2001.02.09 14:13 "turning TIFF Images", by Juergen Braukmann

2001.02.09 19:21 "Re: turning TIFF Images", by Alex

Hi Juergen,

As a PostScript expert here I can recommend to convert the TIFF to PostScript and use rotate operator. This is a fine approach if you want to print your map.

if you want to get another TIFF or display the result on the screen you need to write a simple program that iterates over the rotated image and picks pixels from the source image. This is simple approach but it can be slow.

At small angle rotation can be done as 2 shifts in X and Y direction proportional to the distance to the row or column. This is a simple operation that can easily use processor-specific tricks to shuffle bits around.

Regards,
Alex