ZoomButtons class

放大缩小按钮组（公开 API）。

这是一个简单的 StatelessWidget，提供标准的放大缩小按钮组 UI。 外部可以在任意位置使用，如自定义桌面 Chrome。

功能特性

• 显示两个按钮：放大按钮（+）和缩小按钮（-）
• 可选显示当前缩放级别（如 "100%"）
• 使用半透明黑色背景 + 圆角容器
• 垂直排列，按钮之间有间距

使用示例

在自定义桌面 Chrome 中使用

Positioned(
  left: 20,
  bottom: 100,
  child: ZoomButtons(
    onZoomIn: () => _zoomIn(),
    onZoomOut: () => _zoomOut(),
    currentZoomLevel: _currentZoom,
  ),
)

在自定义页面中使用

class MyCustomDesktopPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Stack(
      children: [
        // 图片内容
        MyImageWidget(),
        // 放大缩小按钮
        Positioned(
          left: 20,
          bottom: 100,
          child: ZoomButtons(
            onZoomIn: () {
              // 放大图片
            },
            onZoomOut: () {
              // 缩小图片
            },
            currentZoomLevel: 1.5, // 150%
          ),
        ),
      ],
    );
  }
}

设计说明

此类遵循以下设计原则：

1. 完全独立：不依赖特定的父组件，可以在任意位置使用
2. 简单直观：提供标准的放大缩小按钮 UI，无复杂逻辑
3. 可配置：支持自定义缩放级别显示
4. 样式统一：使用一致的样式，保持视觉统一性

样式说明

• 按钮尺寸：40x40 像素
• 按钮背景：半透明黑色（opacity: 0.5）
• 按钮圆角：8 像素
• 图标尺寸：24 像素
• 图标颜色：白色
• 按钮间距：8 像素
• 缩放级别文字：12 像素，白色

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatelessWidget
• ZoomButtons

Constructors

ZoomButtons({Key? key, required VoidCallback onZoomIn, required VoidCallback onZoomOut, double? currentZoomLevel})

创建放大缩小按钮组。

const

Properties

currentZoomLevel → double?

当前缩放级别（用于显示状态）。

final

hashCode → int

The hash code for this object.

no setter, inherited

key → Key?

Controls how one widget replaces another widget in the tree.

final, inherited

onZoomIn → VoidCallback

放大回调。

final

onZoomOut → VoidCallback

缩小回调。

final

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

build(BuildContext context) → Widget

Describes the part of the user interface represented by this widget.

override

createElement() → StatelessElement

Creates a StatelessElement to manage this widget's location in the tree.

inherited

debugDescribeChildren() → List<DiagnosticsNode>

Returns a list of DiagnosticsNode objects describing this node's children.

inherited

debugFillProperties(DiagnosticPropertiesBuilder properties) → void

Add additional properties associated with the node.

inherited

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode

Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.

inherited

toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) → String

A string representation of this object.

inherited

toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug, int wrapWidth = 65}) → String

Returns a string representation of this node and its descendants.

inherited

toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String

Returns a one-line detailed description of the object.

inherited

toStringShort() → String

A short, textual description of this widget.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited