feat: add split window background support for dock app items

1. Created new AppBackground.qml component to handle split window
background rendering
2. Added splitBackgroundVisible property to control split background
display
3. Enhanced AppletItemBackground.qml with drawDefaultBackground property
for conditional rendering
4. Modified AppItem.qml to use AppBackground instead of
AppletItemBackground
5. Updated text calculation logic to remove extra spacing between icon
and title
6. Added windowSplit property propagation through components
7. Improved title text color handling based on active state and theme

Log: Added split window background visualization for dock app items

Influence:
1. Test dock app items with multiple windows open in split mode
2. Verify background colors change correctly in light and dark themes
3. Check hover and active states for split window backgrounds
4. Test title text color changes when app is active
5. Verify spacing between icon and title in split mode
6. Test transition animations when switching between split and non-
split modes

feat: 为任务栏应用项添加分屏窗口背景支持

1. 创建新的 AppBackground.qml 组件处理分屏窗口背景渲染
2. 添加 splitBackgroundVisible 属性控制分屏背景显示
3. 增强 AppletItemBackground.qml 添加 drawDefaultBackground 属性用于条件
渲染
4. 修改 AppItem.qml 使用 AppBackground 替代 AppletItemBackground
5. 更新文本计算逻辑，移除图标和标题之间的额外间距
6. 添加 windowSplit 属性在组件间传递
7. 改进标题文本颜色处理，基于激活状态和主题

Log: 新增任务栏应用项分屏窗口背景可视化功能

Influence:
1. 测试分屏模式下打开多个窗口的任务栏应用项
2. 验证浅色和深色主题下背景颜色正确变化
3. 检查分屏窗口背景的悬停和激活状态
4. 测试应用激活时标题文本颜色变化
5. 验证分屏模式下图标和标题之间的间距
6. 测试分屏和非分屏模式切换时的过渡动画

