[gdal-dev] geospatialPDF DPI and EXTRA_IMAGES

[Luca Delucchi]

On 19 May 2015 at 10:37, Even Rouault <even.rouault at spatialys.com> wrote:
>
> Luca,
>

Hi Even,

I'm back on this topic because it seems that EXTRA_IMAGES is not
working (at least for me) with GDAL 1.11.3

ogr2ogr -f PDF -lco COMPRESS=Deflate -lco DPI=72 -lco WRITE_INFO=NO
-lco EXTRA_IMAGES=23hq.jpg,100,100,1 /tmp/provaogr2ogr.pdf idrlag.shp

> According to the doc, "x and y are in user units from the lower left corner of
> the page"
>
> If you set a DPI < 72, GDAL will correct it to DPI = 72 since AFAIR, this is
> the minimum accepted value by the PDF spec (not sure of that though).
>
> And since 1 user unit  = DPI / 72, if you increase the DPI, you must divide
> the offset by DPI / 72 so that the image stays at the same location in term of
> pixels.
>
> From the PDF spec:
> """UserUnit
> number
> (Optional; PDF 1.6) A positive number giving the size of default user space
> units, in multiples of 1 ⁄ 72 inch. The range of supported values is
> implementation-dependent; see implementation note 177 in Appendix H.
> Default value: 1.0 (user unit is 1 ⁄ 72 inch).
> """
>

Thanks for explanation, it is clear and it was working sometime ago

> Even
>

-- 
ciao
Luca

www.lucadelu.org