LiveFlow.Viewport (LiveFlow v0.2.3)

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Viewport data structure for LiveFlow.

The viewport represents the current pan/zoom state of the flow canvas. It tracks the translation (x, y) and zoom level to transform flow coordinates to screen coordinates.

Fields

  • :x - Horizontal pan offset
  • :y - Vertical pan offset
  • :zoom - Zoom level (1.0 = 100%)

Coordinate Transformation

To convert from flow space to screen space:

screen_x = flow_x * zoom + viewport.x
screen_y = flow_y * zoom + viewport.y

To convert from screen space to flow space:

flow_x = (screen_x - viewport.x) / zoom
flow_y = (screen_y - viewport.y) / zoom

Examples

iex> vp = LiveFlow.Viewport.new()
%LiveFlow.Viewport{x: 0.0, y: 0.0, zoom: 1.0}

iex> LiveFlow.Viewport.pan(vp, 100, 50)
%LiveFlow.Viewport{x: 100.0, y: 50.0, zoom: 1.0}

Summary

Types

t()

Functions

fit_bounds(container, bounds, opts \\ [])

Calculates viewport to fit given bounds with optional padding.

flow_to_screen(viewport, flow_x, flow_y)

Converts flow coordinates to screen coordinates.

new(opts \\ [])

Creates a new viewport with optional initial values.

pan(vp, dx, dy)

Pans the viewport by the given delta.

pan_to(vp, x, y)

Sets the viewport pan position.

screen_to_flow(viewport, screen_x, screen_y)

Converts screen coordinates to flow coordinates.

set(viewport, x, y, zoom)

Sets the viewport position and zoom.

transform_style(viewport)

Gets the CSS transform string for the viewport.

zoom_by(vp, factor, opts \\ [])

Zooms the viewport by a factor.

zoom_to(vp, zoom, opts \\ [])

Sets the zoom level directly.

Types

t()

@type t() :: %LiveFlow.Viewport{x: float(), y: float(), zoom: float()}

Functions

fit_bounds(container, bounds, opts \\ [])

@spec fit_bounds(map(), map(), keyword()) :: t()

Calculates viewport to fit given bounds with optional padding.

Options

  • :padding - Padding ratio (default: 0.1 = 10%)
  • :min_zoom - Minimum zoom level (default: 0.1)
  • :max_zoom - Maximum zoom level (default: 4.0)

Examples

iex> bounds = %{x: 0, y: 0, width: 400, height: 300}
iex> LiveFlow.Viewport.fit_bounds(%{width: 800, height: 600}, bounds)
%LiveFlow.Viewport{x: 80.0, y: 60.0, zoom: 1.6}

flow_to_screen(viewport, flow_x, flow_y)

@spec flow_to_screen(t(), number(), number()) :: {float(), float()}

Converts flow coordinates to screen coordinates.

Examples

iex> vp = LiveFlow.Viewport.new(x: 100, y: 50, zoom: 2.0)
iex> LiveFlow.Viewport.flow_to_screen(vp, 50, 50)
{200.0, 150.0}

new(opts \\ [])

@spec new(keyword()) :: t()

Creates a new viewport with optional initial values.

Options

  • :x - Initial x pan (default: 0.0)
  • :y - Initial y pan (default: 0.0)
  • :zoom - Initial zoom level (default: 1.0)

Examples

iex> LiveFlow.Viewport.new()
%LiveFlow.Viewport{x: 0.0, y: 0.0, zoom: 1.0}

iex> LiveFlow.Viewport.new(x: 100, y: 50, zoom: 1.5)
%LiveFlow.Viewport{x: 100.0, y: 50.0, zoom: 1.5}

pan(vp, dx, dy)

@spec pan(t(), number(), number()) :: t()

Pans the viewport by the given delta.

pan_to(vp, x, y)

@spec pan_to(t(), number(), number()) :: t()

Sets the viewport pan position.

screen_to_flow(viewport, screen_x, screen_y)

@spec screen_to_flow(t(), number(), number()) :: {float(), float()}

Converts screen coordinates to flow coordinates.

Examples

iex> vp = LiveFlow.Viewport.new(x: 100, y: 50, zoom: 2.0)
iex> LiveFlow.Viewport.screen_to_flow(vp, 200, 150)
{50.0, 50.0}

set(viewport, x, y, zoom)

@spec set(t(), number(), number(), number()) :: t()

Sets the viewport position and zoom.

transform_style(viewport)

@spec transform_style(t()) :: String.t()

Gets the CSS transform string for the viewport.

Examples

iex> vp = LiveFlow.Viewport.new(x: 100, y: 50, zoom: 1.5)
iex> LiveFlow.Viewport.transform_style(vp)
"translate(100.0px, 50.0px) scale(1.5)"

zoom_by(vp, factor, opts \\ [])

@spec zoom_by(t(), number(), keyword()) :: t()

Zooms the viewport by a factor.

Options

  • :center - Point to zoom towards {x, y} in screen coordinates
  • :min_zoom - Minimum zoom level (default: 0.1)
  • :max_zoom - Maximum zoom level (default: 4.0)

Examples

iex> vp = LiveFlow.Viewport.new()
iex> LiveFlow.Viewport.zoom_by(vp, 1.5)
%LiveFlow.Viewport{x: 0.0, y: 0.0, zoom: 1.5}

zoom_to(vp, zoom, opts \\ [])

@spec zoom_to(t(), number(), keyword()) :: t()

Sets the zoom level directly.

Options

  • :center - Point to zoom towards {x, y} in screen coordinates
  • :min_zoom - Minimum zoom level (default: 0.1)
  • :max_zoom - Maximum zoom level (default: 4.0)