Author: wjyrich

panels/dock/AppBackground.qml

@@ -0,0 +1,217 @@
+// SPDX-FileCopyrightText: 2026 UnionTech Software Technology Co., Ltd.
+//
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+import QtQuick
+import QtQuick.Controls
+
+import org.deepin.ds.dock 1.0
+import org.deepin.dtk
+
+AppletItemBackground {
+    id: control
+    drawDefaultBackground: false
+    property bool splitBackgroundVisible: false
+    property bool windowSplit: false
+    property int windowCount: 0
+    property int displayMode: Dock.Efficient
+    property bool isHovered: false
+
+    property Palette splitBackgroundColor: Palette {
+        normal {
+            common: ("transparent")
+        }
+        hovered {
+            crystal: Qt.rgba(1.0, 1.0, 1.0, 0.45)
+        }
+        hoveredDark: {
+            crystal: Qt.rgba(1.0, 1.0, 1.0, 0.2)
+        }
+        pressed {
+            crystal: Qt.rgba(1.0, 1.0, 1.0, 0.1)
+        }
+        pressedDark: {
+            crystal: Qt.rgba(1.0, 1.0, 1.0, 0.35)
+        }
+    }
+    backgroundColor: Palette {
+        normal {
+            common: ("transparent")
+        }
+        hovered {
+            crystal: Qt.rgba(1.0, 1.0, 1.0, 0.15)
+        }
+        hoveredDark {
+            crystal: Qt.rgba(1.0, 1.0, 1.0, 0.15)
+        }
+        pressed {
+            crystal: Qt.rgba(1.0, 1.0, 1.0, 0.25)
+        }
+        pressedDark {
+            crystal: Qt.rgba(1.0, 1.0, 1.0, 0.25)
+        }
+    }
+    property Palette splitActiveBackgroundColor: Palette {
+        normal {
+            common: ("transparent")
+        }
+        hovered {
+            crystal: Qt.rgba(1.0, 1.0, 1.0, 0.35)
+        }
+        hoveredDark: {
+            crystal: Qt.rgba(1.0, 1.0, 1.0, 0.1)
+        }
+        pressed {
+            crystal: Qt.rgba(1.0, 1.0, 1.0, 0.25)
+        }
+        pressedDark: pressed
+    }
+    activeBackgroundColor: Palette {
+        normal {
+            common: ("transparent")
+           // crystal: Qt.rgba(1.0, 1.0, 1.0, 0.15)
+        }
+        normalDark: normal
+        hovered {
+            crystal: Qt.rgba(1.0, 1.0, 1.0, 0.25)
+        }
+        hoveredDark: hovered
+        pressed {
+            crystal: Qt.rgba(1.0, 1.0, 1.0, 0.30)
+        }
+        pressedDark: pressed
+    }
+    insideBorderColor: Palette {
+        normal {
+            common: ("transparent")
+
+        }
+        hovered {
+            crystal: Qt.rgba(0, 0, 0, 0.05)
+        }
+        hoveredDark: hovered
+        pressed: hovered
+        pressedDark: pressed
+    }
+
+    activeInsideBorderColor: Palette {
+        normal {
+            common: ("transparent")
+        }
+        normalDark: normal
+        hovered {
+            crystal: Qt.rgba(0.0, 0.0, 0.0, 0.10)
+        }
+        hoveredDark: hovered
+        pressed: hovered
+        pressedDark: pressed
+    }
+    outsideBorderColor: Palette {
+        normal {
+            common: ("transparent")
+        }
+        hovered {
+            crystal: ("transparent")
+        }
+        hoveredDark: hovered
+        pressed: hovered
+        pressedDark: pressed
+    }
+    activeOutsideBorderColor: Palette {
+        normal {
+            common: ("transparent")
+        }
+        normalDark: normal
+        hovered {
+            crystal: Qt.rgba(0.0, 0.0, 0.0, 0.10)
+        }
+        hoveredDark: hovered
+        pressed: Qt.rgba(0.0, 0.0, 0.0, 0.05)
+        pressedDark: pressed
+    }
+
+    Rectangle {
+        anchors.fill: parent
+        radius: control.radius
+        visible: control.windowCount > 0 && control.displayMode === Dock.Efficient
+        color: {
+            if (displayMode === Dock.Efficient) {
+                if (isActive) {
+                    return DTK.themeType === ApplicationHelper.DarkType
+                        ? Qt.rgba(1.0, 1.0, 1.0, 0.6) : Qt.rgba(1.0, 1.0, 1.0, 0.8)
+                } else {
+                    return DTK.themeType === ApplicationHelper.DarkType
+                        ? Qt.rgba(1.0, 1.0, 1.0, 0.1) : Qt.rgba(1.0, 1.0, 1.0, 0.35)
+                }
+            }
+        }
+    }
+    InsideBoxBorder {
+        anchors.fill: parent
+        radius: control.radius
+        visible: control.windowCount > 0 && control.displayMode === Dock.Efficient
+        color: {
+            if (displayMode === Dock.Efficient) {
+                if (isActive) {
+                    return DTK.themeType === ApplicationHelper.DarkType
+                        ? Qt.rgba(0, 0, 0, 0.1) : Qt.rgba(0, 0, 0, 0.1)
+                } else {
+                    return DTK.themeType === ApplicationHelper.DarkType
+                        ? Qt.rgba(0, 0, 0, 0.05) : Qt.rgba(0, 0, 0, 0.05)
+                }
+            }
+        }
+        borderWidth: 1 / Screen.devicePixelRatio
+    }
+    OutsideBoxBorder {
+        anchors.fill: parent
+        radius: control.radius
+        visible: control.windowCount > 0 && control.displayMode === Dock.Efficient
+        color: {
+            if (displayMode === Dock.Efficient) {
+                if (isActive) {
+                    return DTK.themeType === ApplicationHelper.DarkType
+                        ? Qt.rgba(0, 0, 0, 0.1) : Qt.rgba(0, 0, 0, 0.1)
+                } else {
+                    return ("transparent")
+                }
+            }
+        }
+        borderWidth: 1 / Screen.devicePixelRatio
+    }
+
+    Rectangle {
+        anchors.fill: parent
+        radius: control.radius
+        color: {
+            if (control.splitBackgroundVisible) {
+                if (isActive) {
+                    return control.ColorSelector.splitActiveBackgroundColor
+                } 
+                return control.ColorSelector.splitBackgroundColor
+            } else {
+                if (isActive) {
+                    return control.ColorSelector.activeBackgroundColor
+                }
+                return control.ColorSelector.backgroundColor
+            }
+            
+        }
+    }
+    InsideBoxBorder {
+        anchors.fill: parent
+        radius: control.radius
+
+        color: isActive ? control.ColorSelector.activeInsideBorderColor
+                        : control.ColorSelector.insideBorderColor
+        borderWidth: 1 / Screen.devicePixelRatio
+    }
+    OutsideBoxBorder {
+        anchors.fill: parent
+        radius: control.radius
+
+        color: isActive ? control.ColorSelector.activeOutsideBorderColor
+                        : control.ColorSelector.outsideBorderColor
+        borderWidth: 1 / Screen.devicePixelRatio
+    }
+}

panels/dock/AppletItemBackground.qml

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2024 UnionTech Software Technology Co., Ltd.
+// SPDX-FileCopyrightText: 2024 - 2026 UnionTech Software Technology Co., Ltd.
 //
 // SPDX-License-Identifier: GPL-3.0-or-later
 
@@ -12,6 +12,7 @@ MouseArea {
     id: control
     property bool isActive
     property real radius: 4
+    property bool drawDefaultBackground: true
 
     // can accept mouse event,prevent further event delivery
     acceptedButtons: Qt.LeftButton | Qt.RightButton
@@ -89,19 +90,22 @@ MouseArea {
     Rectangle {
         anchors.fill: parent
         radius: control.radius
+        visible: control.drawDefaultBackground
         color: isActive ? control.ColorSelector.activeBackgroundColor
                         : control.ColorSelector.backgroundColor
     }
     InsideBoxBorder {
         anchors.fill: parent
         radius: control.radius
+        visible: control.drawDefaultBackground
         color: isActive ? control.ColorSelector.activeInsideBorderColor
                         : control.ColorSelector.insideBorderColor
         borderWidth: 1 / Screen.devicePixelRatio
     }
     OutsideBoxBorder {
         anchors.fill: parent
         radius: control.radius
+        visible: control.drawDefaultBackground
         color: isActive ? control.ColorSelector.activeOutsideBorderColor
                         : control.ColorSelector.outsideBorderColor
         borderWidth: 1 / Screen.devicePixelRatio

panels/dock/CMakeLists.txt

@@ -135,6 +135,7 @@ qt_add_qml_module(dock-plugin
     QML_FILES DockCompositor.qml OverflowContainer.qml MenuHelper.qml DockPalette.qml
     AppletItemButton.qml
     AppletItemBackground.qml
+    AppBackground.qml
     OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}/plugins/org/deepin/ds/dock/
 )