QW-ACT-R07 Visningsretning på nettsida er ikkje avgrensa med bruk av CSS-transformeringseigenskap

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  • 1.3.4 Visningsretning

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Applicability

This rule applies to any HTML element that is visible and has a CSS transform property that is applied conditionally on the orientation media feature with a value of landscape or portrait, where the CSS transform property has any of the below transformation functions:

Note: These specific transformation functions are of interest to this rule as they have the potential to affect the rotation of a given element.

Note: The rotate3d, rotateZ and matrix3d are currently part of a W3C Editor's Draft.

Expectation

The target element is neither rotated clockwise nor counter clockwise around the Z-axis at an angle corresponding to 90 degrees relative from the position of the element in landscape orientation to the position of the element in portrait orientation, and vice versa.

Note: Imagine the display of a smartphone with cartoon figure at its center. With this example, if a user turns the smartphone a quarter turn, that is a partial move from one orientation to the other, the user would expect that the cartoon figure continues to remain facing upwards. The smartphone accomplishes this by rotating the contents of its display a quarter turn to counter the users change in orientation. In effect, the cartoon figure has remained in place and its rotation relative from one orientation to the other is 0 degrees. Now imagine that a developer facilitated this rotation of the cartoon figure by a quarter turn only when the smartphone starts from one orientation and not the other; its rotation relative from one orientation to the other would then be 90 degrees and it would appear stuck, or locked, as the user moves between orientations. What the developer has done is effectively counter the smartphones attempt at countering the users change in orientation.

Assumptions

This rule does not consider and may produce incorrect results for:

  • Elements for which a particular display orientation is essential.
  • The existence of any control on the page that can change the orientation on demand.