The whole intention of my little test hack in the first place was to show, that without being able to define layout with device native unit precision, the end r

The whole intention of my little test hack in the first place was to show, that without being able to define layout with device native unit precision, the end result becomes unpredictable. The idea was to apply a checkerboard background image to to body and div, but translate the checkerboard by 1px in the div. By their very nature pixel based images are defined in pixels. And the most naive way to display images is by a 1:1 mapping of image pixels to CSS px units. This is how things started out, and only later features like page zooming, responsive scaling, HiDPI and so on came to be. Of course that means that images must be scaled. But this scaling must be well defined, so that the output will only differ in resolution, but not layout or visual outcome after scaling. And right now browsers fail to do this. Two years ago, when I wrote came up with that test Opera and Android WebView did even fail to properly translate the position of the div background; it looked like if somewhere in the scaling at some point the translation was coerced into the device native units grid. A checkerboard pattern can be understood as a Haar wavelet; or in terms of spatial frequency space as ΣₖΣₗsin(x-k)/(x-k)·sin(x-l+π)/(x-l+π) When applied to the pixel sampling grid a 2×2 checkerboard pattern is right at the Nyquist limit. Upscaling it with an ideal filtering kernel (sin(x)/x = sinc(x) = Lanczos) yields a single frequency (sinusoid). Adding two such signals at exactly π phase difference gives perfect destructive interference. Add some phase difference and it becomes constructive. This little detour into signal theory should make it clear, that you have to take great care when scaling and positioning stuff in a layout. Scale corresponds to frequency, position corresponds to phase. And it should be noted, that in a visual signal, phase carries the bulk of information, hence image transformations should preserve the phase, where possible. That it also shows, that interpolation and blending is broken, too (i.e. doesn't respect gamma) is a secondary outcome.