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Posted to batik-users@xmlgraphics.apache.org by pe...@gresham-forms.co.uk on 2004/08/27 15:58:07 UTC
quality issue with svg barcodes on printer with less than 600dpi
Hello,
When I print small interleaved 2 of 5 barcodes on printers with less than
600dpi from my application I am getting quality problems.
The barcode has 14 digits and has to fit on a label 35mm wide. I am using
Krysalis Barcode (now Barcode4J) to generate the barcode svg.
My attached sample svg has 2 barcodes side by side, they look identical when
viewed in Squiggle but are not identical when printed at a resolution of
300dpi or less.
With printers that have 300 dpi or less I find that the bar widths can be
smaller or larger by one printer dot, likewise the rendered position of the
line can also vary by a dot in either direction. Although the barcodes scan,
they can be of very variable quality when checked with a barcode verifier
(ranging from grade B to F). I frequently find that the barcode on the left
scans as B and the one on the right fails as an F.
The bars are perfect when printed on printers with 600+ dpi and scan as
grade A.
Is there anything I can do to improve things ?
<<f1.svg>>
Thanks,
Patrick
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Re: quality issue with svg barcodes on printer with less than 600dpi
Posted by Jeremias Maerki <de...@greenmail.ch>.
I'm Barcode4J's main author and may be ableto add a bit to this. I think
Thomas is probably right with his suspicion. I'm not sure if it helps
but also look at http://barcode4j.krysalis.org/troubleshooting.html for
a checklist when barcodes don't read.
And I've learned from Thomas during the last few weeks how "real world
units" are suboptimal within SVG files. I'll change the SVG generator in
Barcode4J shortly to use a viewBox and a logical unit space. FWIW, I'm
working to release Barcode4J 1.0 final within 2 or 3 weeks. But I should
have the changes for the SVG generation in by tomorrow evening (CEST) in
the codebase (accessible using CVS).
The suboptimal SVG code generated worked fine in Apache FOP (for which
the whole thing was written in the first place) but is obviously flawed
for SVG-embedded-in-SVG scenarios.
On 29.08.2004 02:32:13 Thomas DeWeese wrote:
> Hi Pegan,
>
> I suspect that this is an aliasing issue. This basically
> means that the width of your bar codes might be 3.5 pixels
> wide, does the renderer draw 3 or 4 pixels. In this case
> the most likely problem is that the bar is 4 pixels wide
> but it starts on 1/2 a pixel, this means that the renderer
> needs to decide if it should render 5 pixels, 4 pixels or
> 3 pixels. The way the barcode is currently specified it
> is difficult to know.
>
> You may not be aware but the use of 'real world units' like 'mm'
> means essentially nothing except on the width/height of the outermost
> SVG element. For all other contexts the mapping from the real world
> units to userspace units is fixed.
>
> pegan@gresham-forms.co.uk wrote:
>
> > When I print small interleaved 2 of 5 barcodes on printers with less
> > than 600dpi from my application I am getting quality problems.
> >
> > The barcode has 14 digits and has to fit on a label 35mm wide. I am
> > using Krysalis Barcode (now Barcode4J) to generate the barcode svg.
> >
> > My attached sample svg has 2 barcodes side by side, they look identical
> > when viewed in Squiggle but are not identical when printed at a
> > resolution of 300dpi or less.
> >
> > With printers that have 300 dpi or less I find that the bar widths can
> > be smaller or larger by one printer dot, likewise the rendered position
> > of the line can also vary by a dot in either direction. Although the
> > barcodes scan, they can be of very variable quality when checked with a
> > barcode verifier (ranging from grade B to F). I frequently find that
> > the barcode on the left scans as B and the one on the right fails as an F.
> >
> > The bars are perfect when printed on printers with 600+ dpi and scan as
> > grade A.
> >
> > Is there anything I can do to improve things ?
> > <<f1.svg>>
> > Thanks,
> > Patrick
Jeremias Maerki
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Re: quality issue with svg barcodes on printer with less than 600dpi
Posted by Thomas DeWeese <Th...@Kodak.com>.
Hi Pegan,
I suspect that this is an aliasing issue. This basically
means that the width of your bar codes might be 3.5 pixels
wide, does the renderer draw 3 or 4 pixels. In this case
the most likely problem is that the bar is 4 pixels wide
but it starts on 1/2 a pixel, this means that the renderer
needs to decide if it should render 5 pixels, 4 pixels or
3 pixels. The way the barcode is currently specified it
is difficult to know.
You may not be aware but the use of 'real world units' like 'mm'
means essentially nothing except on the width/height of the outermost
SVG element. For all other contexts the mapping from the real world
units to userspace units is fixed.
pegan@gresham-forms.co.uk wrote:
> When I print small interleaved 2 of 5 barcodes on printers with less
> than 600dpi from my application I am getting quality problems.
>
> The barcode has 14 digits and has to fit on a label 35mm wide. I am
> using Krysalis Barcode (now Barcode4J) to generate the barcode svg.
>
> My attached sample svg has 2 barcodes side by side, they look identical
> when viewed in Squiggle but are not identical when printed at a
> resolution of 300dpi or less.
>
> With printers that have 300 dpi or less I find that the bar widths can
> be smaller or larger by one printer dot, likewise the rendered position
> of the line can also vary by a dot in either direction. Although the
> barcodes scan, they can be of very variable quality when checked with a
> barcode verifier (ranging from grade B to F). I frequently find that
> the barcode on the left scans as B and the one on the right fails as an F.
>
> The bars are perfect when printed on printers with 600+ dpi and scan as
> grade A.
>
> Is there anything I can do to improve things ?
> <<f1.svg>>
> Thanks,
> Patrick
>
>
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