Every copy of Mac OS (and iOS) uses Quartz to draw and composite on-screen graphics. This mystery revolves around Quartz, the display engine at the heart of Apple’s operating systems. Time to put on the deerstalker cap and do some old-fashioned detective work. Concealed in those files was code that could clarify this this calamitous conundrum of colorful confusion. I requested a copy of the problem file, and almops sent along both the PDF they imported into Keynote and the PostScript file used to generate said PDF. This wasn't the first time I've seen an interpreter mangle something beyond recognition, but there's almost always a way to work around it. I was part of the QA teams for these companies, where I designed features, sniffed out bugs, and figured out why things go sideways. These applications do the hard work of managing color, rasterizing vectors, and compositing transparencies so designs can be put on paper, film, or plates. For fifteen years I worked for OEMs in the graphic arts industry-more specifically, in workflow software. It’s the kind of obscure problem that calls for my very particular set of skills, skills I acquired over a long career. When I saw that thread, I knew I had to tackle the mystery. Anything Apple, on the other hand-be it iWork, Preview, or Safari-displayed those color blocks as a gradient, ruining his presentation. Almops said Adobe Acrobat displayed the PDF correctly, as did Chrome, and PDF viewers on other operating systems. The PDFs in question had been created by a suite of command line apps called generic-mapping-tools, or GMT, which generates maps and map accessories… like color bars. When a specific PDF was placed into Keynote, its contents-a series of colored squares-became a smooth rainbow gradient! Don't get me wrong, rainbows look cool, but they're not helpful when you need distinct solid blocks of color. Forum user almops was having a weird problem with Keynote. I ran into an interesting thread on one of my usual Mac haunts: Ars Technica’s Macintoshian Achaia forum. One such mystery crossed my path back in June. And, as with any whodunit, they may only be obvious in retrospect. It’s not always obvious why bad things happen to good programs. Computers do exactly what they’re told, like a vexatiously literal genie. But there’s nothing supernatural about software. When there’s something strange in the Network Neighborhood, I’m the one you called. But I'm one of the few who feels compelled to learn why. When weird things happen, most people just mutter and/or swear. Computer software, like everything made by us imperfect humans, is full of imperfections of its own.
0 Comments
Leave a Reply. |