Need trig & LCB help

hh hh at hyperhh.de
Wed Oct 30 17:34:45 EDT 2019


Greg, I've been away from LCB for a while. When reading the last post
again I remembered an improvement that you could try to use:

The current version computes the pathes with every redraw (onPaint).
This is far too often. We could compute the pathes once (in onCreate)
and then update ONLY when needed (= when one of its params changes).
This will give your widget a lot of time for other things and makes
the OnPaint code shorter.

variable mBCircles as List
variable mBigRad as Number
variable mLilRad as Number
variable mInnerRad as Number
variable mBigX as Number
variable mBigY as Number
variable mBNum as Number

[1] in OnCreate write:
put the number of elements in mData into mBNum
put my width/2 into mBigX
put my height/2 into mBigY
put mBigRad-mLilRad into mInnerRad
updateCirclePaths([mBNum,mInnerRad,mLilRad,mBigX,mBigY])

[2] in OnPaint write:
repeat with tButtonNumber from 1 up to mBNum
   fill mBCircles[tButtonNumber] on this canvas
end repeat

[3] This does the job minimal often:
Whenever you change one of its params write also

updateCirclePaths([mBNum,mInnerRad,mLilRad,mBigX,mBigY])

[4] This handler computes already the small circle paths:

-- sets the list mBCircles of regularly placed circle paths,
-- turns clockwise from high noon, is centered at point [cX,cY]
-- pL = [numOfCircles,bigRadius,smallRadius,cX,cY]
handler updateCirclePaths (in pL as List) returns nothing
   variable tI as Number
   variable tPi as Number
   variable tPaths as List
   put 2*pi/pL[1] into tPi
   put [] into tPts
   repeat with tI from 0 up to pL[1]-1
      push circle path centered at point \
        [pL[4]+pL[2]*sin(tI*tPi), pL[5]-pL[2]*cos(tI*tPi)] \
          with radius pL[3] onto tPaths
  end repeat
  put tPaths into mBCircles
end handler

Hope you'll show us your shining new widget ...




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