100 Days of SwiftUI

Day 66

2026-07-19

Project 13, part 5

Finishing up the basic app

Customizing our filter using confirmationDialog()

Here are the filters we’re offering

Button("Crystallize") { setFilter(CIFilter.crystallize()) }
Button("Edges") { setFilter(CIFilter.edges()) }
Button("Gaussian Blur") { setFilter(CIFilter.gaussianBlur()) }
Button("Pixellate") { setFilter(CIFilter.pixellate()) }
Button("Sepia Tone") { setFilter(CIFilter.sepiaTone()) }
Button("Unsharp Mask") { setFilter(CIFilter.unsharpMask()) }
Button("Vignette") { setFilter(CIFilter.vignette()) }

Because they have different ways of describing “how much” (Intensity, Radius, Scale) you have to do some machinations in the processing step, e.g.

let inputKeys = currentFilter.inputKeys

if inputKeys.contains(kCIInputIntensityKey) {
    currentFilter.setValue(
        filterIntensity,
        forKey: kCIInputIntensityKey
    )
}
if inputKeys.contains(kCIInputRadiusKey) {
    currentFilter.setValue(
        filterIntensity * 200,
        forKey: kCIInputRadiusKey
    )
}
if inputKeys.contains(kCIInputScaleKey) {
    currentFilter.setValue(
        filterIntensity * 10,
        forKey: kCIInputScaleKey
    )
}

A simple slider like we’re using doesn’t really give a lot of control, but really, too many dials means too much confusion.

I am wondering why it’s a series of if statements. Would Switch be better?

Also at the moment there is no way to combine filters…

Sharing an image using ShareLink

One line (but Xcode formatted it in long-form)

if let processedImage {
    ShareLink(
        item: processedImage,
        preview: SharePreview(
            "Instafilter image",
            image: processedImage
        )
    )
}

We also learned how to ask for a review — it seems like it could go very badly, except Apple has some tools to mitigate over-eager devs.