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Issue 15.5 ('Touch Bar')
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FEATURE

The Case of the Broken Upgrade

Following clues to solve a Xojo mystery

Issue: 15.5 (September/October 2017)
Author: Mattias Sandstrom
Author Bio: >Mattias is the programming CEO of Tangix Design & Development, a Sweden-based company developing software solutions for the web and for the Windows platform
Article Description: >No description available
Article Length (in bytes): 11,763
Starting Page Number: >1
Article Number: 15504
Related Web Link(s):

>http://www.libpng.org/pub/png/spec/1.2/PNG-Structure.html
http://entropymine.com/jason/tweakpng/

Excerpt of article text...

>Keeping your tools sharp and clean is an excellent way to succeed in most projects in the real world. I do it myself all the time—sharpen knives, make sure the battery to the cordless screwdriver is charged, and not using cheap brushes when painting.

But when I'm in front of my computer I turn into the Muppet's grouchy old men, Statler and Waldorf: "Don't touch my computer," "I'm not changing anything," "I hate these constant updates," and "Get off my lawn!"

It turns out there's a good reason for my grouchiness. This is a detective story of how a "simple" Xojo upgrade could turn a working project into a forum-hunt and a deep-dive into the inner workings of the PNG file-format.

Just a Minor Upgrade, Right?

My most up-to-date project is a 64-bit, HiDPI software that is used to manage and edit exam databases. There are not that many users, probably less than a hundred, and thus this is where most of the new stuff delivered from Xojo is being used. This application was compiled in Xojo 2016r4.1 and was working just fine (see Figure 1).

Notice the small icons in the legend at the bottom of the screen. The same icons are used in the ListBox to indicate status of the questions. They are 16 by 16 pixels in size and have a corresponding 32 by 32 pixel image.

...End of Excerpt. Please purchase the magazine to read the full article.