layer, surface->opacity);
+        surface->opacity_dirty = 0;
+    }
+
+    /* Flush location and hierarchy */
+    if (surface->location_dirty) {
+        guac_protocol_send_move(socket, surface->layer,
+                surface->parent, surface->x, surface->y, surface->z);
+        surface->location_dirty = 0;
+    }
+
+}
+
 void guac_common_surface_flush(guac_common_surface* surface) {
 
     /* Flush final dirty rectangle to queue. */
@@ -1523,6 +1570,9 @@ void guac_common_surface_flush(guac_common_surface* surface) {
 
     }
 
+    /* Flush any applicable layer properties */
+    guac_common_surface_flush_properties(surface);
+
     /* Flush complete */
     surface->bitmap_queue_length = 0;
 
@@ -1535,8 +1585,21 @@ void guac_common_surface_dup(guac_common_surface* surface, guac_user* user,
     if (!surface->realized)
         return;
 
+    /* Synchronize layer-specific properties if applicable */
+    if (surface->layer->index > 0) {
+
+        /* Synchronize opacity */
+        guac_protocol_send_shade(socket, surface->layer, surface->opacity);
+
+        /* Synchronize location and hierarchy */
+        guac_protocol_send_move(socket, surface->layer,
+                surface->parent, surface->x, surface->y, surface->z);
+
+    }
+
     /* Sync size to new socket */
-    guac_protocol_send_size(socket, surface->layer, surface->width, surface->height);
+    guac_protocol_send_size(socket, surface->layer,
+            surface->width, surface->height);
 
     /* Get entire surface */
     cairo_surface_t* rect = cairo_image_surface_create_for_data(