Passing effect as parameter to a function

Audio and Graphics
#1

Hi all,

I’m trying to generalize a method so that I can apply a predefined filter across multiple display objects.

Based on applying an effect like this:

displayObject.fill.effect = "filter.colorPolynomial" displayObject.fill.effect.coefficients = { 0, 0, 1, 0, --red coefficients 0, 0, 1, 0, --green coefficients 0, 1, 0, 0, --blue coefficients 0, 0, 0, 1 --alpha coefficients }

I tried the following:

--Applies the given effect to the view and overviews displayViewImageFilter = function (thisEffect) --Apply to back image viewBackImage.fill.effect = thisEffect --Apply to all overviews for i, overviewImage in pairs(overviews) do overviewImage.fill.effect = thisEffect end end

But I can’t figure out how to build the thisEffect parameter so that it can be passed into the method.  Trying code below will return “Attempt to index thisEffect (a string value)”:

local thisEffect = "filter.colorPolynomial" thisEffect.coefficients = { 0, 0, 1, 0, --red coefficients 0, 0, 1, 0, --green coefficients 0, 1, 0, 0, --blue coefficients 0, 0, 0, 1 --alpha coefficients } displayViewImageFilter(thisEffect)

I assume there’s something going on behind the scenes when you set displayObject.fill.effect to a String.  Is what I’m trying to do even possible?

Cheers.

#2

Yeah, you can’t do that.

You’ll need to pass the effect name and parameters as two separate arguments and then apply them to your object.
 
This isn’t really assigning a string to effect: 

displayObject.fill.effect = "filter.colorPolynomial"

I’m pretty sure this is actually doing more behind the scenes and the results is that fill is a special object afterwards.

You can confirm this on your own by doing this:

print(displayObject.fill.effect )
#3

Maybe do this instead:

displayViewImageFilter = function (details) --Apply to back image viewBackImage.fill.effect = details.name --Apply to all overviews for k,v in pairs( details.params ) do viewBackImage.fill.effect[k] = v end end

Then do this:
 

local thisEffect = { name = "filter.colorPolynomial", params = { coefficients = { 0, 0, 1, 0, --red coefficients 0, 0, 1, 0, --green coefficients 0, 1, 0, 0, --blue coefficients 0, 0, 0, 1 --alpha coefficients }, } displayViewImageFilter(thisEffect)
#4

Worked like a charm!  Thanks, RG!!

#5

Yeah, you can’t do that.

You’ll need to pass the effect name and parameters as two separate arguments and then apply them to your object.
 
This isn’t really assigning a string to effect: 

displayObject.fill.effect = "filter.colorPolynomial"

I’m pretty sure this is actually doing more behind the scenes and the results is that fill is a special object afterwards.

You can confirm this on your own by doing this:

print(displayObject.fill.effect )
#6

Maybe do this instead:

displayViewImageFilter = function (details) --Apply to back image viewBackImage.fill.effect = details.name --Apply to all overviews for k,v in pairs( details.params ) do viewBackImage.fill.effect[k] = v end end

Then do this:
 

local thisEffect = { name = "filter.colorPolynomial", params = { coefficients = { 0, 0, 1, 0, --red coefficients 0, 0, 1, 0, --green coefficients 0, 1, 0, 0, --blue coefficients 0, 0, 0, 1 --alpha coefficients }, } displayViewImageFilter(thisEffect)
#7

Worked like a charm!  Thanks, RG!!