Monthly Archives: June 2017

Xcode GitHub Integration

Apple’s beta release of Xcode 9 features impressive improvements to its source control features, including streamlined integration with GitHub. There’s even a fancy “Open in Xcode” button when you go to clone a project:

Screen capture of the GitHub interface for cloning a project

This integration is amazing. You just click the button, specify a save folder in Xcode, and boom! You’re off and …

Screen capture of build failure indicating a missing signing certificate

Oh, right. Code signing. The otherwise stellar GitHub integration in Xcode underscores a longstanding deficiency in how it manages code signing identities for multi-team, collaborative projects. Precisely the kinds of projects you’re liable to find on GitHub.

The problem could be solved, or at least diminished greatly, by providing some mechanism for declaring that a project should be code signed “with the user’s own default developer team.” The default branch of any open source project targeting Apple platforms, would specify the DEVELOPMENT_TEAM as something like:

DEVELOPMENT_TEAM = Automatic

Xcode would provide a user-level setting for “Default Development Team”, and in the absence of any overriding setting, that team would be used whenever a project was configured as above.

I wrote about this problem once before, but with all the work being put into streamlining the experience of cloning from and pushing to GitHub, now is an ideal time for Apple to embrace a fix. Radar #32614751.

Another issue that stops short the cloning, and immediate building and running, of open source projects, is the need to fulfill external dependencies. In some cases this might require manually downloading and installing libraries, or cloning projects, but in the vast majority of cases the dependencies will be specified using built-in Git submodule support, or a popular package manager. In each of these cases, it should be trivial for Xcode to detect that the project it has just cloned also has dependencies:

  • Git submodules: there is a .gitmodules directory.
  • Carthage: there is a Cartfile file.
  • CocoaPods: there is a Podfile file.
  • Swift Package Manager: there is a Swift.package file.

If Xcode sees evidence of any of these techniques at play, it could do the favor of checking them out immediately after cloning the project. Radar #32615265.

The GitHub integration coming in Xcode 9 provides a nearly effortless capability for cloning, building, and running open source projects that target Apple platforms. Ideally it would also go the extra mile and provide for variable, dynamic development teams, as well as conduct a rudimentary check for dependencies that must be checked out before commencing work on the project.

Evergreen Images

Brent Simmons, the original developer of MarsEdit and NetNewsWire, is building a new feed reader app called Evergreen:

Evergreen is an open source, productivity-style feed reader for Macs.

It’s at a very early stage — we use it, but we don’t expect other people to use it yet.

I’ve never been one to shy away from early-stage software, so of course I ran to the GitHub project page, cloned the repository, and built it immediately on my own Mac.

Screenshot of Evergreen about box without a custom icon.

Ahh, the tell-tale sign of a young app: the generic about box. Personally, I like to give apps-in-progress an icon, even if only a placeholder image, as soon as possible. It occurred to me that Apple has done the favor of providing a pretty-darned-suitable image for “Evergreen” in the form of its Emoji glyph of the same name:

🌲

Since I have the source code right here, why don’t I render that tree at a large size in a graphics app, resize it to a million different resolutions, bundle it up and check it in to the Evergreen source base?

Because that’s not nearly as fun as doing it in code. I dove into the Evergreen application delegate class, adding the following function:

private func evergreenImage() -> NSImage? {
	var image: NSImage? = nil
	let imageWidth = 1024
	let imageHeight = 1024
	let imageSize = NSMakeSize(CGFloat(imageWidth), CGFloat(imageHeight))

	if let drawingContext = CGContext(data: nil, width: imageWidth, height: imageHeight, bitsPerComponent: 8, bytesPerRow: 0, space: CGColorSpaceCreateDeviceRGB(), bitmapInfo: CGImageAlphaInfo.premultipliedFirst.rawValue) {

		let graphicsContext = NSGraphicsContext(cgContext: drawingContext, flipped: false)
		NSGraphicsContext.saveGraphicsState()
		NSGraphicsContext.setCurrent(graphicsContext)

		let targetRect = NSRect(origin: NSZeroPoint, size: imageSize)
		NSString(string: "🌲").draw(in: targetRect, withAttributes: [NSFontAttributeName: NSFont.systemFont(ofSize: 1000)])

		NSGraphicsContext.restoreGraphicsState()

		if let coreImage = drawingContext.makeImage() {
			image = NSImage(cgImage: coreImage, size: imageSize)
		}
	}

	return image
}

In summary this code: creates a CoreGraphics drawing context, renders a huge evergreen Emoji glyph into it, and creates an NSImage out of it.

Then from the “applicationDidFinishLaunching()” function:

if let appIconImage = evergreenImage() {
	appIconImage.setName("NSApplicationIcon")
	NSApplication.shared().applicationIconImage = appIconImage
}

Give the newly created image the canonical name, used by AppKit, for looking up the application icon, and immediately change the application’s icon image to reflect the new value. It worked a treat:

EvergreenEmoji

In programming there is usually a hard way, an easy way, and a fun way. Be sure to take the third option as often as possible.