Is it possible to change the rule direction

[duncang]

Hi, I want to change the vertical ruler direct in Affinity Designer to be +ve going up and _ve going down. Very weird to have -ve on the top side of the axis when drawing. 0,0 is usually bottom left.

[Joachim_L]

2 hours ago, duncang said:

0,0 is usually bottom left.

Not where I come from. You can drag the ruler to the origin you want manually or use View > Guides Manager. Unfortunately there is no option to makes this a fixed setting, but you can export your document as a template for later re-use and 0,0 bottom left.

[Alfred]

10 minutes ago, Joachim_L said:

You can drag the ruler to the origin you want manually or use View > Guides Manager.

Moving the origin doesn’t alter the fact that down is positive and up is negative (as in every other computer graphics application but unlike graphs in mathematics).

[Pšenda]

13 minutes ago, Alfred said:

as in every other computer graphics application

... let me just add that this is because all standards (both for vector and raster graphics) respect this direction of the y-axis. So it's not a flaw/illogicality of these applications, but a necessity, which comes from the wooden days of computer beginnings, when it was displayed using terminals, whose characters output goes from left to right and from top to bottom.

[GarryP]

This sort of thing has already been requested, e.g:
https://forum.affinity.serif.com/index.php?/topic/137117-ruler-x-and-y-swap/
and some related threads:
https://forum.affinity.serif.com/index.php?/topic/125141-publisher-for-windows-spread-origin-can-be-made-to-stick/
https://forum.affinity.serif.com/index.php?/topic/138515-change-xy-origin-to-page-instead-of-spread/

[lacerto]

5 hours ago, Alfred said:

Moving the origin doesn’t alter the fact that down is positive and up is negative (as in every other computer graphics application but unlike graphs in mathematics).

4 hours ago, Pšenda said:

So it's not a flaw/illogicality of these applications, but a necessity,

Not every other computer graphics application, and not a necessity. CorelDRAW still uses Cartesian coordinate system (Y increases upwards from bottom left):

Older versions of Adobe Illustrator did, too, and still use it internally in DOM as document origin so when scripting, you need to use this system:

Xara Designer Pro lets you choose the behavior freely:

Windows 2D GDI uses top-left Y increasing downwards system, as does iOS. macOS however uses Cartesian system:

And 3D apps typically use (left or right-hand) Cartesian system.

[Pšenda]

3 hours ago, Lagarto said:

and not a necessity

If, in your opinion, compliance with the standards for exported images is not necessary (including coordinates), what do these exports look like after loading / importing into other applications?

[lacerto]

2 hours ago, Pšenda said:

If, in your opinion, compliance with the standards for exported images is not necessary

I do not understand what you mean. I was just stating facts rather than expressing my own opinions. The OP asked about a feature in the UI, and I wanted to leave a comment to arguments that gave an impression that such a request is not plausible because it is against a technical "necessity", or even if possible, "not done by anyone". So I showed that different apps can and do use different kinds of coordinate spaces, and may also give the user a possibility to choose the system that best suits them.

All these apps naturally produce output according to specific format specs (to be able to communicate or interchange information at all), which is a different question, but even then, e.g. in PDF, it is possible to describe positions in different coordinates spaces, "device dependently", so "necessity" does not necessarily exist in this respect, either.

For example, when CorelDRAW outputs to PDF it does not need to translate its native coordinate system to create a device-independent PDF user coordinate space (which is Cartesian), which, on the other hand, Affinity apps or Illustrator can read correctly even if they need to translate the coordinates to the 0,0 top left downward increasing Y device coordinate space when they render the objects in the user interface. I suppose that most apps export to PDF using the PDF device-independent Cartesian coordinate space no matter how they natively draw on canvas. On the other hand, CorelDRAW would need to translate the native coordinates when it exports to SVG (which I suppose uses top-left downward Y increasing coordinate space, but might be able to use other systems, as well), while apps not using Cartesian coordinate system natively would not.

[Pšenda]

1 hour ago, Lagarto said:

I do not understand what you mean.

I mention the necessity of applications to respect the mentioned coordinate system in connection with format standards,

10 hours ago, Pšenda said:

that this is because all standards (both for vector and raster graphics) respect this direction of the y-axis. So it's not a flaw/illogicality of these applications, but a necessity,

So if you react negatively to this information of mine ("not a necessity"), then I assume that in your opinion it is not necessary to respect these standards in these applications.

 

1 hour ago, Lagarto said:

All these apps naturally produce output according to specific format specs (to be able to communicate or interchange information at all), which is a different question,

No, it's not another question, it's exactly what I'm writing about.
And in my opinion, it is also easier, and for experienced users (these standards/formats familiar) also more natural, if the application respects these coordinate systems. Personally, I have no problem with that - because it's just been like that for decades.

[lacerto]

23 minutes ago, Pšenda said:

No, it's not another question, it's exactly what I'm writing about.

