GUAC-240: Add function for streaming PNG images via img instruction. Use for surface.

src/common/guac_surface.c

@@ -969,7 +969,8 @@ static void __guac_common_surface_flush_to_png(guac_common_surface* surface) {
                                                                     surface->stride);
 
         /* Send PNG for rect */
-        guac_protocol_send_png(socket, GUAC_COMP_OVER, layer, surface->dirty_rect.x, surface->dirty_rect.y, rect);
+        guac_client_stream_png(surface->client, socket, GUAC_COMP_OVER,
+                layer, surface->dirty_rect.x, surface->dirty_rect.y, rect);
         cairo_surface_destroy(rect);
         surface->realized = 1;
 

src/libguac/client.c

@@ -24,6 +24,7 @@
 
 #include "client.h"
 #include "client-handlers.h"
+#include "encode-png.h"
 #include "error.h"
 #include "instruction.h"
 #include "layer.h"
@@ -375,3 +376,24 @@ void guac_client_abort(guac_client* client, guac_protocol_status status,
 
 }
 
+void guac_client_stream_png(guac_client* client, guac_socket* socket,
+        guac_composite_mode mode, const guac_layer* layer, int x, int y,
+        cairo_surface_t* surface) {
+
+    /* Allocate new stream for image */
+    guac_stream* stream = guac_client_alloc_stream(client);
+
+    /* Declare stream as containing image data */
+    guac_protocol_send_img(socket, stream, mode, layer, "image/png", x, y);
+
+    /* Write PNG data */
+    guac_png_write(socket, stream, surface);
+
+    /* Terminate stream */
+    guac_protocol_send_end(socket, stream);
+
+    /* Free allocated stream */
+    guac_client_free_stream(client, stream);
+
+}
+

src/libguac/guacamole/client.h

@@ -40,6 +40,7 @@
 #include "stream-types.h"
 #include "timestamp-types.h"
 
+#include <cairo/cairo.h>
 #include <stdarg.h>
 
 struct guac_client_info {
@@ -627,6 +628,39 @@ guac_object* guac_client_alloc_object(guac_client* client);
  */
 void guac_client_free_object(guac_client* client, guac_object* object);
 
+/**
+ * Streams the image data of the given surface over an image stream ("img"
+ * instruction) as PNG-encoded data. The image stream will be automatically
+ * allocated and freed.
+ *
+ * @param client
+ *     The Guacamole client from which the image stream should be allocated.
+ *
+ * @param socket
+ *     The socket over which instructions associated with the image stream
+ *     should be sent.
+ *
+ * @param mode
+ *     The composite mode to use when rendering the image over the given layer.
+ *
+ * @param layer
+ *     The destination layer.
+ *
+ * @param x
+ *     The X coordinate of the upper-left corner of the destination rectangle
+ *     within the given layer.
+ *
+ * @param y
+ *     The Y coordinate of the upper-left corner of the destination rectangle
+ *     within the given layer.
+ *
+ * @param surface
+ *     A Cairo surface containing the image data to be streamed.
+ */
+void guac_client_stream_png(guac_client* client, guac_socket* socket,
+        guac_composite_mode mode, const guac_layer* layer, int x, int y,
+        cairo_surface_t* surface);
+
 /**
  * The default Guacamole client layer, layer 0.
  */