[gdal-dev] Anchor point in PDF EXTRA_IMAGES

[Jukka Rahkonen]

Hi,

In the PDF creation option parameter EXTRA_IMAGES=image_file_name,x,y,scale the
anchor point (x,y) is in the lower left corner of the resulting PDF file.
However, the anchor point of the extra images to be added seems to be in the
upper left corner. If someone tries to use this parameter as
EXTRA_IMAGES=logo.png,1,1,1 the top left pixel of logo.png will be placed at the
lower lext pixel of the PDF file. Thus the logo.png will never come into PDF
because it is draws totally below the PDF print area.

Could it be possible to make EXTRA_IMAGES and the actual images to understand
anchor points in a similar way? Either so that
EXTRA_IMAGES=image_file_name,x,y,scale takes also the top left coordinates, or
if it continues to use lower left anchor point then the PDF driver is placing
the lower left pixel of the extra image to that place.

The curret behaviour is somewhat surprising. At minimum the document page should
mention this somehow, for example as

"Notice, that x and y are in user units from the lower left corner of the page.
Use some reasonably high value for y or otherwise the extra image will slide out
of the PDF page".


-Jukka Rahkonen-