Fix guac_rdp_clip_rect() handling of completely clipped rects.

src/protocols/rdp/client.c

@@ -619,7 +619,7 @@ int guac_client_init(guac_client* client, int argc, char** argv) {
 
 }
 
-void guac_rdp_clip_rect(rdp_guac_client_data* data, int* x, int* y, int* w, int* h) {
+int guac_rdp_clip_rect(rdp_guac_client_data* data, int* x, int* y, int* w, int* h) {
 
     if (data->bounded) {
 
@@ -631,18 +631,18 @@ void guac_rdp_clip_rect(rdp_guac_client_data* data, int* x, int* y, int* w, int*
 
         /* Clip left */
         if      (clipped_left < data->bounds_left)  clipped_left = data->bounds_left;
-        else if (clipped_left > data->bounds_right) clipped_left = data->bounds_right;
+        else if (clipped_left > data->bounds_right) return 1;
 
         /* Clip right */
-        if      (clipped_right < data->bounds_left)  clipped_right = data->bounds_left;
+        if      (clipped_right < data->bounds_left)  return 1;
         else if (clipped_right > data->bounds_right) clipped_right = data->bounds_right;
 
         /* Clip top */
         if      (clipped_top < data->bounds_top)    clipped_top = data->bounds_top;
-        else if (clipped_top > data->bounds_bottom) clipped_top = data->bounds_bottom;
+        else if (clipped_top > data->bounds_bottom) return 1;
 
         /* Clip bottom */
-        if      (clipped_bottom < data->bounds_top)    clipped_bottom = data->bounds_top;
+        if      (clipped_bottom < data->bounds_top)    return 1;
         else if (clipped_bottom > data->bounds_bottom) clipped_bottom = data->bounds_bottom;
 
         /* Store new rect dimensions */
@@ -653,6 +653,8 @@ void guac_rdp_clip_rect(rdp_guac_client_data* data, int* x, int* y, int* w, int*
 
     }
 
+    return 0;
+
 }
 
 

src/protocols/rdp/client.h

@@ -222,8 +222,11 @@ typedef struct rdp_freerdp_context {
 /**
  * Given the coordinates and dimensions of a rectangle, clips the rectangle to be
  * within the clipping bounds of the client data, if clipping is active.
+ *
+ * Returns 0 if the rectangle given is visible at all, and 1 if the entire
+ * rectangls is outside the clipping rectangle and this invisible.
  */
-void guac_rdp_clip_rect(rdp_guac_client_data* data, int* x, int* y, int* w, int* h);
+int guac_rdp_clip_rect(rdp_guac_client_data* data, int* x, int* y, int* w, int* h);
 
 #endif
 

src/protocols/rdp/rdp_gdi.c

@@ -115,7 +115,8 @@ void guac_rdp_gdi_dstblt(rdpContext* context, DSTBLT_ORDER* dstblt) {
 
     /* Clip operation to bounds */
     rdp_guac_client_data* data = (rdp_guac_client_data*) client->data;
-    guac_rdp_clip_rect(data, &x, &y, &w, &h);
+    if (guac_rdp_clip_rect(data, &x, &y, &w, &h))
+        return;
 
     switch (dstblt->bRop) {
 
@@ -201,7 +202,8 @@ void guac_rdp_gdi_patblt(rdpContext* context, PATBLT_ORDER* patblt) {
             "negotiated client capabilities)");
 
     /* Clip operation to bounds */
-    guac_rdp_clip_rect(data, &x, &y, &w, &h);
+    if (guac_rdp_clip_rect(data, &x, &y, &w, &h))
+        return;
 
     /* Render rectangle based on ROP */
     switch (patblt->bRop) {
@@ -289,7 +291,8 @@ void guac_rdp_gdi_scrblt(rdpContext* context, SCRBLT_ORDER* scrblt) {
 
     /* Clip operation to bounds */
     rdp_guac_client_data* data = (rdp_guac_client_data*) client->data;
-    guac_rdp_clip_rect(data, &x, &y, &w, &h);
+    if (guac_rdp_clip_rect(data, &x, &y, &w, &h))
+        return;
 
     /* Update source coordinates */
     x_src += x - scrblt->nLeftRect;
@@ -326,7 +329,8 @@ void guac_rdp_gdi_memblt(rdpContext* context, MEMBLT_ORDER* memblt) {
     }
 
     /* Clip operation to bounds */
-    guac_rdp_clip_rect(data, &x, &y, &w, &h);
+    if (guac_rdp_clip_rect(data, &x, &y, &w, &h))
+        return;
 
     /* Update source coordinates */
     x_src += x - memblt->nLeftRect;
@@ -431,7 +435,8 @@ void guac_rdp_gdi_opaquerect(rdpContext* context, OPAQUE_RECT_ORDER* opaque_rect
     int h = opaque_rect->nHeight;
 
     /* Clip operation to bounds */
-    guac_rdp_clip_rect(data, &x, &y, &w, &h);
+    if (guac_rdp_clip_rect(data, &x, &y, &w, &h))
+        return;
 
     guac_protocol_send_rect(client->socket, current_layer, x, y, w, h);
 

src/protocols/rdp/rdp_glyph.c

@@ -222,24 +222,26 @@ void guac_rdp_glyph_enddraw(rdpContext* context,
     if (height > max_height) height = max_height;
 
     /* Clip operation to clipping region, if any */
-    guac_rdp_clip_rect(guac_client_data, &x, &y, &width, &height);
+    if (!guac_rdp_clip_rect(guac_client_data, &x, &y, &width, &height)) {
 
-    /* Ensure data is ready */
+        /* Ensure data is ready */
-    cairo_surface_flush(glyph_surface);
+        cairo_surface_flush(glyph_surface);
 
-    /* Create surface for subsection with text */
+        /* Create surface for subsection with text */
-    cairo_surface_t* surface = cairo_image_surface_create_for_data(
+        cairo_surface_t* surface = cairo_image_surface_create_for_data(
-            cairo_image_surface_get_data(glyph_surface) + 4*x + y*stride,
+                cairo_image_surface_get_data(glyph_surface) + 4*x + y*stride,
-            cairo_image_surface_get_format(glyph_surface),
+                cairo_image_surface_get_format(glyph_surface),
-            width, height, stride);
+                width, height, stride);
 
-    /* Send surface with all glyphs to layer */
+        /* Send surface with all glyphs to layer */
-    guac_protocol_send_png(client->socket,
+        guac_protocol_send_png(client->socket,
-            GUAC_COMP_OVER, current_layer, x, y,
+                GUAC_COMP_OVER, current_layer, x, y,
-            surface);
+                surface);
 
-    /* Destroy surface */
+        /* Destroy surface */
-    cairo_surface_destroy(surface);
+        cairo_surface_destroy(surface);
+
+    }
 
     /* Destroy cairo instance */
     cairo_destroy(guac_client_data->glyph_cairo);