Vexillomorphic transformations (Flag-Waving) in Photo

[John Rostron]

This is an extension of my tutorial on Trigonometrical transformations using Filter > Distort > Equations. This one is focused on simulating flags waving in a light  wind. Flags have an advantage in that they have a standard shape (width is twice the height).

Edit: I have been told that this is not true. I stand corrected.

To get the desired waving, I apply a sine transformation to each of the x and y-axes. The equations to apply are:

x=(x+20*sin(360*y/h))/c-100*b
y=y+a*(h/10)*sin(2*360*x/w)-(x/w)*h/10

I add a sideways sine wave to the x-axis as a function of the y-position. When the flag waves, the visual width is decreased, so I have added a parameter c which scales the width of the flag. The parameter b is an offset, since the left-hand corners of the flag can otherwise move outside the canvas.

The y-axis also has a sine wave, depending on the x-position. The parameter a determines the magnitude of this sine wave. The final expression (-(x/w)*h/10) ensures that the fly  (RHS in this case) is below the hoist (LHS here). (Definitions: hoist is the part next to the flagpole; fly is the part flying free.)

Here is the UK Union Flag, plus a bit of extra space above and below to create room:

And waving in the breeze:

And here is a macro that implements these transformations:

FlagWaving.afmacro

And a macro library containing the single macro:

FlagWaving.afmacros

The parameters should appear when you run the macro. Parameter a controls the vertical wave; parameter b controls the horizontal offset; parameter c controls the overall horizontal scaling.

This macro will not simulate a flag in too strong a wind, where the parts overlap!

John

 

[PaulEC]

Quote

Flags have an advantage in that they have a standard shape (width is twice the height).

 

Sorry but this is just not correct. Flags come in all sorts of different shapes and sizes. Just Google "flags" and take a look!

[John Rostron]

54 minutes ago, PaulEC said:

 

Sorry but this is just not correct. Flags come in all sorts of different shapes and sizes. Just Google "flags" and take a look!

You are quite right. I was still remembering what I learned as a Scout sixty years ago. It was probably incorrect then!

John

[Richard S.]

Any chance someone could convert this macro to a macroS file, so that it can be used on Photo for iPad?

Any help appreciated, as I don’t have my Mac available to convert it myself.

Thank you.

[Alfred]

56 minutes ago, DesignMeister said:

Any chance someone could convert this macro to a macroS file, so that it can be used on Photo for iPad?

Library (*.macros) file duly attached.

Flag-waving.afmacros

[Richard S.]

Alfred to the rescue once again.

Thanks mate.

[GryphonArt]

Thank you John Rostron, took me a while to find where to do this and made mine a little calmer in the wind.TeamTigsisle_Flag3B2_Flying2"B&W.pdfTeamTigsisle_Flag3B2_Flying2"B&W.pdfTeamTigsisle_Flag3B2_Flying2"B&W.pdf