terminal: refactor default background/foreground to use JBColor.lazy instead of direct color updating on colors scheme changes

Now, it's as simple as `component.background = TerminalUi.defaultBackground()` to use terminal default background color as component background and update it properly on colors scheme changes.

GitOrigin-RevId: c507f417a7042d22a17afc0a01a80ff67b997787

plugins/terminal/src/org/jetbrains/plugins/terminal/exp/BlockTerminalView.kt

@@ -13,7 +13,6 @@ import com.intellij.openapi.fileEditor.FileDocumentManager
 import com.intellij.openapi.project.Project
 import com.intellij.openapi.util.Disposer
 import com.intellij.openapi.wm.IdeFocusManager
-import com.intellij.terminal.BlockTerminalColors
 import com.intellij.terminal.JBTerminalSystemSettingsProviderBase
 import com.intellij.terminal.TerminalTitle
 import com.intellij.terminal.bindApplicationTitle
@@ -261,9 +260,7 @@ class BlockTerminalView(
 
   private inner class BlockTerminalPanel : JPanel(), DataProvider {
     init {
-      bindBackgroundToColorKey(BlockTerminalColors.DEFAULT_BACKGROUND,
-                               this@BlockTerminalView,
-                               outputView.controller.outputModel.editor)
+      background = TerminalUi.defaultBackground(outputView.controller.outputModel.editor)
     }
 
     override fun getData(dataId: String): Any? {

plugins/terminal/src/org/jetbrains/plugins/terminal/exp/SimpleTerminalView.kt

@@ -11,9 +11,9 @@ import com.intellij.openapi.editor.impl.DocumentImpl
 import com.intellij.openapi.editor.impl.EditorImpl
 import com.intellij.openapi.project.Project
 import com.intellij.openapi.util.Disposer
-import com.intellij.terminal.BlockTerminalColors
 import com.intellij.terminal.JBTerminalSystemSettingsProviderBase
 import com.intellij.util.ui.JBUI
+import org.jetbrains.plugins.terminal.exp.TerminalUi.useTerminalDefaultBackground
 import java.awt.BorderLayout
 import java.awt.Dimension
 import javax.swing.JComponent
@@ -46,7 +46,7 @@ class SimpleTerminalView(
   init {
     editor = createEditor()
     controller = SimpleTerminalController(settings, session, editor)
-    component = SimpleTerminalPanel(editor, this)
+    component = SimpleTerminalPanel(editor)
     editor.addFocusListener(object : FocusChangeListener {
       override fun focusGained(editor: Editor) {
         controller.isFocused = true
@@ -61,9 +61,7 @@ class SimpleTerminalView(
   private fun createEditor(): EditorImpl {
     val document = DocumentImpl("", true)
     val editor = TerminalUiUtils.createOutputEditor(document, project, settings)
-    bindColorKey(BlockTerminalColors.DEFAULT_BACKGROUND, this, editor) {
-      editor.setBackgroundColor(it)
-    }
+    editor.useTerminalDefaultBackground(this)
     editor.settings.isLineMarkerAreaShown = false
     editor.scrollPane.verticalScrollBarPolicy = if (withVerticalScroll) {
       JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED
@@ -83,9 +81,9 @@ class SimpleTerminalView(
    * This wrapper is needed to provide the editor to the DataContext.
    * Editor is not proving it itself, because renderer mode is enabled ([EditorImpl.isRendererMode]).
    */
-  private inner class SimpleTerminalPanel(editor: Editor, parentDisposable: Disposable) : JPanel(), DataProvider {
+  private inner class SimpleTerminalPanel(editor: Editor) : JPanel(), DataProvider {
     init {
-      bindBackgroundToColorKey(BlockTerminalColors.DEFAULT_BACKGROUND, parentDisposable, editor)
+      background = TerminalUi.defaultBackground(editor)
       border = JBUI.Borders.emptyLeft(TerminalUi.alternateBufferLeftInset)
       layout = BorderLayout()
       add(editor.component, BorderLayout.CENTER)

