Skip to main content
A Selection represents the currently selected area in a sprite.

​
Constructor

​
Selection([rectangle])

​
rectangle
Rectangle
Initial selection bounds.
local selection = Selection(Rectangle(10, 10, 20, 20))
local emptySelection = Selection()

​
Properties

​
bounds
Rectangle
Bounding rectangle of the selection.
​
origin
Point
Selection origin point.
​
isEmpty
boolean
True if the selection is empty.

​
Methods

​
selection:deselect()

Clears the selection. 
selection:deselect()

​
selection:select(rectangle)

​
rectangle
Rectangle | Selection
required
Rectangle or selection to use.
Replaces the current selection. 
selection:select(Rectangle(0, 0, 32, 32))
selection:select(otherSelection)

​
selection:selectAll()

Selects the entire sprite. 
selection:selectAll()

​
selection:add(rectangle)

​
rectangle
Rectangle | Selection
required
Area to add to selection.
Adds to the current selection. 
selection:add(Rectangle(10, 10, 20, 20))
selection:add(otherSelection)

​
selection:subtract(rectangle)

​
rectangle
Rectangle | Selection
required
Area to subtract from selection.
Subtracts from the current selection. 
selection:subtract(Rectangle(10, 10, 10, 10))
selection:subtract(otherSelection)

​
selection:intersect(rectangle)

​
rectangle
Rectangle | Selection
required
Area to intersect with.
Intersects the current selection. 
selection:intersect(Rectangle(5, 5, 30, 30))
selection:intersect(otherSelection)

​
selection:contains(point)

​
point
Point
required
Point to test.
Returns true if the point is inside the selection. 
if selection:contains(Point(10, 10)) then
  print("Point is selected")
end

​
Examples

​
Creating and Using Selections

local sprite = Sprite(64, 64)
local selection = sprite.selection

-- Select a rectangular area
selection:select(Rectangle(10, 10, 32, 32))
print("Selection bounds:", selection.bounds)

-- Add to selection
selection:add(Rectangle(40, 40, 20, 20))

-- Check if point is selected
if selection:contains(Point(20, 20)) then
  print("Point 20,20 is selected")
end

​
Selection Operations

local sprite = app.sprite
local sel = sprite.selection

-- Create initial selection
sel:select(Rectangle(0, 0, 32, 32))

-- Add another area
sel:add(Rectangle(32, 32, 32, 32))

-- Subtract from selection
sel:subtract(Rectangle(16, 16, 32, 32))

-- Intersect with another area
sel:intersect(Rectangle(8, 8, 48, 48))

​
Working with Selection Bounds

local sprite = app.sprite
local sel = sprite.selection

if not sel.isEmpty then
  local bounds = sel.bounds
  print(string.format(
    "Selection: x=%d y=%d w=%d h=%d",
    bounds.x, bounds.y, bounds.width, bounds.height
  ))
  
  -- Crop sprite to selection
  sprite:crop(bounds)
else
  print("No selection")
end

​
Moving Selection Origin

local sprite = app.sprite
local sel = sprite.selection

sel:select(Rectangle(10, 10, 20, 20))
print("Original origin:", sel.origin)

-- Move selection
sel.origin = Point(30, 30)
print("New origin:", sel.origin)
print("Bounds:", sel.bounds)

​
Selecting All and Deselecting

local sprite = app.sprite
local sel = sprite.selection

-- Select everything
sel:selectAll()
print("Selected all, bounds:", sel.bounds)

-- Clear selection
sel:deselect()
print("Is empty:", sel.isEmpty)

​
Testing Points in Selection

local sprite = Sprite(64, 64)
local sel = sprite.selection

sel:select(Rectangle(20, 20, 24, 24))

local points = {
  Point(10, 10),
  Point(30, 30),
  Point(50, 50)
}

for i, pt in ipairs(points) do
  local inside = sel:contains(pt)
  print(string.format(
    "Point (%d,%d): %s",
    pt.x, pt.y,
    inside and "inside" or "outside"
  ))
end