tart set: support optional "pt" and "px" units for "--display" argument (#1155)

* tart set: support optional "pt" and "px" units for "--display" argument

* Don't forget to update "unit" too

Sources/tart/Commands/Set.swift

@@ -14,7 +14,7 @@ struct Set: AsyncParsableCommand {
   @Option(help: "VM memory size in megabytes")
   var memory: UInt64?
 
-  @Option(help: "VM display resolution in a format of <width>x<height>. For example, 1200x800")
+  @Option(help: "VM display resolution in a format of WIDTHxHEIGHT[pt|px]. For example, 1200x800, 1200x800pt or 1920x1080px. Units are treated as hints and default to \"pt\" (points) for macOS VMs and \"px\" (pixels) for Linux VMs when not specified.")
   var display: VMDisplayConfig?
 
   @Flag(inversion: .prefixedNo, help: ArgumentHelp("Whether to automatically reconfigure the VM's display to fit the window"))
@@ -56,6 +56,7 @@ struct Set: AsyncParsableCommand {
       if (display.height > 0) {
         vmConfig.display.height = display.height
       }
+      vmConfig.display.unit = display.unit
     }
 
     vmConfig.displayRefit = displayRefit
@@ -88,12 +89,24 @@ struct Set: AsyncParsableCommand {
 
 extension VMDisplayConfig: ExpressibleByArgument {
   public init(argument: String) {
+    var argument = argument
+    var unit: Unit? = nil
+
+    if argument.hasSuffix(Unit.pixel.rawValue) {
+      argument = String(argument.dropLast(Unit.pixel.rawValue.count))
+      unit = Unit.pixel
+    } else if argument.hasSuffix(Unit.point.rawValue) {
+      argument = String(argument.dropLast(Unit.point.rawValue.count))
+      unit = Unit.point
+    }
+
     let parts = argument.components(separatedBy: "x").map {
       Int($0) ?? 0
     }
     self = VMDisplayConfig(
       width: parts[safe: 0] ?? 0,
-      height: parts[safe: 1] ?? 0
+      height: parts[safe: 1] ?? 0,
+      unit: unit,
     )
   }
 }

Sources/tart/Platform/Darwin.swift

@@ -82,7 +82,7 @@ struct UnsupportedHostOSError: Error, CustomStringConvertible {
     func graphicsDevice(vmConfig: VMConfig) -> VZGraphicsDeviceConfiguration {
       let result = VZMacGraphicsDeviceConfiguration()
 
-      if let hostMainScreen = NSScreen.main {
+      if (vmConfig.display.unit ?? .point) == .point, let hostMainScreen = NSScreen.main {
         let vmScreenSize = NSSize(width: vmConfig.display.width, height: vmConfig.display.height)
         result.displays = [
           VZMacGraphicsDisplayConfiguration(for: hostMainScreen, sizeInPoints: vmScreenSize)

Sources/tart/VMConfig.swift

@@ -32,14 +32,24 @@ enum CodingKeys: String, CodingKey {
   case hardwareModel
 }
 
-struct VMDisplayConfig: Codable {
+struct VMDisplayConfig: Codable, Equatable {
+  enum Unit: String, Codable {
+    case point = "pt"
+    case pixel = "px"
+  }
+
   var width: Int = 1024
   var height: Int = 768
+  var unit: Unit?
 }
 
 extension VMDisplayConfig: CustomStringConvertible {
   var description: String {
-    "\(width)x\(height)"
+    if let unit {
+      "\(width)x\(height)\(unit.rawValue)"
+    } else {
+      "\(width)x\(height)"
+    }
   }
 }
 

Tests/TartTests/VMConfigTests.swift

@@ -0,0 +1,18 @@
+import XCTest
+@testable import tart
+
+final class VMConfigTests: XCTestCase {
+  func testVMDisplayConfig() throws {
+    // Defaults units (points)
+    var vmDisplayConfig = VMDisplayConfig.init(argument: "1234x5678")
+    XCTAssertEqual(VMDisplayConfig(width: 1234, height: 5678, unit: nil), vmDisplayConfig)
+
+    // Explicit units (points)
+    vmDisplayConfig = VMDisplayConfig.init(argument: "1234x5678pt")
+    XCTAssertEqual(VMDisplayConfig(width: 1234, height: 5678, unit: .point), vmDisplayConfig)
+
+    // Explicit units (pixels)
+    vmDisplayConfig = VMDisplayConfig.init(argument: "1234x5678px")
+    XCTAssertEqual(VMDisplayConfig(width: 1234, height: 5678, unit: .pixel), vmDisplayConfig)
+  }
+}