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GreenGirl

[RESOLVED] Lack of precision / rounding errors

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I'm making a clock face.

I set the guides to the dead centre, and I draw a 'tick' mark centrally using the guides. It's placed evenly over the vertical guide at 12 o'clock or 0/360 degrees around the clock face, then set the rotation anchor to the dead centre of the page using the guides.

I duplicate that layer, and translate it using keyboard entry to exactly 5 or 10 degrees (depending on the tick mark I need).

I press CMD+J to duplicate layer and transformation and populate the outside of the clock face. 

NOTICE:

The rotation text field only allows single decimal places; this is functionally unusable, because in many cases we need multiple decimal place precision, and in fact if you manually rotate a layer you see displayed 2 decimal places, yet you can't manually set that in the text field. 

At least 4 is required, preferably 8 decimal places.

Continuing with the bug description:

I do the same for the 5 degree marks until the clock face is populated with marks at 5 degree and 10 degree points all around. 

To verify the correctness of these 'tick marks' I draw a long (extending past outer edge of clock face) 2 pixel wide line from the centre and rotate it so an random 'degree' that is a multiple of 5. 

e.g. 135.

Then I see how it lays along the computed 'tick' marks.

BUG:

NOTICE that the tick mark at 135 isn't placed correctly, in fact none are except 0 degrees, 90, 180 and 270. All others are off by small amounts from those cardinal points up to the greatest amount of imperfection at the points directly between the cardinal points. 

If you MANUALLY drag the pink line you'll see that you still can't set it perfectly (due to poor 2 decimal place precision) but the black 135 tick mark is somewhere between 134 and 135, 

This level of precision isn't enough for my work.

 

Suggestion:

Please fix immediately the rounding / precision bug when doing rotations, and increase the decimal place precision on dragging AND by text entry to at least 4 decimal places, but preferably up to 8 decimal places. 

Current implementation is too inaccurate to use. 

Designer_Errors in rotating paths (lack of precision).afdesign

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Hi GreenGirl,

Quote

The rotation text field only allows single decimal places; this is functionally unusable, because in many cases we need multiple decimal place precision, and in fact if you manually rotate a layer you see displayed 2 decimal places, yet you can't manually set that in the text field. 

At least 4 is required, preferably 8 decimal places.

 

You can enter 4 or 8 decimal places in the rotation field and the rotation will be honoured though I agree it would be 'helpful' and 'useful' to have a preference setting that allows you to set the number of decimal places shown in numerical entry boxes. If you follow your procedure with multiple tick marks and rotate each by an additional 0.1, e.g. 5.0, 5.1, 5.2, 5.3 and so on you will see the entered rotation is honoured.

Quote

NOTICE that the tick mark at 135 isn't placed correctly, in fact none are except 0 degrees, 90, 180 and 270. All others are off by small amounts from those cardinal points up to the greatest amount of imperfection at the points directly between the cardinal points. 

If you MANUALLY drag the pink line you'll see that you still can't set it perfectly (due to poor 2 decimal place precision) but the black 135 tick mark is somewhere between 134 and 135, 

 

If you look at the pink line you've drawn, it's rotation centre is not centred on your clock face's rotational centre. The central selection handle needs to sit on the overlapping guides, not the left selection handle

rotation.thumb.jpg.419878d1674e2c4a98acbd8c5f8344c6.jpg

If you move the pink line so it's centre sits centrally on your guides then it matches exactly with your tick mark at 135 degrees.

If you follow your logic and set the first tick mark, then duplicate and rotate by either 5 or 10 degrees or any value that 360 degress is divisable by and repeat you will find that the last tick overlaps the first exactly, at least it does for me so apart from having the option to display a set number of decimal points which should be a feature request I don't think there is a bug that needs fixing.

 


Affinity Photo 1.7.0, Affinity Designer 1.7.0, Affinity Publisher 1.7.0.384 Beta

MacBook Pro 16GB, macOS Mojave 10.14.5

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Posted (edited)

You're saying that there is 4 decimals places of precision even though the text field and angle displayed don't show it? 

Can I get proof because when I rotated a line to 12 degrees, another to 13, and another to 14, with a final line at 12 (over the top of the first) and tried to move it by increasingly small amounts between those 'supposedly' correct degrees, I got completely inconsistent results, and after moving the needle from 12 to 13 and back again it would never line up exactly with 12 again. 

But to your point, that midline of the pink line needs to be on the centre of the image / guidelines, so if my example was wrong, colour me embarrassed... I'll double check. 

And is there a way to force Designer to remember where you dragged the rotation anchor to? It resets every time I leave a path. 

 

Edited by GreenGirl

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Quote

The lines have to be centred the example image you gave is not centred, it's it's offset.

That's my point, that pink line is from your AD file, not something I've created, your pink line isn't centred, hence the problem when you view it in conjunction with your tick mark at 135 degrees. Centre it and it matches your 135 degree tick mark exactly.

Quote

Can I get proof because when I rotated a line to 12 degrees, another to 13, and another to 14, with a final line at 12 (over the top of the first) and tried to move it by increasingly small amounts between those 'supposedly' correct degrees, I got completely inconsistent results, and after moving the needle from 12 to 13 and back again it would never line up exactly with 12 again.

 

This is a simple test following your technique where I've rotated each line by an additional 0.1 degrees by entering 10.1, 10.2, 10.3 and so on. This works if you enter 10.0001, 10.0002, 10.0003 as well. The 'issue' or 'problem' is simply that the rotation box doesn't display the decimal places which I agree with you would be extremely helpful for precision work but entering 4 or 8 decimal places does honour the value entered even when entering multiple decimal places. This is something that should be a feature request if it hasn't already been requested...

lines.thumb.jpg.b3b00a4060ef04f25ae73daa408802cf.jpg


Affinity Photo 1.7.0, Affinity Designer 1.7.0, Affinity Publisher 1.7.0.384 Beta

MacBook Pro 16GB, macOS Mojave 10.14.5

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Thanks for your help; I saw the line was from my file, and in extreme embarrassment, I edited my reply post - please check out the changes. 

So to recap, you're still seeing rotational changes even over x.0001 of a degree? 

I couldn't get that to work... :/

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Ok, your help, in conjunction with : 

 

Has basically fixed this. 

 

Thank you all for tolerating my frustration and for helping me. 


MOD: Please delete this thread as it's not a bug, and a fix (or correcting a faulty user) has been found.

 

Thanks again.

 

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Hi,

Apologies, I hadn't seen your update... and of course, I'd actually also stupidly forgotten you could set this in the preferences already!

This is how it looks to four decimal places... subtle but it does work regardless of how many decimal places are actually displayed.

rotation-to-four-decimal-places.thumb.jpg.0bfd6a8b28ff96d6b9e806e105c9ed0e.jpg

 

rotation.afdesign


Affinity Photo 1.7.0, Affinity Designer 1.7.0, Affinity Publisher 1.7.0.384 Beta

MacBook Pro 16GB, macOS Mojave 10.14.5

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