The Pink Circle Example

[Peter Wood]

As well as the choice of colour, I found one "real" issues and a couple of other annoynances with the pink circle example.

The issue is the example uses "real" instead of "Real" which causes a compilation error.

The first annoyance is the radius of the circle is set to the width of the widget so it can display a "window" on a circle at times. I made the following change to the paint handler:

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public handler onPaint()
  variable tCirclePath as Path
  variable tShortest as Real
  if my width < my height then
    put my width into tShortest
  else
    put my height into tShortest
  end if
  put circle path centered at point [my width / 2, my height / 2] with radius ((tShortest - mMargin)/2) into tCirclePath
  set the paint of this canvas to solid paint with color [0, 1, 0]
  fill tCirclePath on this canvas
end handler 

A another minor annoyance, some of the handlers start with "On" and some with "on".

It would be good if the docs could be updated in the next release.

[FourthWorld]

I think I missed something: I remember when "private" was introduced - now we have to declare "public" for all non-private handlers?

[Peter Wood]

I can only answer by experimenting. It seems the public keyword is necessary. When I removed it from the onPaint handler, the code compiles but the widget doesn't display anything.

By the way, I am using the 8.0 DP 1 release.

[peter-b]

To confirm, the default visibility of handlers, variables, etc. is private. Only explicitly "public" definitions are exported from a module.

[dave.kilroy]

Thank you @PeterWood for the hint about "real" and "Real". I seem to have found another issue in the example as it appears in the "Extending LiveCode" bit of the Guide:

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public handler setMargin(in pMargin as real) as undefined
    put pMargin into mMargin
    redraw all
end handler

It's that final "as undefined" that is the problem - as far as I can tell this is a typo and it certainly won't compile for me when it's in place. In fact the only thing I can get to compile which has anything after the final bracket is "return as <type>". Is this correct or is there some other way of defining handlers I don't know about?

By the way, please note the "real" as opposed to "Real" in the above example from the Guide, I plan to attempt to send in pull requests on the Guide to tidy up these and other little niggles...

EDIT: forgot to say, "undefined" seems to be deprecated as a type anyway

[pink]

is this example available publicly?

and what is wrong with pink?

[dave.kilroy]

Hi @pink!

Yes, in LC8 open the dictionary, choose the 'Guide' tab, then from the drop-down choose "Expanding LiveCode" - it's a really nice intro to LCB (at least it appeared so to me as a LCB newbie) - but it has several little typos and the example doesn't compile!

[[-hh]]

Hi all.

This example compiled here in one of the early dp-versions of LC8.
Meanwhile LCBuilder has changed some things, also lowercase and uppercase rules.
So the point is not a "wrong" example but a missing update to LCBuilder as of LC 8.0.0-rc-1.

Since you have it already running, please post the running code here, so others (including me) can use it.

Thanks, Hermann

[dave.kilroy]

Hi all - this is a version of what is in Guide that compiles and runs for me (i.e. with capitalised "Real", without "as undefined" - and also without Peter's tweak for it's width and height)

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widget community.livecode.beaumont.pinkCircle

   metadata title is "My Pink Circle"
   metadata author is "Benjamin Beaumont"
   metadata version is "1.0.0"

   use com.livecode.canvas
   use com.livecode.widget
   use com.livecode.engine

   // Properties
   property circleMargin get mMargin set setMargin

   // Local variables
   private variable mMargin as Real

   public handler onCreate()
      put 0 into mMargin
   end handler

   public handler OnPaint()
      // Create a path with a radius of half the width of the canvas
      // Set the paint to a solid pink color
      // Fill the path
      variable tCirclePath as Path
      put circle path centered at point [my width / 2, my height / 2] with radius ((my width - mMargin)/2) into tCirclePath
      set the paint of this canvas to solid paint with color [1, 0, 1]
      fill tCirclePath on this canvas
   end handler

   public handler setMargin(in pMargin as Real)
      put pMargin into mMargin
      redraw all
   end handler

end widget