Using Proportional Gradients

ok, i've looked at the prof grads and still dont see how to hook them up to make a non-square image work right with an effect. and now that there seems to be more than one prof grad filter, i'm even more confused. would someone care to write a tutorial on these?

Hi Kraellin,

The implementation will depend on your filter somewhat. In the simplest of cases you can just replace the Profile Gradient with the Proportional Gradient. It gets more complicated when you want to use a Proportional Gradient and expect for example the Offset component to work the same way as it does for a square image. It doesn't.

Let's take the 3 and 5 color gradient matter as an example. If you had a filter that was using a 5-color Gradient to make a "landscape," you would go about converting the square 5-color gradient to non-square as follows:

1) Copy the Proportional Gradient snippet into you filter. (Ronviers made a handy-dandy version thereof that is the easiest to include, but you can also take my modified Uberzev version. Both of them work without requiring a checkbox for vertical vs. horizontal.)

Ronviers version ("Proportional Gradient var b.ffxml") can be found in this thread:

http://www.filterforge.com/forum/read...1&TID=4916

2) Add an Elevation Gradient component.

3) Connect the vertical Proportional Gradient to the Elevation input of an Elevation Gradient

4) Connect the 5-color Gradient to the Gradient input of the same Elevation Gradient

A sample filter of what I described above is attached here. In this sample I have also shown how to use the Switch Component to enable faster rendering for square images for a filter that includes non-square support.

(Note: You can remove the unused proportional gradients -- the two horizontal ones and the second vertical one -- from the filter, as they are not needed in this particular filter. I simply copied the Ronviers snippet complete.)

If you have a filter you are trying to get to work that you are having trouble with, you can attach it to this thread and I'll take a look at it.

Proportional Gradient sample.ffxml

3D, it doesnt work. well, not like i thought, anyways. i have image and threshold componets plugged into the 3 color gradient 'colors' nodes and that data doesnt now get passed through like before. i guess i'll have to post the filter. i may do that after i submit this as a square only.

Kraellin,

One idea to create that Side Shadowing effect on non-square images, could be to use Proportional Gradients as opacity masks.
I'll attach an example filter. (The added controller is there to let you choose between a Square image (using your filter), a Wide image (using uberzev's snippet), a Tall image (using uberzev's snippet), or Any image (with any proportion (using ThreeDee's snippet) -- which probably runs the slowest).)

There's also ways you could adjust the gradients/masks (e.g. putting the gradients through a Tone Curve adjustment with tweaked Curves...)


I hope this helps somehow...

Side Shadowing 1M.ffxml

Here is just one more trick for replacing a five color gradient with a single.

rG a.ffxml

As to having more than one gradient in the filter, it would be best to just connect the output from one copy of the Proportional Gradient snippet to the inputs of the different components that need it.

I didn't mean to say you can't do anything non-square.

You CAN make non-square filters using the Proportional Gradient.

You CAN replace a Profile Gradient with a Proportional Gradient.

You CAN'T directly replace a 3-color gradient (especially one that uses an external image as an input) by a proportional gradient. You will have to construct the filter differently.

The sample filter I attached shows one way to do the side lighting effect, albeit not a very good one.

Hope that's clearer.