Export -> resized text looks ugly

[madrian]

Hi,

 

When I export and resize image in Affinity Photo, text looks not anti aliased - crispy compared to resize from Document -Resize and export with new size.

Let me demonstrate this problem.

Source height 512px:

Export and exported image at 256px:

 

You see the problem?

Now I resize image with Document -> Resize document and export with new size.

 

 

It looks much better.

 

Why is that?

[John Rostron]

57 minutes ago, madrian said:

You see the problem?

No, I do not. It could be that the images in this posting are all displayed at the same size, so any scaling effects are cancelled out. You have also exported with a transparent background, which means that on my Android Chrome browser, the background appears black when I click on an image, and the text is thus rendered invisible!

[madrian]

Here is comparison with white background. On the bottom is the image "ugly" with crisp borders.

 

[lepr]

4 hours ago, madrian said:

Hi,

 

When I export and resize image in Affinity Photo, text looks not anti aliased - crispy compared to resize from Document -Resize and export with new size.

Let me demonstrate this problem.

Source height 512px:

Export and exported image at 256px:

 

You see the problem?

Now I resize image with Document -> Resize document and export with new size.

 

 

It looks much better.

 

Why is that?

 

There clearly is a distinct difference. I think you'll need to provide the Affinity document or another that has the same problem or you'll probably start seeing wild guesses being posted and wasting your time.

[carl123]

The first time you export the file's size is...

744 x 256

The second time it is...

743 x 256

The 1px difference may be responsible for some sort of anti-aliasing issue. 

But we need the document to see exactly what could be the cause

[John Rostron]

44 minutes ago, anon2 said:

There clearly is a distinct difference

Not to me there isn't.As @anon2 and @carl123 say, you would do better by posting your original files for others to look at.

John

[madrian]

I can't reproduce now. Very weird. I had opened many tabs, this can't be a memory issue, right? I'll post update, when this problem appears again.

[Dan C]

Hi madrian

My apologies for the delayed response!

If you're using Document - Resize with text objects in your document then these objects will remain in vector until you export to PNG.

When resizing the document at export (using the export dialog with PNG selected) you are resampling a pixel document and this may cause the slight difference you're seeing.

Resizing the document will retain the vector objects until you export, whereas resizing at export will resample the image so we always recommend resizing the document before export, where possible!

[lepr]

3 hours ago, Dan C said:

When resizing the document at export (using the export dialog with PNG selected) you are resampling a pixel document and this may cause the slight difference you're seeing.

Resizing the document will retain the vector objects until you export, whereas resizing at export will resample the image so we always recommend resizing the document before export, where possible!

No, resizing at export is no different to resizing the document and then exporting at the new size. In both cases, all vector objects are resized without being rasterised and then everything is flattened to a composite raster image that is exported to PNG (or other raster image format).

[madrian]

Another example. Source is a flattened .png. I opened in Designer and resized to 256x256 and 512x512 from File -> Export, after resize looks awful. I attached the original image.

[madrian]

I get same result when I resized in Photo with Document - Resize.

On the left, resized with Photo (Document - Resize and File - Export with new size.), on the right resized with Preview app (looks good).

Very weird.

 

Again, resized with Photo

 

Resized with Preview on Mac:

 

 

[lepr]

Looks like you used bilinear resampling in Affinity.

Preview app takes your image that has a gamma-encoded colour space, converts to a linear colour space, resizes with Lanczos (separable) resampling and then converts back to the gamma-encoded space.

The same procedure done in Affinity Photo will give an almost identical result.

However, just using Lanczos (separable) without the colour space conversions will give an even better result in the case of your stark black and white (and red) image because the ringing artefacts generated by Lanczos will be less obvious than if the resampling is done in a linear space. Some images do benefit from resampling in a temporary linear space, but not your icon.

So, in short, use Lanczos (separable) or bicubic resampling in Affinity to reduce the size of your raster icon. Do not use Lanczos (non-separable)!

(By the way, I see your 1000 x 1000 PNG was sourced from a JPEG. That''s not relevant to this particular resizing problem, but try to use sources without JPEG artefacts.)