GUAC-1305: Add functions for checking WebP support and streaming WebP images.

src/libguac/client.c

@@ -36,6 +36,10 @@
 #include "stream.h"
 #include "timestamp.h"
 
+#ifdef ENABLE_WEBP
+#include "encode-webp.h"
+#endif
+
 #ifdef HAVE_OSSP_UUID_H
 #include <ossp/uuid.h>
 #else
@@ -419,3 +423,54 @@ void guac_client_stream_jpeg(guac_client* client, guac_socket* socket,
 
 }
 
+void guac_client_stream_webp(guac_client* client, guac_socket* socket,
+        guac_composite_mode mode, const guac_layer* layer, int x, int y,
+        cairo_surface_t* surface, int quality) {
+
+#ifdef ENABLE_WEBP
+    /* 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/webp", x, y);
+
+    /* Write WebP data */
+    guac_webp_write(socket, stream, surface, quality);
+
+    /* Terminate stream */
+    guac_protocol_send_end(socket, stream);
+
+    /* Free allocated stream */
+    guac_client_free_stream(client, stream);
+#else
+    /* Do nothing if WebP support is not built in */
+#endif
+
+}
+
+int guac_client_supports_webp(guac_client* client) {
+
+#ifdef ENABLE_WEBP
+    const char** mimetype = client->info.image_mimetypes;
+
+    /* Search for WebP mimetype in list of supported image mimetypes */
+    while (*mimetype != NULL) {
+
+        /* If WebP mimetype found, no need to search further */
+        if (strcmp(*mimetype, "image/webp") == 0)
+            return 1;
+
+        /* Next mimetype */
+        mimetype++;
+
+    }
+
+    /* Client does not support WebP */
+    return 0;
+#else
+    /* Support for WebP is completely absent */
+    return 0;
+#endif
+
+}
+

src/libguac/guacamole/client.h

@@ -696,11 +696,67 @@ void guac_client_stream_png(guac_client* client, guac_socket* socket,
  *
  * @param surface
  *     A Cairo surface containing the image data to be streamed.
+ *
+ * @param quality
+ *     The JPEG image quality, which must be an integer value between 0 and
+ *     100 inclusive.
  */
 void guac_client_stream_jpeg(guac_client* client, guac_socket* socket,
         guac_composite_mode mode, const guac_layer* layer, int x, int y,
         cairo_surface_t* surface, int quality);
 
+/**
+ * Streams the image data of the given surface over an image stream ("img"
+ * instruction) as WebP-encoded data at the given quality. The image stream
+ * will be automatically allocated and freed. If the server does not support
+ * WebP, this function has no effect, so be sure to check the result of
+ * guac_client_supports_webp() prior to calling this function.
+ *
+ * @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.
+ *
+ * @param quality
+ *     The WebP image quality, which must be an integer value between 0 and
+ *     100 inclusive.
+ */
+void guac_client_stream_webp(guac_client* client, guac_socket* socket,
+        guac_composite_mode mode, const guac_layer* layer, int x, int y,
+        cairo_surface_t* surface, int quality);
+
+/**
+ * Returns whether the given client supports WebP. If the client does not
+ * support WebP, or the server cannot encode WebP images, zero is returned.
+ *
+ * @param client
+ *     The Guacamole client to check for WebP support.
+ *
+ * @return
+ *     Non-zero if the given client claims to support WebP and the server has
+ *     been built with WebP support, zero otherwise.
+ */
+int guac_client_supports_webp(guac_client* client);
+
 /**
  * The default Guacamole client layer, layer 0.
  */