bpo-33679: IDLE: Re-enable color configuration for code context (GH-7199)

The difference from before is that the settings are now on the
Highlights tab instead of the Extensions tab and only change one theme
at a time instead of all themes. The default for light themes is black
on light gray, as before. The default for the IDLE Dark theme is white
on dark gray, which better fits the dark theme.

When one starts IDLE from a console and loads a custom theme without
definitions for 'context', one will see a warning message on the console.
To stop the warning, go to Options => Configure IDLE => Highlights,
select the custom theme if not selected already, select 'Code Context',
and select foreground and background colors.

6 files changed, 79 insertions, 35 deletions

diff --git a/Lib/idlelib/codecontext.py b/Lib/idlelib/codecontext.py
index b061f3b..78edf12 100644
--- a/Lib/idlelib/codecontext.py
+++ b/Lib/idlelib/codecontext.py
@@ -20,7 +20,7 @@ from idlelib.config import idleConf
 BLOCKOPENERS = {"class", "def", "elif", "else", "except", "finally", "for",
                 "if", "try", "while", "with", "async"}
 UPDATEINTERVAL = 100 # millisec
-FONTUPDATEINTERVAL = 1000 # millisec
+CONFIGUPDATEINTERVAL = 1000 # millisec
 
 
 def get_spaces_firstword(codeline, c=re.compile(r"^(\s*)(\w*)")):
@@ -45,9 +45,6 @@ def get_line_info(codeline):
 class CodeContext:
     "Display block context above the edit window."
 
-    bgcolor = "LightGray"
-    fgcolor = "Black"
-
     def __init__(self, editwin):
         """Initialize settings for context block.
 
@@ -69,22 +66,20 @@ class CodeContext:
         self.editwin = editwin
         self.text = editwin.text
         self.textfont = self.text["font"]
+        self.contextcolors = CodeContext.colors
         self.label = None
         self.topvisible = 1
         self.info = [(0, -1, "", False)]
         # Start two update cycles, one for context lines, one for font changes.
         self.t1 = self.text.after(UPDATEINTERVAL, self.timer_event)
-        self.t2 = self.text.after(FONTUPDATEINTERVAL, self.font_timer_event)
+        self.t2 = self.text.after(CONFIGUPDATEINTERVAL, self.config_timer_event)
 
     @classmethod
     def reload(cls):
         "Load class variables from config."
         cls.context_depth = idleConf.GetOption("extensions", "CodeContext",
                                        "maxlines", type="int", default=15)
-##        cls.bgcolor = idleConf.GetOption("extensions", "CodeContext",
-##                                     "bgcolor", type="str", default="LightGray")
-##        cls.fgcolor = idleConf.GetOption("extensions", "CodeContext",
-##                                     "fgcolor", type="str", default="Black")
+        cls.colors = idleConf.GetHighlight(idleConf.CurrentTheme(), 'context')
 
     def __del__(self):
         "Cancel scheduled events."
@@ -118,7 +113,8 @@ class CodeContext:
             self.label = tkinter.Label(
                     self.editwin.top, text="",
                     anchor=W, justify=LEFT, font=self.textfont,
-                    bg=self.bgcolor, fg=self.fgcolor,
+                    bg=self.contextcolors['background'],
+                    fg=self.contextcolors['foreground'],
                     width=1,  # Don't request more than we get.
                     padx=padx, border=border, relief=SUNKEN)
             # Pack the label widget before and above the text_frame widget,
@@ -202,13 +198,17 @@ class CodeContext:
             self.update_code_context()
         self.t1 = self.text.after(UPDATEINTERVAL, self.timer_event)
 
-    def font_timer_event(self):
-        "Event on editor text widget triggered every FONTUPDATEINTERVAL ms."
+    def config_timer_event(self):
+        "Event on editor text widget triggered every CONFIGUPDATEINTERVAL ms."
         newtextfont = self.text["font"]
-        if self.label and newtextfont != self.textfont:
+        if (self.label and (newtextfont != self.textfont or
+                            CodeContext.colors != self.contextcolors)):
             self.textfont = newtextfont
+            self.contextcolors = CodeContext.colors
             self.label["font"] = self.textfont
-        self.t2 = self.text.after(FONTUPDATEINTERVAL, self.font_timer_event)
+            self.label['background'] = self.contextcolors['background']
+            self.label['foreground'] = self.contextcolors['foreground']
+        self.t2 = self.text.after(CONFIGUPDATEINTERVAL, self.config_timer_event)
 
