GUAC-936: Use initial resolution for all future resizing of display. Suggest reasonable resolution only if resolution of display is not provided/forced.

src/protocols/rdp/Makefile.am

@@ -43,6 +43,7 @@ libguac_client_rdp_la_SOURCES = \
 	rdp_settings.c              \
 	rdp_stream.c                \
 	rdp_svc.c                   \
+	resolution.c                \
 	unicode.c
 
 guacsvc_sources =          \
@@ -95,6 +96,7 @@ noinst_HEADERS =                             \
 	rdp_status.h                             \
 	rdp_stream.h                             \
 	rdp_svc.h                                \
+	resolution.h                             \
 	unicode.h
 
 # Add compatibility layer for WinPR if not available

src/protocols/rdp/client.c

@@ -33,6 +33,7 @@
 #include "rdp_pointer.h"
 #include "rdp_stream.h"
 #include "rdp_svc.h"
+#include "resolution.h"
 
 #ifdef HAVE_FREERDP_DISPLAY_UPDATE_SUPPORT
 #include "rdp_disp.h"
@@ -509,56 +510,6 @@ void __guac_rdp_client_load_keymap(guac_client* client,
 
 }
 
-/**
- * Reduces the resolution of the client to the given resolution in DPI if
- * doing so is reasonable. This function returns non-zero if the resolution
- * was successfully reduced to the given DPI, and zero if reduction failed.
- */
-static int __guac_rdp_reduce_resolution(guac_client* client, int resolution) {
-
-    int width  = client->info.optimal_width  * resolution / client->info.optimal_resolution;
-    int height = client->info.optimal_height * resolution / client->info.optimal_resolution;
-
-    /* Reduced resolution if result is reasonably sized */
-    if (width*height >= GUAC_RDP_REASONABLE_AREA) {
-        client->info.optimal_width = width;
-        client->info.optimal_height = height;
-        client->info.optimal_resolution = resolution;
-        guac_client_log(client, GUAC_LOG_INFO,
-                "Reducing resolution to %i DPI (%ix%i)", resolution, width, height);
-        return 1;
-    }
-
-    /* No reduction performed */
-    return 0;
-
-}
-
-/**
- * Forces the client resolution to the given value, without checking whether
- * the resulting width and height are reasonable.
- */
-static void __guac_rdp_force_resolution(guac_client* client, int resolution) {
-
-    int width  = client->info.optimal_width  * resolution / client->info.optimal_resolution;
-    int height = client->info.optimal_height * resolution / client->info.optimal_resolution;
-
-    /* Do not force DPI to zero */
-    if (resolution == 0) {
-        guac_client_log(client, GUAC_LOG_WARNING,
-                "Cowardly refusing to force resolution to %i DPI", resolution);
-        return;
-    }
-
-    /* Reduced resolution if result is reasonably sized */
-    client->info.optimal_width = width;
-    client->info.optimal_height = height;
-    client->info.optimal_resolution = resolution;
-    guac_client_log(client, GUAC_LOG_INFO,
-            "Resolution forced to %i DPI (%ix%i)", resolution, width, height);
-
-}
-
 int guac_client_init(guac_client* client, int argc, char** argv) {
 
     rdp_guac_client_data* guac_client_data;
@@ -648,23 +599,22 @@ int guac_client_init(guac_client* client, int argc, char** argv) {
     if (argv[IDX_PORT][0] != '\0')
         settings->port = atoi(argv[IDX_PORT]);
 
-    guac_client_log(client, GUAC_LOG_INFO, "Client resolution is %ix%i at %i DPI",
+    guac_client_log(client, GUAC_LOG_DEBUG,
+            "Client resolution is %ix%i at %i DPI",
             client->info.optimal_width,
             client->info.optimal_height,
             client->info.optimal_resolution);
 
-    /* Use optimal resolution unless overridden */
+    /* Use suggested resolution unless overridden */
+    settings->resolution = guac_rdp_suggest_resolution(client);
     if (argv[IDX_DPI][0] != '\0')
-        __guac_rdp_force_resolution(client, atoi(argv[IDX_DPI]));
+        settings->resolution = atoi(argv[IDX_DPI]);
-
-    /* If resolution not forced, attempt to reduce resolution for high DPI */
-    else if (client->info.optimal_resolution > GUAC_RDP_NATIVE_RESOLUTION
-            && !__guac_rdp_reduce_resolution(client, GUAC_RDP_NATIVE_RESOLUTION)
-            && !__guac_rdp_reduce_resolution(client, GUAC_RDP_HIGH_RESOLUTION))
-        guac_client_log(client, GUAC_LOG_INFO, "No reasonable lower resolution");
 
