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John Rostron

Error in Distort > Equations

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I have been trying to use the Filter >Distort > Equations to perform a simple Perspective correction. However when inserting formulae into the Equations filter, it seems to act on the wrong axis. I therefore tried a much simpler pair of formulae:

x=x-100*(1-a)
y=y-100*(1-b)

By default there is no change, since the default parameter value is 1.

If I reduce parameter a, a transparent area appears at the top of the image, increasing as I reduce parameter a.
If I reduce parameter b, a transparent area appears at the right of the image, increasing as I reduce parameter b.

So, the formula for the x-axis affects the y-axis, and the formula for the y-axis affects the x-axis.

John


Windows 10, Affinity Photo 1.8,5 Designer 1.8.5 and Publisher 1.8.5 (mainly Photo), now ex-Adobe CC

CPU: AMD A6-3670. RAM: 16 GB DDR3 @ 666MHz, Graphics: 2047MB NVIDIA GeForce GT 630

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Hi John

I'm not seeing any problem either

The only way I can get it to do what you say it is doing is if I first rotate the document 90 degrees clockwise


Due to the fact that Boris Johnson is now our Prime Minister, punctuation, spelling and grammar will never be worried about ever again.  We now have far bigger problems to be worried about.

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@carl123, you may have the answer. The image I was using was taken  in portrait mode. I recall from other posts that sometimes this gets embedded into the image information as the image having been rotated. I recall that there was a solution, which I cannot recall! I shall have to do a search.

 

Following a search:

 

Apparently there is an icon on the context toolbar that I can click on, or at least in Designer. I shall have to see if there is one in Photo.

 

John


Windows 10, Affinity Photo 1.8,5 Designer 1.8.5 and Publisher 1.8.5 (mainly Photo), now ex-Adobe CC

CPU: AMD A6-3670. RAM: 16 GB DDR3 @ 666MHz, Graphics: 2047MB NVIDIA GeForce GT 630

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I have now checked on this. There is indeed an icon in the context toolbar in Photo. It seems to be called 'Reset'. If I open the Transform panel, by defaut it shows the width and height reversed (in my portrait-mode image). Clicking on the Reset icon reverses these.

However, if I now try the formulae as before, there is no change: x= affects y and vice-versa. If I now export my image, close it and re-open it, all is now well and it behaves as expected.

So, although my original 'bug' was not actualy a bug, I think that this other behaviour is a bug. Having reset the dimensions, the equations filter should act accordingly, without having to save and reload first.-

 

John


Windows 10, Affinity Photo 1.8,5 Designer 1.8.5 and Publisher 1.8.5 (mainly Photo), now ex-Adobe CC

CPU: AMD A6-3670. RAM: 16 GB DDR3 @ 666MHz, Graphics: 2047MB NVIDIA GeForce GT 630

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Using the Reset icon (button) on an object temporarily resets the rotation parameters but it is not permanent

Clicking elsewhere on the canvas then reselecting the object will show the previous rotation parameters

There have been requests to make this Reset operation permanent but that is up to the Devs to decide if they want to do that

Based on the above I would not have expected hitting Reset to have changed the problem you were originally seeing with Equations

 


Due to the fact that Boris Johnson is now our Prime Minister, punctuation, spelling and grammar will never be worried about ever again.  We now have far bigger problems to be worried about.

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So, my exporting will save the rotation status as I want it, provided that I do it straight away. And doing this does actually work!


Windows 10, Affinity Photo 1.8,5 Designer 1.8.5 and Publisher 1.8.5 (mainly Photo), now ex-Adobe CC

CPU: AMD A6-3670. RAM: 16 GB DDR3 @ 666MHz, Graphics: 2047MB NVIDIA GeForce GT 630

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