plugins/terminal/src/org/jetbrains/plugins/terminal/exp/TerminalOutputView.kt

@@ -9,10 +9,10 @@ import com.intellij.openapi.editor.EditorFactory
 import com.intellij.openapi.editor.impl.DocumentImpl
 import com.intellij.openapi.editor.impl.EditorImpl
 import com.intellij.openapi.project.Project
-import com.intellij.terminal.BlockTerminalColors
 import com.intellij.terminal.JBTerminalSystemSettingsProviderBase
 import com.intellij.ui.components.JBLayeredPane
 import com.intellij.util.concurrency.annotations.RequiresEdt
+import org.jetbrains.plugins.terminal.exp.TerminalUi.useTerminalDefaultBackground
 import java.awt.Component
 import java.awt.Dimension
 import javax.swing.JComponent
@@ -69,6 +69,7 @@ class TerminalOutputView(
     val document = DocumentImpl("", true)
     val editor = TerminalUiUtils.createOutputEditor(document, project, settings)
     editor.settings.isUseSoftWraps = true
+    editor.useTerminalDefaultBackground(this)
     stickScrollBarToBottom(editor.scrollPane.verticalScrollBar)
     return editor
   }
@@ -115,9 +116,6 @@ class TerminalOutputView(
     init {
       isOpaque = false
       add(editor.component, JLayeredPane.DEFAULT_LAYER as Any)  // cast to Any needed to call right method overload
-      bindColorKey(BlockTerminalColors.DEFAULT_BACKGROUND, this@TerminalOutputView, editor) {
-        editor.setBackgroundColor(it)
-      }
     }
 
     override fun getData(dataId: String): Any? {

plugins/terminal/src/org/jetbrains/plugins/terminal/exp/TerminalPromptView.kt

@@ -13,7 +13,6 @@ import com.intellij.openapi.fileEditor.FileDocumentManager
 import com.intellij.openapi.fileTypes.PlainTextLanguage
 import com.intellij.openapi.project.Project
 import com.intellij.openapi.wm.IdeFocusManager
-import com.intellij.terminal.BlockTerminalColors
 import com.intellij.terminal.JBTerminalSystemSettingsProviderBase
 import com.intellij.ui.LanguageTextField
 import com.intellij.ui.SimpleColoredComponent
@@ -23,6 +22,7 @@ import com.intellij.ui.components.panels.ListLayout
 import com.intellij.util.ui.JBInsets
 import com.intellij.util.ui.JBUI
 import org.jetbrains.plugins.terminal.exp.TerminalPromptController.PromptStateListener
+import org.jetbrains.plugins.terminal.exp.TerminalUi.useTerminalDefaultBackground
 import org.jetbrains.plugins.terminal.exp.completion.TerminalShellSupport
 import org.jetbrains.plugins.terminal.exp.history.CommandHistoryPresenter
 import org.jetbrains.plugins.terminal.exp.history.CommandSearchPresenter
@@ -77,7 +77,7 @@ class TerminalPromptView(
     }
     component.border = JBUI.Borders.compound(outerBorder, innerBorder)
 
-    component.bindBackgroundToColorKey(BlockTerminalColors.DEFAULT_BACKGROUND, this, editor)
+    component.background = TerminalUi.defaultBackground(editor)
     component.layout = ListLayout.vertical(TerminalUi.promptToCommandInset)
     component.add(promptComponent)
     component.add(editorTextField)
@@ -167,9 +167,7 @@ class TerminalPromptView(
     val editor = textField.getEditor(true) as EditorImpl
     editor.scrollPane.border = JBUI.Borders.empty()
     editor.gutterComponentEx.isPaintBackground = false
-    bindColorKey(BlockTerminalColors.DEFAULT_BACKGROUND, this, editor) {
-      editor.setBackgroundColor(it)
-    }
+    editor.useTerminalDefaultBackground(this)
     editor.colorsScheme.apply {
       editorFontName = settings.terminalFont.fontName
       editorFontSize = settings.terminalFont.size
@@ -195,8 +193,8 @@ class TerminalPromptView(
         font = EditorUtil.getEditorFont()
       }
     }
-    component.bindBackgroundToColorKey(BlockTerminalColors.DEFAULT_BACKGROUND, this, editor)
-    component.bindForegroundToColorKey(BlockTerminalColors.DEFAULT_FOREGROUND, this, editor)
+    component.background = TerminalUi.defaultBackground(editor)
+    component.foreground = TerminalUi.defaultForeground(editor)
     component.myBorder = JBUI.Borders.emptyBottom(2)
     component.ipad = JBInsets.emptyInsets()
     return component

plugins/terminal/src/org/jetbrains/plugins/terminal/exp/TerminalUi.kt

@@ -1,6 +1,18 @@
 // Copyright 2000-2023 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 package org.jetbrains.plugins.terminal.exp
 
+import com.intellij.openapi.Disposable
+import com.intellij.openapi.application.ApplicationManager
+import com.intellij.openapi.editor.Editor
+import com.intellij.openapi.editor.colors.ColorKey
+import com.intellij.openapi.editor.colors.EditorColorsListener
+import com.intellij.openapi.editor.colors.EditorColorsManager
+import com.intellij.openapi.editor.colors.EditorColorsScheme
+import com.intellij.openapi.editor.ex.EditorEx
+import com.intellij.terminal.BlockTerminalColors
+import com.intellij.ui.JBColor
+import java.awt.Color
+
 @Suppress("ConstPropertyName")
 object TerminalUi {
   const val blockTopInset = 8
@@ -22,4 +34,35 @@ object TerminalUi {
   const val alternateBufferLeftInset = 4
 
