I'm finishing a nice app with a relatively small text editor. During implementation of the syntax highlight I found myself in need to change foreground colour attribute of recognized tokens. I noticed that there is a property of NSTextStorage:
var fixesAttributesLazily: Bool { get }
The documentation, regarding it is:
A Boolean value indicating whether the text storage object fixes attributes lazily. (read-only)
Discussion
When subclassing, the default value of this property is NO, meaning that your subclass fixes attributes immediately when they are changed. The system’s concrete subclass overrides this property and sets it to YES.
I really don't know how to interpret this ... but this is what I did:
- I'm changing the attributes of th recognised tokens inside
textStorage(textStorage: NSTextStorage, didProcessEditing editedMask: NSTextStorageEditActions, range editedRange: NSRange, changeInLength delta: Int)(which is a delegate method of NSTextStorage). Here I'm checking the value of this property - it's FALSE. - I subclassed NSTextStorage exactly as Apple suggest (https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/TextStorageLayer/Tasks/Subclassing.html) and overrode the property. The text view started to behave very strange. Actually with small text it performs OK, but as soon as I open a 4 Mbytes file - it hangs and ... well ... bad things start to happen to my mac. Actually this behaviour doesn't depend on the value of the
fixesAttributesLazilyproperty. Maybe my implementation of NSTextStorage is bad or at least not sophisticated.
Any trick of applying attributes in background or lazily or ... something like this is welcomed.
In additional: I know that there are many ways to optimise a syntax highlighted. It may highlight partially, use some kind of logic, based on the changed range ... etc. What I'm looking for is a way to process attribute changes in background. For example currently when I paste 4 Mbyte file to the text view, it first highlights it (which takes 2-3 seconds) and then it visualises it. The effect I'm looking for is the text to appear right away and after time - the colors.
The project I'm working on is written in Swift.
Thanks to everyone in advance for the help. You may reach me via ivailon at gmail dot com for specifics, since I don't want to expose the app here ... at least not yet ;-)
