IJPL-251582 [editor, markdown, terminal] soft-wraps: make optimized grid mode soft-wrapping algo opt-in

IJ-CR-217736

Because the optimization also alters behavior by not respecting LineWrapPositionStrategy

(cherry picked from commit a402c423489e5b679babc7e7986b8e6635342aa9)

GitOrigin-RevId: 9c3665181035655699f28d5deb3d5bb55d3c736f

platform/platform-impl/src/com/intellij/openapi/editor/impl/SoftWrapEngine.java

@@ -42,6 +42,7 @@ public final class SoftWrapEngine {
   private final int mySoftWrapWidth;
   private final IncrementalCacheUpdateEvent myEvent;
   private final int myRelativeIndent;
+  private final boolean myAllowGridModeOptimizations;
 
   private LineWrapPositionStrategy myLineWrapPositionStrategy;
 
@@ -52,7 +53,8 @@ public final class SoftWrapEngine {
                         @NotNull IncrementalCacheUpdateEvent event,
                         @Nullable LineWrapPositionStrategy lineWrapStrategy,
                         int visibleWidth,
-                        int relativeIndent) {
+                        int relativeIndent,
+                        boolean allowGridModeOptimizations) {
     myEditor = editor;
     myDocument = editor.getElfDocument();
     myText = myDocument.getImmutableCharSequence();
@@ -65,6 +67,7 @@ public final class SoftWrapEngine {
     myEvent = event;
     myRelativeIndent = relativeIndent;
     myLineWrapPositionStrategy = lineWrapStrategy;
+    myAllowGridModeOptimizations = allowGridModeOptimizations;
   }
 
   public void generate() {
@@ -79,7 +82,8 @@ public final class SoftWrapEngine {
     var customWraps = myEditor.getCustomWrapModel().getWrapsInRange(startOffset, maxEndOffset);
 
     var grid = myEditor.getCharacterGrid();
-    if (grid != null && inlineInlays.isEmpty() && afterLineEndInlays.isEmpty() && customWraps.isEmpty()
+    if (grid != null && myAllowGridModeOptimizations
+        && inlineInlays.isEmpty() && afterLineEndInlays.isEmpty() && customWraps.isEmpty()
         && !SoftWrapHelper.hasCollapsedOffsetsIn(myEditor.getFoldingModel(), startOffset, maxEndOffset)) {
       generateGridSoftWraps(grid, startOffset, minEndOffset, maxEndOffset);
       return;

platform/platform-impl/src/com/intellij/openapi/editor/impl/softwrap/mapping/SoftWrapApplianceManager.java

@@ -98,6 +98,7 @@ public final class SoftWrapApplianceManager implements Dumpable {
   private int                            myDocumentChangeEndOffset = -1;
   private int                            myAvailableWidth = QUICK_DUMMY_WRAPPING;
   private @Nullable LineWrapPositionStrategy myLineWrapPositionStrategy;
+  private boolean                        myAllowGridModeOptimizations;
 
 
   @ApiStatus.Internal
@@ -125,6 +126,12 @@ public final class SoftWrapApplianceManager implements Dumpable {
     mySoftWrapsUnderScrollBar = softWrapsUnderScrollBar;
   }
 
+  @ApiStatus.Internal
+  public void setAllowGridModeOptimizations(boolean allowGridModeOptimizations) {
+    myAllowGridModeOptimizations = allowGridModeOptimizations;
+    reset();
+  }
+
   @ApiStatus.Internal
   public void reset() {
     myIsDirty = true;
@@ -215,7 +222,7 @@ public final class SoftWrapApplianceManager implements Dumpable {
       }
       else {
         new SoftWrapEngine(myEditor, myPainter, myStorage, myDataMapper, event, myLineWrapPositionStrategy, myVisibleAreaWidth,
-                           myCustomIndentUsedLastTime ? myCustomIndentValueUsedLastTime : -1).generate();
+                           myCustomIndentUsedLastTime ? myCustomIndentValueUsedLastTime : -1, myAllowGridModeOptimizations).generate();
       }
       if (LOG.isDebugEnabled()) {
         LOG.debug("Soft wrap recalculation done: " + event + ". " + (event.getActualEndOffset() - event.getStartOffset()) + " characters processed");

platform/platform-tests/testSrc/com/intellij/openapi/editor/impl/EditorCharacterGridSizeTest.java

@@ -1,16 +1,30 @@
 // Copyright 2000-2026 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 package com.intellij.openapi.editor.impl;
 
+import com.intellij.openapi.editor.Document;
+import com.intellij.openapi.editor.LineWrapPositionStrategy;
 import com.intellij.openapi.editor.ex.EditorEx;
+import com.intellij.openapi.editor.impl.softwrap.mapping.SoftWrapApplianceManager;
+import com.intellij.openapi.project.Project;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 public class EditorCharacterGridSizeTest extends AbstractEditorTest {
   private static final String LONG_LINE = "x".repeat(200);
   private static final int CONTENT_WIDTH = LONG_LINE.length() * TEST_CHAR_WIDTH;
+  private static final char WRAP_MARKER = '|';
 
