Archive for the ‘How To’ Category

Importing Web-based SwiftPM packages to your Xcode Playground

I’ve been kicking the wheels on Xcode 12 and its ability to use frameworks and packages with playgrounds. Up until now, I’ve only been able to import packages that are either downloaded or developed locally on my home system. However, a lot of the packages I want to work with are hosted from GitHub.

I decided to follow a hunch and see if I could import my dependency through a local Forwarding package and then use that code. Long story short: I could.

Here’s my playground, successfully running.

The RuntimeImplementation is declared in a GitHub-hosted package called Swift-General-Utility:

What I did to make this work was that I created what I called a Forwarding Utility, whose sole job is to create a shell package that depends on the remote package and forwards it to the playground. It looks like this. It is a single file called “Forwarding.swift” (no, the name is not at all magic.) in Sources/. I use @_exported to forward the import.

 Use this to forward web-based dependencies to Swift Pkg

@_exported import GeneralUtility

Its Package.swift installs the dependency:

    dependencies: [ .package(url: "", .exact("0.0.4")), ],
    targets: [
            name: "ForwardingUtility",
            dependencies: [ .product(name: "GeneralUtility"), ],
            path: "Sources/"

And that’s pretty much all that there is to it, other than (as I mentioned in my other post about how to use SwiftPM packages in playground workspaces) that you may have to quit and re-open the first beta before you can import the forwarding.

Let me know anything that I messed up. But also let me know if this was helpful to you!

Coloring SVG assets in SwiftUI

Update: Huge thanks to Justin.

Retain the same code as the system image but use the asset inspector to change the SVG resource to a template image! So much easier and better. Thank you, Justin!

Coloring a SFIcon is simple. Here’s the default rendering:

struct ContentView: View {
  var body: some View {
    Image(systemName: "bandage")
      .aspectRatio(contentMode: .fit)

And here’s the same using a red tint:

Image(systemName: "bandage")
  .aspectRatio(contentMode: .fit)

But what about the new SVG image support? (The seal image is by mungang kim, the Noun project):

SVGs carry their own color information. I edited the seal in Adobe Illustrator CS4 (I have a computer dedicated to Mojave) to add intrinsic colors:

Again, the foregroundColor(.red) modifier is ignored and the native colors are shown. From my developer’s point of view, what I want is to be able to modify the SVG asset to use normal SwiftUI coloring. So the first thing I did was to create a ZStack and use blending modes to set my foreground color.

I finally got my first hint of victory by using a content blend with .colorDodge:

I discovered, though, that dodge wasn’t a great choice for non B&W assets. I needed a better blending mode.

When I tried to layer images in a ZStack, I discovered the color mode would bleed through:

I needed to:

  • Use a better blend mode that wouldn’t be affected by the SVG Image source colors and whether they were native Color s (like or system ones (like Color(.red), which uses UIColor/NSColor).
  • Isolate the blend mode so it wouldn’t affect other Views.
  • Move that functionality to a simple modifier, allowing a SVG Image to blend with a color.

I soon discovered that the sourceAtop blend mode got me the coloring I needed, whether I used the B&W or colorized asset:

ZStack {

Then, I needed to isolate the blend. I first turned to .drawingGroup(opaque:false) but it kept failing to provide the result I was aiming for until I discovered that isolating that into its own VStack bypassed any blends with ZStack elements at the same level:

VStack {
  ZStack {
  .drawingGroup(opaque: false)

I then moved this into a custom View modifier:

public struct ColorBlended: ViewModifier {
  fileprivate var color: Color
  public func body(content: Content) -> some View {
    VStack {
      ZStack {
      .drawingGroup(opaque: false)

extension View {
  public func blending(color: Color) -> some View {
    modifier(ColorBlended(color: color))

This allowed me to create a standard SwiftUI ZStack that used the modifier in a normal cascade:

struct ContentView: View {
  var body: some View {
    ZStack {
      Image(systemName: "bandage.fill").resizable()
        .aspectRatio(contentMode: .fit)
        .aspectRatio(contentMode: .fit)
        .blending(color: Color(.red))

Here’s how that renders:

You’ll want to make sure the blending happens after the image resizable and aspectRatio calls but other than that it can appear before or after the padding.

What I got out of this was a way to use Xcode 12’s new SVG asset support, standard SwiftUI layout, and flexibility when applying my color blend to assets that might not just be black and white.

I hope this helps others. If you have thoughts, corrections, or suggestions, let me know.

Swift Process and osascript: so much easier than the command line

I use osascript a lot to automate things that need automating and until yesterday, I did so almost exclusively from shell scripts. Then,  while developing some sample code the other day, I discovered how much easier it is to call osascript from a command-line utility, even for the most trivial of scripts.

let script = """
  set appName to "\(appName)"
  tell application "System Events"
	if visible of application process appName is true then
		set visible of application process appName to false
		set visible of application process appName to true
	end if
  end tell

With Swift’s triple-quoted multiline string, you need little if any escaping and your script can basically be copy/pasted from the Script Editor app. Plus string interpolation enables you programmatically customize your AppleScript code.

