Ability to export diagrams

[blacktau]

Is your feature request related to a problem? Please describe.
It would be useful to export the diagrams as they are rendered in obsidian out to the file system

Describe the solution you'd like
It would be useful to add a menu item to the the right click to allow exporting.
the format of the export would be determined by the rendering being performed (i.e. plantuml-svg = svg, plantuml = png etc)

Additionally it would be useful to be able to configure an export location in the settings int he following way
if the setting is blank (this would be the default) the file will be output in the same folder was the .md file.
if the setting starts with a leading / then the path would be relative to the vault root.
if the setting does not have a leading / then the path would be relative to the path for the .md file.
if the folder determined by the above does not exist then it should be created

the file name could be extracted from the title of the plantuml diagram (i.e. text following the @startuml)
if no title is specified for the diagram then the filename will be based on a combination of the .md filename and the current date and time.

Describe alternatives you've considered
The alternative is a manual process of using the 'copy image' function and pasting into an image editor. this is less than ideal.

Additional context
I have created a fork with the changes in here: https://github.com/blacktau/obsidian-plantuml but did not wish to create a PR for the changes until a discussion has been had around the proposal.

[joethei]

Feel free to send a PR, it's a good idea.

[joethei]

forgot to close this when merging your PR.