Glew has the problem that it has to be selected at build time if GLX or
EGL is supported by the library, and this in not encoded in the library
name, nor ABI, nor anything.
Then it's easy to get into the situation that a binary is built but
cannot run because glew supports an API different from the one used by
wxWidgets, or the binary fails to link in the end after all objects are
compiled.
epoxy can support both with the same library avoiding this problem.
epoxy is not initialized explicitly, replaced initialization with
version check where one was not done already.
It seems to be available as vcpkg https://vcpkg.link/ports/libepoxy
There are problems related to GL context switching on Windows which does
not seem to be used in kicad
https://github.com/anholt/libepoxy#known-issues-when-running-on-windows
There is also a problem related to multithreaded rendering on Windows
https://github.com/anholt/libepoxy/pull/265 It's harder to tell if
threading is used for rendering but it does not look like kicad is doing
anything complex enough to warrant using multiple rendering threads.
Fixes https://gitlab.com/kicad/code/kicad/-/issues/20630
Fixes https://gitlab.com/kicad/code/kicad/-/issues/12543
Recommendation is to avoid using the year nomenclature as this
information is already encoded in the git repo. Avoids needing to
repeatly update.
Also updates AUTHORS.txt from current repo with contributor names
wxWidgets 3.1.5+ on Linux will compile with the Wayland EGL
canvas as the backend instead of the X11 backend. This requires a
version of GLEW compiled with the proper EGL defines and a different
header/code for certain parts that are X11 GLEW specific.
This introduces an in-tree version of GLEW that will be built with the
GLEW_EGL flag then statically linked into the KiCad executables when
EGL support is needed.
gal: pixel alignment for Cairo.
gal: pixel alignment for OpenGL
Cleanup of pixel alignment patches
gal/opengl: more pixel alignment patches:
- works on Retina displays now
- pixel alignment for circles
- correct 1-pixel strokes
- fixed unfinished 1-pixel line ends
GAL: Restore antialiasing options in Cairo
GAL: Fix arc drawing
Removes DrawArcSegment, which drew arcs whose edge was optionally
stroked (a feature that we did not use). Fixes Cairo arc drawing issue
where arcs were not visible in pcbnew.
gal: further cleanup
gal: removed unused shader parameter
New classes:
- VIEW - represents view that is seen by user, takes care of layer ordering & visibility and how it is displayed (which location, how much zoomed, etc.)
- VIEW_ITEM - Base class for every item that can be displayed on VIEW (the biggest change is that now it may be necessary to override ViewBBox & ViewGetLayers method for derived classes).
- EDA_DRAW_PANEL_GAL - Inherits after EDA_DRAW_PANEL, displays VIEW output, right now it is not editable (in opposite to usual EDA_DRAW_PANEL).
- GAL/OPENGL_GAL/CAIRO_GAL - Base Graphics Abstraction Layer class + two different flavours (Cairo is not fully supported yet), that offers methods to draw primitives using different libraries.
- WX_VIEW_CONTROLS - Controller for VIEW, handles user events, allows zooming, panning, etc.
- PAINTER/PCB_PAINTER - Classes that uses GAL interface to draw items (as you may have already guessed - PCB_PAINTER is a class for drawing PCB specific object, PAINTER is an abstract class). Its methods are invoked by VIEW, when an item has to be drawn. To display a new type of item - you need to implement draw(ITEM_TYPE*) method that draws it using GAL methods.
- STROKE_FONT - Implements stroke font drawing using GAL methods.
Most important changes to Kicad original code:
* EDA_ITEM now inherits from VIEW_ITEM, which is a base class for all drawable objects.
* EDA_DRAW_FRAME contains both usual EDA_DRAW_PANEL and new EDA_DRAW_PANEL_GAL, that can be switched anytime.
* There are some new layers for displaying multilayer pads, vias & pads holes (these are not shown yet on the right sidebar in pcbnew)
* Display order of layers is different than in previous versions (if you are curious - you may check m_galLayerOrder@pcbnew/basepcbframe.cpp). Preserving usual order would result in not very natural display, such as showing silkscreen texts on the bottom.
* Introduced new hotkey (Alt+F12) and new menu option (View->Switch canvas) for switching canvas during runtime.
* Some of classes (mostly derived from BOARD_ITEM) now includes ViewBBox & ViewGetLayers methods.
* Removed tools/class_painter.h, as now it is extended and included in source code.
Build changes:
* GAL-based rendering option is turned on by a new compilation CMake option KICAD_GAL.
* When compiling with CMake option KICAD_GAL=ON, GLEW and Cairo libraries are required.
* GAL-related code is compiled into a static library (common/libgal).
* Build with KICAD_GAL=OFF should not need any new libraries and should come out as a standard version of Kicad
Currently most of items in pcbnew can be displayed using OpenGL (to be done are DIMENSIONS and MARKERS).
More details about GAL can be found in: http://www.ohwr.org/attachments/1884/view-spec.pdf
