Our image is 256 x 256 but the display area size is bigger than that, saying 512 x 512.
When we do annotation, should the annotations (text/lines) be inside the 256 x 256 area or they can be put outside the 256 x 256 image area?
If we put the annotation outside the 256 x 256 area, how other viewers with only 256 x 256 display area can display the images with these annotations?
Or these annotations are not for next viewers to display and they are for GSPS and SR only?
I think the answer may be found in:
ftp://medical.nema.org/medical/dicom/final/sup120_ft.pdf
tag 0070,0282 "Compound Graphic Units" is an enumerated value that is either "PIXEL" or "DISPLAY"
If it is "PIXEL", it seems your coordinates must be within the range 0\0 to Columns\Rows. (Quoted from the tag description).
If it is "DISPLAY", then the values must be within the range 0.0 to 1.0, and they are fractions of the "Displayed Area"
Displayed Area is a separate IOD you can find around page 1200 in
http://medical.nema.org/Dicom/2011/11_03pu.pdf
I think you can define the Displayed Area to be whatever you want and you can specify if you want the underlying image to scale or magnify etc according to the "Presentation Size Mode" tag.
I imagine you will find some viewers support this better than others...