terminal: modernize color palette

The terminal now got a configurable palette for 16 colors (8 normal, 8
bright/bold).

  <config>
    <palette>
      <color index="0" value="#000000"/> <!-- black is real black -->
      <color index="8" value="#101010"/> <!-- bright black stands out a bit -->
    </palette>
  </config>

Note, the old (undocumented) <color index="..." bg="..."> configuration
scheme is no longer supported.

Also, this commit adds a pleasing default palette that ensures
readability of ViM's standard hightlighting.

Fixes #3406

repos/gems/run/sculpt/fonts.config

@@ -22,5 +22,5 @@
 	<default-policy root="/fonts" />
 
 	<!-- color definition when this file is used as terminal config -->
-	<color index="0" bg="#1c2232"/>
+	<palette> <color index="0" value="#1c2232"/> </palette>
 </config>

repos/gems/run/sculpt/leitzentrale.config

@@ -244,8 +244,10 @@
 				<resource name="RAM" quantum="4M"/>
 				<provides> <service name="Terminal"/> </provides>
 				<config>
-					<color index="0" bg="#2f3953"/>
+					<palette>
-					<color index="8" bg="#2f3953"/>
+						<color index="0" value="#2f3953"/>
+						<color index="8" value="#2f3953"/>
+					</palette>
 					<vfs>
 						<rom name="VeraMono.ttf"/>
 						<dir name="fonts">

repos/gems/src/app/sculpt_manager/main.cc

@@ -956,9 +956,11 @@ void Sculpt::Main::_handle_nitpicker_mode()
 			xml.node("default-policy", [&] () { xml.attribute("root", "/fonts"); });
 
 			auto gen_color = [&] (unsigned index, Color color) {
-				xml.node("color", [&] () {
+				xml.node("palette", [&] () {
-					xml.attribute("index", index);
+					xml.node("color", [&] () {
-					xml.attribute("bg", String<16>(color));
+						xml.attribute("index", index);
+						xml.attribute("value", String<16>(color));
+					});
 				});
 			};
 

repos/gems/src/server/terminal/README

@@ -0,0 +1,19 @@
+This is a graphical terminal implementation. It provides the Terminal
+service and uses a nitpicker session for screen representation.
+
+Configuration
+~~~~~~~~~~~~~
+
+The default color palette can be configured via the <palette> XML
+configuration node like follows. There are 16 colors configurable -
+index 0-7 normal color and index 8-15 bright (bold) colors.
+
+
+! <config>
+!   <palette>
+!     <color index="0" value="#000000"/> <!-- black is real black -->
+!     <color index="8" value="#101010"/> <!-- bright black stands out a bit -->
+!   </palette>
+! ...
+! </config>
+

repos/gems/src/server/terminal/color_palette.h

@@ -1,11 +1,12 @@
 /*
  * \brief  Terminal color palette
  * \author Norman Feske
+ * \author Christian Helmuth
  * \date   2018-02-06
  */
 
 /*
- * Copyright (C) 2018 Genode Labs GmbH
+ * Copyright (C) 2018-2019 Genode Labs GmbH
  *
  * This file is part of the Genode OS framework, which is distributed
  * under the terms of the GNU Affero General Public License version 3.
@@ -16,6 +17,7 @@
 
 /* Genode includes */
 #include <util/color.h>
+#include <util/xml_node.h>
 
 /* local includes */
 #include "types.h"
@@ -33,44 +35,61 @@ class Terminal::Color_palette
 
 		struct Highlighted { bool value; };
 
-		struct Inverse { bool value; };
-
 	private:
 
 		enum { NUM_COLORS = 16U };
 
 		Color _colors[NUM_COLORS];
 
+		static constexpr char const * _default_palette {
+			"<palette>"
+			" <color index=\"0\"  value=\"#000000\"/>" /* black */
+			" <color index=\"1\"  value=\"#AC4142\"/>" /* red */
+			" <color index=\"2\"  value=\"#90A959\"/>" /* green */
+			" <color index=\"3\"  value=\"#F4BF75\"/>" /* yellow */
+			" <color index=\"4\"  value=\"#6A9FB5\"/>" /* blue */
+			" <color index=\"5\"  value=\"#AA759F\"/>" /* magenta */
+			" <color index=\"6\"  value=\"#75B5AA\"/>" /* cyan */
+			" <color index=\"7\"  value=\"#D0D0D0\"/>" /* white */
+			" <color index=\"8\"  value=\"#101010\"/>" /* bright black */
+			" <color index=\"9\"  value=\"#AC4142\"/>" /* bright red */
+			" <color index=\"10\" value=\"#90A959\"/>" /* bright green */
+			" <color index=\"11\" value=\"#F4BF75\"/>" /* bright yellow */
+			" <color index=\"12\" value=\"#6A9FB5\"/>" /* bright blue */
+			" <color index=\"13\" value=\"#AA759F\"/>" /* bright magenta */
+			" <color index=\"14\" value=\"#75B5AA\"/>" /* bright cyan */
+			" <color index=\"15\" value=\"#F5F5F5\"/>" /* bright white */
+			"</palette>" };
+
+		Genode::Xml_node const _default { _default_palette };
+
+		void _apply_palette(Xml_node palette)
+		{
+			palette.for_each_sub_node("color", [&] (Xml_node node) {
+				if (!node.has_attribute("index")) return;
+				if (!node.has_attribute("value")) return;
+
+				unsigned const index = node.attribute_value("index", 0U);
+				if (!(index <= NUM_COLORS)) return;
+				_colors[index] = node.attribute_value("value", Color());
+			});
+		}
+
 	public:
 
