Set macOS dock icon when applying ImGuiApp window icon

[Copilot]

IconPath/SetWindowIcon updated the GLFW window icon but did not reliably affect the macOS app icon shown in the Dock. This change adds a macOS-specific app-icon path while keeping existing cross-platform window-icon behavior intact.

• macOS app icon path

  • Added TrySetMacOSApplicationIcon(string iconPath) in ImGui.App to call AppKit via Objective-C runtime (NSApplication.sharedApplication.setApplicationIconImage:).
  • Invoked from SetWindowIcon before calling Silk/GLFW SetWindowIcon, so macOS receives both app-level and window-level icon updates.

• Native interop surface

  • Added Objective-C runtime bindings in NativeMethods:
    • objc_getClass
    • sel_registerName
    • objc_msgSend overloads used by icon setup

• API/docs alignment

  • Updated API docs for SetWindowIcon and ImGuiAppConfig.IconPath to state macOS dock icon behavior explicitly.

public static void SetWindowIcon(string iconPath)
{
	// existing image decode/resize for window icons
	_ = TrySetMacOSApplicationIcon(iconPath); // macOS dock/app icon
	Invoker.Invoke(() => window?.SetWindowIcon([.. icons])); // existing behavior
}

• Fixes Application icon doesnt seem to work on macos #402

[matt-edmondson]

@copilot do the other platforms need something similar, for the taskbar and whatever?

[Copilot]

@copilot do the other platforms need something similar, for the taskbar and whatever?

Not usually. On Windows/Linux, window.SetWindowIcon(...) (GLFW/Silk) is the normal path and is what taskbar/window icons use where the desktop supports runtime icon updates. macOS is the outlier because the Dock app icon is app-level (NSApplication) rather than just window-level. The only things this won’t change cross-platform are package/shortcut-level icons (e.g., pinned shortcut icons, desktop-file bundle icons), which are build/distribution metadata, not runtime window state.

[matt-edmondson]

@copilot pkease address the sonar gate

[Copilot]

@copilot pkease address the sonar gate

Addressed in 96ca55c. I fixed the Sonar gate failure by adding coverage for the new icon path and excluding the macOS-native AppKit interop helper from coverage (platform-dependent interop boundary), then validated with the window-management/icon tests.

[matt-edmondson]

@copilot please address the code quality comments

[Copilot]

@copilot please address the code quality comments

Addressed in bf5a0fb. I removed the generic catch (Exception)/Assert.Fail pattern and kept cleanup via try/finally in SetWindowIcon_WithValidPng_DoesNotThrow, then ran ImGuiAppWindowManagementTests (50/50 passing).

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud