GUACAMOLE-278: Merge 256-color support for terminal.

src/terminal/Makefile.am

@@ -27,6 +27,7 @@ noinst_HEADERS =                 \
     terminal/char_mappings.h     \
     terminal/common.h            \
     terminal/display.h           \
+    terminal/palette.h           \
     terminal/scrollbar.h         \
     terminal/terminal.h          \
     terminal/terminal_handlers.h \
@@ -38,6 +39,7 @@ libguac_terminal_la_SOURCES =   \
     char_mappings.c             \
     common.c                    \
     display.c                   \
+    palette.c                   \
     scrollbar.c                 \
     terminal.c                  \
     terminal_handlers.c         \

src/terminal/display.c

@@ -22,6 +22,7 @@
 #include "common/surface.h"
 #include "terminal/common.h"
 #include "terminal/display.h"
+#include "terminal/palette.h"
 #include "terminal/types.h"
 
 #include <math.h>
@@ -36,30 +37,6 @@
 #include <guacamole/socket.h>
 #include <pango/pangocairo.h>
 
-const guac_terminal_color guac_terminal_palette[16] = {
-
-    /* Normal colors */
-    {0x00, 0x00, 0x00}, /* Black   */
-    {0x99, 0x3E, 0x3E}, /* Red     */
-    {0x3E, 0x99, 0x3E}, /* Green   */
-    {0x99, 0x99, 0x3E}, /* Brown   */
-    {0x3E, 0x3E, 0x99}, /* Blue    */
-    {0x99, 0x3E, 0x99}, /* Magenta */
-    {0x3E, 0x99, 0x99}, /* Cyan    */
-    {0x99, 0x99, 0x99}, /* White   */
-
-    /* Intense colors */
-    {0x3E, 0x3E, 0x3E}, /* Black   */
-    {0xFF, 0x67, 0x67}, /* Red     */
-    {0x67, 0xFF, 0x67}, /* Green   */
-    {0xFF, 0xFF, 0x67}, /* Brown   */
-    {0x67, 0x67, 0xFF}, /* Blue    */
-    {0xFF, 0x67, 0xFF}, /* Magenta */
-    {0x67, 0xFF, 0xFF}, /* Cyan    */
-    {0xFF, 0xFF, 0xFF}, /* White   */
-
-};
-
 /**
  * Clears the currently-selected region, removing the highlight.
  */
@@ -127,24 +104,29 @@ int __guac_terminal_hash_codepoint(int codepoint) {
 int __guac_terminal_set_colors(guac_terminal_display* display,
         guac_terminal_attributes* attributes) {
 
-    int background, foreground;
+    const guac_terminal_color* background;
+    const guac_terminal_color* foreground;
 
     /* Handle reverse video */
     if (attributes->reverse != attributes->cursor) {
-        background = attributes->foreground;
+        background = &attributes->foreground;
-        foreground = attributes->background;
+        foreground = &attributes->background;
     }
     else {
-        foreground = attributes->foreground;
+        foreground = &attributes->foreground;
-        background = attributes->background;
+        background = &attributes->background;
     }
 
     /* Handle bold */
-    if (attributes->bold && foreground <= 7)
+    if (attributes->bold
-        foreground += 8;
+            && foreground->palette_index >= GUAC_TERMINAL_FIRST_DARK
+            && foreground->palette_index <= GUAC_TERMINAL_LAST_DARK) {
+        foreground = &guac_terminal_palette[foreground->palette_index
+            + GUAC_TERMINAL_INTENSE_OFFSET];
+    }
 
-    display->glyph_foreground = foreground;
+    display->glyph_foreground = *foreground;
-    display->glyph_background = background;
+    display->glyph_background = *background;
 
     return 0;
 
@@ -163,12 +145,10 @@ int __guac_terminal_set(guac_terminal_display* display, int row, int col, int co
     char utf8[4];
 
     /* Use foreground color */
-    const guac_terminal_color* color =
+    const guac_terminal_color* color = &display->glyph_foreground;
-        &guac_terminal_palette[display->glyph_foreground];
 
     /* Use background color */
-    const guac_terminal_color* background =
+    const guac_terminal_color* background = &display->glyph_background;
-        &guac_terminal_palette[display->glyph_background];
 
     cairo_surface_t* surface;
     cairo_t* cairo;
@@ -259,7 +239,7 @@ int __guac_terminal_set(guac_terminal_display* display, int row, int col, int co
 
 guac_terminal_display* guac_terminal_display_alloc(guac_client* client,
         const char* font_name, int font_size, int dpi,
-        int foreground, int background) {
+        guac_terminal_color* foreground, guac_terminal_color* background) {
 
     PangoFontMap* font_map;
     PangoFont* font;
@@ -303,8 +283,8 @@ guac_terminal_display* guac_terminal_display_alloc(guac_client* client,
         return NULL;
     }
 
-    display->default_foreground = display->glyph_foreground = foreground;
+    display->default_foreground = display->glyph_foreground = *foreground;
-    display->default_background = display->glyph_background = background;
+    display->default_background = display->glyph_background = *background;
 
     /* Calculate character dimensions */
     display->char_width =
@@ -688,14 +668,11 @@ void __guac_terminal_display_flush_clear(guac_terminal_display* display) {
                 int rect_width, rect_height;
 
                 /* Color of the rectangle to draw */
-                int color;
+                const guac_terminal_color* color;
                 if (current->character.attributes.reverse != current->character.attributes.cursor)
-                   color = current->character.attributes.foreground;
+                   color = &current->character.attributes.foreground;
                 else
-                   color = current->character.attributes.background;
+                   color = &current->character.attributes.background;
-
-                const guac_terminal_color* guac_color =
-                    &guac_terminal_palette[color];
 
