exported PNG edge problem

[Burpee]

Hi all, I use Xara sometimes to resize images/photos. Quite often I use the clip view function to crop the image to the precise size I need.

I just recently found that when I export my clipped views, always as pngs, they have a very small 1 to 2 pixel edge around them. I can keep clipping but it continues to stay there. I exported with alpha and without to see if it made a difference but it doesn't.

I am now having to use my raster program to resize but had liked using Xara for it. The raster program works fine and I suppose every program has its uses so I just won't use Xara for photo clipping and exporting anymore. I just think that there shouldn't be an issue since Xara seems to want to handle photos more.

I'm very curious is anyone knows why this happens. the attached images show extreme closeup of a blue image on a black background (the black background is used for checking this very problem).

[mwenz]

Hi Burpee,

I have attached a test. While you may see an artifact, one is clipped, exported as a png and brought back in and the other is not touched.

Also note how far I am zoomed in. All this to say I cannot reproduce the problem you are experiencing.

Take care, Mike

[ad1066]

The issue has to do with the edges of the object falling on partial pixel borders. The fix has to do with setting up your rulers and the grid (and snapping to it) very specifically. You mainly want to make sure everything that's either exactly horizontal or vertical will fall directly on a whole pixel line, otherwise it will anti-alias the edge. There are some previous threads about it.

-- Ben

[gwpriester]

Nancy - I have noticed this too. And sometimes even when my image is even pixels and located solidly on the grid. Most often when I see this is when I am creating repeating patterns for my stereograms.

My work around is to export the image over a background that is closer to the colors used in the graphic.

[zaphodeist]

Whole pixels for the image and aligned on the grid, but some folk have their grid set up to CM, for instance, which won't always translate to whole pixels. Just a thought

[Burpee]

Thanks everyone, appreciate the help. I understand the reason now. I think it will be easier for what I do to use the raster program for this function. It seems to work quite well now that I am using it. Xara is still my 'go to' program for object creation.

I've never gotten the rulers to work properly so I rarely use them....even with Gary's tutorials I saved on the subject. Think it has something to do with the snap units...I just don't understand them...things don't snap to like I think they should and I end up zooming in very close to fix gaps where things didn't snap correctly.

things to learn to use in XX:
named colors
rulers and grids
text around a circle

[jimhanus]

I've found I have this same issue. A search produced this thread, and by making the image whole pixels and aligned to whole XY coordinates the problem goes away.

Jim