Your reply is off-topic (not user-interface related), and opinionated, which you are of course fully entitled to. I much share your opinion, but that is another thing. CorelDRAW alone shows that this question is not "absurd" (or "obsolete", "non-standard", etc.; the native coordinate system of PostScript and PDF is Cartesian).

[R C-R]

Hey, @Lagarto I give up. In "OS X" (or more properly these days in macOS) how do you "flip" a view's coordinate system?

Is this a system or application level thing?

[lacerto]

21 minutes ago, R C-R said:

Is this a system or application level thing?

In code, you can just define that all coordinates (of the app or just a sub routine) are given "iowise" (rather than "natively").

https://stackoverflow.com/questions/763867/how-do-you-flip-the-coordinate-system-of-an-nsview

It basically just makes the life a bit easier not needing to translate coordinates depending on the platform. Often coordinates need translation anyway so it is not a problem to have them (or the largest involved object group) be handled via some kind of a helper routine, anyway.

[R C-R]

3 minutes ago, Lagarto said:

In code, you can just define that all coordinates (of the app or just a sub routine) are given "iowise" (rather than "natively").

So you are talking about using Interface Builder or the equivalent when creating an app, not something users can do in whatever app they happen to be using?

[lacerto]

2 minutes ago, R C-R said:

not something users can do in whatever app they happen to be using?

Yes.

[Old Bruce]

In all the computer code the coordinates are top left of the monitor screen as 0, 0 and then positive integers for pixels to the right for the x axis and positive integers for the y axis pixels going down.

In an application's window the code is the same but then we could make a situation where there is an artboard of 100 pixels x 100 pixels and the displayed coordinates are set to be (in this 100 x100 case) x and the absolute value of (y - 100). So we wind up with the display of 0 at the lowest part of the artboard for y and 100 for the uppermost part of the artboard. Absolute value of (100 - 100) and Absolute value of (0 - 100).

It is just a displayed value thing. The coordinates are the same.   

[lacerto]

2 minutes ago, Old Bruce said:

monitor screen

A device.

[Old Bruce]

21 minutes ago, Lagarto said:

A device.

Yes, it is one part of a complex device where my applications' document windows and their artboards live.

[lacerto]

30 minutes ago, Old Bruce said:

In all the computer code

"A device" and this statement are in contradiction.

[R C-R]

31 minutes ago, Old Bruce said:

In all the computer code the coordinates are top left of the monitor screen as 0, 0 and then positive integers for pixels to the right for the x axis and positive integers for the y axis pixels going down.

Hasn't @Lagarto shown application examples where this is not true, like for CorelDRAW & optionally for Xara Designer Pro?

I think the short version is there is more than one standard, & not all apps use the same one.

What would be nice is if Affinity offered a choice; thus the feature requests @GarryP cited above.

[Old Bruce]

10 minutes ago, Lagarto said:

"A device" and this statement are in contradiction.

How are the two in contradiction? Is a computer and its peripheral parts not reliant on code? 

[lacerto]

6 minutes ago, Old Bruce said:

How are the two in contradiction?

You state that ALL computer positioning code is given in a specific coordinate system, which is simply just untrue. It is a bit same as stating that RGB 255, 0, 0 always produces the same color (not depending on the device).

[Old Bruce]

2 minutes ago, R C-R said:

Hasn't @Lagarto shown application examples where this is not true, like for CorelDRAW & optionally for Xara Designer Pro?

 

Yes Lagarto did. All I did was explain how that is achieve. Just some integer arithmetic and getting the absolute value of the result. Again, it is just the displayed values.

Don't get me wrong this 0, 0 at the upper left with positive y values going down has been bugging me since the 80's. I too grew up with the Cartesian plane.

[R C-R]

13 minutes ago, Old Bruce said:

How are the two in contradiction? Is a computer and its peripheral parts not reliant on code? 

They do not all use the same code for specifying coordinates in every application that runs on the computer. That's what the feature request for Affinity is all about.

[Old Bruce]

5 minutes ago, Lagarto said:

You state that ALL computer positioning code is given in a specific coordinate system, which is simply just untrue. It is a bit same as stating that RGB 255, 0, 0 always produces the same color (not depending on the device).

I was speaking generally of the coordinate system Windows and Macs use. Cannot say anything about Linux because I didn't spend too much time with it back in the 90's. There may well be a computer OS that has a coordinates system that employs the Cartesian plane (and let us face it, that is far more logical. Higher numbers going up) but I have never come across one.

Your code has to take into account that 0, 0 is at the upper left, not the lower left, and increasing positive y values are farther down on the screen. How you choose to have your application display those coordinates is up to you. Toss in a routine to take your applications drawing area and invert the values for the y axis, just a bit of runtime integer math every time you want to draw something to the screen.

[lacerto]

I am not sure if we are discussing the same topic, but perhaps this clarifies something:

https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/CocoaDrawingGuide/Transforms/Transforms.html

But returning to OP's topic: no, an alternative coordinate system is not available in Affinity apps (and in most apps, it is not, even if they need to internally translate between different systems when reading in and writing out positioning coordinates in different systems and units).