object:contentToLocal()

Overview

Maps the given x and y values in content (stage) coordinates to the target object's local coordinates (center point).

Syntax

object:contentToLocal( xContent, yContent )

Return Values

This function returns the x and y coordinates of the given values in the object's local coordinate space. The values returned are relative to the center point of the display object, and these values will be negative if the given point is above or left of the object's center point.

Example

-- Rectangle that fills screen
local rect = display.newRect( 0, 0, display.contentWidth, display.contentHeight )
rect.x = display.contentCenterX ; rect.y = display.contentCenterY
rect.strokeWidth = 4 ; rect:setStrokeColor( 1, 0, 0 )
rect:setFillColor( 0, 0, 0 )

-- Create text objects to display content and local coordinates
local contentText = display.newText( "", 0, 0, display.nativeSystemFont, 16 )
local localText = display.newText( "", 0, 0, display.nativeSystemFont, 16 )
localText.anchorX = 0 ; localText.anchorY = 0
contentText.anchorX = 0 ; contentText.anchorY = 0
 
function showCoordinates( event )
    -- Get x and y of touch event in content coordinates
    local contentX, contentY = event.x, event.y

    -- Convert to local coordinates of 
    local localX, localY = event.target:contentToLocal( contentX, contentY )        

    -- Display content and local coordinate values
    contentText.text = "CONTENT: " .. tostring(contentX) .. ", " .. tostring(contentY)
    localText.text = "LOCAL: " .. tostring(localX) .. ", " .. tostring(localY)
    contentText.x, contentText.y = event.x+20, event.y
    localText.x, localText.y = event.x+20, event.y+20
    localText.anchorX = 0 ; localText.anchorY = 0
    contentText.anchorX = 0 ; contentText.anchorY = 0
    return true
end

rect:addEventListener( "touch", showCoordinates )