Can I paint in full resolution and 100% zoom on iPad?

[Elado]

I'd like to paint as if I were holding a real canvas the size of my iPad, but can't get ArtRage to do that.
I'm using ArtRage Vitae on an 11-inch iPad Pro.
My device's native resolution (held horizontally) is 2388x1668 pixels.
When I create a canvas at this resolution, ArtRage automatically zooms out to show a scaled-down view of my canvas.
It seems like if I want to paint on a canvas that fits my screen exactly and fills it up completely at 100% zoom, I have to make the canvas size 1194x834 (exactly half of my native resolution).
How can I paint on a full screen at full resolution and 100% zoom?

[markw]

Hello Elado and welcome to the ArtRage forums
Interesting question this…
First off, when you say; “at full resolution” are you meaning you want to view things on screen 1:1 i.e life size?

If so then 100% zoom will not necessarily equate to “life size” on screen.
Different screens will require different zoom percentages to show things 1:1 depending on the particular pixel density of a given screen.
A long time back I calculated the zoom required for 1:1 life size on my laptop screen and it’s actually 86% zoom in ArtRage when working with 300ppi/dpi canvases (a very common ppi/dpi for print).
Note: if a different ppi/dpi is used for the canvas, the zoom% for 1:1 on any given screen will need to be recalculated.

Now there might be some complex maths that would tell you what zoom % you would need on your iPad for 1:1 viewing but as the iOS versions of AR do not consider canvas ppi/dpi at all, I’m not sure it could be worked out with just maths

But there is a low tech method for calculating this on the desktop versions of AR and that is to make an A4 canvas at 300 ppi/dpi (ARV desktop comes with a preset for this size & ppi/dpi canvas) and then get an A4 pice of paper or thin card and hold it against the screen and zoom in or out untill they match.
And note the Zoom level % when they are 1:1.
That Zoom level % will work for viewing any sized canvas 1:1 you make in the future so long as it has a ppi/dpi of 300.

You could use a similar method on your iPad.
But first you would need to know approximately, in terms of pixels W x H, what is needed to make a print quality image at a given physical size.
So if printing at 300dpi;
An A4 canvas (210mm x 297mm) would need to be approximately; 2480px x 3508px
An A5 canvas (148mm x 210mm) would need to be approximately; 1748px x 2480px
An A6 canvas (105mm x 148mm) would need to be approximately; 1240px x 1748px

Depending on the size of your model iPad’s screen you could make a canvas at one of the above sizes; let us say A5 for this example and then place an A5 sized sheet of paper on the screen, then zoom in or out till AR’s canvas matches the size of the paper.
And note the Zoom % at which this happens.

I don’t have an iPad but do have ARV on my iPhone and I tried this out, obviously an A5 sheet wasn’t going to fit so I made a Print sized canvas 55mm x55mm @300ppi on my laptop.
This gave me pixel dimensions of; 650px x 650px.
Making a canvas 650px x 650px on the iPhone, and I find, with the aid of a small ruler, that 1:1 is achieved at 54% zoom!
So making an A4 canvas on my phone would need a canvas of; 2480px x 3508px and that viewing any part of it 1:1 needs a zoom level of 54%.

Hope all that was understandable and helpful

[nekomata]

I'd like to paint as if I were holding a real canvas the size of my iPad, but can't get ArtRage to do that.
I'm using ArtRage Vitae on an 11-inch iPad Pro.
My device's native resolution (held horizontally) is 2388x1668 pixels.
When I create a canvas at this resolution, ArtRage automatically zooms out to show a scaled-down view of my canvas.
It seems like if I want to paint on a canvas that fits my screen exactly and fills it up completely at 100% zoom, I have to make the canvas size 1194x834 (exactly half of my native resolution).
How can I paint on a full screen at full resolution and 100% zoom?

I don't use portable artrage apps, but can you check under application preferences if you have retina screen support turned on?

it sounds like the app re-calculates and upscales pixel dimensions of your document instead of rendering true pixel size 1:1.

you can also send this question to the app team directly via the support form

[markw]

I don’t think the iPad is doing anything strange in how it shows the canvas on screen.
And unlike the Desktop versions of ARV, there is no HD Screen option in Preferences.

What High Definition screens, like Apples iPad Retina screens, are effectively doing is using 2 pixels on screen for every 1 pixel that a non Retina screen would use.
So an 11” iPad Retina screen has twice as many pixels packed into the same physical area as a non Retina 11” screen would.

With this higher pixel density you have two choices of how to display an image of a given size;
1: Still use 1 pixel to display the same image area as the non Retina screen’s 1 pixel. Result; the image you will see on screen is half the size it was on the non Retina screen and showing the same amount of detail.
Or, which is what actually happens;
2: 2 Retina pixels are used for every 1 of the old screen pixels which keeps the image visually the same size on screen and allows for finer image detail to be shown.

So Retina screens have both a Physical pixel size and a Logical pixel size which is half the Physical size.
And Apples new iPhone 15 screens are using pixels at 3:1!

With regards to Zoom levels generally in AR, mobile or desktop versions;
1% > 1000% on the mobile
1% > 800% on the desktop.
The zoom percentage shown is only really telling you how much of the available zoom range within AR has been used.
Without knowing the intended physical canvas size, it’s ppi/dpi and the screen pixel density it can relate to nothing more.

With regards your 11” iPad Pro screen size;
Looking online just now, and I think your screen is physically actually: 9.01” by 6.30”.
If this is correct, then to get a print quality canvas (assuming printing @300dpi) that same size it would need to be approximately 2703px x 1893px.

[Elado]

when you say; “at full resolution” are you meaning you want to view things on screen 1:1 i.e life size?

Thanks! That's not exactly what I meant though
What I meant was, that if my device's resolution is X, I would expect that if I set my canvas size to X it would fill up my screen completely and without cropping when I set the zoom level to 100%.
This doesn't seem to be the case in ArtRage mobile, and I'd like to understand what settings I should use to get that result (if it's even possible).

What you described is more like creating a "What you see is what you get" type of painting, where ideally there would be no difference in size and quality between what you see on an iPad screen and what you eventually print.

But maybe what you said about the iPad's Retina display using twice as many pixels explains why I can only fill up the screen if I set my canvas to be exactly half of the device's resolution.

[Elado]

can you check under application preferences if you have retina screen support turned on?

Thanks, but I couldn't find such a function on the iPad app. Does it exist?

[markw]

Thanks for clarifying for me what you are wanting to see, much appreciated
Which means that if printing is not your intent then the sometimes confusing effects of dpi on what is “real” or "life size" can be ignored.

...But maybe what you said about the iPad's Retina display using twice as many pixels explains why I can only fill up the screen if I set my canvas to be exactly half of the device's resolution.

Yes, I think you are correct in that assessment.
Based on your iPad's Physical screen pixel size a canvas of those same physical pixel dimensions should neatly fill the screen at 50% zoom.
At this zoom level you are not loosing any document “resolution”. It’s just how the Retina screen handles the pixels and AR interprets that.
And as you have already seen a canvas at Logical screen pixel size, may neatly fill your screen at 100% zoom but you only have half the number of pixels to play with. Which is probably not what you want!