Editor Font Size Settings Implementation

[CopeFiend]

Issue: #910
Pull Request: #911

Summary

This is to discuss the implementation of Editor font size settings.

Goals

• Add a SettingsWindow option to configure Editor font size.
• Group Text widgets into categories (World Viewer, Asset Browser, Inspector, etc.).
• Allow updating Text widgets by category so each area can have an independent font size.

Implementation

• The plan is to split changes from feature branch into multiple smaller branches and make a PR for each, check Add editor font size settings #911 for details.

Looking for suggestions and/or feedback, thanks.

[CopeFiend]

#911 (comment)
From what I've gathered, despite carrying the key Style::FONT_SIZE, ui.set_style() does not update font_size values.

In fyrox-ui/src/lib.rs:

    pub fn set_style(&mut self, style: StyleResource) {
        self.style = style;
        fn notify_depth_first(node: Handle<UiNode>, ui: &UserInterface) {
            if let Ok(node_ref) = ui.try_get_node(node) {
                for child in node_ref.children.iter() {
                    notify_depth_first(*child, ui);
                }
                ui.send(node, WidgetMessage::Style(ui.style.clone()));
            }
        }
        notify_depth_first(self.root_canvas, self);
    }

the Ui sends WidgetMessage::Style to every single UiNode in the tree, which is handled in fyrox-ui/src/widget.rs:

    WidgetMessage::Style(style) => {
        self.invalidate_visual();
        self.background.update(style);
        self.foreground.update(style);
        self.style = Some(style.clone());
    }

but as shown, the method only updates foreground and background, since there is no font_size to update anyway.

Yet, widgets that carry font_size i.e. fyrox-ui/src/text.rs and fyrox-ui/src/text_box.rs do not handle WidgetMessage::Style, only TextMessage::FontSize

    TextMessage::FontSize(height) => {
        if text_ref.font_size() != height {
            text_ref.set_font_size(height.clone());
            drop(text_ref);
            self.invalidate_layout();
        }
    }

which updates the text directly, this means per-category updates (World Viewer, Asset Browser etc.) are impossible as every text will be updated upon calling ui.set_style().

PR #914 addresses this by adding

• WidgetMessage::Style handling to widgets with a font_size property and
• pub fn set_style() to fyrox-ui/src/formatted_text.rs

so ui.set_style() actually updates text widgets by "Style key" when called.

Then why not use Style::FONT_SIZE when it is used in almost every widget?

Because "almost every widget" includes project-manager and every custom widget in editor/src/plugins. It would be weird if a font size change in Editor ends up affecting somewhere unrelated.

Instead, having every text widget explicitly provide their own font_size Style key would be a safer choice, and that is mostly what the heap of additional methods are:

• calling TextBuilder::with_font_size() to override the default Style::FONT_SIZE
• adding pub fn with_font_size() to builders with internal TextBuilders.

To proportionally change the font size for every styled variable I'd change the type of FONT_SIZE variable to a new type called FontSize and after that it'd be possible to iterate over all such properties in the style and scale them accordingly. So basically: take the default style, create its copy, scale all the FontSize properties accordingly, then call ui.set_style. This should be enough.

I'm not quite sure what "proportional change" means? font_size values are currently all absolute units, they do not care for the proportion of anything (which is an issue because large font sizes will grow past their container). I suppose a new FontSize type could have "proportional sizing", but I feel like that should be in widget.rs instead.