CLI: Implement new command 'open-step'

[ubruhin]

Add a new CLI command to minify and validate individual STEP files without requiring to open a whole LibrePCB library. This is intended mainly for librepcb-parts-generator to post-process generated STEP files.

Usage

Usage: ./librepcb-cli [options] open-step [command_options] file
LibrePCB Command Line Interface

Options:
  -h, --help        Print this message.
  -V, --version     Displays version information.
  -v, --verbose     Verbose output.
  --minify          Minify the STEP model before validating it. Use in
                    conjunction with '--save-to' to save the output of the
                    operation.
  --tesselate       Tesselate the loaded STEP model to check if LibrePCB is
                    able to render it. Reports failure (exit code = 1) if no
                    content is detected.
  --save-to <file>  Write the (modified) STEP file to this output location (may
                    be equal to the opened file path). Only makes sense in
                    conjunction with '--minify'.

Arguments:
  open-step         Open a STEP model to execute STEP-related tasks outside of
                    a library.
  file              Path to the STEP file (*.step).

Example

$ librepcb-cli open-step --minify --tesselate --save-to=minified.step model.step
Open STEP file 'model.step'...
Perform minify...
 - Minified from 138,951 bytes to 54,462 bytes (-61%)
Save to 'minified.step'...
Load model...
Tesselate model...
 - Built 6360 vertices with 1 different colors
SUCCESS

@dbrgn Maybe you like to take a look at this API before it gets released(?)

[dbrgn]

I wonder if it makes sense to have separate flags for --minify and --save-to, given that "[save-to] only makes sense in conjunction with '--minify'".

However, there might be other modification commands in the future, so it is probably good as-is.

[ubruhin]

However, there might be other modification commands in the future, so it is probably good as-is.

That was exactly my idea behind this concept 🙂

EDIT: An alternative would be to replace --save-to=<file> by just --save as we already have for the open-project and open-library commands, but I thought when modifying standalone files (like STEP) one might keep the original as-is.