Resized document does not export at the new size

[Cobalt]

-Open an empty file
-Resize the document (either change dimensions or DPI)
-Export persona -> export at 1x

The exported size is not the size reported while exporting.
The exported size is the original size when the document was created instead of the resized one.

[Greyfox]

2 hours ago, Cobalt said:

Open an empty file

Not sure why or even how you would do that.

My try:

Use the attached RGB 8 bit Non compressed TIFF image (500px x 500px, 300 dpi). File size is 733KB (751,114 bytes)

1. Open the TIFF image

2. Resize the image to 1000px x 1000px x 300dpi  (Document->Resize Document)

3. Change to Export Persona

4. Under Export options set Preset to TIFF RGB 8 bit, untick Embed ICC profile, untick Embed metadata, set compression to None

5. Export - Indicates file size will be 2.87MB

Actual size of exported file is 2.86MB (3,004,314 bytes).

All very much as expected.

 

 

 

500x500.tiff

[Cobalt]

Let's try this again.

1. Open "Image1 input"
2. Document -> Resize Document -> DPI 192 -> and set to 1008px X 680px
3. Export persona -> leave everything as is: JPEG (High quality) -> Export
4. You get "Image1 export" (attached below) which is NOT different in size (still 504px X 340px).

[Greyfox]

10 hours ago, Cobalt said:

You get "Image1 export" (attached below) which is NOT different in size (still 504px X 340px).

Your input image was 504 x 340px and is shown in the Resize Document dialogue as 72dpi

After I change the dpi to 192, and then change the Sixe to 1008 x 680px and resize, the image then is shown as 1008 x 680px  and 192 dpi, and it exports as a JPG with exactly those dimensions. So it's working here as it should.

Your exported image however is as you have said, exactly the same size as the input image, which prompts the question, did you have the resample box ticked in the Resize operation before you clicked on Resample..

Also after the Resample operation, and before export, can you check the size at the top left of the screen. As shown in the attached screen shot, it should confirm that the resize has taken place.

[Cobalt]

Yes, resample was on by default and on my screen it shows 1008x680 every time, but the exported image is NOT the size it shows on screen during export.

[carl123]

 

On 10/11/2019 at 2:31 AM, Cobalt said:

-Resize the document (either change dimensions or DPI)
-Export persona -> export at 1x

It's complicated or to be more precise overly complicated

https://forum.affinity.serif.com/index.php?/topic/85643-incorrect-pixel-dimensions-from-designer-export-persona-current-mas-beta17/

https://forum.affinity.serif.com/index.php?/topic/83492-export-persona-scale-problems/

 

 

[Greyfox]

2 hours ago, carl123 said:

It's complicated or to be more precise overly complicated

Both the links you provided refer to Affinity Designer.

As this thread is in the "Report a bug in Affinity Photo" section I had assumed it was referring to Affinity Photo.

If it is Photo, then I certainly can't get the problem to occur.

Perhaps @Cobalt could clarify

[Cobalt]

The problem happens in Photo (Designer is using the same underlying code. So both should be affected).

One more time to make it super clear:

Resizing Dialog looks like this:

- Photo is reported as 1008x680

-The export persona reports 1008x680

The export dialog looks like this:

---> REOPEN the exported image and it is back to 504x340

[carl123]

Change the DPI  to 190DPI

But keep the document the same size 1008 x 680px

Now export in the Export Persona

Is the exported pixel size correct?

[Greyfox]

3 hours ago, Cobalt said:

The export dialog looks like this:

You screen shot shows you are using the Slices Tab.  I'm not sure why you would do this for a simple full size export.

(That said, if I use that tab without actually selecting a slice, it still exports here at the correct size).

To maybe narrow down the issue, after you resize your image, and whilst still in Photo persona can you try an export by using File->Export.  In the Export Settings dialogue select the JPG tab, then either Best Quality, or High Quality for the preset. Leave Area set to Whole document.

