Viewer Parameter > viewer > viewer.paper

viewer.paper_orientation

Changes the paper orientation of the report.

Values

vertical	Change the paper orientation to portrait
horizontal	Change the paper orientation to landscape
empty string	Do not change(The default value)

Reference

If the height of the band designed in the report is greater than the height of the landscape paper when changing from portrait to landscape, the report does not change to the landscape orientation.

If the "viewer.largebundle" parameter value is "true", this parameter does not apply.