| Re: [platform-swt-dev] macOS 10.14 (mojave) |
No no, you can definitely support both macOS 10.14 and older versions in the same application. It’s possible to specify the minimum deployment target when building an application. If you need to use features of a newer version of macOS than the minimum deployment target you need to guard those usages with an if statement. Swift and Objective-C has language support for this, but how it’s actually working is that most symbols in the SDK have weak linkage, that means that the symbols don’t need to be present at runtime. Then you need to check if the symbols are available at runtime before using a feature requiring the new symbol. In Swift it would look something like: @available(macOS 10.14, *) func fooBar() And the usage: if #available(macOS 10.14, *) { fooBar() // 10.14 specific code } else { // fallback for older versions } Doing that manually in C would be something like: void fooBar() __attribute__ ((weak_import)); if (fooBar) { fooBar(); // foo is available } else { // fallback for older versions } With Java I’m guessing the native dynamic libraries are loaded with the a method similar to “dlopen” and symbols loaded using “dlsym”. In that case the same approach as described above should be possible to use. I’ve attached a screen shot of the Scala IDE (based on Eclipse which uses SWT, using the NSRequiresAquaSystemAppearance method) when dark mode is enabled. This shows that some parts are correctly using the dark mode colors (like the background color in the side bar and the two bottom views). At the same time it’s possible to see that the text color looks hard coded in the side bar (it would otherwise be white). Also, since Eclipse uses quite a few of the custom controls (like the tab bar and tool bar) that SWT provides, very few parts of the application has the correct colors. SWT needs to use the dynamic colors, that will change depending on if dark mode or light mode is enabled, and not hard coded RGB values. This will also give the correct values for the high contrast versions (an accessibility feature) that are available as well. In the 10.14 SDK there are quite a few new semantic colors (as they are called) which instead of specifying a color like white or blue specifies what it should be used for, i.e. label color, tab background color and so on. These colors are dynamic and change according to the selected mode. Also standard colors like red, blue, green and so on are available as dynamic colors that change slightly between dark and light mode. macOS 10.14 also added a new feature making it possible for the users to select the accent color (i.e. usually the color of the “Ok” button in a dialog). This needs to be handled as well.  --
/Jacob Carlborg
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