                 /* Current row within a subrect */
                 guac_terminal_operation* rect_current_row;
@@ -709,16 +686,16 @@ void __guac_terminal_display_flush_clear(guac_terminal_display* display) {
                     /* Find width */
                     for (rect_col=col; rect_col<display->width; rect_col++) {
 
-                        int joining_color;
+                        const guac_terminal_color* joining_color;
                         if (rect_current->character.attributes.reverse != rect_current->character.attributes.cursor)
-                           joining_color = rect_current->character.attributes.foreground;
+                           joining_color = &rect_current->character.attributes.foreground;
                         else
-                           joining_color = rect_current->character.attributes.background;
+                           joining_color = &rect_current->character.attributes.background;
 
                         /* If not identical operation, stop */
                         if (rect_current->type != GUAC_CHAR_SET
                                 || guac_terminal_has_glyph(rect_current->character.value)
-                                || joining_color != color)
+                                || guac_terminal_colorcmp(joining_color, color) != 0)
                             break;
 
                         /* Next column */
@@ -754,16 +731,16 @@ void __guac_terminal_display_flush_clear(guac_terminal_display* display) {
 
                     for (rect_col=0; rect_col<rect_width; rect_col++) {
 
-                        int joining_color;
+                        const guac_terminal_color* joining_color;
                         if (rect_current->character.attributes.reverse != rect_current->character.attributes.cursor)
-                           joining_color = rect_current->character.attributes.foreground;
+                           joining_color = &rect_current->character.attributes.foreground;
                         else
-                           joining_color = rect_current->character.attributes.background;
+                           joining_color = &rect_current->character.attributes.background;
 
                         /* Mark clear operations as NOP */
                         if (rect_current->type == GUAC_CHAR_SET
                                 && !guac_terminal_has_glyph(rect_current->character.value)
-                                && joining_color == color)
+                                && guac_terminal_colorcmp(joining_color, color) == 0)
                             rect_current->type = GUAC_CHAR_NOP;
 
                         /* Next column */
@@ -783,7 +760,7 @@ void __guac_terminal_display_flush_clear(guac_terminal_display* display) {
                         row * display->char_height,
                         rect_width * display->char_width,
                         rect_height * display->char_height,
-                        guac_color->red, guac_color->green, guac_color->blue,
+                        color->red, color->green, color->blue,
                         0xFF);
 
