Resolving percentage for 1 pixel width?

spinx,

i think this answer is already on the forums somewhere, and not that long ago...i think.

no, not really. when uber and dilla and you and vlad start talking tech, i pack up and go argue about copyrights and licenses

but, it wasnt that long ago, certainly not a year ago. more like a couple or three months back at the most, i would say. and it had to do with moving an offset by one pixel regardless of image size. that's the part i do recall. so, maybe search 'pixel'?

Quote
Mousewrites wrote: http://www.filterforge.com/forum/read...ssage29754 Is that it?

Been there already, no good. It would be easy to grab the calculator and calculate the relative percentage for a given image - but I want to find some generic approach... I don't think its possible

Hi Sphinx,

I took up your challenge and made a slider-based solution for offsetting an image by pixel, which works in the image-size range of 10 to 1000 pixels.

(I'm attaching the filter file here -- hopefully comes through)

The user has to input the image size using a slider (and a checkbox to extend the range from 100 to 1000), and the filter does the calculation based on it. Of course, only works correctly at the right slider value.

As to the mathematics involved, I used the bias curve to convert the slider input to a percentage. (The final percentage is expressed by luminosity. You'll have to look at the filter to see how this works.)

Hope this helps. If so, I'll submit it as a snippet.

TD

Pixel-based offset.ffxml

Generic solution found!

The attached filter exploits the motion blur offset issue (dunno if it really is a bug..) to find the correct 1 pixel relative offset values.

When a slider is positioned in the middle (value 2), there is no offset. Value = 1 equals a -1 pixel offset, value = 3 equals a +1 pixel offset.

This approach or a modification of it can be used to control any offset or percentage input with exact pixel measures.

1 Pixel Offset.ffxml