PdfMarkupDataQuadrilaterals Property

NOTE: According to Table 179 in ISO 32000-1, the QuadPoints array lists the vertices in counterclockwise order and the text orientation is defined by the first and second vertex. This basically means QuadPoints is specified as lower-left, lower-right, top-right, top-left. HOWEVER, Adobe's interpretation (tested at least with Acrobat 10, Acrobat 11, Reader 11) is top-left, top-right, lower-left, lower-right (Z-shaped order). This means that if the QuadPoints array is specified according to the standard, the rendering is not as expected. Other viewers seem to follow Adobe's interpretation. Hence we recommend to use and expect QuadPoints array in Z-order, just as Acrobat and probably most other viewers expect.