Struct HandleService 

pub struct HandleService;

Stateless service for selection handle operations on drawings.

All methods are static (&self-free) since HandleService carries no state. It computes handle positions, performs hit testing, updates handle positions during drags, and renders the handles onto the chart.

Implementations

impl HandleService

pub fn get_handles(drawing: &Drawing) -> Vec<(HandlePos, Pos2)>

Returns the selection handles for a drawing based on its tool type.

Handle layouts vary by tool type:

• Two-point tools (TrendLine, Fibonacci, etc.): Start and End handles
• Rectangle and Gann box: Four corner handles and four edge handles
• Single-point tools (HorizontalLine, VerticalLine): One Start handle
• Glyphs: Four resize corners around the centre and a Middle move handle
• Image: One bottom-right corner that resizes with locked proportions
• Brushes: One Middle handle on the stroke, which moves it whole
• Three-anchor channels: Four indexed handles, one at each line end
• Bars pattern: Start and End at the ends of its copy
• Multi-point tools: Indexed handles at each anchor

pub fn hit_test_handle( drawing: &Drawing, point: Pos2, handle_size: f32, ) -> Option<HandlePos>

Hit-tests to find which handle (if any) is at a screen position.

Returns Some(HandlePos) if point is within handle_size * 1.5 pixels of a handle center, None otherwise.

pub fn update_handle<F, G, H>( drawing: &mut Drawing, handle: HandlePos, new_pos: Pos2, x_to_bar: F, y_to_price: G, translate_price: H, )

where F: Fn(f32) -> f32, G: Fn(f32) -> f64, H: Fn(f64, f32, f32) -> f64,

Moves a handle to a new screen position, updating both screen coordinates and chart coordinates using the provided conversion closures.

For the Middle handle, every anchor that moves with the drawing (all but a bars pattern’s source) is translated by the delta between the old and new centroid positions. translate_price(price, from_y, to_y) shifts their prices in scale units; other handles use y_to_price.

pub fn render_handles( painter: &Painter, drawing: &Drawing, config: &HandleConfig, dragging_handle: Option<HandlePos>, )

Renders selection handles like the selection dots of a series: an accent ring around the chart background.

The actively dragged handle (if any) is filled with HandleConfig::selected_color; the others are ringed with HandleConfig::color.