Bad quality export to PNG

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LearningByDoodling
Posts: 13
Joined: Mon Apr 28, 2014 2:33 pm
Location: Sweden

Bad quality export to PNG

Postby LearningByDoodling » Sat May 24, 2014 8:35 pm

Hi!

I just exported my new logo i created in Inkscape to a large bitmap ca 1000x1000px and the end result was horrible. I haven't seen these issues before...
    The colours are noisy (especially the shadows) and
    The seams between objects are visible even though there is no space between them

In inkscape:
Image

Exported version:
Image

It lookes like ordinary jpg-compression issues but I can't find any quality settings to change. Are there any settings I need to tweak somewhere?
Regarding the seam-issue I can live with the fact that Inkscape shows the border between the objects but this shouldn't be visible in the export. It makes no sense... And no, I dont have stroke on the objects.
Windows 7, Wacom Bamboo Fun Pen and Touch Medium (2011), Inkscape 0.48 + devel r13348
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ragstian
Posts: 1181
Joined: Thu Oct 11, 2012 2:44 am
Location: Stavanger-Norway

Re: Bad quality export to PNG

Postby ragstian » Sat May 24, 2014 11:30 pm

Hi.

Both your issues are most likely due to the fact that your objects are not pixel-aligned.

Do a search here on the forum for 'pixel snap' or 'export quality'.

To pixel snap an object; Extensions - Modify Path - Pixel Snap.

Good Luck
RGDS
Ragnar
Good Luck!
( ͡° ͜ʖ ͡°)
RGDS
Ragnar
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LearningByDoodling
Posts: 13
Joined: Mon Apr 28, 2014 2:33 pm
Location: Sweden

Re: Bad quality export to PNG

Postby LearningByDoodling » Sun May 25, 2014 12:19 am

Thanks Ragnar!

I've tried this now and at first I thought it worked to solve the seam-issue... but it simly created overlap. When rearranging the nodes to actually snap to the SAME "pixels" (not making the objects to overlap) the issue came back.

Inkscape with Pixel Snapped objects:
Image

Bitmap export of Pixel snapped vectors:
Image

And the noise colors was not effected at all.

It doesn't make sense that I can make better exports by just taking screen dumps...
Windows 7, Wacom Bamboo Fun Pen and Touch Medium (2011), Inkscape 0.48 + devel r13348
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hulf2012
Posts: 716
Joined: Sat Nov 24, 2012 12:37 pm

Re: Bad quality export to PNG

Postby hulf2012 » Sun May 25, 2014 12:55 am

Hello:

For exporting are you using this dialog?:
http://tavmjong.free.fr/INKSCAPE/MANUAL ... Export-PNG
-Try to change the DPI or bitmap size.
- Try to put or scale or move your image in rounded or integer pixel sizes


About the seam-issue:
It's a known bug (or special feature :roll: ) of inkscape. You can hide that putting a shape of the same colour, behind or over the junction of the shapes. Also I think that if you duplicate (Ctrl+D) your design, the visualization of the problem improves.
I assume that you are using Inkscape 0.48. It's supposed that on Inkscape 0.91 (the next realease), that issue would be solved or at least mitigated. GO to
http://www.inkscape.org/en/download/
and search for the development version for your system (hope is not Mac OS!)
If you have problems:
1.- Post a sample (or samples) of your file please.
2.- Please check here:
http://tavmjong.free.fr/INKSCAPE/MANUAL/html/index.html
3.- If you manage to solve your problem, please post here your solution.
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Maestral
Posts: 982
Joined: Sat Aug 27, 2011 7:10 am

Re: Bad quality export to PNG

Postby Maestral » Sun May 25, 2014 12:57 am

* hulf2012 was faster /

I presume you`re showing us screenshots, but could you please tell us how much did you zoomed in and what settings did you use while exporting bitmaps?
:tool_zoom: <<< click! - but, those with a cheaper tickets should go this way >>> :!:
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LearningByDoodling
Posts: 13
Joined: Mon Apr 28, 2014 2:33 pm
Location: Sweden

Re: Bad quality export to PNG

Postby LearningByDoodling » Sun May 25, 2014 1:49 am

Solved!

Thanks for the explenation on the seam-issue. I'll download the dev version and try that. :-)

Regarding the noisy colors:

Yes! That's the export dialog I use.

The images are not zoomed in at all. Just taken as is, by the snippet tool.

Inkscape page size: 3200x1800
Export bitmap size: 1920x1080 (54dpi)

But now when I was double checking I seem to have found a bug in Windows. I used explorer to set the image as wallpaper. Right click image choose "set as wallpaper" and the result was terrible (as I've demonstarted). Now when I looked at the image with ACDSee the colors are perfect and crisp.
I can even replicate this issue and I'm not using the wrong image. I've tripple checked. Really strange!!!

But now I have crisp desktop image put there by ACDSee. :-)

I just have to fix the seam-issue. ;-)

Lots of thanks to you all! You are the best!
Last edited by LearningByDoodling on Sun May 25, 2014 8:15 am, edited 1 time in total.
Windows 7, Wacom Bamboo Fun Pen and Touch Medium (2011), Inkscape 0.48 + devel r13348
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Lazur
Posts: 4717
Joined: Tue Jun 14, 2016 10:38 am

Re: Bad quality export to PNG

Postby Lazur » Sun May 25, 2014 3:55 am

You could fix the rendering issue by avoiding such seams.
A possible solution is attached.
Attachments
vector2x.svg
(5.93 KiB) Downloaded 201 times
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LearningByDoodling
Posts: 13
Joined: Mon Apr 28, 2014 2:33 pm
Location: Sweden

Re: Bad quality export to PNG

Postby LearningByDoodling » Sun May 25, 2014 8:12 am

Yes indeed Lazur!

But this is just a small part of the entire logo which is a band that overlaps itself a few times and the parts need different fill effects. I can reduce the number of seams but not eliminate them.
A feasible workaround is definitely to make some overlap. But I would like to avoid workarounds as far as possible.

I'll try the dev version tomorrow and report my results. :-)
Windows 7, Wacom Bamboo Fun Pen and Touch Medium (2011), Inkscape 0.48 + devel r13348
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LearningByDoodling
Posts: 13
Joined: Mon Apr 28, 2014 2:33 pm
Location: Sweden

Re: Bad quality export to PNG

Postby LearningByDoodling » Sun May 25, 2014 5:43 pm

Ok. Now I've tried the same thing with v 0.48 dev r13348 and I still get the same result. PixelSnap enabled on objects. :-(
I guess I have to make some overlap.

In Inkscpae:
Image

From bitmap export:
Image

I also found a bug in the bitmap export but I can't find the bug reporting page. The URL from the download page (http://inkscape.org/en/report_bugs.html
Windows 7, Wacom Bamboo Fun Pen and Touch Medium (2011), Inkscape 0.48 + devel r13348
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Lazur
Posts: 4717
Joined: Tue Jun 14, 2016 10:38 am

Re: Bad quality export to PNG

Postby Lazur » Sun May 25, 2014 8:35 pm

Probably that is a known issue, may worth a check if it's already listed before reporting here:
https://bugs.launchpad.net/inkscape/
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