Add diff options as icon buttons

gitfourchette/assets/style.qss

@@ -27,4 +27,5 @@ DiffView[dark="true"] { selection-background-color: rgba(255, 255, 255, 26%); }
 QFaintSeparator { border: none; background: rgba(0, 0, 0, 15%); }
 
 /* Remove QToolButton dropdown arrow in Fusion style */
+DiffButtons QToolButton::menu-indicator,
 GpgButton::menu-indicator { image: none; }

gitfourchette/codeview/codehighlighter.py

@@ -1,12 +1,13 @@
 # -----------------------------------------------------------------------------
-# Copyright (C) 2025 Iliyas Jorio.
+# Copyright (C) 2026 Iliyas Jorio.
 # This file is part of GitFourchette, distributed under the GNU GPL v3.
 # For full terms, see the included LICENSE file.
 # -----------------------------------------------------------------------------
 
 import logging
 
 from gitfourchette import colors
+from gitfourchette import settings
 from gitfourchette.syntax import ColorScheme, LexJob
 from gitfourchette.qt import *
 from gitfourchette.toolbox import benchmark, CallbackAccumulator
@@ -18,6 +19,10 @@ class CodeHighlighter(QSyntaxHighlighter):
     scheme: ColorScheme
     lexJobs: list[LexJob]
 
+    _whitespaceRegex = QRegularExpression("[ \t]+")
+    _whitespaceRegex.optimize()
+    assert _whitespaceRegex.isValid()
+
     def __init__(self, parent):
         super().__init__(parent)
 
@@ -50,8 +55,20 @@ def stopLexJobs(self):
         self.lexJobs.clear()
 
     def highlightBlock(self, text: str):
-        if self.scheme and self.lexJobs:
-            self.highlightSyntax(text)
+        if self.scheme:
+            # Highlight pygments tokens
+            if self.lexJobs:
+                self.highlightSyntax(text)
+
+            # Override highlighting on whitespace with a nicer muted color
+            if settings.prefs.showFormattingMarks:
+                charFormat = self.scheme.whitespaceFormat
+                wsIter = self._whitespaceRegex.globalMatch(text)
+                while wsIter.hasNext():
+                    match = wsIter.next()
+                    self.setFormat(match.capturedStart(), match.capturedLength(), charFormat)
+
+        # Override highlighting on search term
         if self.searchTerm:
             self.highlightSearch(text)
 

gitfourchette/codeview/codeview.py

@@ -40,6 +40,8 @@ class CodeView(QPlainTextEdit):
     currentLocator: NavLocator
     isDetachedWindow: bool
 
+    FormattingMarkFlags = QTextOption.Flag.ShowTabsAndSpaces
+
     def __init__(self, gutterClass, highlighterClass=CodeHighlighter, parent=None):
         super().__init__(parent)
 
@@ -284,6 +286,7 @@ def refreshPrefs(self, changeColorScheme=True):
         tabWidth = settings.prefs.tabSpaces
         self.setTabStopDistance(QFontMetricsF(monoFont).horizontalAdvance(' ' * tabWidth))
         self.refreshWordWrap()
+        self.refreshFormattingMarksOption()
         self.setCursorWidth(2)
 
         self.gutter.syncFont(monoFont)
@@ -307,7 +310,6 @@ def setColorScheme(self, scheme: ColorScheme):
         styleSheet = scheme.basicQss(self)
         self.setStyleSheet(styleSheet)
 
-
     def refreshWordWrap(self):
         if settings.prefs.wordWrap:
             wrapMode = QPlainTextEdit.LineWrapMode.WidgetWidth
@@ -327,7 +329,20 @@ def refreshWordWrap(self):
     def toggleWordWrap(self):
         settings.prefs.wordWrap = not settings.prefs.wordWrap
         settings.prefs.write()
-        self.refreshWordWrap()
+        GFApplication.instance().prefsChanged.emit(["wordWrap"])
+
+    def refreshFormattingMarksOption(self):
+        doc = self.document()
+        if doc is None:
+            return
+        opt = QTextOption(doc.defaultTextOption())
+        flags = opt.flags()
+        if settings.prefs.showFormattingMarks:
+            flags |= self.FormattingMarkFlags
+        else:
+            flags &= ~self.FormattingMarkFlags
+        opt.setFlags(flags)
+        doc.setDefaultTextOption(opt)
 
     # ---------------------------------------------
     # Context menu

gitfourchette/diffarea.py

@@ -8,6 +8,8 @@
 import typing
 from typing import Literal
 
+from gitfourchette.application import GFApplication
+from gitfourchette.diffbuttons import DiffButtons
 from gitfourchette.diffview.diffview import DiffView
 from gitfourchette.diffview.specialdiffview import SpecialDiffView
 from gitfourchette.filelists.committedfiles import CommittedFiles
@@ -80,6 +82,9 @@ def __init__(self, repoModel, parent):
         ):
             passiveWidget.setTextInteractionFlags(Qt.TextInteractionFlag.NoTextInteraction)
 