For your Process, set your launchPath to "/usr/bin/osascript" and your arguments to ["-e", script]. Then launch and wait until exit.

if #available(macOS 10.13, *) {
    guard (try? != nil
        else { throw RuntimeError.operationError }
} else {

Why is it worth creating an entire Xcode project to deal with a little osascript work? For me, it’s a big win when it is part of a larger utility. With the Swift Argument Parser, I’ve been porting a lot of my scripts — both shell scripts and swift scripts — to compiled utilities and I find that I tend to lean on osascript a lot more than I thought I did to automate my system.

SwiftPM and Tagging

A couple of days ago, I was having the oddest issues fetching a SwiftPM package. The package resolution/version solving failed. I still don’t know why this was happening as my package was tagged as “0.1.0” at the time, as confirmed over at Github.

In any case, I found that removing the tag locally and remotely and retagging and re-pushing my tags resolved the issue. The package resolved correctly afterwards.

While I was at this, I decided to update my .gitconfig to add tagging aliases. Here’s what I came up with. They work but they’re not pretty and I’m sure there are better ways to approach this:

# Tagging
retag = "!f(){ name=`git tag | tail -1`; \
	git tag -d \"$name\"; echo "Retagged $name"; \
	remote=`git remote -v`; \
	if [ \"$remote\" != \"\" ]; \
	then git push origin --delete \"$name\"; fi; \
	git tag \"$name\"; \
	if [ \"$remote\" != \"\" ]; \
	then git push --tags; \
	else echo "No remote"; fi; };f"
untag = "!f(){ name=`git tag | tail -1`; git tag -d \"$name\"; \
	remote=`git remote -v`; \
	if [ \"$remote\" != \"\" ]; \
	then git push origin --delete \"$name\"; \
	else echo "No remote"; fi; };f"
tagit = "!f(){ git tag \"$@\"; echo "Tagged $name";\
	remote=`git remote -v`; \
	if [ \"$remote\" != \"\" ]; \
	then git push --tags; \
	else echo "No remote"; fi; };f"

retag, which solved my issue, grabs the name of the current tag, removes it, and retags locally and remotely. untag removes the tag and tagit adds a new tag to the current commit.

Feel free to suggest improvements.

p.s. If you’re looking for it, I took down the time machine rant post at the suggestion of several commenters.

Broken App Store downloads on Mojave: We could not complete your purchase

This has been happening to a lot of people recently. You open App Store and try to update apps or download new ones. Instead:

And if you have 48 apps to update, you have to click OK 48 times. Argh.

I spent nearly two hours with Apple yesterday trying to resolve.

Instead, I should have just tweeted because when I did Bas Broek had the answer almost immediately:

I had already rebooted, reset NVRAM/PRAM, cleaned out my Application Support for the App Store, and, get this, at the advice of Apple itself, reinstalled freaking Mojave to try to resolve it.

What a waste of time.

I hope this may come up in someone’s Google search to save them time.

  1. Quit App Store
  2. At the terminal: open $TMPDIR/../C/
  3. In Finder: trash everything in that folder including any pending updates / stuck items.
  4. Relaunch App Store
  5. Done

Update: Gwynne Raskind adds: “$TMPDIR/../C is confstr(_CS_DARWIN_USER_CACHE_DIR)”.

Catalina permissions: Chrome, Zoom, etc

Ran into trouble this weekend where I was unable to add permissions for a number of apps to allow access to my microphone and camera.  (And yes, I’m aware of the security horrors of Zoom but I had work to do.)

They wouldn’t give the normal permissions request:

Instead, I got a message directing me to System Preferences:

Once there, the prefs did not list the app for normal check-to-enable:

I couldn’t unlock and drag on an app.

With some help from Bas Broek and this article, which specifically addressed the inability to grant access in Catalina, I discovered that rebooting with a NVRAM/PRAM reset might help. It sounded like sacrificing chicken entrails but it worked. While a regular reboot didn’t help, the Cmd+Option+PR reboot did.

Apple Support Article: How to reset NVRAM or PRAM on your Mac.

I hope this helps someone else to avoid the time I wasted.

Adjusting HDMI volume on Catalina

Normally when you output audio through HDMI, you cannot control its volume from your Mac. You adjust it on the output device instead, whether it is a monitor or TV.

I’m working on my Catalina laptop while my mini is in the shop and using my newish DELL monitor without my normal speakers, which plug into the headphone jacks. With this setup, my music is loud, even when I have the monitor settings fairly low.

