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Working with Files: FolderItem

Sooner or later your app will need to work with files, maybe to save the data generated with the app itself, to open the files created with other apps or because is the main purpose of the utility you are working on. Xojo gives you the class FolderItem fully loaded with a useful bunch of properties that allow you to examine the attributes of any file; for example, the creation or modification of dates, the file path (in several formats), if the file is an alias, etc. The FolderItem class also gives you the methods to do a lot of file operations without effort. Continue reading Working with Files: FolderItem

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Do you still ASCII?

From time to time we get code that illustrates a problem a user is having when they rely on old-school ASCII. This problem can occur when using the Chr function to create a character.

One example we see reasonably frequently is code to create a string that contains a quote like:

 dim someString as String = chr(34) + "someValue" + chr(34)

This style is not necessary and may give unwanted results if you have an unusual string encoding. Instead, you can write this without the use of the Chr function. Here’s how:

Continue reading Do you still ASCII?

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Fractional Scale Factors

With all the Retina/HiDPI work done in the past few years, we’ve had to add some new features along with it. One of these newer features is the Graphics ScaleX and ScaleY properties.  For the purposes of Retina/HiDPI, the scale factor is used when converting user space coordinates to backing store coordinates.  While mostly integral on MacOS (unless originating from some code that’s probably not ours), it can vary on Windows, and perhaps arguably mostly fractional.  This is because Windows allows you to set DPI scales at 125%, 150%, etc. So when dealing with fractional scales there are a few things to watch out for:

  1. Rounding issues
  2. Anti-alias effect

While the framework takes care of rounding issues, for the most part, the secondary issue of anti-aliasing is up to you.

Continue reading Fractional Scale Factors

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