+        GFApplication.instance().prefsChanged.connect(self.diffButtons.refreshPrefs)
+        self.diffButtons.refreshPrefs()
+
         # Ignore height in size policy to keep DiffArea from jumping around when we're showing a banner.
         self.setSizePolicy(self.sizePolicy().horizontalPolicy(), QSizePolicy.Policy.Ignored)
         self.setMinimumHeight(175)
@@ -253,13 +258,18 @@ def _makeDiffContainer(self, repoModel):
         header.setObjectName("diffHeader")
         header.setMinimumHeight(FILEHEADER_HEIGHT)
         header.setContentsMargins(4, 0, 4, 0)
-        # Don't let header dictate window width if displaying long filename
+        header.setAlignment(Qt.AlignmentFlag.AlignLeft | Qt.AlignmentFlag.AlignVCenter)
+        # Absorb horizontal space so the path stays left and toolbar stays right.
         header.setSizePolicy(QSizePolicy.Policy.Ignored, QSizePolicy.Policy.Minimum)
 
+        diffTools = DiffButtons(self)
+
         topContainer = QWidget(self)
         topLayout = QHBoxLayout(topContainer)
         topLayout.setContentsMargins(0, 0, 0, 0)
-        topLayout.addWidget(header)
+        topLayout.setSpacing(0)
+        topLayout.addWidget(header, 1)
+        topLayout.addWidget(diffTools, 0)
 
         diff = DiffView(self)
 
@@ -296,17 +306,25 @@ def _makeDiffContainer(self, repoModel):
         self.conflictView = conflict
         self.specialDiffView = specialDiff
         self.diffView = diff
+        self.diffButtons = diffTools
 
         return stackContainer
 
     def applyCustomStyling(self):
-        for smallButton in self.discardButton, self.unstageButton, self.stageButton:
+        for smallButton in (
+                self.discardButton,
+                self.unstageButton,
+                self.stageButton,
+                *self.diffButtons.buttons,
+        ):
             smallButton.setMaximumHeight(FILEHEADER_HEIGHT)
-            smallButton.setEnabled(False)
             smallButton.setFocusPolicy(Qt.FocusPolicy.NoFocus)
             smallButton.setAutoRaise(True)
             smallButton.setToolButtonStyle(Qt.ToolButtonStyle.ToolButtonIconOnly)
 
+        for button in self.stageButton, self.unstageButton, self.discardButton:
+            button.setEnabled(False)
+
         for button in self.stageButton, self.unstageButton:
             button.setToolButtonStyle(Qt.ToolButtonStyle.ToolButtonTextBesideIcon)
 
@@ -320,6 +338,7 @@ def applyCustomStyling(self):
                 self.stageButton,
                 self.unstageButton,
                 self.discardButton,
+                *self.diffButtons.buttons,
         ):
             tweakWidgetFont(smallWidget, 90)
 

