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Re: Hyperion (vector graphics editor and GUI designer using Athens)

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Bob Williams

Re: Hyperion (vector graphics editor and GUI designer using Athens)

Kilon

I can probably help you as it was in a Smalltalk application that I developed in the early 1990s, ObjectiveFM, for my doctoral dissertation and later was a commercial product. The method is below and it is for a cubic Bezier spline. I am considering add a GIS package to Pharo and would like to have assistance. I would also note that you should look at the series of books called Graphics Gems (5 books) that are a great resource.

Bob Williams

correlatesTo: testPoint within: correlationDistance

    | dz index point return singleSpline aPoint testReturn |
"self halt."
    aPoint := testPoint.
    return := nil.
    dz := self controlPoints first - aPoint.
    ((dz dotProduct: dz) < self minimumDistance)
        ifTrue: [
            ^ self controlPoints first ].

    dz := self controlPoints last - aPoint.
    ((dz dotProduct: dz) < self minimumDistance)
        ifTrue: [
            ^ self controlPoints last].

    index := -2.
    ((controlPoints size) // 3) timesRepeat: [
        index := index + 3.
    "eliminate segments from consideration if the bounding box about them does not contain aPoint"
        singleSpline := OFMSingleBezierSpline createFrom:
            (Array                                                     with: (controlPoints at: index)
            with: (controlPoints at: index +1)
            with: (controlPoints at: index +2)
            with: (controlPoints at: index +3)

        point := singleSpline nearestPointOnCurveFor: aPoint.
        (point notNil)
            ifTrue: [
                ((point distanceFrom: aPoint) <= correlationDistance)
                    ifTrue: [ testReturn := true ]
                    ifFalse: [ testReturn := false ] ]
            ifFalse: [
                point := ((singleSpline z1 distanceFrom: aPoint) < (singleSpline z2 distanceFrom: aPoint))
                ifTrue: [ singleSpline z1 ] ifFalse: [singleSpline z2 ].
                    ((point distanceFrom: aPoint) < correlationDistance)
                    ifTrue: [ testReturn := true ]
                    ifFalse: [ testReturn := false ] ].
        (testReturn)
            ifTrue: [
                (return isNil)
                    ifTrue: [
                        return := point ]
                    ifFalse: [
                        ((point distanceFrom: aPoint) < (return distanceFrom: aPoint))
                            ifTrue: [return := point] ]]].
    ^return

kilon.alios

Re: Hyperion (vector graphics editor and GUI designer using Athens)

Thank you Bob . I almost completely missed your post cause Pharo-dev has exploded with messages lately. Sorry for the late reply.

Its awesome that you land the solution to my plate, cant thank you enough.The books you recommended are exactly what I needed.

I see also there is even a github repo here -> https://github.com/erich666/GraphicsGems . I am definitely going to study them.

Unfortunately I am new to coding graphics and completely unfamiliar with GIS and CAD. I plan to use Ephestos for interfacing with Blender though ( I have been developing Blender python addons before using Pharo) . What kind of assistance you are looking for ?

On Sat, Feb 1, 2014 at 4:27 PM, Bob Williams <[hidden email]> wrote:

Kilon

I can probably help you as it was in a Smalltalk application that I developed in the early 1990s, ObjectiveFM, for my doctoral dissertation and later was a commercial product. The method is below and it is for a cubic Bezier spline. I am considering add a GIS package to Pharo and would like to have assistance. I would also note that you should look at the series of books called Graphics Gems (5 books) that are a great resource.

Bob Williams

correlatesTo: testPoint within: correlationDistance

    | dz index point return singleSpline aPoint testReturn |
"self halt."
    aPoint := testPoint.
    return := nil.
    dz := self controlPoints first - aPoint.
    ((dz dotProduct: dz) < self minimumDistance)
        ifTrue: [
            ^ self controlPoints first ].

    dz := self controlPoints last - aPoint.
    ((dz dotProduct: dz) < self minimumDistance)
        ifTrue: [
            ^ self controlPoints last].

    index := -2.
    ((controlPoints size) // 3) timesRepeat: [
        index := index + 3.
    "eliminate segments from consideration if the bounding box about them does not contain aPoint"
        singleSpline := OFMSingleBezierSpline createFrom:
            (Array                                                     with: (controlPoints at: index)
            with: (controlPoints at: index +1)
            with: (controlPoints at: index +2)
            with: (controlPoints at: index +3)

        point := singleSpline nearestPointOnCurveFor: aPoint.
        (point notNil)
            ifTrue: [
                ((point distanceFrom: aPoint) <= correlationDistance)
                    ifTrue: [ testReturn := true ]
                    ifFalse: [ testReturn := false ] ]
            ifFalse: [
                point := ((singleSpline z1 distanceFrom: aPoint) < (singleSpline z2 distanceFrom: aPoint))
                ifTrue: [ singleSpline z1 ] ifFalse: [singleSpline z2 ].
                    ((point distanceFrom: aPoint) < correlationDistance)
                    ifTrue: [ testReturn := true ]
                    ifFalse: [ testReturn := false ] ].
        (testReturn)
            ifTrue: [
                (return isNil)
                    ifTrue: [
                        return := point ]
                    ifFalse: [
                        ((point distanceFrom: aPoint) < (return distanceFrom: aPoint))
                            ifTrue: [return := point] ]]].
    ^return