Added dim text style support

Author: kmvanbrunt

CHANGELOG.md

@@ -2,11 +2,16 @@
 * Bug Fixes
     * Fixed bug where startup script containing a single quote in its file name was incorrectly quoted
     * Added missing implicit dependency on `setuptools` due to build with `setuptools_scm`
+* Enhancements
+    * Added dim text style support via `style()` function and `ansi.INTENSITY_DIM` setting.
 * Breaking changes
     * Renamed the following `ansi` members for accuracy in what types of ANSI escape sequences are handled
         * `ansi.allow_ansi` -> `ansi.allow_style`
         * `ansi.ansi_safe_wcswidth()` -> `ansi.style_aware_wcswidth()`
         * `ansi.ansi_aware_write()` -> `ansi.style_aware_write()`
+    * Renamed the following `ansi` members for clarification
+        * `ansi.BRIGHT` -> `ansi.INTENSITY_BRIGHT`
+        * `ansi.NORMAL` -> `ansi.INTENSITY_NORMAL`
 
 ## 0.9.22 (December 9, 2019)
 * Bug Fixes

cmd2/ansi.py

@@ -22,9 +22,8 @@
 # Controls when ANSI style style sequences are allowed in output
 allow_style = STYLE_TERMINAL
 
-# Regular expression to match ANSI style sequences
-# This matches: colorama.ansi.CSI + 0 or more digits + m
-ANSI_STYLE_RE = re.compile(r'\033\[[0-9]*m')
+# Regular expression to match ANSI style sequences (including 8-bit and 24-bit colors)
+ANSI_STYLE_RE = re.compile(r'\x1b\[[^m]*m')
 
 # Foreground color presets
 FG_COLORS = {
@@ -72,8 +71,10 @@
 BG_RESET = BG_COLORS['reset']
 RESET_ALL = Style.RESET_ALL
 
-BRIGHT = Style.BRIGHT
-NORMAL = Style.NORMAL
+# Text intensities
+INTENSITY_BRIGHT = Style.BRIGHT
+INTENSITY_DIM = Style.DIM
+INTENSITY_NORMAL = Style.NORMAL
 
 # ANSI style sequences not provided by colorama
 UNDERLINE_ENABLE = colorama.ansi.code_to_chars(4)
@@ -139,7 +140,8 @@ def bg_lookup(bg_name: str) -> str:
     return ansi_escape
 
 
-def style(text: Any, *, fg: str = '', bg: str = '', bold: bool = False, underline: bool = False) -> str:
+def style(text: Any, *, fg: str = '', bg: str = '', bold: bool = False,
+          dim: bool = False, underline: bool = False) -> str:
     """
     Apply ANSI colors and/or styles to a string and return it.
     The styling is self contained which means that at the end of the string reset code(s) are issued
@@ -148,7 +150,8 @@ def style(text: Any, *, fg: str = '', bg: str = '', bold: bool = False, underlin
     :param text: Any object compatible with str.format()
     :param fg: foreground color. Relies on `fg_lookup()` to retrieve ANSI escape based on name. Defaults to no color.
     :param bg: background color. Relies on `bg_lookup()` to retrieve ANSI escape based on name. Defaults to no color.
-    :param bold: apply the bold style if True. Defaults to False.
+    :param bold: apply the bold style if True. Can be combined with dim. Defaults to False.
+    :param dim: apply the dim style if True. Can be combined with bold. Defaults to False.
     :param underline: apply the underline style if True. Defaults to False.
     :return: the stylized string
     """
@@ -171,8 +174,12 @@ def style(text: Any, *, fg: str = '', bg: str = '', bold: bool = False, underlin
         removals.append(BG_RESET)
 
     if bold:
-        additions.append(Style.BRIGHT)
-        removals.append(Style.NORMAL)
+        additions.append(INTENSITY_BRIGHT)
+        removals.append(INTENSITY_NORMAL)
+
+    if dim:
+        additions.append(INTENSITY_DIM)
+        removals.append(INTENSITY_NORMAL)
 
     if underline:
         additions.append(UNDERLINE_ENABLE)

tests/test_ansi.py

@@ -45,10 +45,16 @@ def test_style_bg():
 
 def test_style_bold():
     base_str = HELLO_WORLD
-    ansi_str = ansi.BRIGHT + base_str + ansi.NORMAL
+    ansi_str = ansi.INTENSITY_BRIGHT + base_str + ansi.INTENSITY_NORMAL
     assert ansi.style(base_str, bold=True) == ansi_str
 
 
+def test_style_dim():
+    base_str = HELLO_WORLD
+    ansi_str = ansi.INTENSITY_DIM + base_str + ansi.INTENSITY_NORMAL
+    assert ansi.style(base_str, dim=True) == ansi_str
+
+
 def test_style_underline():
     base_str = HELLO_WORLD
     ansi_str = ansi.UNDERLINE_ENABLE + base_str + ansi.UNDERLINE_DISABLE
@@ -59,9 +65,12 @@ def test_style_multi():
     base_str = HELLO_WORLD
     fg_color = 'blue'
     bg_color = 'green'
-    ansi_str = ansi.FG_COLORS[fg_color] + ansi.BG_COLORS[bg_color] + ansi.BRIGHT + ansi.UNDERLINE_ENABLE + \
-               base_str + ansi.FG_RESET + ansi.BG_RESET + ansi.NORMAL + ansi.UNDERLINE_DISABLE
-    assert ansi.style(base_str, fg=fg_color, bg=bg_color, bold=True, underline=True) == ansi_str
+    ansi_str = (ansi.FG_COLORS[fg_color] + ansi.BG_COLORS[bg_color] +
+                ansi.INTENSITY_BRIGHT + ansi.INTENSITY_DIM + ansi.UNDERLINE_ENABLE +
+                base_str +
+                ansi.FG_RESET + ansi.BG_RESET +
+                ansi.INTENSITY_NORMAL + ansi.INTENSITY_NORMAL + ansi.UNDERLINE_DISABLE)
+    assert ansi.style(base_str, fg=fg_color, bg=bg_color, bold=True, dim=True, underline=True) == ansi_str
 
 
 def test_style_color_not_exist():