Somehow Pixel Object Splitting Pixels- Affecting Seamless Pattern Export

[cpaliocha]

Hi! I'm troubleshooting a disruption in my seamless pattern when I export to PDF- thin white line that shows up between two repeating patterns. I set the document to move only by whole pixels, yet when I zoom into a pixel by pixel view, I see that the bottom and top row of pixels on each object is split. This is not reflected in the transform panel (object sizes and positions are only whole pixels. I'm trying to clip the top or bottom fraction of a pixel, but I can't figure out how this would be done. Thanks!

Mountain Pattern.afdesign

[BofG]

You don't want "move by whole pixels" on. That would mean anything that is slightly off pixel will always remain that way. It's a confusing name, but it means it moves in pixel increments from the origin, so if the origin is 0.77px, it will always be on something.77px.

Set the preferences to show at least two decimal places as it might be out but it's being rounded to the nearest whole number so you won't see.

[cpaliocha]

Thanks for the response. I only turned on the "move by whole pixels" after I'd rounded off my existing objects- but I changed the preferences to show two decimal places, and still, all my object sizes and positions are still showing as whole numbers in the transform panel. Is there a way I can use exporting or some sort of whole document manipulation to sort of refresh the pixel readings? Or a more precise setting for cropping, so I can just manually slice off that half pixel?

[BofG]

If you export to a raster format (e.g. png) does the white line appear still?

[Old Bruce]

1 hour ago, cpaliocha said:

I changed the preferences to show two decimal places,

Won't show X.004 pixels you'll see X pixels. Toggle the Transform x, y and H, W boxes by selecting the whole number and use the up down arrow key to toggle up and then down. Now you will have integers.

[cpaliocha]

Yes, so I have integers in the Transform boxes, the issue is that the object (with many layers therein) has x fraction of pixel hanging off the top and 1-x fraction pixel hanging off the bottom (i.e. row of 1/4 pixels at the top and 3/4 at the bottom). This means my object is an integer dimension of pixels, and its position is also an integer. But the split pixel shared between the top and bottom remains and cause issues. 

The only way for me to crop a portion of a pixel (or move the object in "crop" mode, to align the object with a whole integer pixel), is to have all snapping and pixel alignment off, which in turn means I can't ensure my adjustment lands exactly on a whole pixel.

I tried exporting as a png, there's still a line that shows up and disappears at different zoom levels.

[R C-R]

2 hours ago, cpaliocha said:

This means my object is an integer dimension of pixels, and its position is also an integer.

At least for the Mountain Pattern file you uploaded, the X position of many of the layers are not on whole pixel values. To see this, set display precision to at least 3 decimal places.

So for example, X value of the "BL Corner (Pixel) (Pixel) (Pixel) (Pixel)" layer in the "Bottom Right Pattern SemiFinal" group of Artboard 2 is -1110.002 px.

[cpaliocha]

Ok, I'll change the settings to show more decimals. So if I correct all these individual layers to whole integers first, any adjustment to the whole object to slice of the pixel fractions returns the many layers underneath to partial pixel values again.

[BofG]

I've had a look at the actual file, it's more complex than I had assumed. Anyway, no need to do much to it - select Artboard 1, right click it in the layers panel and choose "rasterise & trim" (do this on a copy of your document or copy the artboard if you want to preserve it for future use as is). Now, take that resultant pixel layer (it will be named "Artboard1" but it's not an artboard any longer) and tile to your heart's content. Just make sure that it's on whole pixels as mentioned before, and if you use an artboard, that too has to be on whole pixels.

For export to PDF, you need to choose the "flatten" option otherwise you will get that line rendering artefact. If you want to add vector content in there with the pattern then make the full pattern up on an artboard and rasterise the artboard, then use that pixel layer along with the vector content and any of the pdf export options will work.

[cpaliocha]

Thank you- I realized I don't have a need to keep it from being rasterized at this point, and either that or flattening the PDF made the seams disappear!