libicon: Fix dangling references to VertexSource in PathTransformer

PathTransformer keeps a reference to the VertexSource used (which can be
either another PathTransformer, or the base path for a shape). When a
shape is cloned, this should be retargetted to the new object in the
clone.

However, references are not settable, and so, what would happen instead
is the original (non-cloned) vertex source was reinitialized (through
the default implementation of the assignment operator) using data from
the clone, and the clone would still point to it. Then, if the original
object is deleted, the clone would point to freed memory.

To avoid this problem, replace the reference with a pointer (which can
be set to point elsewhere, as the code intended to do). To make sure
this does not happen again, make the VertexSource copy constructor and
assignment operator private, and deleted when the compiler supports
that.

Fixes #18577

Change-Id: I8870d9471c5064e922a84eff8447cbda783b13e6
Reviewed-on: https://review.haiku-os.org/c/haiku/+/7052
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Zardshard <0azrune6@zard.anonaddy.com>

Icon-O-Matic: Add perspective transformations

As part of adding perspective transformations, agg_trans_perspective.h
was patched to fix a multiple definitions error. This change has been
submitted for review to the "upstream" repositories at [1], [2],
and [3].

Also includes various other improvements such as VertexSource being
split into its own file, code style improvements, and documentation
improvements.

[1] https://sourceforge.net/p/agg/patches/6/
[2] https://github.com/ghaerr/agg-2.6/pull/9
[3] https://github.com/aggeom/agg-2.6/pull/7

Change-Id: I4bffd2f87354bde10155e23145a232a925be6ff3
Reviewed-on: https://review.haiku-os.org/c/haiku/+/6801
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>

* Merged weak-symbols branch.
* Fixed trivial merge conflict in src/system/libroot/posix/locale/nl_langinfo.cpp
* Fixed gcc 2 compilation of src/system/glue/init_term_dyn.c.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@39571 a95241bf-73f2-0310-859d-f6bbb57e9c96

Enable just enough of the message based format used in Icon-O-Matic to allow
BIconUtils to understand and render it. This makes it possible to use the
HVIFTranslator to also read Icon-O-Matic files out of the box. Will cleanup
now duplicated files next.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@30794 a95241bf-73f2-0310-859d-f6bbb57e9c96

* make sure that the ApproximationScale() implementation of any Transformer
not negative
* PathSource can now remember a global scale, and the IconRenderer sets
it, since this value is used in the curve converter for on the fly
generation of vertices, this change does not affect anything and doesn't
create the need to "update" the conversion pipeline to render an icon at
different sizes (like Icon-O-Matic does)

-> this change fixes edgy curves on icons rendered bigger than 64x64 as
reported by Axel some time ago


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@23093 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Put the remaining libicon.a classes into the BPrivate::Icon namespace.
* Minor cleanup (like removing the extra blank line between the copyright and the
header guard).


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@20507 a95241bf-73f2-0310-859d-f6bbb57e9c96

* min/max visibility scale is now between 0 and 4
* flat icon format optimizes for grays in styles


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@18508 a95241bf-73f2-0310-859d-f6bbb57e9c96

* moved all the classes actually needed for reading a
vector icon to this place, #ifdef'd out all the editing
features (listening, referencing, converting to
PropertyObject... etc)
* TODO: put into BPrivate namespace...


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@18396 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Merged weak-symbols branch.
* Fixed trivial merge conflict in src/system/libroot/posix/locale/nl_langinfo.cpp
* Fixed gcc 2 compilation of src/system/glue/init_term_dyn.c.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@39571 a95241bf-73f2-0310-859d-f6bbb57e9c96

Enable just enough of the message based format used in Icon-O-Matic to allow
BIconUtils to understand and render it. This makes it possible to use the
HVIFTranslator to also read Icon-O-Matic files out of the box. Will cleanup
now duplicated files next.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@30794 a95241bf-73f2-0310-859d-f6bbb57e9c96

* make sure that the ApproximationScale() implementation of any Transformer
not negative
* PathSource can now remember a global scale, and the IconRenderer sets
it, since this value is used in the curve converter for on the fly
generation of vertices, this change does not affect anything and doesn't
create the need to "update" the conversion pipeline to render an icon at
different sizes (like Icon-O-Matic does)

-> this change fixes edgy curves on icons rendered bigger than 64x64 as
reported by Axel some time ago


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@23093 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Put the remaining libicon.a classes into the BPrivate::Icon namespace.
* Minor cleanup (like removing the extra blank line between the copyright and the
header guard).


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@20507 a95241bf-73f2-0310-859d-f6bbb57e9c96

* min/max visibility scale is now between 0 and 4
* flat icon format optimizes for grays in styles


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@18508 a95241bf-73f2-0310-859d-f6bbb57e9c96

* moved all the classes actually needed for reading a
vector icon to this place, #ifdef'd out all the editing
features (listening, referencing, converting to
PropertyObject... etc)
* TODO: put into BPrivate namespace...


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@18396 a95241bf-73f2-0310-859d-f6bbb57e9c96