Re: [Inkscape-devel] pdf - blur/filter support ?
I feared that someone would say this. Probably we have to fall-back into a kind of rasterizer in order to realize those features. Same scary story to alpha/transparency on PS output. Uh ...,
Adib.
Stathis Sideris schrieb:
Not sure whether blur can be supported natively in PDF, but I know that other programs (such as Illustrator for example) seem to handle this by "rasterising" the blur (and other effects) by the use of numerous little boxes (vector "pixels"!) that approximate the effect. Needless to say that the inclusion of such "rasterised" effects results in significantly larger files.
Adib Taraben wrote:
Hello,
I wonder whether pdf has the ability to output blur/filter natively. I do a lot now with blur like shadows but the exported pdf is not the same. I already downloaded the pdf reference but there might be to much pages so I did not found the reference.
I am looking for something that corresponds to svg filters. Could someone point me to the right direction ?
Thx,
Adib.
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On 2007-June-09 , at 17:38 , Adib Taraben wrote:
I feared that someone would say this. Probably we have to fall-back into a kind of rasterizer in order to realize those features. Same scary story to alpha/transparency on PS output. Uh ...,
Quartz (the equivalent of Cairo on Mac OS X) produces pdfs with drop- shadows that look quite like vector effects rather than raster blurs to me. These are two examples produced from an Export to PDF (1) and Print to PDF (2): http://jo.irisson.free.fr/dropbox/inkscape/quartz_pdf_1.pdf http://jo.irisson.free.fr/dropbox/inkscape/quartz_pdf_2_print.pdf I already looked at PDFs produced by quartz on other platforms and the blur was still there. Maybe that could be a lead in the right direction.
Stathis Sideris schrieb:
Not sure whether blur can be supported natively in PDF, but I know that other programs (such as Illustrator for example) seem to handle this by "rasterising" the blur (and other effects) by the use of numerous little boxes (vector "pixels"!) that approximate the effect. Needless to say that the inclusion of such "rasterised" effects results in significantly larger files.
Adib Taraben wrote:
Hello,
I wonder whether pdf has the ability to output blur/filter natively. I do a lot now with blur like shadows but the exported pdf is not the same. I already downloaded the pdf reference but there might be to much pages so I did not found the reference.
I am looking for something that corresponds to svg filters. Could someone point me to the right direction ?
JiHO --- http://jo.irisson.free.fr/
Tue, 12 Jun 2007 23:44:06 +0200 jiho <jo.irisson@...400...> kirjoitti:
Quartz (the equivalent of Cairo on Mac OS X) produces pdfs with drop- shadows that look quite like vector effects rather than raster blurs to me. These are two examples produced from an Export to PDF (1) and Print to PDF (2): http://jo.irisson.free.fr/dropbox/inkscape/quartz_pdf_1.pdf http://jo.irisson.free.fr/dropbox/inkscape/quartz_pdf_2_print.pdf I already looked at PDFs produced by quartz on other platforms and the blur was still there. Maybe that could be a lead in the right direction.
Seems like a raster blur to me, with a quite low resolution too.
It looks like most pdf viewers apply bilinear or better filtering when enlarging images. With blur, this filtering is not apparent. If you look at those round edges in letters (especially o) you can notice, they're slightly jagged. Or if you try those with kpdf, which seems to use nearest neighbour filtering, the raster blocks are quite obvious.
Actually, this is the same thing Inkscape does when rendering blur with anything but the best quality: blur a smaller version of the image and then enlarge it to original size with bilinear filtering. It seems quite correct, too.
On 2007-June-13 , at 09:35 , Niko Kiirala wrote:
Tue, 12 Jun 2007 23:44:06 +0200 jiho <jo.irisson@...400...> kirjoitti:
Quartz (the equivalent of Cairo on Mac OS X) produces pdfs with drop- shadows that look quite like vector effects rather than raster blurs to me. These are two examples produced from an Export to PDF (1) and Print to PDF (2): http://jo.irisson.free.fr/dropbox/inkscape/quartz_pdf_1.pdf http://jo.irisson.free.fr/dropbox/inkscape/quartz_pdf_2_print.pdf I already looked at PDFs produced by quartz on other platforms and the blur was still there. Maybe that could be a lead in the right direction.
Seems like a raster blur to me, with a quite low resolution too.
It looks like most pdf viewers apply bilinear or better filtering when enlarging images. With blur, this filtering is not apparent. If you look at those round edges in letters (especially o) you can notice, they're slightly jagged. Or if you try those with kpdf, which seems to use nearest neighbour filtering, the raster blocks are quite obvious.
