Klayout

* Images: it is possible now to load image files (JPG, GIF, TIFF etc.) and
display them below the drawn layout. The display of the images can be
adjusted in many ways, i.e. placement, scaling, rotation, mirroring,
color/contrast/brightness adjustments and false color mapping for gray
level images. Images are fully supported by RBA. The feature is described
in detail in Adding images.
* Marker browser: the marker browser is based on the report database (RDB).
This is a new concept that has been introduced as a container for report
items, in particular marker objects but also for a number of additional
annotations including screenshots for documentation. An import of Calibre
DRC databases is provided. The RDB is fully supported by RBA.
The feature is described in detail in The marker browser.
* Some enhancements for the layer views: invisible layers are now shown
differently in a "collapsed" way. Thus, the layer's colors and styles are
still recognizable. The new features are described in detail in Telling
used from unused layers.
* In the layer list, unused layers can now be hidden and layers without
shapes in view can be marked unused or hidden. The normal mode of marking
layers unused when the cell does not contain any shapes at all is still
available. Both modes are available as checkable items in the layer list's
context menu.
* A "View" menu has been added with fast access to certain display options,
i.e. turn grid on an off. A number of default grids can be defined for
quick selection in the "View" menu. On request, the tool bar can now be
hidden as well as the layer and hierarchy lists.
* A key binding editor is provided. This way, all menu functions can be
assigned arbitrary key shortcuts in a more comfortable ways.
* The mid mouse button can be used to pan (drag) the view window now.
* Various RBA enhancements, i.e. a method to compute the intersection point
between edges.

* Enhancements for building with gcc 4.4.x and Qt 4.5.x.
* OASIS reader now also supports text objects with forward references to
text string definitions.

* Some bugfixes (for a list of fixed bugs see Known bugs in version 0.18)
in particular for MacOS users.

* Some bugfixes (for a list of fixed bugs see Known bugs in version 0.17.2).
* Added support for the GDS2 text format. This is a contribution by
Romain Gauci from Oscillated Recall Technology (http://www.or-tech.co.jp).
* Session persistence: sessions (files, layers, bookmarks, setup) can be
saved and restored. Details for this feature can be found here.
* Reader options can be specified in a dialog now (File menu). Some GDS2
specific reader options are available: allow multi XY, allow big records
and several box record handling modes. Details for this feature can be
found here.
* GDS2 specific writer options (max vertex option, multi XY record option,
max cell name length).
* The stipple palette now is editable. A corresponding page has been added
in the setup dialog.
* Flatten cell function. A cell can be flattened which will remove the cell
and all the subcells unless not specified otherwise. This function can be
found in the cell's context menu. Details for this feature can be found
here.
* The 'Make Cell' operation provides a nice origin now. Before, the origin
of the new cell was far off sometimes.
* Accept drag & drop of .lyb, .lys, .lyp, .rb, .rbm and layout files.
* Switched to standard file dialogs where this has not been the case yet.
In particular on the Windows platform, the application will behave somewhat
more consistent.
* Added an option to draw only border instances of arrays. This option can be
found on the 'Misc.' tab of the setup dialog.
* Added the capability to define global ruby modules using the ".rbm"
extension and putting them into the installation directory.
* Full cell copy & paste functions can now be found in hierarchy panel
context menu.
* Enhancement of grid snapping in partial mode. Before, a offgrid vertex could
not be brought on-grid because movement was confined to grid steps.
* Number of points for polygons is shown now in the polygon property dialog.
* Hole resolution for GDS2 and OASIS writer. Before, polygons with holes
(which can be produced by scripts) were rejected.
* Some bugfixes for clip, using booleans for clip to overcome some problems
with hole connectors and spikes - slow but safe..
* '' character is not longer used when creating cell variants - instead '$'
is used to enhance the compatibility with other tools which do not allow
the "" character as part of cell names.
* On paste, a 'fit selection' is done to show what has been pasted.
* Mouse wheel mode is configurable now (shift/ctrl modifier behaviour).
The 'alternative mode' can be found on the 'Misc.' tab in the setup dialog.
* Option to clear all rulers when cell is changed. This option can be found
on the 'Misc.' tab in the setup dialog in the 'On Cell Change' group.

RBA enhancements:
* A new class: ICplxTrans and related functions.
* A recursive shape iterator simplifies hierarchical region queries and
"as if flat" traversal of cells.
* Polygon: hull and hole can be assigned now, compress method, point accessors.
* The installation path now is available.
* Added a method which allows to display a message in the status bar.
* The transient selection now is available for RBA procedures.
* New events are generated if selection and transient selection changes.
* Added a generic assign method for copyable objects.
* Added new classes 'LayerMap' and 'LoadLayoutOptions'.
* Added two 'read' methods to Layout class.
* Added a couple of methods to 'LayerInfo' (constructors, compare, ...).
* Added a 'load_layout' method to LayoutView.
* Added more cm_* methods to MainWindow.

* Some bugs are fixed now (for a list of fixed bugs see Known bugs in
version 0.17.1).
* The GDS2 writer now normalizes AREF records. This way compatibility with
other EDA systems is enhanced.

* The display freezing bug on Windows is fixed now (i.e. see Known bugs
in version 0.17).