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CedarHouse

Crop tool absolute size resampling

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In reply to Mark Ingram I am going to do a reply in two parts to attempt to illustrate the resampling of pixels in the Absolute Size Crop Tool function. Have sized an image to 4500 px by 3000px to easily show the pixel number changes more easily. First image set as 15in by 10in at 300 DPI with pixel crop 4500px by 3000px.  Second image 15in by 10in at 50 DPI with pixel crop now at 750px by 500px.

Third image at 15in by 10in and a large DPI of 3000 and pixel crop now 45000px by 30000px. This is action for changing only the DPI when a dimension such as inches is selected. Does not happen when only pixels are selected. 

Image1.jpg

Image2DPI50.jpg

Image3DPI3000.jpg

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Second part is same image but comes into Affinity Photo 1.7.404 for Windows at the same 4500px by 3000px. Set crop tool to Absolute Size and image size is 46.88in by 31.25in at 96 DPI and crop of 4500px by 3000px. Change DPI to 300 and the image size in inches remains the same but the crop has changed to 14062px by 9375px.

This action is to resample by changing the pixel dimensions of a photo and this should only be done in the Export personae. Resampling is irreversible and can damage a photo. 

It should be resizing the image from 46.88in by 31.25in at 96 DPI  to 15in by 10in at 300 DPI.  The similar actions are also occurring in 1.7.2.424(Beta) in which I have used the same example but in a different way.

ImageAoriginal.jpg

ImageBresample.jpg

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The third action with the Absolute size crop tool is producing a cropping grid outside of the image size. Image claimed to be 3000px by 3000px at 300 DPI and 10in by 10in. Switching to the Unconstrained mode indicates 4500px by 4500px. This crop grid is some 750px greater top and bottom of the image in Absolute size mode. One can then click on the corner grips in Absolute size mode and pull the corners in until one places the grid to the edge of the image to get a 3000px by 3000px selection. If one then decides to change the DPI to say 260, then this must be done by clicking the pixel button before entering the new DPI value. On clicking on the inches button the display will show 11.24in by 11.24in but if one changes one's mind and decides to revert back to 300 DPI then the pixel count will begin to change. (Resampling). Before changing the DPI to any value, one must click the pixel button and have pixels displayed before changing the DPI. If the Inches are displayed then any change of the DPI will result in pixel resampling rather than image resizing. The only option to escape this is to click in Edit and undo the action or if in a complete mess cancel the whole crop operation and start over again.

Image1unconstraied1.jpg

Image2absolutesize.jpg

Image410by10inches.jpg

Image53000.jpg

Image64500.jpg

Image3Inches.jpg

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I personally think that the Absolute size crop tool is resampling the image rather than resizing the image. The pixel quantity is changing either up or down on the DPI change.

But there is no algorithm (such as Nearest neighbour, Linear, Bicubic, Lanczos) available to smooth out the change if one accepts (Apply) the crop made.

Resampling means that one is changing the number of pixels in an image. Downsampling is reducing the number of pixels for e-mail, web, or for display devices.

Upsampling is were there is not sufficient pixels in an image to print at a size one requires, this is rare now that camera sensor resolutions are high at above 16Mpixels and can easily achieve larger prints without the need to Upsample the pixels, by adding more pixels than in the original image.

Resizing vs resampling an image.pdf

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On reflection over the last week have done a search through other software and their respective cropping methods, could I make a suggestion that the Absolute Size be changed to something like - "Preserve Aspect ratio". That is basically what the Absolute size is actually doing in version 1.7 both in the Develop personae and Photo Personae. Change Unconstrained to something like "Freeform" but unlock the alternative sizes to allow any size cropping in pixels, centimetres, millimetres, inches and any other dimension type. Link the DPI (ppi) in Unconstrained (Freeform) to the Resize Document so one can chose the required DPI (ppi) in the Document resize and the DPI (ppi) is shown in the Unconstrained (Freeform) as reference value only. The DPI (ppi) should not be allowed to change in the cropping tool. 

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Hi @CedarHouse, we had a discussion internally last week about potentially changing the name of "Absolute Size", because it is indeed doing a resampling resize. The name right now is a little confusing admittedly... Also we don't currently offer a method of choosing the resampler, that's something else we could look at adding, if there's a need.

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5 hours ago, CedarHouse said:

could I make a suggestion that the Absolute Size be changed to something like - "Preserve Aspect ratio". That is basically what the Absolute size is actually doing in version 1.7

No, it's not preserving aspect ratio. Or, at least not the current aspect ratio of the image.

You can specify any size you want, with any aspect ratio. That aspect ratio will be preserved, no matter how you scale the crop box, and at the end you have the size you specified.

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25 minutes ago, Mark Ingram said:

Also we don't currently offer a method of choosing the resampler, that's something else we could look at adding, if there's a need.

I would appreciate having the choice, Mark. I'm not convinced that one fixed resampling method would be good for all images.

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Just now, walt.farrell said:

I would appreciate having the choice, Mark. I'm not convinced that one fixed resampling method would be good for all images.

Well we choose the best resampler, the only reason to change it would be if you want to perform a faster but less visually pleasing resampling. Which I really can't think anyone would want?

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2 minutes ago, Mark Ingram said:

Well we choose the best resampler, the only reason to change it would be if you want to perform a faster but less visually pleasing resampling. Which I really can't think anyone would want?