As it is a pain to adjust volume through the monitor menu, I decided to give Soundflower/SoundflowerBed a try. I was quite sure that Catalina would have killed it by now.

I was wrong.

In SoundflowerBed, I chose HDMI for the 2-channel output.

In System Preferences, I selected Soundflower (2ch) as my sound output device.

Boom. My volume control came back to life and my ears are recovering from the onslaught.

Seeing an old friend keep plugging along and doing what I need is remarkably satisfying. Thank you to everyone who has worked on Soundflower through the years, from Alexander Hudek and RogueAmoeba to MattIngalls and Maciej Wilczyński.

Apple Pencil: Too much information

I own a first generation refurbished Apple Pencil. I bought it when I picked up the new 5th gen iPad mini. It’s a delight. I use it for freehand note-taking when I don’t want to tip-tap into the onscreen keyboard or lug around my folding bluetooth keyboard. I use it doodle and draw. I use it to annotate PDFs. I especially love  how it knows what is the pencil and what is my hand so I can rest against the screen and still get work done.

My pencil keeps its charge for days with light use. When I need to top it up, I can stick it into my iPad’s lightning port. In under 10 minutes it goes from flatline to 100% charge. Yes, it looks a bit odd sticking out like that, but it isn’t for long and it’s easy enough to rest the iPad on a desk until the charge is complete.

Keep track of your current pencil charge in your iPad widget gallery. The Batteries  section shows how much juice is currently available:

When talking about charging, you should think about that tiny cap at the end of the first generation pencil. Fortunately, there are many extremely useful and inexpensive helpers for keeping track of the cap and the charging adapter, the short flat item at the bottom of this picture. It’s used for charging off a USB lightning cable by providing a female-to-female connector between the cable and the pencil:

Many third party gizmos service these tiny pieces. You can purchase replacement magnetic caps that better stick to your pencil and replacement charging adapters for when you lose them. If you’d rather not lose them in the first place, consider a simple holder set like this one. Mine is clear silicon and did not include the tip that covers the nib. The holders make sure the two tiny pieces aren’t easily lost, and that they’re kept along-side the equipment that uses them:

In addition, I purchased a magnetic sleeve to attach my pencil to my iPad and/or its smart cover when not in use. Again, this helps ensure I don’t lose the things I need. I roll the flat part away from my hand and find that it doesn’t interfere with holding the pencil or writing with it.

I use the Selvy PenScript keyboard plug-in to convert handwriting to text. It’s available from my normal keyboard. I tap-and-hold the globe to select it. Make sure when installing that you enable it in Settings > General > Keyboards.

As you see from this screenshot, I also installed the Kaomoji.HW keyboard that allows me to draw emoticons. It’s not very good at its job but it’s pretty hilarious to play with.

The SelvyPen keyboard is surprisingly useful across apps. It’s as easy to enter a URL as it is to type free text.

If you’re looking to enter large tracts of text by hand, Nebo does a great job with handwriting-to-text conversion, allowing you to enter information into notebooks using your pencil. Notice how the app keeps track of the ongoing interpretation in light gray just above the handwriting:

Use the ellipsis (3-dot) menu on the right to convert paragraphs to text and remove the handwriting entry. The accuracy is surprisingly good.

For annotating PDFs, I use Notability. I admit that it’s mostly because I already own it and it’s a great app. There are many other excellent options on the market. I’d love to hear what else you recommend. I apologize for all the blurring but I was reviewing someone else’s work and I wanted to respect their privacy:

For presentation, I have a half dozen apps of varying quality and I can’t really recommend one or the other as being particularly outstanding:

What other apps, tweaks, and gadgets have you found to enhance your pencil-using experience? I love my pencil and am always looking for more ways to get the most from it!

Reader recs:

  • Many readers agree with my use of Notability
  • Mike recs Concepts. “I use it as a vectorized infinite whiteboard for sketching and note taking.”
  • Teddy likes GoodNotes, “which will hide the UI when projecting to an external screen. Also has a nice laser pointer with a trail so you can make temporary markings as you go” and PDF Viewer for annotation.
  • Paper by WeTransfer gets a thumbs up from Paul.

Trackpad dragging the easy way

I’m surprised it took me as long as it did to discover that there’s an accessibility alternative for dragging. In System Preferences, visit Accessibility > Pointer Control > Mouse & Trackpad.

Click on Trackpad Options, enable dragging, and choose three finger drag from the pop-down.

I’ve been using three finger dragging for about a week now and it’s been a vast improvement over my attempts to drag items the normal way. Yes, I still end up running out of trackpad room as I always do, but using a finger from the other hand to nudge things where they need to go does the trick for getting my dragged items to their destinations.

I am using this almost entirely in Finder, although the same approach should work for moving words in a document or views in IB.