MemBar

A lightweight macOS menu bar system monitor. A donut gauge in the menu bar fills as memory usage rises. Click it for a popover with a large ring chart, live network throughput, CPU, and battery temperature.

轻量级 macOS 菜单栏系统监控工具。菜单栏小圆环随内存使用填充,点开是带大圆环、实时网速、CPU 和电池温度的弹窗。

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Screenshots / 截图

Menu bar	Popover (memory mode)	Popover (network mode)
16-pt donut + percentage (or ↓X ↑Y in network mode), auto-tinted by system appearance.	92-pt color-coded ring, end-cap dot that follows the trim, percentage in the center, used/total bytes, status caption.	Two stacked 16-bar rolling charts (download / upload) with the latest bar pulsing between samples.

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Features / 功能

📊 Menu bar / 菜单栏

• Live donut gauge — 16-pt ring, system-foreground tint via NSImage.isTemplate = true, redrawn only when displayed state changes.
• Two display modes:
  • memory — percentage text alongside the ring
  • network — ↓1.2MB ↑234KB download/upload text
• Mode is picked from the popover and persisted to UserDefaults.
• Re-renders on appearance change (light ⇄ dark, Auto Dark Mode).
• The current menu-bar arc is vertically flipped relative to the earlier builds, so the fill starts from the lower half of the ring.

🖱️ Popover / 弹窗

Click the menu bar icon to open a 292-pt wide SwiftUI popover:

• Mode picker — segmented control at the top: 内存使用 / 网速.
• Memory mode — a 92-pt ring with a 10-pt stroke:
  • Color shifts green → orange → red at 60 % / 85 %
  • A small end-cap dot rides the trim end (.rotationEffect driven by the same fraction)
  • The percentage is centered as a 22-pt rounded monospaced number with .contentTransition(.numericText()) so the digits roll over smoothly
  • A subtle shadow halo appears above 85 %
  • Used / total bytes and a 稳定 / 偏高 / 告急 status caption round out the row
  • The whole ring is GPU-rendered via .drawingGroup() for retina crispness
  • The chart and metrics areas use a light grouped panel treatment for quicker scanning
• Network mode — two stacked rolling-window bar charts (download in blue, upload in green):
  • 16 bars per chart, 2 s per sample, history ≈ 32 s
  • Each bar's height is normalized to the window's max, so spikes always fill the chart
  • The latest bar interpolates smoothly between real samples instead of adding decorative fake activity
  • 1-pt baseline rule under each row keeps the eye anchored when traffic is near zero
• Data table — 内存 / CPU / 网络 / 温度, with monospaced values and per-row accent color.
• 退出 button to quit.

⚙️ Engineering / 实现

• Swift 6 + strict concurrency; @MainActor @Observable SystemMonitor posts a systemMonitorDidRefresh notification on each 2 s tick.
• Native macOS APIs only — no third-party dependencies:
  • host_statistics for CPU
  • vm_statistics64 for memory
  • getifaddrs for network throughput (delta between samples)
  • IORegistry for battery temperature
• All charts animate via value-driven .animation(.smooth, value:) or .animation(.easeInOut, value:) modifiers — the popover root does not use .id(refreshCounter), so in-flight transitions are never torn down by a forced rebuild.
• The memory donut uses .smooth(duration: 0.5) for its main transition.
• The latest network bar (LiveBar) interpolates from the previous sample to the current one over 2 seconds with an ease-out quadratic curve, so the chart flows smoothly between refresh ticks.
• Historical bar heights use .smooth(duration: 0.45) and the latest bar is timeline-driven.
• ~1,440 lines of Swift.

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Installation / 安装

Download / 下载

Download MemBar.dmg from the Releases page.

Latest release: v1.1.2. This release fixes Settings opening from the popover and right-click menu, adds a provider-based metrics engine, and improves local release diagnostics while preserving the lightweight menu-bar experience.