Actually, this is the same thing Inkscape does when rendering blur with anything but the best quality: blur a smaller version of the image and then enlarge it to original size with bilinear filtering. It seems quite correct, too.
Indeed, sorry to have leaded you in the wrong way. I opened the pdf in Adobe Reader and zooming on the letters shows the raster nature of the blur pretty obviously. Previously I only checked in Adobe Reader that the blur was there and used only Preview (the PDF viewer of OS X) to zoom in. It seems Preview is optimized for this kind of blur since the pixels are much less visible with it that with Adobe Reader. So rasterizing seems to be the way to go indeed.
JiHO --- http://jo.irisson.free.fr/
I just can keep on telling you: it does work. Even if this particular example doesn't do the job: Exporting from InDesign does. I sent Adib a PDF, that clearly shows this in my opinion. Evince however, cannot display it and displays a semi-transparent black box instead. Curiously, the semi-transparent box that _is_ in the document is displayed without the transparency :D
Greetings
David
On Tue, 2007-06-12 at 23:44 +0200, jiho wrote:
On 2007-June-09 , at 17:38 , Adib Taraben wrote:
I feared that someone would say this. Probably we have to fall-back into a kind of rasterizer in order to realize those features. Same scary story to alpha/transparency on PS output. Uh ...,
Quartz (the equivalent of Cairo on Mac OS X) produces pdfs with drop- shadows that look quite like vector effects rather than raster blurs to me. These are two examples produced from an Export to PDF (1) and Print to PDF (2): http://jo.irisson.free.fr/dropbox/inkscape/quartz_pdf_1.pdf http://jo.irisson.free.fr/dropbox/inkscape/quartz_pdf_2_print.pdf I already looked at PDFs produced by quartz on other platforms and the blur was still there. Maybe that could be a lead in the right direction.
Stathis Sideris schrieb:
Not sure whether blur can be supported natively in PDF, but I know that other programs (such as Illustrator for example) seem to handle this by "rasterising" the blur (and other effects) by the use of numerous little boxes (vector "pixels"!) that approximate the effect. Needless to say that the inclusion of such "rasterised" effects results in significantly larger files.
Adib Taraben wrote:
Hello,
I wonder whether pdf has the ability to output blur/filter natively. I do a lot now with blur like shadows but the exported pdf is not the same. I already downloaded the pdf reference but there might be to much pages so I did not found the reference.
I am looking for something that corresponds to svg filters. Could someone point me to the right direction ?
JiHO
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On Wed, 13 Jun 2007 20:16:18 +0200, David Christian Berg <david@...407...> wrote:
I just can keep on telling you: it does work. Even if this particular example doesn't do the job: Exporting from InDesign does. I sent Adib a PDF, that clearly shows this in my opinion. Evince however, cannot display it and displays a semi-transparent black box instead. Curiously, the semi-transparent box that _is_ in the document is displayed without the transparency :D
Not to be a wet blanket, but the PDF specification doesn't provide for filters at all; the specification is publicly available, so you can verify this yourself. What you're seeing for the shadow here appears to be a high-resolution (but very compressable) greyscale image. (It's more evident on the text, where the shadow image is not as high-resolution for some reason.)
-mental
OK, I checked, and really cannot find anything :( After reading it, I assume that there is a "soft mask" applied to a black object with a high rest b/w image as soft mask. Then, I'd however also suggest to do this, where possible... however: how do we judge? what cases does it work for?
Sorry for being so stubborn, but it really, really looks like a real blur in my file and the fact that evince cannot display it, reassured me.
Greetings!
David
On Wed, 2007-06-13 at 12:07 -0700, MenTaLguY wrote:
On Wed, 13 Jun 2007 20:16:18 +0200, David Christian Berg <david@...407...> wrote:
I just can keep on telling you: it does work. Even if this particular example doesn't do the job: Exporting from InDesign does. I sent Adib a PDF, that clearly shows this in my opinion. Evince however, cannot display it and displays a semi-transparent black box instead. Curiously, the semi-transparent box that _is_ in the document is displayed without the transparency :D
Not to be a wet blanket, but the PDF specification doesn't provide for filters at all; the specification is publicly available, so you can verify this yourself. What you're seeing for the shadow here appears to be a high-resolution (but very compressable) greyscale image. (It's more evident on the text, where the shadow image is not as high-resolution for some reason.)
-mental
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participants (5)
-
Adib Taraben -
David Christian Berg -
jiho -
MenTaLguY -
Niko Kiirala