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PDF generation and DPI of it
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| When you create a PDF can you specify what DPI you want it to be? When you
add an existing image to a blank PDF, is the DPI of the image saved?
Can someone push me in a right direction with DPI in PDFs please.
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| Philip Ronan 2005-02-24, 3:56 pm |
| Hello wrote:
> When you create a PDF can you specify what DPI you want it to be? When you
> add an existing image to a blank PDF, is the DPI of the image saved?
>
> Can someone push me in a right direction with DPI in PDFs please.
PDF files aren't bitmap images, so they don't have any particular dpi value.
You can embed bitmap images *inside* a PDF file, but the DPI of these
embedded images is an attribute of the images themselves, not the PDF file.
So you could quite easily make a PDF file containing a 72 dpi JPEG image and
a 300 dpi TIFF image on the same page.
--
phil [dot] ronan @ virgin [dot] net
http://vzone.virgin.net/phil.ronan/
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| Thank you for clarification.
However, I have another question. If in PHP (meaning with PHP's PDF library)
when I will insert a picture into a new blank PDF, a 300DPI JPG, will the
JPG's header including DPI info be transfered intact? Also, will it try to
re-compress an image?
Basically, the question is, if I'll use pdf_open_image() will it make any
changes to the image header or data while inserting it into a PDF?
"Philip Ronan" <invalid@invalid.invalid> wrote in message
news:BE43A43E.2BD09%invalid@invalid.invalid...
> Hello wrote:
>
>
> PDF files aren't bitmap images, so they don't have any particular dpi
> value.
> You can embed bitmap images *inside* a PDF file, but the DPI of these
> embedded images is an attribute of the images themselves, not the PDF
> file.
> So you could quite easily make a PDF file containing a 72 dpi JPEG image
> and
> a 300 dpi TIFF image on the same page.
>
> --
> phil [dot] ronan @ virgin [dot] net
> http://vzone.virgin.net/phil.ronan/
>
>
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| Philip Ronan 2005-02-24, 3:56 pm |
| Hello wrote:
> Thank you for clarification.
>
> However, I have another question. If in PHP (meaning with PHP's PDF library)
> when I will insert a picture into a new blank PDF, a 300DPI JPG, will the
> JPG's header including DPI info be transfered intact? Also, will it try to
> re-compress an image?
> Basically, the question is, if I'll use pdf_open_image() will it make any
> changes to the image header or data while inserting it into a PDF?
I don't know. But it shouldn't have to. When a JPEG file is inserted into a
PDF file, the actual JPEG data doesn't have to be changed one bit.
Why don't you try it and see what happens?
--
phil [dot] ronan @ virgin [dot] net
http://vzone.virgin.net/phil.ronan/
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