     /* Use optimal width unless overridden */
-    settings->width = client->info.optimal_width;
+    settings->width = client->info.optimal_width
+                    * settings->resolution
+                    / client->info.optimal_resolution;
+
     if (argv[IDX_WIDTH][0] != '\0')
         settings->width = atoi(argv[IDX_WIDTH]);
 
@@ -680,7 +630,10 @@ int guac_client_init(guac_client* client, int argc, char** argv) {
     settings->width = settings->width & ~0x3;
 
     /* Use optimal height unless overridden */
-    settings->height = client->info.optimal_height;
+    settings->height = client->info.optimal_height
+                     * settings->resolution
+                     / client->info.optimal_resolution;
+
     if (argv[IDX_HEIGHT][0] != '\0')
         settings->height = atoi(argv[IDX_HEIGHT]);
 
@@ -692,6 +645,12 @@ int guac_client_init(guac_client* client, int argc, char** argv) {
                 argv[IDX_WIDTH], settings->height);
     }
 
+    guac_client_log(client, GUAC_LOG_DEBUG,
+            "Using resolution of %ix%i at %i DPI",
+            settings->width,
+            settings->height,
+            settings->resolution);
+
     /* Domain */
     settings->domain = NULL;
     if (argv[IDX_DOMAIN][0] != '\0')

src/protocols/rdp/guac_handlers.c

@@ -480,6 +480,13 @@ int rdp_guac_client_size_handler(guac_client* client, int width, int height) {
 
     freerdp* rdp_inst = guac_client_data->rdp_inst;
 
+    /* Convert client pixels to remote pixels */
+    width  = width  * guac_client_data->settings.resolution
+                    / client->info.optimal_resolution;
+
+    height = height * guac_client_data->settings.resolution
+                    / client->info.optimal_resolution;
+
     /* Send display update */
     pthread_mutex_lock(&(guac_client_data->rdp_lock));
     guac_rdp_disp_set_size(guac_client_data->disp, rdp_inst->context,

src/protocols/rdp/rdp_settings.h

@@ -122,6 +122,12 @@ typedef struct guac_rdp_settings {
      */
     int height;
 
+    /**
+     * The DPI of the remote display to assume when converting between
+     * client pixels and remote pixels.
+     */
+    int resolution;
+
     /**
      * Whether audio is enabled.
      */

src/protocols/rdp/resolution.c

@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2014 Glyptodon LLC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "client.h"
+#include "resolution.h"
+
+#include <guacamole/client.h>
+
+int guac_rdp_resolution_reasonable(guac_client* client, int resolution) {
+
+    int width  = client->info.optimal_width;
+    int height = client->info.optimal_height;
+
+    /* Convert client pixels to remote pixels */
+    width  = width  * resolution / client->info.optimal_resolution;
+    height = height * resolution / client->info.optimal_resolution;
+
+    /*
+     * Resolution is reasonable if the same as the client optimal resolution
+     * OR if the resulting display area is reasonable
+     */
+    return client->info.optimal_resolution == resolution
+        || width*height >= GUAC_RDP_REASONABLE_AREA;
+
+}
+
+int guac_rdp_suggest_resolution(guac_client* client) {
+
+    /* Prefer RDP's native resolution */
+    if (guac_rdp_resolution_reasonable(client, GUAC_RDP_NATIVE_RESOLUTION))
+        return GUAC_RDP_NATIVE_RESOLUTION;
+
+    /* If native resolution is too tiny, try higher resolution */
+    if (guac_rdp_resolution_reasonable(client, GUAC_RDP_HIGH_RESOLUTION))
+        return GUAC_RDP_HIGH_RESOLUTION;
+
+    /* Fallback to client-suggested resolution */
+    return client->info.optimal_resolution;
+
+}
+

src/protocols/rdp/resolution.h

@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2014 Glyptodon LLC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef GUAC_RDP_RESOLUTION_H
+#define GUAC_RDP_RESOLUTION_H
+
+#include <guacamole/client.h>
+
+/**
+ * Returns whether the given resolution is reasonable for the given client,
+ * based on arbitrary criteria for reasonability.
+ *
+ * @param client The guac_client to test the given resolution against.
+ * @param resolution The resolution to test, in DPI.
+ * @return Non-zero if the resolution is reasonable, zero otherwise.
+ */
+int guac_rdp_resolution_reasonable(guac_client* client, int resolution);
+
+/**
+ * Returns a reasonable resolution for the remote display, given the size and
+ * resolution of a guac_client.
+ *
+ * @param client The guac_client whose size and resolution shall be used to
+ *               determine an appropriate remote display resolution.
+ * @return A reasonable resolution for the remote display, in DPI.
+ */
+int guac_rdp_suggest_resolution(guac_client* client);
+
+#endif
+