gitfourchette/diffbuttons.py

@@ -0,0 +1,131 @@
+# -----------------------------------------------------------------------------
+# Copyright (C) 2026 Iliyas Jorio.
+# This file is part of GitFourchette, distributed under the GNU GPL v3.
+# For full terms, see the included LICENSE file.
+# -----------------------------------------------------------------------------
+
+from gitfourchette import settings
+from gitfourchette.application import GFApplication
+from gitfourchette.qt import *
+from gitfourchette.settings import ComparisonMethod
+from gitfourchette.toolbox import *
+from gitfourchette.trtables import TrTables
+
+_ComparisonMethodIconTable = {
+    ComparisonMethod.Strict: "diff-whitespace-strict",
+    ComparisonMethod.IgnoreCrAtEol: "diff-whitespace-ignore-eol",
+    ComparisonMethod.IgnoreCrAtEolAndSpaceChange: "diff-whitespace-ignore-space-change",
+    ComparisonMethod.IgnoreCrAtEolAndAllSpace: "diff-whitespace-ignore-all-space",
+}
+
+
+class DiffButtons(QWidget):
+    def __init__(self, parent):
+        super().__init__(parent)
+
+        self.diffMethodActions: dict[ComparisonMethod, QAction] = {}
+
+        self.wordWrapButton = self._makeWordWrapButton()
+        self.marksButton = self._makeMarksButton()
+        self.diffMethodButton = self._makeDiffMethodButton()
+
+        layout = QHBoxLayout(self)
+        layout.setContentsMargins(0, 0, 2, 0)
+        layout.setSpacing(2)
+        for button in self.buttons:
+            layout.addWidget(button)
+
+    @property
+    def buttons(self):
+        return self.wordWrapButton, self.marksButton, self.diffMethodButton
+
+    # -------------------------------------------------------------------------
+    # Constructor helpers
+
+    def _makeWordWrapButton(self):
+        button = QToolButton(self)
+        button.setCheckable(True)
+        button.setIcon(stockIcon("format-text-wrap"))
+        button.setToolTip(TrTables.prefKey("wordWrap"))
+        button.toggled.connect(self.onWordWrapToggled)
+        return button
+
+    def _makeMarksButton(self):
+        button = QToolButton(self)
+        button.setCheckable(True)
+        button.setIcon(stockIcon("paragraph"))
+        button.setToolTip(TrTables.prefKey("showFormattingMarks"))
+        button.toggled.connect(self.onMarksToggled)
+        return button
+
+    def _makeDiffMethodButton(self):
+        menu = QMenu(self)
+
+        actionGroup = QActionGroup(menu)
+        actionGroup.setExclusive(True)
+
+        for method in ComparisonMethod:
+            label = escamp(TrTables.enum(method))
+            action = QAction(label)
+            action.setIcon(stockIcon(_ComparisonMethodIconTable[method]))
+            action.triggered.connect(lambda _dummy, m=method: self.onDiffMethodChosen(m))
+            action.setActionGroup(actionGroup)
+            action.setCheckable(True)
+            menu.addAction(action)
+            self.diffMethodActions[method] = action
+
+        button = QToolButton(self)
+        button.setMenu(menu)
+        button.setPopupMode(QToolButton.ToolButtonPopupMode.InstantPopup)
+        button.setToolButtonStyle(Qt.ToolButtonStyle.ToolButtonIconOnly)
+        return button
+
+    # -------------------------------------------------------------------------
+    # Sync with preferences
+
+    def refreshPrefs(self):
+        with QSignalBlockerContext(
+                self.wordWrapButton,
+                self.marksButton,
+                *self.diffMethodActions.values(),
+        ):
+            self.wordWrapButton.setChecked(settings.prefs.wordWrap)
+            self.marksButton.setChecked(settings.prefs.showFormattingMarks)
+
+            method = settings.prefs.comparisonMethod
+            for m, action in self.diffMethodActions.items():
+                action.setChecked(m == method)
+            action = self.diffMethodActions[method]
+
+            toolTip = stripAccelerators(action.text())
+            self.diffMethodButton.setIcon(action.icon())
+            self.diffMethodButton.setToolTip(toolTip)
+
+    # -------------------------------------------------------------------------
+    # Button callbacks
+
+    def onWordWrapToggled(self, checked: bool):
+        if settings.prefs.wordWrap == checked:
+            return
+        settings.prefs.wordWrap = checked
+        settings.prefs.write()
+        GFApplication.instance().prefsChanged.emit(["wordWrap"])
+
+    def onMarksToggled(self, checked: bool):
+        if settings.prefs.showFormattingMarks == checked:
+            return
+        settings.prefs.showFormattingMarks = checked
+        settings.prefs.write()
+        GFApplication.instance().prefsChanged.emit(["showFormattingMarks"])
+
+    def onDiffMethodChosen(self, method: settings.ComparisonMethod):
+        if settings.prefs.comparisonMethod == method:
+            return
+        settings.prefs.comparisonMethod = method
+        settings.prefs.write()
+
+        GFApplication.instance().prefsChanged.emit(["comparisonMethod"])
+
+        # Trigger a reload of the patch
+        # TODO: This is inelegant, but it does the job for now. Ideally prefsChanged would suffice?
+        GFApplication.instance().mainWindow.onAcceptPrefsDialog({"comparisonMethod": method})

gitfourchette/diffview/diffhighlighter.py

@@ -44,7 +44,7 @@ def highlightSyntax(self, text: str):
         if not lineData.origin:  # Hunk header, etc.
             return
 
-        if lineData.origin == '+':
+        if lineData.origin != '-':
             lexJob = self.newLexJob
             lineNumber = lineData.newLineNo
         else:

gitfourchette/diffview/diffview.py

@@ -61,6 +61,7 @@ def __init__(self, parent=None):
         self.gutter.lineDoubleClicked.connect(self.selectClumpOfLinesAt)
         self.gutter.selectionMiddleClicked.connect(self.onMiddleClick)
 
+
     def _initRubberBandButtons(self):
         self.stageButton = QToolButton()
         self.stageButton.setText(_("Stage Selection"))

gitfourchette/diffview/specialdiff.py

@@ -21,6 +21,7 @@
 from gitfourchette.nav import NavLocator, NavContext, NavFlags
 from gitfourchette.porcelain import *
 from gitfourchette.qt import *
+from gitfourchette.settings import ComparisonMethod
 from gitfourchette.tasks import RepoTask
 from gitfourchette.toolbox import *
 from gitfourchette.trtables import TrTables
@@ -98,6 +99,14 @@ def noChange(repo: Repo, delta: GitDelta, stderr: str = ""):
                 assert delta.status in "A?"  # added or untracked
                 message = _("New empty file.")
 
+        if (newFileExists
+                and oldFileExists
+                and newFile.id != oldFile.id
+                and settings.prefs.comparisonMethod != ComparisonMethod.Strict):
+            message = _("Whitespace changes ignored. Contents otherwise identical.")
+            detailsLine = "{}{} {}.".format(TrTables.prefKey("comparisonMethod"), _(":"), TrTables.enum(settings.prefs.comparisonMethod))
+            details.append(detailsLine)
+
         if oldFile.path != newFile.path:
             intro = _("Renamed:")
             details.append(f"{intro} {hquo(oldFile.path)} → {hquo(newFile.path)}.")