             } /* end if clear operation */

src/terminal/palette.c

@@ -0,0 +1,308 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include "config.h"
+#include "terminal/palette.h"
+
+const guac_terminal_color guac_terminal_palette[256] = {
+
+    /* Normal colors */
+    {0, 0x00, 0x00, 0x00}, /* Black   */
+    {1, 0x99, 0x3E, 0x3E}, /* Red     */
+    {2, 0x3E, 0x99, 0x3E}, /* Green   */
+    {3, 0x99, 0x99, 0x3E}, /* Brown   */
+    {4, 0x3E, 0x3E, 0x99}, /* Blue    */
+    {5, 0x99, 0x3E, 0x99}, /* Magenta */
+    {6, 0x3E, 0x99, 0x99}, /* Cyan    */
+    {7, 0x99, 0x99, 0x99}, /* White   */
+
+    /* Intense colors */
+    {8,  0x3E, 0x3E, 0x3E}, /* Black   */
+    {9,  0xFF, 0x67, 0x67}, /* Red     */
+    {10, 0x67, 0xFF, 0x67}, /* Green   */
+    {11, 0xFF, 0xFF, 0x67}, /* Brown   */
+    {12, 0x67, 0x67, 0xFF}, /* Blue    */
+    {13, 0xFF, 0x67, 0xFF}, /* Magenta */
+    {14, 0x67, 0xFF, 0xFF}, /* Cyan    */
+    {15, 0xFF, 0xFF, 0xFF}, /* White   */
+
+    /* Remainder of xterm's 256-color palette */
+    {16,  0x00, 0x00, 0x00},
+    {17,  0x00, 0x00, 0x5F},
+    {18,  0x00, 0x00, 0x87},
+    {19,  0x00, 0x00, 0xAF},
+    {20,  0x00, 0x00, 0xD7},
+    {21,  0x00, 0x00, 0xFF},
+    {22,  0x00, 0x5F, 0x00},
+    {23,  0x00, 0x5F, 0x5F},
+    {24,  0x00, 0x5F, 0x87},
+    {25,  0x00, 0x5F, 0xAF},
+    {26,  0x00, 0x5F, 0xD7},
+    {27,  0x00, 0x5F, 0xFF},
+    {28,  0x00, 0x87, 0x00},
+    {29,  0x00, 0x87, 0x5F},
+    {30,  0x00, 0x87, 0x87},
+    {31,  0x00, 0x87, 0xAF},
+    {32,  0x00, 0x87, 0xD7},
+    {33,  0x00, 0x87, 0xFF},
+    {34,  0x00, 0xAF, 0x00},
+    {35,  0x00, 0xAF, 0x5F},
+    {36,  0x00, 0xAF, 0x87},
+    {37,  0x00, 0xAF, 0xAF},
+    {38,  0x00, 0xAF, 0xD7},
+    {39,  0x00, 0xAF, 0xFF},
+    {40,  0x00, 0xD7, 0x00},
+    {41,  0x00, 0xD7, 0x5F},
+    {42,  0x00, 0xD7, 0x87},
+    {43,  0x00, 0xD7, 0xAF},
+    {44,  0x00, 0xD7, 0xD7},
+    {45,  0x00, 0xD7, 0xFF},
+    {46,  0x00, 0xFF, 0x00},
+    {47,  0x00, 0xFF, 0x5F},
+    {48,  0x00, 0xFF, 0x87},
+    {49,  0x00, 0xFF, 0xAF},
+    {50,  0x00, 0xFF, 0xD7},
+    {51,  0x00, 0xFF, 0xFF},
+    {52,  0x5F, 0x00, 0x00},
+    {53,  0x5F, 0x00, 0x5F},
+    {54,  0x5F, 0x00, 0x87},
+    {55,  0x5F, 0x00, 0xAF},
+    {56,  0x5F, 0x00, 0xD7},
+    {57,  0x5F, 0x00, 0xFF},
+    {58,  0x5F, 0x5F, 0x00},
+    {59,  0x5F, 0x5F, 0x5F},
+    {60,  0x5F, 0x5F, 0x87},
+    {61,  0x5F, 0x5F, 0xAF},
+    {62,  0x5F, 0x5F, 0xD7},
+    {63,  0x5F, 0x5F, 0xFF},
+    {64,  0x5F, 0x87, 0x00},
+    {65,  0x5F, 0x87, 0x5F},
+    {66,  0x5F, 0x87, 0x87},
+    {67,  0x5F, 0x87, 0xAF},
+    {68,  0x5F, 0x87, 0xD7},
+    {69,  0x5F, 0x87, 0xFF},
+    {70,  0x5F, 0xAF, 0x00},
+    {71,  0x5F, 0xAF, 0x5F},
+    {72,  0x5F, 0xAF, 0x87},
+    {73,  0x5F, 0xAF, 0xAF},
+    {74,  0x5F, 0xAF, 0xD7},
+    {75,  0x5F, 0xAF, 0xFF},
+    {76,  0x5F, 0xD7, 0x00},
+    {77,  0x5F, 0xD7, 0x5F},
+    {78,  0x5F, 0xD7, 0x87},
+    {79,  0x5F, 0xD7, 0xAF},
+    {80,  0x5F, 0xD7, 0xD7},
+    {81,  0x5F, 0xD7, 0xFF},
+    {82,  0x5F, 0xFF, 0x00},
+    {83,  0x5F, 0xFF, 0x5F},
+    {84,  0x5F, 0xFF, 0x87},
+    {85,  0x5F, 0xFF, 0xAF},
+    {86,  0x5F, 0xFF, 0xD7},
+    {87,  0x5F, 0xFF, 0xFF},
+    {88,  0x87, 0x00, 0x00},
+    {89,  0x87, 0x00, 0x5F},
+    {90,  0x87, 0x00, 0x87},
+    {91,  0x87, 0x00, 0xAF},
+    {92,  0x87, 0x00, 0xD7},
+    {93,  0x87, 0x00, 0xFF},
+    {94,  0x87, 0x5F, 0x00},
+    {95,  0x87, 0x5F, 0x5F},
+    {96,  0x87, 0x5F, 0x87},
+    {97,  0x87, 0x5F, 0xAF},
+    {98,  0x87, 0x5F, 0xD7},
+    {99,  0x87, 0x5F, 0xFF},
+    {100, 0x87, 0x87, 0x00},
+    {101, 0x87, 0x87, 0x5F},
+    {102, 0x87, 0x87, 0x87},
+    {103, 0x87, 0x87, 0xAF},
+    {104, 0x87, 0x87, 0xD7},
+    {105, 0x87, 0x87, 0xFF},
+    {106, 0x87, 0xAF, 0x00},
+    {107, 0x87, 0xAF, 0x5F},
+    {108, 0x87, 0xAF, 0x87},
+    {109, 0x87, 0xAF, 0xAF},
+    {110, 0x87, 0xAF, 0xD7},
+    {111, 0x87, 0xAF, 0xFF},
+    {112, 0x87, 0xD7, 0x00},
+    {113, 0x87, 0xD7, 0x5F},
+    {114, 0x87, 0xD7, 0x87},
+    {115, 0x87, 0xD7, 0xAF},
+    {116, 0x87, 0xD7, 0xD7},
+    {117, 0x87, 0xD7, 0xFF},
+    {118, 0x87, 0xFF, 0x00},
+    {119, 0x87, 0xFF, 0x5F},
+    {120, 0x87, 0xFF, 0x87},
+    {121, 0x87, 0xFF, 0xAF},
+    {122, 0x87, 0xFF, 0xD7},
+    {123, 0x87, 0xFF, 0xFF},
+    {124, 0xAF, 0x00, 0x00},
+    {125, 0xAF, 0x00, 0x5F},
+    {126, 0xAF, 0x00, 0x87},
