Add an event to notify the recorder client of the buffer requirements

protocol/lipstick-recorder.xml

@@ -79,6 +79,25 @@
             <entry name="y_inverted" value="2"/>
         </enum>
 
+        <event name="setup">
+            <description summary="notify the requirements for the frame buffers">
+                This event will be sent immediately after creation of the
+                lipstick_recorder object. The wl_buffers the client passes
+                to the frame request must be big enough to store an image
+                with the given width, height and format.
+                If they are not the compositor will send the failed event.
+                If this event is sent again later in the lifetime of the object
+                the pending frames will be cancelled.
+
+                The format will be one of the values as defined in the
+                wl_shm::format enum.
+            </description>
+            <arg name="width" type="int" description="width of the frame, in pixels"/>
+            <arg name="height" type="int" description="height of the frame, in pixels"/>
+            <arg name="stride" type="int" description="stride of the frame"/>
+            <arg name="format" type="int" desciption="format of the frame"/>
+        </event>
+
         <event name="frame">
             <description summary="notify a frame was recorded, or an error">
                 The compositor will send this event after a frame was

src/compositor/lipstickrecorder.cpp

@@ -73,8 +73,10 @@ void LipstickRecorderManager::recordFrame(QWindow *window)
         pixels = static_cast<uchar *>(wl_shm_buffer_get_data(buffer));
         int width = wl_shm_buffer_get_width(buffer);
         int height = wl_shm_buffer_get_height(buffer);
+        int stride = wl_shm_buffer_get_stride(buffer);
+        int bpp = 4;
 
-        if (width != window->width() || height != window->height()) {
+        if (width < window->width() || height < window->height() || stride < window->width() * bpp) {
             qApp->postEvent(recorder, new FailedEvent(QtWaylandServer::lipstick_recorder::result_bad_buffer));
             continue;
         }
@@ -123,6 +125,7 @@ LipstickRecorder::LipstickRecorder(LipstickRecorderManager *manager, wl_client *
                 , m_client(client)
                 , m_window(window)
 {
+    send_setup(window->width(), window->height(), window->width() * 4, WL_SHM_FORMAT_RGBA8888);
 }
 
 LipstickRecorder::~LipstickRecorder()