We host reports embedded in the PBI Service as well as OnPrem from the PBIRS. OnPrem we are filtering reports with parameters and displaying them in an iFrame. The reports all show as Actual Size, and depending on the user resolution there may be a ton of white space around the report. In the service I can edit a report and set the view option (image below) which is respected when the report is embedded. In PBIRS if I view the report I have access to the view menu, but it seems to only apply to that session. I want the report to always be 'Fit to Width'. Is there a way to save that option or to have it load that way in the iFrame through a URL parameter I'm not aware of??
iFrame does not allow you to display a Power BI Report Server report in responsive design. The size of the reports depends on the size of the page. If you want small iframe, you have to reduce the page size of the report.