Expressions not dealt with correctly in batch processing

[jacphoto]

In the dialog box of batch processing if I input an expression like w*2560/max(w, h) in the size definition fields no error occurs but the expression is ignored and the size of the photos not modified

I use Affinity 2.0.4 on Windows 10 Professional 21H2

[Chris B]

Hey jacphoto,

If the expression is wrong nothing will happen other than you just end up with the same sized image. So for example an expression such as w*.5 will work. I cannot get your expression to work in any field that typically accept expressions.l

[David in Яuislip]

On 3/6/2023 at 5:56 PM, jacphoto said:

w*2560/max(w, h)

Although I understand your w*2560/max(w, h) sadly Photo doesn't
However, you appear to want to resize images so that either the width or height becomes 2560
You can achieve this by putting 2560 in both width & height boxes and leaving the A ticked however this will upsize small images
To prevent upsizing use min(2560,w) in the width box and min(2560,h) in the height box

Checking the validity of an expression using eg the Document/Document Resize dialog is of limited use. If you type min(2560,w) into the width box it will fail yet it works in a batch job
I don't consider this to be a bug it's just  hard to work with

[carl123]

1 minute ago, David in Яuislip said:

I don't consider this to be a bug it's just  hard to work with

I think it's a bug

The batch job recognises

w*2560

and

max(w, h)

when entered separately,

so why not when joined, as in... w*2560/max(w, h)

 

[Chris B]

This is what I've been trying to work out. I can feed it back to dev and see what they think.

[jacphoto]

Hi Chris B,

4 hours ago, Chris B said:

Hey jacphoto,

If the expression is wrong nothing will happen other than you just end up with the same sized image. So for example an expression such as w*.5 will work. I cannot get your expression to work in any field that typically accept expressions.l

I thought Affinity Photo used to detect errors using color feed back in the box where the formula is typed. Maybe only in previous versions. Anyhow it would be useful.

[carl123]

The Equations filter highlights errors in red

But even good equations were sometime labeled as bad (red)

[jacphoto]

No red highlighting for me in the dialog box of batch operation. I am using v 2.0.4

[carl123]

The Equations filter not the batch job

Filter > Distort > Equations

[jacphoto]

1 hour ago, David in Яuislip said:

However, you appear to want to resize images so that either the width or height becomes 2560
You can achieve this by putting 2560 in both width & height boxes and leaving the A ticked however this will upsize small images
To prevent upsizing use min(2560,w) in the width box and min(2560,h) in the height box

Yes I am trying to resize a mix of landscape ane portrait orientation photos and possibly smaller ones.

Thanks for the tip to overcome the issue it worked for me.

Although I am surprised of the behavior when typing values which are not proportional to the original sizes of the image while checking A

1 hour ago, David in Яuislip said:

Checking the validity of an expression using eg the Document/Document Resize dialog is of limited use.

I agree that such a formula is not useful if you consider to resize manually one image using Document Resize. But if you intend to build a Macro including the use of Document Resize it would be useful to be able to use the formula there and to have a different behavior so that the formula is not calculated at typing time but at execution time so that in a macro it can produce resizing based on the current size of an image in the lot processed by a batch.

I was considering to do that to be able to modify the dpi resolution of a set of images with the batch function at the same time I rescale them to overcome the lack of a dpi size field in the parameters of the batch function

1 hour ago, David in Яuislip said:

 

 

[David in Яuislip]

1 hour ago, jacphoto said:

Although I am surprised of the behavior when typing values which are not proportional to the original sizes of the image while checking A

What you enter into the batch width & height boxes sets limits for the final size, the A maintains proportions

I see you've noticed that Document Resize in a macro records the values calculated not the formula and this is unfortuneate. If that were possible then a macro could resize then apply sharpening, then it could be called from a batch job but that's not how it works

After resizing most images will need sharpening, whilst you can record sharpening as a step in a macro, when you include that in a resizing batch job then the macro will run before the resizing so the sharpening will be wrong. You could run a batch job to resize images then run another batch to apply sharpening to them but I'd lose the will to live

I've never managed batch changing dpi and gave up shortly after starting with Photo, I use exiftool eg
exiftool -Xresolution=96 -Yresolution=96 *.jpg

Batch jobs and macros used together can be very useful and run quickly but there are a lots of quirks

[jacphoto]

2 hours ago, David in Яuislip said:

What you enter into the batch width & height boxes sets limits for the final size, the A maintains proportions

I see you've noticed that Document Resize in a macro records the values calculated not the formula and this is unfortuneate. If that were possible then a macro could resize then apply sharpening, then it could be called from a batch job but that's not how it works

After resizing most images will need sharpening, whilst you can record sharpening as a step in a macro, when you include that in a resizing batch job then the macro will run before the resizing so the sharpening will be wrong. You could run a batch job to resize images then run another batch to apply sharpening to them but I'd lose the will to live

I've never managed batch changing dpi and gave up shortly after starting with Photo, I use exiftool eg
exiftool -Xresolution=96 -Yresolution=96 *.jpg

Batch jobs and macros used together can be very useful and run quickly but there are a lots of quirks

Thanks for this.

I was previously doing that with an outdated version of Photoshop Elements which includes all the parameters in its batch process. Moving to Affinity Photo for this purpose does not seem then a good move. Hopefully there are a lot of powerful and interesting functions in Affinity.

I have used exiftool through exiftool GUI which does not seem to include the capability to do this, I understand you do this on a file by file basis using exiftool command prompt.

Lets hope Affinity Photo will provide more help for this in the near future.

[David in Яuislip]

16 hours ago, jacphoto said:

I have used exiftool through exiftool GUI which does not seem to include the capability to do this,

Click the ExifTool Direct button then you can run commands from there. In this case 29 files were modified in about a second

[jacphoto]

4 hours ago, David in Яuislip said:

Click the ExifTool Direct button then you can run commands from there. In this case 29 files were modified in about a second

OK thanks, I know see that. I was just using a very outdated version