Struct Canvas2 

pub struct Canvas2 { /* private fields */ }

Stateful abstraction for a 2D canvas supporting drag and zoom

The canvas may be used in either immediate mode or callback mode.

In immediate mode, the user sends the complete cursor state to Canvas2::interact.

In callback mode, lower-level functions should be invoked as callbacks:

• Canvas2::resize
• Canvas2::begin_drag
• Canvas2::drag
• Canvas2::end_drag
• Canvas2::zoom

Implementations

impl Canvas2

pub fn new(image_size: ImageSize) -> Self

Builds a new canvas with the given image size and default view

pub fn components(&self) -> (View2, ImageSize)

Destructures the canvas into its components

pub fn from_components(view: View2, image_size: ImageSize) -> Self

Builds the canvas from components

pub fn interact( &mut self, image_size: ImageSize, cursor_state: Option<CursorState<bool>>, scroll: f32, ) -> bool

Stateful interaction with the canvas

The cursor_state indicates whether cursor is on-screen, and if so, whether the mouse button is down.

Returns a boolean value indicating whether the view has changed

pub fn view(&self) -> View2

Returns the current view

pub fn image_size(&self) -> ImageSize

Returns the current image size

pub fn resize(&mut self, image_size: ImageSize)

Callback when the canvas is resized

pub fn begin_drag(&mut self, pos_screen: Point2<i32>)

Begins a new drag with the mouse at the given screen position

If a drag is already in progress, this function does nothing.

pub fn drag(&mut self, pos_screen: Point2<i32>) -> bool

Callback when the cursor is moved

If a drag is in progress, then the drag continues and this function returns a boolean value indicating whether the view has changed; otherwise, it returns false

pub fn end_drag(&mut self)

Callback when the mouse button is released

pub fn zoom(&mut self, amount: f32, pos_screen: Option<Point2<i32>>) -> bool

Callback when the user scrolls

amount should be a linear amount (either positive or negative); this function converts it into an scaled exponential.

Returns a boolean value indicating whether the view has changed

Trait Implementations

impl Clone for Canvas2

fn clone(&self) -> Canvas2

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Canvas2