Pyslvs-ui

**Features**:

+ Important: File format was changed.
+ Add new examples:
+ "Stephenson I"
+ "Watt I"
+ "Watt II"
+ "Lift Tailgate"
+ "Crank lifter"
+ "Inverted slider"
+ "Ten Fold's levers"
+ Selection label function improvement.
+ UI and selection mode improvements.
+ Add FPS counter.
+ Add background settings.
+ Add limitation of input mechanism in UI.
+ Add command line option to choose specified solver when startup.
+ Adjust interface of about dialog.

**Development**:

+ Database module "peewee" rename to "database".
+ Database function improvements.
+ All PyQt slots renaming to short names.
+ Python version should upgrade to 3.6 or above to support formatted string.

**Features**:

+ Dimensional synthesis data settings and UI has been changed.
+ Input variable settings and UI has been changed.
+ New solving kernel "Sketch Solve" in "pyslvs" core library.
+ Add new examples:
+ "Stephenson II"
+ "Stephenson III"
+ Adjust ask saving message box in "FileWidget" class.

**Development**:

+ Add "Python-Solvespace" kernel as submodule.
+ Merge "-w" flag to "-d" flag.
+ New format with dimensional synthesis function.
+ Example list has been move to "pyslvs" core kernel.
+ Change behavior of auto path preview function.

**Features**:

+ Free move mode:
+ Linkage editing is supported in expression table.
+ Fix the error of angle updating.
+ Show the values on expression table.
+ Add solution selection mode with expression table.
+ Dimensional synthesis function:
+ Re-designed user interface.

**Development**:


+ Update module "dxfwrite" to "ezdxf".
+ Change "Pyslvs" kernel into submodule, including changelog.

**Features**:

+ Linkage selection mode:
+ New link selection function for both of table widget and main canvas.
+ Using ctrl + mouse wheel can adjust the tab of entities table widget.
+ Main canvas:
+ Add cursor tooltips when dragging on main canvas.
+ Center zooming function and option with 'by cursor' and 'by canvas center'.
+ Colors:
+ Pyslvs can support custom color by using '(R, G, B)' string.
+ Add color picker in setting interface.
+ Solvespace format:
+ Comments will be generate into a new layout in Solvespace format.
+ Simple reading function for \*.slvs format (only support R joint).
+ New option to generate part files.
+ Path record:
+ Add "copy path" function in path context menu.
+ Path preview function are support P joint.
+ New solving kernel option "Pyslvs" as default.
+ Add mouse snapping option (default 1 unit).
+ Triple ball lifter example.
+ Shortcut keys adjustment.
+ "Add" command of storage function will not clean the canvas (should do it by self).
+ Add "merge linkages" function in link context menu.
+ Add virtual model option to change linkages appearance.

**Development**:

+ Expression grammar:
+ New highlight module Pygments, use to support Python and PMKS expression.
+ Now PMKS grammar can support color string, one-line annotations, multiple line and indentations.
+ Cython libraries:
+ Pyslvs kernel has been independently.
+ Compile method adjustment.
+ Merge into 'pyslvs' folder.
+ Using Python typing for Python functions in Cython libraries.
+ Add Cython header to sharing declarations between libraries.
+ Add new "PXY" function to make solution of P joint.
+ Compile:
+ Compile process improvement.
+ Reduce the size while packing AppImage file.
+ Reduce the size of images.
+ Solvespace format:
+ Python API for simple 2D sketch IO.
+ Modules and objects naming adjustment.
+ PyQt version should upgrade to 5.10 or above to support Qt graph methods.

**Features**:

+ Auto preview path will be shown when input joint has been set.
+ Triangular solutions can be show in main canvas when switch to "Expression" table.
+ New driver setting mode of triangular iteration.
+ Add a spin box for input QDial.
+ 'New link' functional behavior improvement.
+ Pyslvs will save the settings in local, if user let it to do this.

**Development**:

+ Several functional corrections and optimizations.
+ PLPP function has been optimized.
+ "P0", "P1", "P2" letters will be use as expression, instead of "A", "B", "C".
+ Main window method was split into sub function at "widget" folder.
+ Build process improvements.

**Features**:

+ Fix an error caused by wrong grounded linkage.
+ Auto configuration function in triangular iteration.
+ Backtrack function for the 'Keep DOF' option.
+ Database will saving the inputs variables settings.
+ Inputs variables settings can be support undo function.

**Development**:

+ Script annotations for functions and classes.
+ Separate 'Inputs' tab widget.
+ Cython type checker for Python containers.
+ Windows executable file was compiled by Mysys 2.