diff --git a/css-transforms-2/Overview.bs b/css-transforms-2/Overview.bs index ebdaf8c1b6a..0f7a569619e 100644 --- a/css-transforms-2/Overview.bs +++ b/css-transforms-2/Overview.bs @@ -769,11 +769,9 @@ Computed value: the keyword ''perspective/none'' or an absolute length Animation type: by computed value -Where <> values must be positive. -
: <> - :: Distance to the center of projection. + :: Distance to the center of projection. Negative values are invalid. Issue: Verify that projection is the distance to the center of projection. @@ -902,7 +900,7 @@ In the following 3d transform functions, a <> behaves th : rotateZ() = rotateZ( [ <> | <> ] ) :: same as ''rotate3d(0, 0, 1, <angle>)'', which is a 3d transform equivalent to the 2d transform ''rotate(<angle>)''. : perspective() = perspective( <> ) -:: specifies a perspective projection matrix. This matrix scales points in X and Y based on their Z value, scaling points with positive Z values away from the origin, and those with negative Z values towards the origin. Points on the z=0 plane are unchanged. The parameter represents the distance of the z=0 plane from the viewer. Lower values give a more flattened pyramid and therefore a more pronounced perspective effect. For example, a value of 1000px gives a moderate amount of foreshortening and a value of 200px gives an extreme amount. The value for depth must be greater than zero, otherwise the function is invalid. +:: specifies a perspective projection matrix. This matrix scales points in X and Y based on their Z value, scaling points with positive Z values away from the origin, and those with negative Z values towards the origin. Points on the z=0 plane are unchanged. The parameter represents the distance of the z=0 plane from the viewer. Lower values give a more flattened pyramid and therefore a more pronounced perspective effect. For example, a value of 1000px gives a moderate amount of foreshortening and a value of 200px gives an extreme amount. Negative values are invalid. Transform function primitives and derivatives {#transform-primitives} @@ -1265,10 +1263,12 @@ One translation unit on a matrix is equivalent to 1 pixel in the local coordinat \newline sc = \sin (\alpha/2) \cdot \cos (\alpha/2) \newline sq = \sin^2 (\alpha/2)
  • - A perspective projection matrix with the parameter d is equivalent to the matrix: + A perspective projection matrix with the parameter d is equivalent to the matrix \begin{bmatrix} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 0 & 0 & -1/d & 1 \end{bmatrix} + when d is non-zero, and a 4x4 identity matrix when d is zero. + The SVG 'transform' Attribute {#svg-transform}