PNG export question

**gpholman** · 26 March 2009, 09:51 AM

Hi

Draw a square, 30 x 30 pixels with no line and no effects, and colour it red (size and colour are irrelevant, this is just as an example).

Export it as a PNG and then look at the PNG - it will consist of more than just the red I chose, there are several shades of red in there as well. Why is this?

It's causing me a problem because I created a simple coloured square with a dot in it to act as a tiled website background but these 'extra' colours mean I do not get an even background colour.

**covoxer** · 26 March 2009, 10:08 AM

Originally Posted by gpholman

Export it as a PNG and then look at the PNG - it will consist of more than just the red I chose, there are several shades of red in there as well. Why is this?

This is because of anialiasing. If your rectangle is not pixel aligned and it's size is not whole pixels number it will have antialiasing frame.
To avoid it, simply make it pixel aligned and with even size. Just make sure all these numbers are integer:

**gpholman** · 26 March 2009, 10:12 AM

Fantastic - fixed!

Cheers

**slavelle** · 26 March 2009, 12:14 PM

Would be handy to be able to snap this to the grid and have that force to pixel alignment. Even with snap options set to 10pix majors with 10 subdivisions, grid showing, and snap to grid selected, I'm still able to move and size objects to non-integer points.

If not a function of the grid, there could be a simple "round up" option or something - maybe next to the Position and Size boxes - allowing you to select an object and click the round up button.

I know I sound lazy, cause it's not like it's hard to make the changes, but if you have a lot of objects, that's possibly 4 manually fixed values * number of objects, where at least two clicks would be quick and brainless to get the same result.

**covoxer** · 26 March 2009, 12:24 PM

When you have a grid set, only proportional scaling (draginng the corner blob) can change size in fractional pixels. This can't be avoided if we want a smooth scaling. If you don't do it, all other transformations seems to produce only whole pixels.