Implement table row framing and selection

[vvv]

• Add framing effect to table rows
• Select table row by clicking
• Configure sensitivity of table cells

Demo

2023-06-29.01-12-25.mp4

Closes #1519, #3069

[vvv]

cc @enomado, @max-huster (in case you still are interested in this functionality)

[vvv]

💡 I have an idea of a simpler and more flexible implementation of row selection, that will not require as extensive changes to the library code.

New API

impl<'a> TableBuilder<'a> {
    /// Specify which row(s) are to be painted with [`Selection::bg_fill`][egui::style::Selection] background.
    pub fn select_rows(is_selected: impl Fn(usize) -> bool) -> Self {
        ...
    }
}

Row(s) selection mechanism

• The application tells the library which rows to select by calling TableBuilder::select_rows.
• Each of TableRow::cols (cells) returns a Response. The app checks the Responses to determine if any of this row's cells has been clicked.
• The app has enough contextual information to deduce the index of the clicked row:
  • row index is an argument of add_row_content function, passed to TableBody::rows and TableBody::heterogeneous_rows;
  • in case of TableBody::row, the application can count the rows.

Comparison with the current design

Current implementation (this PR) only supports selecting a single row by storing its index in the table's IdTypeMap. New design allows users to store any number of row indices in the application's state, e.g.

pub struct App {
    selected_row: Option<usize>, // for a single row
}

or

pub struct App {
    selected_rows: Vec<usize>, // for multiple rows
}

The application handles mouse and keyboard events accordingly to its UI requirements. For example, the application can support the following interactions:

• click on a row to select it
• select a row by pressing Up/Down key
• Cmd-click to add a row to selection
• Shift-click to add a range of rows to the selection
• Shift-Up/Down to extend/shrink the selection
• Cmd-a to select all rows

[emilk]

Nice, this is working really well!

I would suggest renaming the "framing effect" to something like "hover highlight" or similar. Seems more descritive.

[vvv]

Nice, this is working really well!

Thanks for your kind feedback, @emilk! 😊

I would suggest renaming the "framing effect" to something like "hover highlight" or similar. Seems more descritive.

Will do.

I don't think that we should merge this PR though. I have come up with a simpler and more flexible solution and marked this PR as draft.

I haven't implemented that other solution yet, I haven't even started.

I will find some hacking time this weekend. Please bear with me till Monday Aug 21st. I should have had plenty of time to finish by then.

Thanks to whoever is expecting this feature for your patience and words of support! And many thanks to @emilk for writing this wonderful piece of software!

[12089897411]

I'm really looking forward to this feature!

[vvv]

I will find some hacking time this weekend.

I am really sorry, folks.

I'm working my way into a stealth startup. And have another contract to deliver on.

I have no bandwidth left to implement this feature. 😞

[laurooyen]

I'll have a go at implementing this feature, including the newly proposed select_row api.

Edit: Expect a draft pull request by the end of the weekend. Deviated from the select_row api to make usage easier but maybe there's other solutions, feedback will be welcome.

[vvv]

@laurooyen That's great!

Do ping me if you need a sounding board or whatever little help I can provide.

Godspeed!