+    {127, 0xAF, 0x00, 0xAF},
+    {128, 0xAF, 0x00, 0xD7},
+    {129, 0xAF, 0x00, 0xFF},
+    {130, 0xAF, 0x5F, 0x00},
+    {131, 0xAF, 0x5F, 0x5F},
+    {132, 0xAF, 0x5F, 0x87},
+    {133, 0xAF, 0x5F, 0xAF},
+    {134, 0xAF, 0x5F, 0xD7},
+    {135, 0xAF, 0x5F, 0xFF},
+    {136, 0xAF, 0x87, 0x00},
+    {137, 0xAF, 0x87, 0x5F},
+    {138, 0xAF, 0x87, 0x87},
+    {139, 0xAF, 0x87, 0xAF},
+    {140, 0xAF, 0x87, 0xD7},
+    {141, 0xAF, 0x87, 0xFF},
+    {142, 0xAF, 0xAF, 0x00},
+    {143, 0xAF, 0xAF, 0x5F},
+    {144, 0xAF, 0xAF, 0x87},
+    {145, 0xAF, 0xAF, 0xAF},
+    {146, 0xAF, 0xAF, 0xD7},
+    {147, 0xAF, 0xAF, 0xFF},
+    {148, 0xAF, 0xD7, 0x00},
+    {149, 0xAF, 0xD7, 0x5F},
+    {150, 0xAF, 0xD7, 0x87},
+    {151, 0xAF, 0xD7, 0xAF},
+    {152, 0xAF, 0xD7, 0xD7},
+    {153, 0xAF, 0xD7, 0xFF},
+    {154, 0xAF, 0xFF, 0x00},
+    {155, 0xAF, 0xFF, 0x5F},
+    {156, 0xAF, 0xFF, 0x87},
+    {157, 0xAF, 0xFF, 0xAF},
+    {158, 0xAF, 0xFF, 0xD7},
+    {159, 0xAF, 0xFF, 0xFF},
+    {160, 0xD7, 0x00, 0x00},
+    {161, 0xD7, 0x00, 0x5F},
+    {162, 0xD7, 0x00, 0x87},
+    {163, 0xD7, 0x00, 0xAF},
+    {164, 0xD7, 0x00, 0xD7},
+    {165, 0xD7, 0x00, 0xFF},
+    {166, 0xD7, 0x5F, 0x00},
+    {167, 0xD7, 0x5F, 0x5F},
+    {168, 0xD7, 0x5F, 0x87},
+    {169, 0xD7, 0x5F, 0xAF},
+    {170, 0xD7, 0x5F, 0xD7},
+    {171, 0xD7, 0x5F, 0xFF},
+    {172, 0xD7, 0x87, 0x00},
+    {173, 0xD7, 0x87, 0x5F},
+    {174, 0xD7, 0x87, 0x87},
+    {175, 0xD7, 0x87, 0xAF},
+    {176, 0xD7, 0x87, 0xD7},
+    {177, 0xD7, 0x87, 0xFF},
+    {178, 0xD7, 0xAF, 0x00},
+    {179, 0xD7, 0xAF, 0x5F},
+    {180, 0xD7, 0xAF, 0x87},
+    {181, 0xD7, 0xAF, 0xAF},
+    {182, 0xD7, 0xAF, 0xD7},
+    {183, 0xD7, 0xAF, 0xFF},
+    {184, 0xD7, 0xD7, 0x00},
+    {185, 0xD7, 0xD7, 0x5F},
+    {186, 0xD7, 0xD7, 0x87},
+    {187, 0xD7, 0xD7, 0xAF},
+    {188, 0xD7, 0xD7, 0xD7},
+    {189, 0xD7, 0xD7, 0xFF},
+    {190, 0xD7, 0xFF, 0x00},
+    {191, 0xD7, 0xFF, 0x5F},
+    {192, 0xD7, 0xFF, 0x87},
+    {193, 0xD7, 0xFF, 0xAF},
+    {194, 0xD7, 0xFF, 0xD7},
+    {195, 0xD7, 0xFF, 0xFF},
+    {196, 0xFF, 0x00, 0x00},
+    {197, 0xFF, 0x00, 0x5F},
+    {198, 0xFF, 0x00, 0x87},
+    {199, 0xFF, 0x00, 0xAF},
+    {200, 0xFF, 0x00, 0xD7},
+    {201, 0xFF, 0x00, 0xFF},
+    {202, 0xFF, 0x5F, 0x00},
+    {203, 0xFF, 0x5F, 0x5F},
+    {204, 0xFF, 0x5F, 0x87},
+    {205, 0xFF, 0x5F, 0xAF},
+    {206, 0xFF, 0x5F, 0xD7},
+    {207, 0xFF, 0x5F, 0xFF},
+    {208, 0xFF, 0x87, 0x00},
+    {209, 0xFF, 0x87, 0x5F},
+    {210, 0xFF, 0x87, 0x87},
+    {211, 0xFF, 0x87, 0xAF},
+    {212, 0xFF, 0x87, 0xD7},
+    {213, 0xFF, 0x87, 0xFF},
+    {214, 0xFF, 0xAF, 0x00},
+    {215, 0xFF, 0xAF, 0x5F},
+    {216, 0xFF, 0xAF, 0x87},
+    {217, 0xFF, 0xAF, 0xAF},
+    {218, 0xFF, 0xAF, 0xD7},
+    {219, 0xFF, 0xAF, 0xFF},
+    {220, 0xFF, 0xD7, 0x00},
+    {221, 0xFF, 0xD7, 0x5F},
+    {222, 0xFF, 0xD7, 0x87},
+    {223, 0xFF, 0xD7, 0xAF},
+    {224, 0xFF, 0xD7, 0xD7},
+    {225, 0xFF, 0xD7, 0xFF},
+    {226, 0xFF, 0xFF, 0x00},
+    {227, 0xFF, 0xFF, 0x5F},
+    {228, 0xFF, 0xFF, 0x87},
+    {229, 0xFF, 0xFF, 0xAF},
+    {230, 0xFF, 0xFF, 0xD7},
+    {231, 0xFF, 0xFF, 0xFF},
+    {232, 0x08, 0x08, 0x08},
+    {233, 0x12, 0x12, 0x12},
+    {234, 0x1C, 0x1C, 0x1C},
+    {235, 0x26, 0x26, 0x26},
+    {236, 0x30, 0x30, 0x30},
+    {237, 0x3A, 0x3A, 0x3A},
+    {238, 0x44, 0x44, 0x44},
+    {239, 0x4E, 0x4E, 0x4E},
+    {240, 0x58, 0x58, 0x58},
+    {241, 0x62, 0x62, 0x62},
+    {242, 0x6C, 0x6C, 0x6C},
+    {243, 0x76, 0x76, 0x76},
+    {244, 0x80, 0x80, 0x80},
+    {245, 0x8A, 0x8A, 0x8A},
+    {246, 0x94, 0x94, 0x94},
+    {247, 0x9E, 0x9E, 0x9E},
+    {248, 0xA8, 0xA8, 0xA8},
+    {249, 0xB2, 0xB2, 0xB2},
+    {250, 0xBC, 0xBC, 0xBC},
+    {251, 0xC6, 0xC6, 0xC6},
+    {252, 0xD0, 0xD0, 0xD0},
+    {253, 0xDA, 0xDA, 0xDA},
+    {254, 0xE4, 0xE4, 0xE4},
+    {255, 0xEE, 0xEE, 0xEE}
+
+};
+
+int guac_terminal_colorcmp(const guac_terminal_color* a,
+        const guac_terminal_color* b) {
+
+    /* Consider red component highest order ... */
+    if (a->red != b->red)
+        return a->red - b->red;
+
+    /* ... followed by green ... */
+    if (a->green != b->green)
+        return a->green - b->green;
+
+    /* ... followed by blue */
+    if (a->blue != b->blue)
+        return a->blue - b->blue;
+
+    /* If all components match, colors are equal */
+    return 0;
+
+}
+