 
 CodeContext.reload()
diff --git a/Lib/idlelib/config-highlight.def b/Lib/idlelib/config-highlight.def
index 4146e28..aaa2b57 100644
--- a/Lib/idlelib/config-highlight.def
+++ b/Lib/idlelib/config-highlight.def
@@ -31,6 +31,8 @@ stderr-foreground= red
 stderr-background= #ffffff
 console-foreground= #770000
 console-background= #ffffff
+context-foreground= #000000
+context-background= lightgray
 
 [IDLE New]
 normal-foreground= #000000
@@ -62,6 +64,8 @@ stderr-foreground= red
 stderr-background= #ffffff
 console-foreground= #770000
 console-background= #ffffff
+context-foreground= #000000
+context-background= lightgray
 
 [IDLE Dark]
 comment-foreground = #dd0000
@@ -91,3 +95,5 @@ stdout-background = #002240
 hit-foreground = #002240
 comment-background = #002240
 break-foreground = #FFFFFF
+context-foreground= #ffffff
+context-background= #454545
diff --git a/Lib/idlelib/config.py b/Lib/idlelib/config.py
index c3e57bc..94b2083 100644
--- a/Lib/idlelib/config.py
+++ b/Lib/idlelib/config.py
@@ -360,6 +360,8 @@ class IdleConf:
                 'stderr-background':'#ffffff',
                 'console-foreground':'#000000',
                 'console-background':'#ffffff',
+                'context-foreground':'#000000',
+                'context-background':'#ffffff',
                 }
         for element in theme:
             if not cfgParser.has_option(themeName, element):
diff --git a/Lib/idlelib/configdialog.py b/Lib/idlelib/configdialog.py
index 28ad458..7df69d5 100644
--- a/Lib/idlelib/configdialog.py
+++ b/Lib/idlelib/configdialog.py
@@ -799,19 +799,20 @@ class HighPage(Frame):
         """
         self.theme_elements = {
             'Normal Text': ('normal', '00'),
-            'Python Keywords': ('keyword', '01'),
-            'Python Definitions': ('definition', '02'),
-            'Python Builtins': ('builtin', '03'),
-            'Python Comments': ('comment', '04'),
-            'Python Strings': ('string', '05'),
-            'Selected Text': ('hilite', '06'),
-            'Found Text': ('hit', '07'),
-            'Cursor': ('cursor', '08'),
-            'Editor Breakpoint': ('break', '09'),
-            'Shell Normal Text': ('console', '10'),
-            'Shell Error Text': ('error', '11'),
-            'Shell Stdout Text': ('stdout', '12'),
-            'Shell Stderr Text': ('stderr', '13'),
+            'Code Context': ('context', '01'),
+            'Python Keywords': ('keyword', '02'),
+            'Python Definitions': ('definition', '03'),
+            'Python Builtins': ('builtin', '04'),
+            'Python Comments': ('comment', '05'),
+            'Python Strings': ('string', '06'),
+            'Selected Text': ('hilite', '07'),
+            'Found Text': ('hit', '08'),
+            'Cursor': ('cursor', '09'),
+            'Editor Breakpoint': ('break', '10'),
+            'Shell Normal Text': ('console', '11'),
+            'Shell Error Text': ('error', '12'),
+            'Shell Stdout Text': ('stdout', '13'),
+            'Shell Stderr Text': ('stderr', '14'),
             }
         self.builtin_name = tracers.add(
                 StringVar(self), self.var_changed_builtin_name)
@@ -842,6 +843,7 @@ class HighPage(Frame):
             ('\n', 'normal'),
             ('#you can click here', 'comment'), ('\n', 'normal'),
             ('#to choose items', 'comment'), ('\n', 'normal'),
+            ('code context section', 'context'), ('\n\n', 'normal'),
             ('def', 'keyword'), (' ', 'normal'),
             ('func', 'definition'), ('(param):\n  ', 'normal'),
             ('"""string"""', 'string'), ('\n  var0 = ', 'normal'),
diff --git a/Lib/idlelib/idle_test/test_codecontext.py b/Lib/idlelib/idle_test/test_codecontext.py
index 4c775ee..d446090 100644
--- a/Lib/idlelib/idle_test/test_codecontext.py
+++ b/Lib/idlelib/idle_test/test_codecontext.py
@@ -110,6 +110,8 @@ class CodeContextTest(unittest.TestCase):
 
