Hi *,
as mentioned in [1] I have now finished and reintegrated the first
version of the Svg replacement from the branch [2] to trunk after
uptating and building Mac and Win versions. It is stable and works well
and is also pretty complete from an Svg point of view. Main
features/differences to the version which was in OOo3.4beta are:
- IP clearance: This change allowed to remove six Gpl/Lgpl libs, namely
librsvg, libcroco, libgsf, gdk-pixbuf, glib, and pango gettext. These
were used as an external renderer. The new Svg uses an internal
interpreter in a new library and some services.
- File Format: In Odf, Svg is now embedded to the Pictures folder as one
would expect and can be easily extracted. There is also a Png file
written there as replacement image. The draw:frame is now multi-image
capable (as the spec allows). In the case of a Svg it writes a good
quality Png and the original Svg as draw:image elements. Since older
(and other) office versions are only capable of loading a single (and
thus the first) image, the Png is written first. This allows file
exchange with other and older offices. At load time, multi-image support
will choose the best quality graphic available for further work, e.g.
preferring vector format over pixel format, pixel format with
transparency over non-transparent and loss less formats over those with
losing info (you get the idea). Other Odf implementations (e.g. a
viewer) may just use the pixel graphic available. Multi-image support is
independent from Svg in principle and will work with all image file
formats. This is implemented for the Drawinglayer graphic object (used
in Draw/Impress/Calc) and the Writer graphic object (used in Writer).
- Interpretation: Svg is no longer interpreted each time it needs to be
rendered (as by an extrenal renderer), but only once transformed to a
sequence of primitives. That sequence is then used for all outputs,
transformed to the graphic object form and viewport (resolution). The
sequence itself is completely view-independent. Internally, it is reused
and thus it makes no difference if you have your Svg graphic added once
or multiple times to your document. The same is true for the replacement
Png image used. Both, the sequence of primitives and the replacement
image are created using new Uno Api services. One is capable of
converting an io::XInputStream to a sequence of primitives, the other is
able to convert every sequence of primitives to a rendering::XBitmap
with given Dpi and discrete sizes (pixels, with automatic resolution
reduction to a given maximum square pixel count). This will be useful
for other purposes, too, since it creates a fully alpha-capable
representation of anything in primitive format to use as e.g. sprite.
- Quality: For all graphic processing the created vector graphic in form
of sequence of primitives is used. This means that You will get best
quality in all zoom situations and all resolutions. This is also true
for all exports, e.g. printing or Pdf export which also use the vector
format. With an external renderer, it is unavoidable to use bitmaps with
discrete solution here, not only looking bad in high resolutions, but
also needing more space in most cases. There is one caveat since not all
paths here already use primitives; some will use the internal MetaFile
format in-between (One more reason for more reworks to primitive usages
in the future).
- Completeness: I implemented most Svg features from Svg1.1, but not yet
using animations or interactions (but possible in the future due to an
own interpreter, impossible with an extern Svg renderer). It supports
all geometric Svg forms. It supports Gradients (using a new primitive
for this which can be reused when we want to add Svg gradients to
SdrObjects one day), these have a resolution-dependent low-level format
to not waste runtime on low resolutions. It supports Masks, clipPath,
Markers, linked content, embedded graphics and Svg (intern, extern,
base64), Use nodes, Text, Text on curve and patterns. It does not yet
support filters, color profiles, embedded scripts, interactions and
linking. These can be added when needed, most of them will need to
implement new basic primitives (e.g. filtering) which would be useful
anyways.
- Side effects: I had to fix cropping (unified with new primitive) which
works now also for mirrored graphics (vecer worked) and quite some other
stuff. We are prepared for Svg gradients as possible future feature (we
can already render them now). You can work with an added Svg as with an
graphic object; crop it, Break it (To SdrObjects, limited to the
transfer over the old MetaFile format, though). You can convert an
inserted Tux to 3D, You can bend the Svg in vector quality in Draw. It
is possible to directly export the original Svg again by selecting the
object and using 'Save as Picture...'. You can add Text, Border, fill
style, pretty much the same as most other graphic objects. You can add
shadow which casts shadow as expected (also never possible with an
external renderer).
- Caveats: This is a bigger change, but most stuff is isolated in the
two mentioned services. There will be errors (I'm too long a programmer
to deny that :-)), but I tried to be as careful as possible. To find
them, Your help will be needed. Please feel free to play around with any
Svg You can find and report problems early.
[1]
http://mail-archives.apache.org/mod_mbox/incubator-ooo-dev/201112.mbox/%[email protected]%3E
[2]
https://svn.apache.org/repos/asf/incubator/ooo/branches/alg/svgreplacement
Sincerely,
Armin
--
ALG
- Ip Clearance: 1st version of Svg replacement available Armin Le Grand
-