src/terminal/terminal.c

@@ -24,6 +24,7 @@
 #include "terminal/buffer.h"
 #include "terminal/common.h"
 #include "terminal/display.h"
+#include "terminal/palette.h"
 #include "terminal/terminal.h"
 #include "terminal/terminal_handlers.h"
 #include "terminal/types.h"
@@ -205,8 +206,7 @@ static void guac_terminal_repaint_default_layer(guac_terminal* terminal,
     guac_terminal_display* display = terminal->display;
 
     /* Get background color */
-    const guac_terminal_color* color =
+    const guac_terminal_color* color = &display->default_background;
-        &guac_terminal_palette[display->default_background];
 
     /* Reset size */
     guac_protocol_send_size(socket, GUAC_DEFAULT_LAYER, width, height);
@@ -296,8 +296,8 @@ guac_terminal* guac_terminal_create(guac_client* client,
     guac_terminal_char default_char = {
         .value = 0,
         .attributes = {
-            .foreground = default_foreground,
+            .foreground = guac_terminal_palette[default_foreground],
-            .background = default_background,
+            .background = guac_terminal_palette[default_background],
             .bold       = false,
             .reverse    = false,
             .underscore = false
@@ -326,8 +326,8 @@ guac_terminal* guac_terminal_create(guac_client* client,
     /* Init display */
     term->display = guac_terminal_display_alloc(client,
             font_name, font_size, dpi,
-            default_char.attributes.foreground,
+            &default_char.attributes.foreground,
-            default_char.attributes.background);
+            &default_char.attributes.background);
 
     /* Fail if display init failed */
     if (term->display == NULL) {
@@ -875,17 +875,18 @@ static bool guac_terminal_is_visible(guac_terminal* term,
     if (guac_terminal_has_glyph(c->value))
         return true;
 
-    int background;
+    const guac_terminal_color* background;
 
     /* Determine actual background color of character */
     if (c->attributes.reverse != c->attributes.cursor)
-        background = c->attributes.foreground;
+        background = &c->attributes.foreground;
     else
-        background = c->attributes.background;
+        background = &c->attributes.background;
 
     /* Blank characters are visible if their background color differs from that
      * of the terminal */
-    return background != term->default_char.attributes.background;
+    return guac_terminal_colorcmp(background,
+            &term->default_char.attributes.background) != 0;
 
 }
 

src/terminal/terminal/common.h

@@ -22,6 +22,7 @@
 #define _GUAC_TERMINAL_COMMON_H
 
 #include "config.h"
+#include "types.h"
 
 #include <stdbool.h>
 

src/terminal/terminal/display.h

@@ -24,6 +24,7 @@
 #include "config.h"
 
 #include "common/surface.h"
+#include "palette.h"
 #include "types.h"
 
 #include <guacamole/client.h>
@@ -37,93 +38,6 @@
  */
 #define GUAC_TERMINAL_MAX_CHAR_WIDTH 2
 
-/**
- * The index of black within the terminal color palette.
- */
-#define GUAC_TERMINAL_COLOR_BLACK 0
-
-/**
- * The index of low-intensity red within the terminal color palette.
- */
-#define GUAC_TERMINAL_COLOR_DARK_RED 1
-
-/**
- * The index of low-intensity green within the terminal color palette.
- */
-#define GUAC_TERMINAL_COLOR_DARK_GREEN 2
-
-/**
- * The index of brown within the terminal color palette.
- */
-#define GUAC_TERMINAL_COLOR_BROWN 3
-
-/**
- * The index of low-intensity blue within the terminal color palette.
- */
-#define GUAC_TERMINAL_COLOR_DARK_BLUE 4
-
-/**
- * The index of low-intensity magenta (purple) within the terminal color
- * palette.
- */
-#define GUAC_TERMINAL_COLOR_PURPLE 5
-
-/**
- * The index of low-intensity cyan (teal) within the terminal color palette.
- */
-#define GUAC_TERMINAL_COLOR_TEAL 6
-
-/**
- * The index of low-intensity white (gray) within the terminal color palette.
- */
-#define GUAC_TERMINAL_COLOR_GRAY 7
-
-/**
- * The index of bright black (dark gray) within the terminal color palette.
- */
-#define GUAC_TERMINAL_COLOR_DARK_GRAY 8
-
-/**
- * The index of bright red within the terminal color palette.
- */
-#define GUAC_TERMINAL_COLOR_RED 9
-
-/**
- * The index of bright green within the terminal color palette.
- */
-#define GUAC_TERMINAL_COLOR_GREEN 10
-
-/**
- * The index of bright brown (yellow) within the terminal color palette.
- */
-#define GUAC_TERMINAL_COLOR_YELLOW 11
-
-/**
- * The index of bright blue within the terminal color palette.
- */
-#define GUAC_TERMINAL_COLOR_BLUE 12
-
-/**
- * The index of bright magenta within the terminal color palette.
- */
-#define GUAC_TERMINAL_COLOR_MAGENTA 13
-
-/**
- * The index of bright cyan within the terminal color palette.
- */
-#define GUAC_TERMINAL_COLOR_CYAN 14
-
-/**
- * The index of bright white within the terminal color palette.
- */
-#define GUAC_TERMINAL_COLOR_WHITE 15
-
-/**
- * The available color palette. All integer colors within structures
- * here are indices into this palette.
- */
-extern const guac_terminal_color guac_terminal_palette[16];
-
 /**
  * All available terminal operations which affect character cells.
  */
@@ -220,22 +134,24 @@ typedef struct guac_terminal_display {
     /**
      * Default foreground color for all glyphs.
      */
-    int default_foreground;
+    guac_terminal_color default_foreground;
 
