Kotlin migration

[elevenetc]

• Converted to Kotlin
  • ScaleValue and Position converted into data classes
  • Getters and setters replaced with fields where possible
  • Static utility methods replaced extensions functions where possible
  • Java collections replaced with Kotlin ones
  • Functional interfaces replaced with lambdas
  • String concat replaced with kotlin templates
• Improved package structure
• Simplified core entities hierarchy
• Removed excessive invalidate calls (text reveal animations)
• Renamed generic Debug to TextSurfaceDebug to avoid spoiling namespace
• Renamed TextBuilder > Text.Builder
• Added @CallSuper to TextEffect.onStart
• Added @CallSuper to SurfaceAnimation.cancel
• Added support of ScrollView Fixes It doesn't work if it's in ScrollView #13

[ptmt]

Seems like using Java API from Kotlin, feels a bit verbose. I would expect something more idiomatic to Kotlin (Data classes, type-safe builders, or just apply with mutable fields as you do earlier?) Maybe any reason for set..?

[elevenetc]

Yeah, I agree. I actually tried to get rid of TextBuilder, but there two problems:

1. Making of Position instance has it's own requirements and there're 3 most frequent cases and they are hidden in setters:

val position1 = Position(align, alignText = alignText)
val position2 = Position(align)
val position3 = Position(point = PointF(px, py))

2. For most cases scale and scale pivot needs to be set correctly and it's done in final build call:

val text = Text(text, position, padding, paint)
text.scaleX = scale
text.scaleY = scale
text.setScalePivot(scalePivot, scalePivot)

So for most cases Builder hides these requirements inside setters and final build function. For custom (and probably very rare cases with weird position and maybe inverted or negative scale) cases developer can use Position and Text constructors without Builder.

But it might be that these requirements can be hidden inside type-safe builder. Need to think about better api.