SwiftOverCoffee3Challenge

Apologies for the choppy gif. Have a look at the mov files instead! :-)

Considerations

I used Xcode 11.4 beta to get the best error messages - based on suggestion on Swift over Coffee. :-)

Adding all the sliders was inspired by the excellent dotSwift talk by Tobias Due Munk.

Challenges faced

Standard color blending didn't work exactly as I envisioned. Luckily the .hardLight blend mode appears to work quite nicely.

I quickly ended up with expressions that could not be type checked in a reasonable time when doing angle math with a ternary operator. I tried to refactor the calculations to happen in the beginning of each ForEach loop, but I could not make that work. I ended up moving the calculations to a function instead.

I found it a bit annoying that the compiler could not infer the type in the specified ranges when using a Slider. It would look nicer if you didn't have to add explicit types to the ranges. UPDATE: The compiler could in fact infer the types - I don't know why I couldn't make it work in the first place.

I was initially quite a bit annoyed with how animations worked, since I thought they had to be applied on the thing you wished to animate. Mind blown when I figured out how to do withAnimation as well as doing animations directly in bindings!

Time constraints

I didn't have time to add a Slider for the petal count. I did not really know the best place to 'map' the floating point values from a slider to integral ones.

It would have been nice to use proportionate sizes for the petals, but I know too little about relative sizing and was not prepared to wrestle with GeometryReader.

Also I would have liked to add a color picker. :-)

I knew up front that I would not have time to add the quickly fading phantom image that appears when the flower is closing in the original animation.

Epilogue

After the challenge, I have spent yet another hour of playing around - and it's so much fun! Please checkout out the branch 'playingaround' for these experiments that I didn't do within the time limit of the challenge.

I have learned to make animations local to specific actions and even to specific bindings! How cool is that?

And I have learned that ForEach with a Range is only intended to be used with constants, but it's really easy to change the code to use ranges in a way that works with variables. Just add an id: \.self parameter as such:

                ForEach(0 ..< count, id: \.self) { index in
                    ...
                }

I have made petal counts, color, opacity and blend modes adjustable among other things.

Looking forward to playing with it even more! :-)