     def test_reload(self):
         codecontext.CodeContext.reload()
+        self.assertEqual(self.cc.colors, {'background': 'lightgray',
+                                          'foreground': '#000000'})
         self.assertEqual(self.cc.context_depth, 15)
 
     def test_toggle_code_context_event(self):
@@ -125,8 +127,8 @@ class CodeContextTest(unittest.TestCase):
         eq(toggle(), 'break')
         self.assertIsNotNone(cc.label)
         eq(cc.label['font'], cc.textfont)
-        eq(cc.label['fg'], cc.fgcolor)
-        eq(cc.label['bg'], cc.bgcolor)
+        eq(cc.label['fg'], cc.colors['foreground'])
+        eq(cc.label['bg'], cc.colors['background'])
         eq(cc.label['text'], '')
 
         # Toggle off.
@@ -275,11 +277,13 @@ class CodeContextTest(unittest.TestCase):
         self.cc.timer_event()
         mock_update.assert_called()
 
-    def test_font_timer_event(self):
+    def test_config_timer_event(self):
         eq = self.assertEqual
         cc = self.cc
         save_font = cc.text['font']
+        save_colors = codecontext.CodeContext.colors
         test_font = 'FakeFont'
+        test_colors = {'background': '#222222', 'foreground': '#ffff00'}
 
         # Ensure code context is not active.
         if cc.label:
@@ -287,24 +291,42 @@ class CodeContextTest(unittest.TestCase):
 
         # Nothing updates on inactive code context.
         cc.text['font'] = test_font
-        cc.font_timer_event()
+        codecontext.CodeContext.colors = test_colors
+        cc.config_timer_event()
         eq(cc.textfont, save_font)
+        eq(cc.contextcolors, save_colors)
 
-        # Activate code context, but no change to font.
+        # Activate code context, but no change to font or color.
         cc.toggle_code_context_event()
         cc.text['font'] = save_font
-        cc.font_timer_event()
+        codecontext.CodeContext.colors = save_colors
+        cc.config_timer_event()
         eq(cc.textfont, save_font)
+        eq(cc.contextcolors, save_colors)
         eq(cc.label['font'], save_font)
+        eq(cc.label['background'], save_colors['background'])
+        eq(cc.label['foreground'], save_colors['foreground'])
 
         # Active code context, change font.
         cc.text['font'] = test_font
-        cc.font_timer_event()
+        cc.config_timer_event()
         eq(cc.textfont, test_font)
+        eq(cc.contextcolors, save_colors)
         eq(cc.label['font'], test_font)
+        eq(cc.label['background'], save_colors['background'])
+        eq(cc.label['foreground'], save_colors['foreground'])
 
+        # Active code context, change color.
         cc.text['font'] = save_font
-        cc.font_timer_event()
+        codecontext.CodeContext.colors = test_colors
+        cc.config_timer_event()
+        eq(cc.textfont, save_font)
+        eq(cc.contextcolors, test_colors)
+        eq(cc.label['font'], save_font)
+        eq(cc.label['background'], test_colors['background'])
+        eq(cc.label['foreground'], test_colors['foreground'])
+        codecontext.CodeContext.colors = save_colors
+        cc.config_timer_event()
 
 
 class HelperFunctionText(unittest.TestCase):
diff --git a/Misc/NEWS.d/next/IDLE/2018-05-29-07-14-37.bpo-33679.MgX_Ui.rst b/Misc/NEWS.d/next/IDLE/2018-05-29-07-14-37.bpo-33679.MgX_Ui.rst
new file mode 100644
index 0000000..43d78b0
--- /dev/null
+++ b/Misc/NEWS.d/next/IDLE/2018-05-29-07-14-37.bpo-33679.MgX_Ui.rst
@@ -0,0 +1,12 @@
+IDLE: Re-enable color configuration for Code Context.
+The difference from before is that the settings are now on the
+Highlights tab instead of the Extensions tab and only change one theme
+at a time instead of all themes.  The default for light themes is black
+on light gray, as before.  The default for the IDLE Dark theme is white
+on dark gray, which better fits the dark theme.
+
+When one starts IDLE from a console and loads a custom theme without
+definitions for 'context', one will see a warning message on the console.
+To stop the warning, go to Options => Configure IDLE => Highlights,
+select the custom theme if not selected already, select 'Code Context',
+and select foreground and background colors.