Blur doesn't count when sizing page to fit drawing

Bug #168349 reported by Bug Importer
28
Affects Status Importance Assigned to Milestone
Inkscape
Fix Released
High
Unassigned

Bug Description

When you blur an object and then set the document properties to fit the
page to the drawing, part of the blur goes outside the page boarders.

Revision history for this message
Molumen (molumen) wrote :

Originator: NO

Yes, this is quite annoying, as this behaviour also occurs when exporting
selected blurred objects: the blur is cutted at the edge of the object.
Shouldn't be the bounding box recalculated for blurred objects?

Revision history for this message
Bryce Harrington (bryce) wrote :

Originator: NO

molumen, could you also attach an example document that shows the problem?

Revision history for this message
pbhj (pbhj) wrote :

Originator: NO

I don't know for sure, but I expect it's mathematically impossible to
bound it.

Gaussian blur appears to be an asymptotically decreasing pixel density and
so is bounded at infinity, ie the bounding box would be infinitely large.

From wikipedia (http://en.wikipedia.org/wiki/Gaussian_blur)

"In theory, the distribution at every point on the image will be non-zero,
meaning that the entire image would need to be included in the calculations
for each pixel. In practice, when computing a discrete approximation of the
Gaussian function, pixels outside of approximately 3σ are small enough to
be considered effectively zero."

It's probably better to describe the effect that you wish to see instead?

For blurred objects you could create an invisible object spanning the area
you wish to export and export that instead - not ideal I guess; perhaps an
option in the export dialog is needed for "include gaussian blur to a
distance of n standard deviations".

Revision history for this message
Molumen (molumen) wrote :

Originator: NO

Bryce, I cannot upload stuff here since I'm not the starter of the thread,
so pease download the files from here:
www.lumenstudio.net/if/blur_outside_of_page.tar.gz

The SVG features a blue blurred circle. I used the "fit page to selection"
function to resize the page at the object's size. When exporting the page
area, the blur is cutted (see png file from the .tar.gz archive). The same
cut of the blurred area occurs when exporting a selected object.

A quick workaround is to create an invisible object that is bigger than
the object's blur area, but it is not very productive...
Would be great to have that fixed somehow...

Revision history for this message
Bryce Harrington (bryce) wrote :

Originator: NO

Thanks Molumen, I've attached the file.

Also, since you've been so helpful with Inkscape bugs, I've granted you
tech & admin permissions in the Inkscape tracker. This will give you more
capabilities to assist with bugs, such as attaching files, prioritizing,
and updating status.

Bryce
File Added: blur_outside_of_page.tar.gz

Revision history for this message
Molumen (molumen) wrote :

Originator: NO

Thanks Bryce!

Revision history for this message
Prokoudine (prokoudine) wrote :

Originator: NO

Confirmed on SVN revision 16423

Changed in inkscape:
importance: Medium → High
status: New → Confirmed
Revision history for this message
Caleb Reach (jtxx000-gmail) wrote :
Changed in inkscape:
status: Confirmed → Fix Committed
Revision history for this message
bbyak (buliabyak) wrote :

just checked and it works as expected in rev 18034, without the patch, so closing

Changed in inkscape:
status: Fix Committed → Fix Released
Revision history for this message
Caleb Reach (jtxx000-gmail) wrote :

Fit to page doesn't seem to work in latest revision if nothing is selected. Here's a (slightly hacky) patch.

Changed in inkscape:
status: Fix Released → Fix Committed
Revision history for this message
bbyak (buliabyak) wrote :
Changed in inkscape:
status: Fix Committed → Fix Released
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