If you want control of metadata embedding, or ICC color profile, click on the More Button

 

 

 

 

 

If as your post suggests, you are trying to export the complete image, then either use the Export Options Tab in the Export Persona, or just simply use File->Export from the Photo persona

 

[Cobalt]

@Greyfox. Somehow I am not quite convinced you are following the steps correctly. As of the slices tab, it doesn't matter (every document has a default full image non-deletable slice). If anything it means something is broken.

@carl123. BINGO ! Changing the dpi to 190 works as expected. At 192 it goes back to exporting half what it's supposed to.

[Cobalt]

@Greyfox Using the export option via File menu works correctly.
This means, there is something wrong with the "slices" interface specifically in association to the 192dpi and 144dpi resizing options.

[carl123]

 

 

 

1

5 minutes ago, Cobalt said:

@carl123. BINGO ! Changing the dpi to 190 works as expected. At 192 it goes back to exporting half what it's supposed to.

I know, there are special DPI's such as 144 & 192 that will always work differently to other DPI's

Serif says this is deliberate and has given an explanation for it but I really don't see the need for it, and it is just majorly confusing whenever someone encounters it in the Export Persona

[Cobalt]

@carl123. It's deliberate ? Exporting half the pixels at 96dpi instead of 192 ?

[carl123]

4 minutes ago, Cobalt said:

@carl123. It's deliberate ? Exporting half the pixels at 96dpi instead of 192 ?

This post explains why you get half the size at 144

https://forum.affinity.serif.com/index.php?/topic/83492-export-persona-scale-problems/&do=findComment&comment=441920

I also saw we get half the size at 96dpi when it should be 192dpi but I had lost the will to live by then 

[Cobalt]

10 minutes ago, carl123 said:

This post explains why you get half the size at 144

https://forum.affinity.serif.com/index.php?/topic/83492-export-persona-scale-problems/&do=findComment&comment=441920

I also saw we get half the size at 96dpi when it should be 192dpi but I had lost the will to live by then 

Quote

Because your document is set to 144 DPI the Export Persona automatically creates half size exports when outputting to 1x format, the correct size when outputting at 2x, and double size when out putting at 3x. If you work at 288dpi, then your document will export at the correct size when using 3x, half size then using 2x and then half that when using 1x.

I don't even care to know in what universe such convoluted logic makes sense.

[Greyfox]

@Cobalt

@carl123

Thank you both. I think I have learned something from this.

It is not my normal practice to use the Export persona, as for photo work  the File->Export route does what I need, and I was certainly not aware of hidden DPI trap (or traps?).

6 hours ago, carl123 said:

This post explains why you get half the size at 144

Carl,  it details what happens if 144 DPI is chosen, but it doesn't explain why that should be, or why it was felt necessary to have it work that way, and I can't find any mention of it in the help file.

I have found this thread which offers some information about the 144, 192 and 216 dpi values, and yes in photo, if you set the document dpi to 216, the export size is 1/3 of that expected.

https://forum.affinity.serif.com/index.php?/topic/85643-incorrect-pixel-dimensions-from-designer-export-persona-current-mas-beta17/

[mcmorry]

It's 2025, and the problem is still there, without any explanation on why this is by design. As previously stated by other users, dpi and screen export should not be related. But I'm eager to learn what I'm missing. So Affinity, enlighten us, please.

I'm exporting icons and sprites that should be of a specific pixel size. How DPI enters in this equation? And especially, why 144, 192, and 216 DPI are treated differently? When creating a new document, the Web group of predefined formats offers a set of screen resolutions at 72 DPI and the "Social Media" set has all formats at 144 DPI. So if you select a Social Media one by mistake, you will incur in this exporting issue and waste 1 hour of your life understanding why... without success.

[carl123]

6 minutes ago, mcmorry said:

As previously stated by other users, dpi and screen export should not be related.

This extract from the link below may be relevant to Affinity's way of doing things

"Use 144DPI

As you’re not designing for print you don’t need worry unduly about working to a print resolution of >200DPI. However, you should keep to a DPI of 144DPI to attain an acceptable level of output quality for @2x Retina screens. Like measurement units, you can set the DPI value on document setup."

https://affinityspotlight.com/article/hi-res-iconui-design-can-be-pixel-perfect/