keeping pixel dimensions in integer values when scaling

[Mike089123]

I have the decimal place for unit types on pixel set to 0, and snapping and move by whole pixel on, yet when I rescale images they will not be integer values. Even when changing the width and height to an integer value, and rescaling, it will not be an integer value anymore. This makes it a pain to create an artboard from selection since it keeps adding extra pixels to the sides, as well as adding more pixels to the dimensions when exporting.

[R C-R]

The decimal places set in Preferences are just for display purposes -- internally, the app always uses the maximum precision possible. "Move by whole pixels" will do exactly that, so for example, if the width is currently 800.2 px dragging a handle will be constrained to values of 799.2 px or 801.2 px & so on.

 

Also, if the aspect ratio lock is on in the Transform panel, changing width or height may force the other setting to a fractional value to maintain that ratio.

[Mike089123]

23 hours ago, R C-R said:

The decimal places set in Preferences are just for display purposes -- internally, the app always uses the maximum precision possible. "Move by whole pixels" will do exactly that, so for example, if the width is currently 800.2 px dragging a handle will be constrained to values of 799.2 px or 801.2 px & so on.

 

Also, if the aspect ratio lock is on in the Transform panel, changing width or height may force the other setting to a fractional value to maintain that ratio.

So how do you scale while keeping integer values?

[Alfred]

29 minutes ago, Mike018 said:

So how do you scale while keeping integer values?

 

In general, you can’t scale an object in a single operation if you want to keep integer values for its dimensions and maintain the aspect ratio at the same time. For example, if you start with an 8" by 5" rectangle and you halve the long side, that length will become 4", but if the aspect ratio is locked the short side will become 2.5", so you would need to unlock the aspect ratio and truncate or round that value.

[R C-R]

36 minutes ago, Mike018 said:

So how do you scale while keeping integer values?

There are several things you need to consider for this. As @Alfred said, the most obvious is the mathematics of aspect ratios & scale factors. If multiplying each dimension by the same scale factor on a calculator does not yield integer values, then it won't in Affinity Designer either.

 

Beyond that, you also have to consider stroke widths & their alignment:

All 3 shapes are 10 X 10 px squares, precisely aligned on integer pixel dimensions. But the left one will never align on integer values because its stroke is an odd integer value & it is center aligned.