     /**
      * Default background color for all glyphs and the terminal itself.
      */
-    int default_background;
+    guac_terminal_color default_background;
 
     /**
-     * Color of glyphs in copy buffer
+     * The foreground color to be used for the next glyph rendered to the
+     * terminal.
      */
-    int glyph_foreground;
+    guac_terminal_color glyph_foreground;
 
     /**
-     * Color of glyphs in copy buffer
+     * The background color to be used for the next glyph rendered to the
+     * terminal.
      */
-    int glyph_background;
+    guac_terminal_color glyph_background;
 
     /**
      * The surface containing the actual terminal.
@@ -292,7 +208,7 @@ typedef struct guac_terminal_display {
  */
 guac_terminal_display* guac_terminal_display_alloc(guac_client* client,
         const char* font_name, int font_size, int dpi,
-        int foreground, int background);
+        guac_terminal_color* foreground, guac_terminal_color* background);
 
 /**
  * Frees the given display.

src/terminal/terminal/palette.h

@@ -0,0 +1,193 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#ifndef GUAC_TERMINAL_PALETTE_H
+#define GUAC_TERMINAL_PALETTE_H
+
+#include "config.h"
+
+#include <stdint.h>
+
+/**
+ * The index of black within the terminal color palette.
+ */
+#define GUAC_TERMINAL_COLOR_BLACK 0
+
+/**
+ * The index of low-intensity red within the terminal color palette.
+ */
+#define GUAC_TERMINAL_COLOR_DARK_RED 1
+
+/**
+ * The index of low-intensity green within the terminal color palette.
+ */
+#define GUAC_TERMINAL_COLOR_DARK_GREEN 2
+
+/**
+ * The index of brown within the terminal color palette.
+ */
+#define GUAC_TERMINAL_COLOR_BROWN 3
+
+/**
+ * The index of low-intensity blue within the terminal color palette.
+ */
+#define GUAC_TERMINAL_COLOR_DARK_BLUE 4
+
+/**
+ * The index of low-intensity magenta (purple) within the terminal color
+ * palette.
+ */
+#define GUAC_TERMINAL_COLOR_PURPLE 5
+
+/**
+ * The index of low-intensity cyan (teal) within the terminal color palette.
+ */
+#define GUAC_TERMINAL_COLOR_TEAL 6
+
+/**
+ * The index of low-intensity white (gray) within the terminal color palette.
+ */
+#define GUAC_TERMINAL_COLOR_GRAY 7
+
+/**
+ * The index of bright black (dark gray) within the terminal color palette.
+ */
+#define GUAC_TERMINAL_COLOR_DARK_GRAY 8
+
+/**
+ * The index of bright red within the terminal color palette.
+ */
+#define GUAC_TERMINAL_COLOR_RED 9
+
+/**
+ * The index of bright green within the terminal color palette.
+ */
+#define GUAC_TERMINAL_COLOR_GREEN 10
+
+/**
+ * The index of bright brown (yellow) within the terminal color palette.
+ */
+#define GUAC_TERMINAL_COLOR_YELLOW 11
+
+/**
+ * The index of bright blue within the terminal color palette.
+ */
+#define GUAC_TERMINAL_COLOR_BLUE 12
+
+/**
+ * The index of bright magenta within the terminal color palette.
+ */
+#define GUAC_TERMINAL_COLOR_MAGENTA 13
+
+/**
+ * The index of bright cyan within the terminal color palette.
+ */
+#define GUAC_TERMINAL_COLOR_CYAN 14
+
+/**
+ * The index of bright white within the terminal color palette.
+ */
+#define GUAC_TERMINAL_COLOR_WHITE 15
+
+/**
+ * The index of the first low-intensity color in the 16-color portion of the
+ * palette.
+ */
+#define GUAC_TERMINAL_FIRST_DARK 0
+
+/**
+ * The index of the last low-intensity color in the 16-color portion of the
+ * palette.
+ */
+#define GUAC_TERMINAL_LAST_DARK 7
+
+/**
+ * The index of the first high-intensity color in the 16-color portion of the
+ * palette.
+ */
+#define GUAC_TERMINAL_FIRST_INTENSE 8
+
+/**
+ * The index of the last high-intensity color in the 16-color portion of the
+ * palette.
+ */
+#define GUAC_TERMINAL_LAST_INTENSE 15
+
+/**
+ * The distance between the palette indices of the dark colors (0 through 7)
+ * and the bright colors (8 - 15) in the 16-color portion of the palette.
+ */
+#define GUAC_TERMINAL_INTENSE_OFFSET 8
+
+/**
+ * An RGB color, where each component ranges from 0 to 255.
+ */
+typedef struct guac_terminal_color {
+
+    /**
+     * The index of this color within the terminal palette, or -1 if the color
+     * does not exist within the terminal palette.
+     */
+    int palette_index;
+
+    /**
+     * The red component of this color.
+     */
+    uint8_t red;
+
+    /**
+     * The green component of this color.
+     */
+    uint8_t green;
+
+    /**
+     * The blue component of this color.
+     */
+    uint8_t blue;
+
+} guac_terminal_color;
+
+/**
+ * Compares two colors, returning a negative value if the first color is less
+ * than the second, a positive value if the first color is greater than the
+ * second, and zero if the colors are identical. Only the color components are
+ * compared (not the palette index). The red component is considered the
+ * highest order component, followed by green, followed by blue.
+ *
+ * @param a
+ *     The first color to compare.
+ *
+ * @param b
+ *     The second color to compare.
+ *
+ * @return
+ *    A negative value if the first color is less than the second, a positive
+ *    value if the first color is greater than the second, and zero if the
+ *    colors are identical.
+ */
+int guac_terminal_colorcmp(const guac_terminal_color* a,
+        const guac_terminal_color* b);
+
+/**
+ * The terminal color palette.
+ */
+extern const guac_terminal_color guac_terminal_palette[256];
+
+#endif
+

