Implement clipping in software.

protocols/rdp/include/client.h

@@ -118,6 +118,36 @@ typedef struct rdp_guac_client_data {
      */
     const guac_layer* current_surface;
 
+    /**
+     * Whether graphical operations are restricted to a specific bounding
+     * rectangle.
+     */
+    int bounded;
+
+    /**
+     * The X coordinate of the upper-left corner of the bounding rectangle,
+     * if any.
+     */
+    int bounds_left;
+
+    /**
+     * The Y coordinate of the upper-left corner of the bounding rectangle,
+     * if any.
+     */
+    int bounds_top;
+
+    /**
+     * The X coordinate of the lower-right corner of the bounding rectangle,
+     * if any.
+     */
+    int bounds_right;
+
+    /**
+     * The Y coordinate of the lower-right corner of the bounding rectangle,
+     * if any.
+     */
+    int bounds_bottom;
+
     /**
      * The keymap to use when translating keysyms into scancodes or sequences
      * of scancodes for RDP.

protocols/rdp/src/rdp_gdi.c

@@ -44,6 +44,42 @@
 #include "client.h"
 #include "rdp_bitmap.h"
 
+static void __guac_rdp_clip_rect(rdp_guac_client_data* data, int* x, int* y, int* w, int* h) {
+
+    if (data->bounded) {
+
+        /* Get rect coordinates */
+        int clipped_left   = *x;
+        int clipped_top    = *y;
+        int clipped_right  = clipped_left + *w - 1;
+        int clipped_bottom = clipped_top  + *h - 1;
+
+        /* Clip left */
+        if      (clipped_left < data->bounds_left) clipped_left = data->bounds_left;
+        else if (clipped_left > data->bounds_left) clipped_left = data->bounds_left;
+
+        /* Clip right */
+        if      (clipped_right < data->bounds_right) clipped_right = data->bounds_right;
+        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_top) clipped_top = data->bounds_top;
+
+        /* Clip bottom */
+        if      (clipped_bottom < data->bounds_bottom) clipped_bottom = data->bounds_bottom;
+        else if (clipped_bottom > data->bounds_bottom) clipped_bottom = data->bounds_bottom;
+
+        /* Store new rect dimensions */
+        *x = clipped_left;
+        *y = clipped_right;
+        *w = clipped_right  - clipped_left + 1;
+        *h = clipped_bottom - clipped_top  + 1;
+
+    }
+
+}
+
 guac_transfer_function guac_rdp_rop3_transfer_function(guac_client* client,
         int rop3) {
 
@@ -110,6 +146,9 @@ void guac_rdp_gdi_dstblt(rdpContext* context, DSTBLT_ORDER* dstblt) {
     rdp_guac_client_data* data = (rdp_guac_client_data*) client->data;
     pthread_mutex_lock(&(data->update_lock));
 
+    /* Clip operation to bounds */
+    __guac_rdp_clip_rect(data, &(dstblt->nLeftRect), &(dstblt->nTopRect), &(dstblt->nWidth), &(dstblt->nHeight));
+
     switch (dstblt->bRop) {
 
         /* Blackness */
@@ -155,6 +194,8 @@ void guac_rdp_gdi_patblt(rdpContext* context, PATBLT_ORDER* patblt) {
     const guac_layer* current_layer =
         ((rdp_guac_client_data*) client->data)->current_surface;
 
+    rdp_guac_client_data* data = (rdp_guac_client_data*) client->data;
+
     /* Layer for actual transfer */
     guac_layer* buffer;
 
@@ -165,6 +206,9 @@ void guac_rdp_gdi_patblt(rdpContext* context, PATBLT_ORDER* patblt) {
     guac_client_log_info(client, "Using fallback PATBLT (server is ignoring "
             "negotiated client capabilities)");
 
+    /* Clip operation to bounds */
+    __guac_rdp_clip_rect(data, &(patblt->nLeftRect), &(patblt->nTopRect), &(patblt->nWidth), &(patblt->nHeight));
+
     /* Render rectangle based on ROP */
     switch (patblt->bRop) {
 
@@ -250,6 +294,9 @@ void guac_rdp_gdi_scrblt(rdpContext* context, SCRBLT_ORDER* scrblt) {
     rdp_guac_client_data* data = (rdp_guac_client_data*) client->data;
     pthread_mutex_lock(&(data->update_lock));
 
+    /* Clip operation to bounds */
+    __guac_rdp_clip_rect(data, &(scrblt->nLeftRect), &(scrblt->nTopRect), &(scrblt->nWidth), &(scrblt->nHeight));
+
     /* Copy screen rect to current surface */
     guac_protocol_send_copy(client->socket,
             GUAC_DEFAULT_LAYER,
@@ -271,6 +318,9 @@ void guac_rdp_gdi_memblt(rdpContext* context, MEMBLT_ORDER* memblt) {
     rdp_guac_client_data* data = (rdp_guac_client_data*) client->data;
     pthread_mutex_lock(&(data->update_lock));
 
+    /* Clip operation to bounds */
+    __guac_rdp_clip_rect(data, &(memblt->nLeftRect), &(memblt->nTopRect), &(memblt->nWidth), &(memblt->nHeight));
+
     switch (memblt->bRop) {
 
         /* If blackness, send black rectangle */
@@ -378,6 +428,10 @@ void guac_rdp_gdi_opaquerect(rdpContext* context, OPAQUE_RECT_ORDER* opaque_rect
     rdp_guac_client_data* data = (rdp_guac_client_data*) client->data;
     pthread_mutex_lock(&(data->update_lock));
 
+    /* Clip operation to bounds */
+    __guac_rdp_clip_rect(data, &(opaque_rect->nLeftRect), &(opaque_rect->nTopRect),
+            &(opaque_rect->nWidth), &(opaque_rect->nHeight));
+
     guac_protocol_send_rect(client->socket, current_layer,
             opaque_rect->nLeftRect, opaque_rect->nTopRect,
             opaque_rect->nWidth, opaque_rect->nHeight);
@@ -404,26 +458,21 @@ void guac_rdp_gdi_palette_update(rdpContext* context, PALETTE_UPDATE* palette) {
 void guac_rdp_gdi_set_bounds(rdpContext* context, rdpBounds* bounds) {
 
     guac_client* client = ((rdp_freerdp_context*) context)->client;
-    const guac_layer* current_layer = ((rdp_guac_client_data*) client->data)->current_surface;
-
     rdp_guac_client_data* data = (rdp_guac_client_data*) client->data;
-    pthread_mutex_lock(&(data->update_lock));
 
-    /* Reset clip */
+    /* If no bounds given, clear bounding rect */
-    guac_protocol_send_reset(client->socket, current_layer);
+    if (bounds == NULL)
+        data->bounded = false;
 
-    /* Set clip if specified */
+    /* Otherwise, set bounding rectangle */
-    if (bounds != NULL) {
+    else {
-        guac_protocol_send_rect(client->socket, current_layer,
+        data->bounded = true;
-                bounds->left, bounds->top,
+        data->bounds_left   = bounds->left;
-                bounds->right - bounds->left + 1,
+        data->bounds_top    = bounds->top;
-                bounds->bottom - bounds->top + 1);
+        data->bounds_right  = bounds->right;
-
+        data->bounds_bottom = bounds->bottom;
-        guac_protocol_send_clip(client->socket, current_layer);
     }
 
-    pthread_mutex_unlock(&(data->update_lock));
-
 }
 
 void guac_rdp_gdi_end_paint(rdpContext* context) {