So does that mean you're using Lanczos 3 Non-Separable for this resizing? If so, that's fine for me. If I need something sharper I could always add some sharpening myself. And possibly just documenting the resampling method would suffice. Thanks.

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6 minutes ago, walt.farrell said:

So does that mean you're using Lanczos 3 Non-Separable for this resizing? If so, that's fine for me. If I need something sharper I could always add some sharpening myself. And possibly just documenting the resampling method would suffice. Thanks.

Yep. 

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Not sure that one should be resampling within the crop tool. Export or Resize Document should be for resampling. I have up to version 1.6 used Export to JPG with down-sampling to 1600 width for digital projection. Maximum pixel dimensions in width 1600 and max pixel dimension in height 1200. At 300 DPI. Seems a duplication to do that in a crop.

The reason I thought that the Absolute Size crop tool was a Aspect ratio was that when opening an original uncropped .afphoto camera image in the Absolute mode and using the grab handles in the corners or sides then the crop grid remains constant to the original image ratio (1:1.51). The troubling problem is that no matter what size one drags the box down to the pixel dimensions and inches dimensions do not change. The Crop box can be dragged down but the size information does not change. Click to accept and the original size is the new cropped image size. But change the dimensions (say inches) then the crop box on screen changes in size, but then grab the corners and the crop box goes back to the original edge and size but no dimensional changes are indicated in the menu bar. Regardless of what unit lengths I put into the dialogue menu the ratio of the Absolute size does not change in comparison to the original 1:1.51 image size. The only way that I can get the crop I want is to use the Absolute Size crop tool twice. Original image is 4950px by 3284px (1:1.51) 16.5in by 10.95in. Change dimension in height to say 10in and click Accept. Then reopen the crop tool and go to Absolute size and then set the width to say 14in. The grid goes outside of the image in height, but can grab the corner handles and pull the grid diagonally back to the top and bottom edge of the image and hopefully will have an image at 14in wide by 10in high. But why does one have to do this in two separate operations? It is a long winded way of working and would be quite tedious when working lots of images. (batch process??).

Only Unconstrained shows the changes in the pixel grid but alternative unit lengths are greyed out, so it is not as useful for sizing an image in Freeform using either mm, cm or inches. I can click from Absolute Size to Unconstrained and Unconstrained will show the changes but only in pixels, while Absolute does not regardless of what size one makes the crop box unless one edits an image using the crop tool twice as indicated above. Absolute Size will not show the changes to dimensions when the crop box is dragged considerably smaller than the original image size. Click to Unconstrained and the new pixel dimensions are shown but no other units are available.

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37 minutes ago, CedarHouse said:

The troubling problem is that no matter what size one drags the box down to the pixel dimensions and inches dimensions do not change

That's because this crop produces an image the absolute size you ask for. Whatever area you select in the crop box is resampled and resized to become the size you requested in the size boxes.

I believe this is Serif's implementation of a Photoshop cropping method that many users had asked for, which crops and resizes in one operation. Previously in 1.6 that was a two-step operation.

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1 hour ago, Mark Ingram said:

If you don't want the resampling crop, use the Unconstrained crop option instead.

Thanks, Mark.

Out of curiosity, is there some reason that the DPI field in the Crop Tool's Context Toolbar remains active when doing an Unconstrained crop? It doesn't seem to actually do anything if you change it in that mode, but it seems a bit odd that it can be changed.

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Hi Mark.

As referenced in the above posts it would be nice to use the Unconstrained crop option but it is in pixels only. There are no other dimension units available.

Want to crop images to a specific size (or the closest size that can be achieved) for printing onto paper media.

Attached an edited image each image was cropped and sized to the same exact size, pasted and spaced on a canvas for a 16in by 12in paper media.

PAGBMastersofPrint.pdf

Crash2 16 by 12.jpg

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I realise it's a little confusing to have the units combo disabled, but you can actually type 6in and 4in into the boxes, to create the correct size image. It will just convert the physical size into pixels. We've just had a discussion on whether to show that width and height in your document's units (as we already preview the output size in pixels anyway), and allow you to change the units for Unconstrained.

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On 7/30/2019 at 4:56 AM, Mark Ingram said:

If you don't want the resampling crop, use the Unconstrained crop option instead.

I'm curious, what was the behavior of the Crop Tool in 1.6.5.  Did cropping also resample the image?  Also, I noticed that you cant save Unconstrained Crop sizes as Presets in 1.7.2.471.  Is that by design?

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On 8/24/2019 at 3:48 PM, drphoto said:

Also, I noticed that you cant save Unconstrained Crop sizes as Presets in 1.7.2.471.  Is that by design?

You shouldn't be able to have presets with Unconstrained Crop.  A preset be it a ratio, or a specified size is in itself a constraint (a limitation or restriction) .

What is unfortunately missing in 1.7.2.471 is the ability to create Absolute presets.

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On 8/27/2019 at 2:39 AM, Greyfox said:

You shouldn't be able to have presets with Unconstrained Crop.  A preset be it a ratio, or a specified size is in itself a constraint (a limitation or restriction) .

What is unfortunately missing in 1.7.2.471 is the ability to create Absolute presets.

Ah yes, thats what I need, an Absolute preset.  I had quite a few in 1.6.5, they do make the editing process easier.

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