src/terminal/terminal/terminal_handlers.h

@@ -138,6 +138,18 @@ int guac_terminal_open_pipe_stream(guac_terminal* term, unsigned char c);
  */
 int guac_terminal_close_pipe_stream(guac_terminal* term, unsigned char c);
 
+/**
+ * Parses the remainder of xterm's OSC sequence for redefining the terminal
+ * emulator's palette.
+ *
+ * @param term
+ *     The terminal that received the given character of data.
+ *
+ * @param c
+ *     The character that was received by the given terminal.
+ */
+int guac_terminal_xterm_palette(guac_terminal* term, unsigned char c);
+
 /**
  * Handles the remaining characters of an Operating System Code (OSC) sequence,
  * typically initiated with "ESC ]".

src/terminal/terminal/types.h

@@ -22,8 +22,10 @@
 #define _GUAC_TERMINAL_TYPES_H
 
 #include "config.h"
+#include "palette.h"
 
 #include <stdbool.h>
+#include <stdint.h>
 
 /**
  * A character which is not truly a character, but rather part of an
@@ -34,28 +36,6 @@
  */
 #define GUAC_CHAR_CONTINUATION -1
 
-/**
- * An RGB color, where each component ranges from 0 to 255.
- */
-typedef struct guac_terminal_color {
-
-    /**
-     * The red component of this color.
-     */
-    int red;
-
-    /**
-     * The green component of this color.
-     */
-    int green;
-
-    /**
-     * The blue component of this color.
-     */
-    int blue;
-
-} guac_terminal_color;
-
 /**
  * Terminal attributes, as can be applied to a single character.
  */
@@ -83,14 +63,14 @@ typedef struct guac_terminal_attributes {
     bool underscore;
 
     /**
-     * The foreground color of this character, as a palette index.
+     * The foreground color of this character.
      */
-    int foreground;
+    guac_terminal_color foreground;
 
     /**
-     * The background color of this character, as a palette index.
+     * The background color of this character.
      */
-    int background;
+    guac_terminal_color background;
 
 } guac_terminal_attributes;
 

src/terminal/terminal_handlers.c

@@ -20,6 +20,7 @@
 #include "config.h"
 
 #include "terminal/char_mappings.h"
+#include "terminal/palette.h"
 #include "terminal/terminal.h"
 #include "terminal/terminal_handlers.h"
 #include "terminal/types.h"
@@ -366,7 +367,8 @@ int guac_terminal_escape(guac_terminal* term, unsigned char c) {
             break;
 
         default:
-            guac_client_log(term->client, GUAC_LOG_INFO, "Unhandled ESC sequence: %c", c);
+            guac_client_log(term->client, GUAC_LOG_DEBUG,
+                    "Unhandled ESC sequence: %c", c);
             term->char_handler = guac_terminal_echo; 
 
     }
@@ -434,6 +436,144 @@ static bool* __guac_terminal_get_flag(guac_terminal* term, int num, char private
 
 }
 
+/**
+ * Parses an xterm SGR sequence specifying the RGB values of a color.
+ *
+ * @param argc
+ *     The number of arguments within the argv array.
+ *
+ * @param argv
+ *     The SGR arguments to parse, with the first relevant argument the
+ *     red component of the RGB color.
+ *
+ * @param color
+ *     The guac_terminal_color structure which should receive the parsed
+ *     color values.
+ *
+ * @return
+ *     The number of arguments parsed, or zero if argv does not contain
+ *     enough elements to represent an RGB color.
+ */
+static int guac_terminal_parse_xterm256_rgb(int argc, const int* argv,
+        guac_terminal_color* color) {
+
+    /* RGB color palette entries require three arguments */
+    if (argc < 3)
+        return 0;
+
+    /* Read RGB components from arguments */
+    int red   = argv[0];
+    int green = argv[1];
+    int blue  = argv[2];
+
+    /* Ignore if components are out of range */
+    if (   red   < 0 || red   > 255
+        || green < 0 || green > 255
+        || blue  < 0 || blue  > 255)
+        return 3;
+
+    /* Store RGB components */
+    color->red   = (uint8_t) red;
+    color->green = (uint8_t) green;
+    color->blue  = (uint8_t) blue;
+
+    /* Color is not from the palette */
+    color->palette_index = -1;
+
+    /* Done */
+    return 3;
+
+}
+
+/**
+ * Parses an xterm SGR sequence specifying the index of a color within the
+ * 256-color palette.
+ *
+ * @param argc
+ *     The number of arguments within the argv array.
+ *
+ * @param argv
+ *     The SGR arguments to parse, with the first relevant argument being
+ *     the index of the color.
+ *
+ * @param color
+ *     The guac_terminal_color structure which should receive the parsed
+ *     color values.
+ *
+ * @return
+ *     The number of arguments parsed, or zero if the palette index is
+ *     absent.
+ */
+static int guac_terminal_parse_xterm256_index(int argc, const int* argv,
+        guac_terminal_color* color) {
+
+    /* 256-color palette entries require only one argument */
+    if (argc < 1)
+        return 0;
+
+    /* Ignore if palette index is out of bounds */
+    int index = argv[0];
+    if (index < 0 || index > 255)
+        return 1;
+
+    /* Copy palette entry */
+    *color = guac_terminal_palette[index];
+
+    /* Done */
+    return 1;
+
+}
+
+/**
+ * Parses an xterm SGR sequence specifying the index of a color within the
+ * 256-color palette, or specfying the RGB values of a color. The number of
+ * arguments required by these sequences varies. If a 256-color sequence is
+ * recognized, the number of arguments parsed is returned.
+ *
+ * @param argc
+ *     The number of arguments within the argv array.
+ *
+ * @param argv
+ *     The SGR arguments to parse, with the first relevant argument being
+ *     the first element of the array. In the case of an xterm 256-color
+ *     SGR sequence, the first element here will be either 2, for an
+ *     RGB color, or 5, for a 256-color palette index. All other values
+ *     are invalid and will not be parsed.
+ *
+ * @param color
+ *     The guac_terminal_color structure which should receive the parsed
+ *     color values.
+ *
+ * @return
+ *     The number of arguments parsed, or zero if argv does not point to
+ *     the first element of an xterm 256-color SGR sequence.
+ */
+static int guac_terminal_parse_xterm256(int argc, const int* argv,
+        guac_terminal_color* color) {
+
+    /* All 256-color codes must have at least a type */
+    if (argc < 1)
+        return 0;
+
+    switch (argv[0]) {
+
+        /* RGB */
+        case 2:
+            return guac_terminal_parse_xterm256_rgb(
+                    argc - 1, &argv[1], color) + 1;
+
+        /* Palette index */
+        case 5:
+            return guac_terminal_parse_xterm256_index(
+                    argc - 1, &argv[1], color) + 1;
+
+    }
+
+    /* Invalid type */
+    return 0;
+
+}
+
 int guac_terminal_csi(guac_terminal* term, unsigned char c) {
 