-  private void enableGridMode() {
+  private @NotNull SoftWrapApplianceManager softWrapApplianceManager() {
+    return ((SoftWrapModelImpl)getEditor().getSoftWrapModel()).getApplianceManager();
+  }
+
+  private void enableGridMode(boolean allowSoftWrapOptimizations) {
     getEditor().getSettings().setCharacterGridWidthMultiplier(1.0f);
     ((EditorEx)getEditor()).reinitSettings();
     assertNotNull(((EditorImpl)getEditor()).getCharacterGrid());
+    var softWrapApplianceManager = softWrapApplianceManager();
+    softWrapApplianceManager.setAllowGridModeOptimizations(allowSoftWrapOptimizations);
+    softWrapApplianceManager.recalculateIfNecessary("allow grid mode optimizations maybe toggled");
   }
 
   private int preferredWidth() {
@@ -22,7 +36,7 @@ public class EditorCharacterGridSizeTest extends AbstractEditorTest {
     initText(LONG_LINE);
     getEditor().getSettings().setAdditionalColumnsCount(0);
     setEditorVisibleSize(20, 10);
-    enableGridMode();
+    enableGridMode(false);
 
     assertTrue(getEditor().getScrollingModel().getVisibleArea().width < CONTENT_WIDTH);
     assertTrue("preferred=" + preferredWidth(), preferredWidth() >= CONTENT_WIDTH);
@@ -33,7 +47,7 @@ public class EditorCharacterGridSizeTest extends AbstractEditorTest {
     initText(LONG_LINE);
     getEditor().getSettings().setAdditionalColumnsCount(0);
     configureSoftWraps(20);
-    enableGridMode();
+    enableGridMode(true);
 
     assertTrue("preferred=" + preferredWidth(), preferredWidth() < CONTENT_WIDTH);
   }
@@ -43,8 +57,46 @@ public class EditorCharacterGridSizeTest extends AbstractEditorTest {
     initText(LONG_LINE.substring(0, 20));
     configureSoftWraps(10, false);
     addCollapsedFoldRegion(8, 14, "..."); // covers the grid column boundary at offset 11
-    enableGridMode();
+    enableGridMode(true);
 
     verifySoftWrapPositions(8);
   }
+
+  // The grid mode soft-wrapping optimization is not a pure optimization:
+  //  it places wraps at grid column boundaries without consulting LineWrapPositionStrategy.
+  // Grid editors that didn't opt in should keep the strategy-based wrap positions.
+  public void testGridEditorWithoutSoftWrapOptimizationsRespectsLineWrapPositionStrategy() {
+    initText(("xxx" + WRAP_MARKER).repeat(10));
+    configureSoftWraps(10, false);
+    softWrapApplianceManager().setLineWrapPositionStrategy(new MarkerLineWrapPositionStrategy());
+    enableGridMode(/* allowSoftWrapOptimizations */ false);
+
+    verifySoftWrapPositions(7, 15, 23, 31);
+  }
+
+  // Wraps right before {@link #WRAP_MARKER} only
+  private static final class MarkerLineWrapPositionStrategy implements LineWrapPositionStrategy {
+    @Override
+    public int calculateWrapPosition(@NotNull Document document,
+                                     @Nullable Project project,
+                                     int startOffset,
+                                     int endOffset,
+                                     int maxPreferredOffset,
+                                     boolean allowToBeyondMaxPreferredOffset,
+                                     boolean isSoftWrap) {
+      assertTrue(isSoftWrap);
+      CharSequence text = document.getImmutableCharSequence();
+      for (int offset = endOffset - 1; offset > startOffset; offset--) {
+        if (text.charAt(offset) == WRAP_MARKER) {
+          return offset;
+        }
+      }
+      return -1;
+    }
+
+    @Override
+    public boolean canWrapLineAtOffset(CharSequence text, int offset) {
+      return false;
+    }
+  }
 }

plugins/terminal/frontend/src/com/intellij/terminal/frontend/view/impl/TerminalEditorFactory.kt

@@ -154,6 +154,7 @@ object TerminalEditorFactory {
     editor.settings.isUseCustomSoftWrapIndent = false
     val softWrapModel = editor.softWrapModel
     softWrapModel.applianceManager.setLineWrapPositionStrategy(TerminalLineWrapPositionStrategy())
+    softWrapModel.applianceManager.setAllowGridModeOptimizations(true)
     softWrapModel.applianceManager.setSoftWrapsUnderScrollBar(true)
     softWrapModel.setSoftWrapPainter(EmptySoftWrapPainter)
   }