Or via Homebrew (planned):

brew install --cask membar

How to install / 安装步骤

1. Download MemBar.dmg from the latest release
2. Open the DMG file
3. Drag MemBar.app into the Applications folder
4. Launch MemBar from Applications — the donut appears in the menu bar

Note: On first launch, macOS may show an unidentified developer warning. Right-click MemBar.app in Applications and select "Open" to bypass.

注意: 首次打开可能提示未识别的开发者, 请在访达中右键点击 MemBar.app → 打开。

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Usage / 使用

1. Launch MemBar — the donut gauge appears in the menu bar (top-right).
2. Click the donut to open the popover.
3. In the popover, use the picker to switch between 内存使用 and 网速.
4. The picker choice is remembered between launches.
5. Use 设置 in the popover, or right-click the donut and choose Settings, to open preferences.
6. Right-click the donut for a "Quit MemBar" menu.

The gauge auto-tints with your system's light / dark appearance. Enable macOS Auto Dark Mode (System Settings → Appearance → Auto) to make it follow the time of day automatically.

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Build from source / 从源码构建

# Requires macOS 15+ and a Swift 6 toolchain (Xcode 16 / Xcode 27 beta both work)
git clone https://github.com/d8dzmf5mfn/MemBar.git
cd MemBar/Monitor
open Monitor.xcodeproj
# Select target "Monitor" → Build & Run (⌘R)

Or from the command line (with Xcode-beta):

cd MemBar/Monitor
DEVELOPER_DIR="$HOME/Downloads/Xcode-beta.app/Contents/Developer" \
  xcodebuild -project Monitor.xcodeproj -scheme Monitor -configuration Release build
# Built .app will be in DerivedData

Run tests with DerivedData outside the workspace to avoid file-provider extended attributes interfering with local codesigning:

DEVELOPER_DIR="$HOME/Downloads/Xcode-beta.app/Contents/Developer" \
  xcodebuild test -project Monitor/Monitor.xcodeproj -scheme Monitor \
  -destination 'platform=macOS' \
  -derivedDataPath /private/tmp/membar-derived-data

Building a DMG locally

./scripts/build-dmg.sh
# Produces MemBar.dmg in the current directory

The build script:

1. Runs xcodebuild in Release configuration
2. Writes DerivedData to /private/tmp/membar-dmg-derived-data by default, keeping build artifacts out of the repository
3. Clears extended attributes, ad-hoc signs the local app bundle, and creates a MemBar.dmg using hdiutil

Local DMG builds are ad-hoc signed only.

GitHub release builds still need Developer ID signing and notarization.

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Project structure / 项目结构

Monitor/
├── Monitor.xcodeproj/
├── Monitor/
│   ├── MemBarApp.swift              # @main App, AppDelegate, NSStatusItem,
│   │                               # StatusBarIconView, MenuBarRenderer
│   │                               # (Core Graphics donut for the menu bar)
│   ├── Models/
│   │   └── MetricsData.swift        # CPUSnapshot / MemorySnapshot /
│   │                               # NetworkSnapshot / ThermalSnapshot
│   ├── MonitorEngine/
│   │   ├── CPUInfo.swift            # host_statistics
│   │   ├── MemoryInfo.swift         # vm_statistics64
│   │   ├── NetworkInfo.swift        # getifaddrs
│   │   ├── SystemMonitor.swift      # @MainActor @Observable, 2 Hz refresh,
│   │   │                           # posts .systemMonitorDidRefresh
│   │   └── TemperatureInfo.swift    # IORegistry
│   ├── Views/
│   │   └── MenuBarView.swift        # popover: mode picker, donut + bar
│   │                               # charts, data rows, quit button
│   └── Assets.xcassets/             # AppIcon, AccentColor
└── scripts/
    └── build-dmg.sh                 # DMG packaging script

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Tech stack / 技术栈

• Swift 6 with strict concurrency
• SwiftUI for the popover (@Observable + Bindable)
• AppKit for NSStatusItem + the menu bar renderer (CGContext donut rasterized to a template-mode NSImage)
• Core Graphics for the menu bar pixel rendering
• macOS 15+ native APIs: host_statistics, vm_statistics64, getifaddrs, IORegistry

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License

MIT