     /* CSI function arguments */
@@ -779,15 +919,32 @@ int guac_terminal_csi(guac_terminal* term, unsigned char c) {
 
                     /* Foreground */
                     else if (value >= 30 && value <= 37)
-                        term->current_attributes.foreground = value - 30;
+                        term->current_attributes.foreground =
+                            guac_terminal_palette[value - 30];
 
-                    /* Underscore on, default foreground */
+                    /* Underscore on, default foreground OR 256-color
+                     * foreground */
                     else if (value == 38) {
+
+                        /* Attempt to set foreground with 256-color entry */
+                        int xterm256_length =
+                            guac_terminal_parse_xterm256(argc - 1, &argv[i + 1],
+                                    &term->current_attributes.foreground);
+
+                        /* If valid 256-color entry, foreground has been set */
+                        if (xterm256_length > 0)
+                            i += xterm256_length;
+
+                        /* Otherwise interpret as underscore and default
+                         * foreground  */
+                        else {
                             term->current_attributes.underscore = true;
                             term->current_attributes.foreground =
                                 term->default_char.attributes.foreground;
                         }
 
+                    }
+
                     /* Underscore off, default foreground */
                     else if (value == 39) {
                         term->current_attributes.underscore = false;
@@ -797,7 +954,13 @@ int guac_terminal_csi(guac_terminal* term, unsigned char c) {
 
                     /* Background */
                     else if (value >= 40 && value <= 47)
-                        term->current_attributes.background = value - 40;
+                        term->current_attributes.background =
+                            guac_terminal_palette[value - 40];
+
+                    /* 256-color background */
+                    else if (value == 48)
+                        i += guac_terminal_parse_xterm256(argc - 1, &argv[i + 1],
+                                    &term->current_attributes.background);
 
                     /* Reset background */
                     else if (value == 49)
@@ -860,11 +1023,11 @@ int guac_terminal_csi(guac_terminal* term, unsigned char c) {
             default:
                 if (c != ';') {
 
-                    guac_client_log(term->client, GUAC_LOG_INFO,
+                    guac_client_log(term->client, GUAC_LOG_DEBUG,
                             "Unhandled CSI sequence: %c", c);
 
                     for (i=0; i<argc; i++)
-                        guac_client_log(term->client, GUAC_LOG_INFO,
+                        guac_client_log(term->client, GUAC_LOG_DEBUG,
                                 " -> argv[%i] = %i", i, argv[i]);
 
                 }
@@ -993,6 +1156,19 @@ int guac_terminal_close_pipe_stream(guac_terminal* term, unsigned char c) {
 
 }
 
+int guac_terminal_xterm_palette(guac_terminal* term, unsigned char c) {
+
+    /* NOTE: Currently unimplemented. Attempts to set the 256-color palette
+     * are ignored. */
+
+    /* Stop on ECMA-48 ST (String Terminator */
+    if (c == 0x9C || c == 0x5C || c == 0x07)
+        term->char_handler = guac_terminal_echo;
+
+    return 0;
+
+}
+
 int guac_terminal_osc(guac_terminal* term, unsigned char c) {
 
     static int operation = 0;
@@ -1020,6 +1196,10 @@ int guac_terminal_osc(guac_terminal* term, unsigned char c) {
         else if (operation == 482203)
             term->char_handler = guac_terminal_close_pipe_stream;
 
+        /* xterm 256-color palette redefinition */
+        else if (operation == 4)
+            term->char_handler = guac_terminal_xterm_palette;
+
         /* Reset parameter for next OSC */
         operation = 0;
 
@@ -1031,7 +1211,8 @@ int guac_terminal_osc(guac_terminal* term, unsigned char c) {
 
     /* Stop on unrecognized character */
     else {
-        guac_client_log(term->client, GUAC_LOG_INFO, "Unexpected character in OSC: 0x%X", c);
+        guac_client_log(term->client, GUAC_LOG_DEBUG,
+                "Unexpected character in OSC: 0x%X", c);
         term->char_handler = guac_terminal_echo;
     }