   const val searchComponentWidth = 500
+
+  fun defaultBackground(editor: Editor? = null): JBColor {
+    return createColorBoundToColorKey(BlockTerminalColors.DEFAULT_BACKGROUND, editor) {
+      it.defaultBackground
+    }
+  }
+
+  fun defaultForeground(editor: Editor? = null): JBColor {
+    return createColorBoundToColorKey(BlockTerminalColors.DEFAULT_FOREGROUND, editor) {
+      it.defaultForeground
+    }
+  }
+
+  private fun createColorBoundToColorKey(colorKey: ColorKey, editor: Editor? = null, default: (EditorColorsScheme) -> Color): JBColor {
+    return JBColor.lazy {
+      val colorsScheme = editor?.colorsScheme ?: EditorColorsManager.getInstance().globalScheme
+      colorsScheme.getColor(colorKey) ?: default(colorsScheme)
+    }
+  }
+
+  /**
+   * Unfortunately, `editor.backgroundColor = terminalDefaultBackground(editor)` doesn't work when
+   * colors scheme is changed. Because [com.intellij.openapi.editor.impl.EditorImpl.setBackgroundColor]
+   * doesn't save a passed in color if the color is equal to the default one.
+   */
+  fun EditorEx.useTerminalDefaultBackground(parentDisposable: Disposable) {
+    backgroundColor = defaultBackground(this)
+    ApplicationManager.getApplication().messageBus.connect(parentDisposable).subscribe(EditorColorsManager.TOPIC, EditorColorsListener {
+      backgroundColor = defaultBackground(this)
+    })
+  }
 }

plugins/terminal/src/org/jetbrains/plugins/terminal/exp/TerminalUiUtils.kt

@@ -10,12 +10,8 @@ import com.intellij.openapi.application.ApplicationManager
 import com.intellij.openapi.application.ModalityState
 import com.intellij.openapi.diagnostic.logger
 import com.intellij.openapi.editor.Document
-import com.intellij.openapi.editor.Editor
 import com.intellij.openapi.editor.EditorFactory
 import com.intellij.openapi.editor.EditorKind
-import com.intellij.openapi.editor.colors.ColorKey
-import com.intellij.openapi.editor.colors.EditorColorsListener
-import com.intellij.openapi.editor.colors.EditorColorsManager
 import com.intellij.openapi.editor.event.EditorMouseEvent
 import com.intellij.openapi.editor.ex.EditorEx
 import com.intellij.openapi.editor.ex.EditorGutterFreePainterAreaState
@@ -232,31 +228,3 @@ object TerminalUiUtils {
   const val GREEN_COLOR_INDEX: Int = 2
   const val YELLOW_COLOR_INDEX: Int = 3
 }
-
-fun Component.bindBackgroundToColorKey(colorKey: ColorKey, parentDisposable: Disposable, editor: Editor? = null) {
-  bindColorKey(colorKey, parentDisposable, editor) {
-    background = it
-  }
-}
-
-fun Component.bindForegroundToColorKey(colorKey: ColorKey, parentDisposable: Disposable, editor: Editor? = null) {
-  bindColorKey(colorKey, parentDisposable, editor) {
-    foreground = it
-  }
-}
-
-fun bindColorKey(colorKey: ColorKey, parentDisposable: Disposable, editor: Editor? = null, applier: (Color?) -> Unit) {
-  applier(getColor(editor, colorKey))
-  ApplicationManager.getApplication().messageBus.connect(parentDisposable).subscribe(EditorColorsManager.TOPIC, EditorColorsListener {
-    applier(getColor(editor, colorKey))
-  })
-}
-
-private fun getColor(editor: Editor?, colorKey: ColorKey): Color? {
-  return if (editor != null) {
-    editor.colorsScheme.getColor(colorKey)
-  }
-  else {
-    EditorColorsManager.getInstance().globalScheme.getColor(colorKey)
-  }
-}

plugins/terminal/src/org/jetbrains/plugins/terminal/exp/TerminalWidgetImpl.kt

@@ -5,7 +5,6 @@ import com.intellij.openapi.Disposable
 import com.intellij.openapi.project.Project
 import com.intellij.openapi.util.Disposer
 import com.intellij.openapi.wm.IdeFocusManager
-import com.intellij.terminal.BlockTerminalColors
 import com.intellij.terminal.TerminalTitle
 import com.intellij.terminal.ui.TerminalWidget
 import com.intellij.terminal.ui.TtyConnectorAccessor
@@ -118,7 +117,7 @@ class TerminalWidgetImpl(private val project: Project,
 
     override val component: JComponent = object : JPanel() {
       init {
-        bindBackgroundToColorKey(BlockTerminalColors.DEFAULT_BACKGROUND, this@TerminalPlaceholder)
+        background = TerminalUi.defaultBackground()
       }
     }