Image size incorrect when New From Clipboard on a precisely sized selection

[Jeff Laing]

Create a simple document by opening a 600DPI PNG with Affinity Photo

Sweep a rectangular selection, then use the transform panel to precisely size the selection to 1500x2100 (those are the numbers I was using, smaller ranges show similar issues)

Copy Merged, then New From Clipboard and look at the dimensions of the resulting image.

For me, it is nearly always off by 2 or more pixels in each dimension.

Over on 

I described the problem initially, but have been redirected here.  Uploading the actual files is prohibitively expensive (>100MB) but the problem seems relatively easy to reproduce.  After some back and forward, Walt managed to create the same symptoms using Photo on Windows (I believe).

(As an aside, the "newbie post limit" is a bit frustrating - I can appreciate that it relates to keeping spamsters and trolls out but when a persons first contact with the forums is to look for support on an issue, it is quite frustrating to discover that you can't provide a response to a question you are asked.  Even switching to personal messaging only allowed a single reply - you should make very visible in the interface "as a newbie, you have (n) posts left today" - I'm going to assume it isn't there because I can't see it on this page)

[Jeff Laing]

Note, I'm really not interested in response of the form "its by design, we grow/shrink the selection to include fuzzy content" - within a document, I can see why that's appropriate, especially if you have masks/blend modes/transparency etc. involved.  But I had *none* of that.  Single layer, Normal Blend, No Mask, Rectangular selection.

I'm talking about the specific case where I told Photo an explicit size to copy and to then create a new document using what I assumed to be the size I copied.  I wanted to include those new documents into another application as part of its texture map, and randomly injecting/omitting a few extra pixels in that context screwed me up...

If you are going to use the information in the Transform panel as "advice" rather than "specification", then you need to make the "effective size" of the clipboard visible somewhere.

[lepr]

8 minutes ago, Jeff Laing said:

Note, I'm really not interested in response of the form "its by design, we grow/shrink the selection to include fuzzy content"

You may have misunderstood my message in the other thread. I was not saying that the resulting pixel selection is deliberately made fuzzy. My point was that it is fuzzy as a consequence of the method used to resize it. A pixel selection is a raster object like a pixel mask, and resizing a raster object is achieved by resampling its pixels. To avoid a rectangular selection becoming fuzzy-edged when resized, it will need to be treated as a special case, and I suggested that you post a request for that.

[Jeff Laing]

10 hours ago, anon2 said:

... and resizing a raster object is achieved by resampling its pixels. To avoid a rectangular selection becoming fuzzy-edged when resized ...

What resize? I didn't ask for any resize. I swept out a visible set of pixels, then used the transform panel to explicitly snap the size of that selection as per the previous suggestion in the thread.  At no point did I attempt to resize any content?  If resizing the content was somehow implied by the transform panel then it does not meet the original requirement.

I could see where someone might argue that the New From Clipboard resampled because it didn't propagate on the 600DPI - which I believe happens, dropping the new file to 96DPI - but downsizing shouldn't make things fuzzier and it shouldn't infer data that wasn't inside the selection set.  Frankly, I think the New From Clipboard should have maintained the source data resolution, not throw away information. In this case, "New From Clipboard" has apparently done "New something that's a lot like but not the same as the clipboard"

Again, I can understand the pixel-level issues involved, but those are not communicated out through the user interface which currently implies exact values being input will be turned into exact output.

[MEB]

Hi Jeff Laing,
Thanks for reporting this. I'm logging it to be looked at.

[lepr]

On 3/23/2020 at 7:50 AM, Jeff Laing said:

What resize? I didn't ask for any resize. I swept out a visible set of pixels, then used the transform panel to explicitly snap the size of that selection as per the previous suggestion in the thread.  At no point did I attempt to resize any content?  If resizing the content was somehow implied by the transform panel then it does not meet the original requirement.

Still a misunderstanding. I was not talking about image content being resized. I was talking about resizing the region of selection itself (the region of the document indicated by marching ants), not resizing a region of a Pixel object. The region of selection is independent of any Pixel object, but it is itself defined by pixels indicating strength of selection, and resizing the region results in these "strength" pixels being resampled in a similar manner to resampling the pixels of a raster image, and so the region of selection becomes fuzzy.

[Jeff Laing]

1 hour ago, anon2 said:

The region of selection is independent of any Pixel object, but it is itself defined by pixels indicating strength of selection...

Since the user has no idea whatsoever what the "strength" of the selection is, it is pointless to offer precision in selection process.  Displaying exact pixel numbers in the user interface is stupidly misleading, particularly when you allow them to be explicitly typed in.

This is all somewhat moot, for this task I have switched to Acorn which has no problem respecting requests for precise selection sizes. When I ask it to crop to a specific selection size, that is the exact size that I get, not something nearby that it thinks is indicated by the transparency of the pixels.  Anyone creating images for use as sprites will understand why transparent edges around the selection and exact sizes are critical.

[lepr]

On 3/23/2020 at 11:12 AM, MEB said:

Hi Jeff Laing,
Thanks for reporting this. I'm logging it to be looked at.

Using AP 1.8.4, I see that selection resizing has been changed with nearest neighbour resampling now being utilised, and so selection edges do not become fuzzy. Thanks.

[Puck]

On 3/22/2020 at 9:47 PM, Jeff Laing said:

Create a simple document by opening a 600DPI PNG with Affinity Photo

Sweep a rectangular selection, then use the transform panel to precisely size the selection to 1500x2100 (those are the numbers I was using, smaller ranges show similar issues)

Copy Merged, then New From Clipboard and look at the dimensions of the resulting image.

For me, it is nearly always off by 2 or more pixels in each dimension.

Hello, I can confirm this behaviour.