How to create a PDF report in landscape mode

There is no landscape flag. A landscape page is one whose width exceeds its height, so you swap the two elements of a PageSize.

c := creator.New()

// A4 rotated: width and height swapped.
c.SetPageSize(creator.PageSize{creator.PageSizeA4[1], creator.PageSizeA4[0]})

c.SetPageMargins(50, 50, 100, 70)

PageSize is a [2]float64 of width and height in points. PageSizeA3, PageSizeA4, PageSizeA5, PageSizeLetter and PageSizeLegal are all declared portrait, so indexing [1] then [0] gives you the rotated form without hard-coding numbers. For a size with no constant, build one from creator.PPMM or creator.PPI.

SetPageSize resets all four margins to 10% of the new page width, so it has to come before SetPageMargins or your margins are silently replaced. It also only affects pages created after the call; pages already added keep the size they had.

Anything positioned in absolute coordinates has to move with the page. Rotated A4 is about 842 points wide instead of 595, so a footer paragraph pinned near the right edge needs a different x. Tables and images sized to the content width adjust themselves.

Refer to our guide for creating landscape report.