[ANN] and Re: Problem with mask

[Wilhelm Sanke]

I have uploaded a sample stack containing 8 different scripts for 
creating masks and generating oval images.

<http://www.sanke.org/Software/ThreeMasks.zip>.

Stack "Three Masks" demonstrates and lets you compare the approaches of 
Jim Hurley, Scott Rossi, and my own.

All examples use the same basic selelection procedure with a draggable, 
resizable, and reshapable and already grouped selection graphic 
(applying the same routines I use for my selection graphic of  stack 
"Seamless Tiles 2"), which makes it easy  to compare the effects of a 
specific identical size and shape of the selection graphic across the 8 
examples.

There are three examples based on Jim's script:

- The first uses his almost unchanged script, which produced the "mask 
problem" with flattened edges on the right and at the bottom.
- In the second exampled I have reversed the direction of Jim's 
"within"-scan, with the result that now the edges appear on the left and 
on top

Because of the different edge effects I am not sure if  the "mask 
problem" is caused by a bug in the within-function or could rather be 
remedied by more precise (?) scan routines. I have tried to change this 
part of the script in various ways, but without success. Maybe Bernd 
Niggemann' approach, which I could not yet include here, will show other 
possibilities.

- The workaround-solution of the "mask problem" in the third example 
based on Jim's script combines the two examples above. I use a scan in 
two directions producing two masks with edges at different places. I 
then combine the two masks, which then results in a perfectly rounded 
mask without any flattened edges.
All oval images produced by the above examples display a slight "roughness".

Scott Ross's approach, taking a snapshot from the rect of the selection 
graphic, produces oval images with a very smooth fringe.
As my selection tool is already a grouped one, in my minor necessary 
adaptation of Scott's script the grouping and later ungrouping of the 
oval graphic was no longer needed, as was also the resetting the 
templategroup.
I am wondering if we could avoid or suppress the flickering that appears 
when taking the snapshot?

In my own 4 examples no masks are created by script. I use prefabricated 
masks in the form of imported invisible images that are then adapted to 
the size and shape of the oval selection graphic. Hence, basically only 
4 script lines are needed to crop the image and apply the mask.
The masks selected as examples are named "plain oval", "small fringe", 
"wide fringe", and "transition".

Best regards,

Wilhelm Sanke
<http://www.sanke.org/MetaMedia>