Bill Atkinson wrote QuickDraw (the graphics libraries that underpinned the Lisa and Mac UI), and MacPaint, and HyperCard.
Along the way he kept having to both invent new ways for user interfaces to work, and new ways to write software to solve for them. There's a kind of synergy that emerged out of the fact that he was optimizing both for 'can be done quickly in the hardware available on the Mac', and 'provides a great user experience', which means that his fingerprints are all over the aesthetic of the old black and white Mac. That dither style is another example of that kind of marriage of algorithmic genius and aesthetic sensibility.
And it shows up in things like the 'marching ants' selection boundary (https://en.wikipedia.org/wiki/Marching_ants). Or the way lots of user feedback in the classic Mac UI comes in the form of inverting pixels (text selection, menu highlighting, the way buttons appear during a mouse-down, the boundary of a window while it's being dragged), because drawing over something in XOR mode was a great way to generate that effect. The way he approached putting these tools together in QuickDraw also had the effect of things like his famous conversation with Steve Jobs about rounded rectangles (https://www.folklore.org/Round_Rects_Are_Everywhere.html) manifesting as it being as easy to draw a rounded rectangle as a square one in QuickDraw, which led to them showing up everywhere in the operating system.
The success of the Mac UI was not just that it looked good; it was in large parts that Bill Atkinson made a really cleaver, small set of tools that made making things that looked good easy to make.
Susan Kare's amazing icons wouldn't be nearly as fondly remembered if Bill hadn't built the tools that made it easy to drop 32x32 pixel masked bitmaps into the UI and invert them when you clicked on them.
Along the way he kept having to both invent new ways for user interfaces to work, and new ways to write software to solve for them. There's a kind of synergy that emerged out of the fact that he was optimizing both for 'can be done quickly in the hardware available on the Mac', and 'provides a great user experience', which means that his fingerprints are all over the aesthetic of the old black and white Mac. That dither style is another example of that kind of marriage of algorithmic genius and aesthetic sensibility.
And it shows up in things like the 'marching ants' selection boundary (https://en.wikipedia.org/wiki/Marching_ants). Or the way lots of user feedback in the classic Mac UI comes in the form of inverting pixels (text selection, menu highlighting, the way buttons appear during a mouse-down, the boundary of a window while it's being dragged), because drawing over something in XOR mode was a great way to generate that effect. The way he approached putting these tools together in QuickDraw also had the effect of things like his famous conversation with Steve Jobs about rounded rectangles (https://www.folklore.org/Round_Rects_Are_Everywhere.html) manifesting as it being as easy to draw a rounded rectangle as a square one in QuickDraw, which led to them showing up everywhere in the operating system.
The success of the Mac UI was not just that it looked good; it was in large parts that Bill Atkinson made a really cleaver, small set of tools that made making things that looked good easy to make.
Susan Kare's amazing icons wouldn't be nearly as fondly remembered if Bill hadn't built the tools that made it easy to drop 32x32 pixel masked bitmaps into the UI and invert them when you clicked on them.