 		Color_palette()
 		{
-			_colors[0] = Color(  0,   0,   0);  /* black */
+			_apply_palette(_default);
-			_colors[1] = Color(255, 128, 128);  /* red */
-			_colors[2] = Color(128, 255, 128);  /* green */
-			_colors[3] = Color(255, 255,   0);  /* yellow */
-			_colors[4] = Color(128, 128, 255);  /* blue */
-			_colors[5] = Color(255,   0, 255);  /* magenta */
-			_colors[6] = Color(  0, 255, 255);  /* cyan */
-			_colors[7] = Color(255, 255, 255);  /* white */
-
-			/* the upper portion of the palette contains highlight colors */
-			for (unsigned i = 0; i < NUM_COLORS/2; i++) {
-				Color const col = _colors[i];
-				_colors[i + NUM_COLORS/2] = Color((col.r*2)/3, (col.g*2)/3, (col.b*2)/3);
-			}
 		}
 
 		void apply_config(Xml_node config)
 		{
-			config.for_each_sub_node("color", [&] (Xml_node color) {
+			_apply_palette(_default);
-				unsigned const index = min(color.attribute_value("index", 0U), 15U);
+			if (config.has_sub_node("palette"))
-				Color const bg = color.attribute_value("bg", Color());
+				_apply_palette(config.sub_node("palette"));
-				_colors[index] = bg;
-			});
 		}
 
-		Color foreground(Index index, Highlighted highlighted, Inverse inverse) const
+		Color foreground(Index index, Highlighted highlighted) const
 		{
 			if (index.value >= NUM_COLORS/2)
 				return Color(0, 0, 0);
@@ -78,18 +97,15 @@ class Terminal::Color_palette
 			Color const col =
 				_colors[index.value + (highlighted.value ? NUM_COLORS/2 : 0)];
 
-			return (inverse.value) ? Color(col.r/2, col.g/2, col.b/2) : col;
+			return col;
 		}
 
-		Color background(Index index, Highlighted highlighted, Inverse inverse) const
+		Color background(Index index, Highlighted highlighted) const
 		{
-			Color const color =
+			Color const color = foreground(index, highlighted);
-				_colors[index.value + (highlighted.value ? NUM_COLORS/2 : 0)];
 
-			return (inverse.value) ? Color((color.r + 255)/2,
+			/* reduce the intensity of background colors */
-			                               (color.g + 255)/2,
+			return Color(color.r*3/4, color.g*3/4, color.b*3/4);
-			                               (color.b + 255)/2)
-			                       : color;
 		}
 };
 

repos/gems/src/server/terminal/text_screen_surface.h

@@ -1,6 +1,7 @@
 /*
  * \brief  Terminal graphics backend for textual screen
  * \author Norman Feske
+ * \author Christian Helmuth
  * \date   2018-02-06
  */
 
@@ -177,8 +178,7 @@ class Terminal::Text_screen_surface
 			{
 				Color const bg_color =
 					_palette.background(Color_palette::Index{0},
-					                    Color_palette::Highlighted{false},
+					                    Color_palette::Highlighted{false});
-					                    Color_palette::Inverse{false});
 				Rect r[4] { };
 				Rect const all(Point(0, 0), _geometry.fb_size);
 				_geometry.fb_rect().cut(_geometry.used_rect(), &r[0], &r[1], &r[2], &r[3]);
@@ -197,20 +197,24 @@ class Terminal::Text_screen_surface
 					Fixpoint_number x { (int)_geometry.start().x() };
 					for (unsigned column = 0; column < _cell_array.num_cols(); column++) {
 
-						Char_cell     cell  = _cell_array.get_cell(column, line);
+						Char_cell const cell = _cell_array.get_cell(column, line);
 
 						_font.apply_glyph(cell.codepoint(), [&] (Glyph_painter::Glyph const &glyph) {
 
 							Color_palette::Highlighted const highlighted { cell.highlight() };
-							Color_palette::Inverse     const inverse     { cell.inverse() };
 
-							Color fg_color =
+							Color_palette::Index fg_idx { cell.colidx_fg() };
-								_palette.foreground(Color_palette::Index{cell.colidx_fg()},
+							Color_palette::Index bg_idx { cell.colidx_bg() };
-								                    highlighted, inverse);
 
-							Color bg_color =
+							/* swap color index for inverse cells */
-								_palette.background(Color_palette::Index{cell.colidx_bg()},
+							if (cell.inverse()) {
-								                    highlighted, inverse);
+								Color_palette::Index tmp { fg_idx };
+								fg_idx = bg_idx;
+								bg_idx = tmp;
+							}
+
+							Color fg_color = _palette.foreground(fg_idx, highlighted);
+							Color bg_color = _palette.background(bg_idx, highlighted);
 
 							if (cell.has_cursor()) {
 								fg_color = Color( 63,  63,  63);