hello,
I’m trying to implement the tutorial (sample10), but with any separate objects
http://www.coronalabs.com/blog/2013/01/22/implementing-pinch-zoom-rotate/#comment-26267
and I have a problem I do not understand.
I need to apply the rotation, move and scale to several separate objects, so that the dots are attached to each object.
In the simulator works fine (not multitouch ), but on the devices (android) when I touch the object (multitouch starts), suddenly too increases the scale of the object.
There are also problems with the coordinates x, y
I’m doing wrong?
Thank you very much in advance.
-- pinch centre translation -- turn on multitouch system.activate("multitouch") -- which environment are we running on? local isDevice = (system.getInfo("environment") == "device") -- returns the distance between points a and b function lengthOf( a, b ) local width, height = b.x-a.x, b.y-a.y return (width\*width + height\*height)^0.5 end -- returns the degrees between (0,0) and pt -- note: 0 degrees is 'east' function angleOfPoint( pt ) local x, y = pt.x, pt.y local radian = math.atan2(y,x) local angle = radian\*180/math.pi if angle \< 0 then angle = 360 + angle end return angle end -- returns the degrees between two points -- note: 0 degrees is 'east' function angleBetweenPoints( a, b ) local x, y = b.x - a.x, b.y - a.y return angleOfPoint( { x=x, y=y } ) end -- returns the smallest angle between the two angles -- ie: the difference between the two angles via the shortest distance function smallestAngleDiff( target, source ) local a = target - source if (a \> 180) then a = a - 360 elseif (a \< -180) then a = a + 360 end return a end -- rotates a point around the (0,0) point by degrees -- returns new point object function rotatePoint( point, degrees ) local x, y = point.x, point.y local theta = math.rad( degrees ) local pt = { x = x \* math.cos(theta) - y \* math.sin(theta), y = x \* math.sin(theta) + y \* math.cos(theta) } return pt end -- rotates point around the centre by degrees -- rounds the returned coordinates using math.round() if round == true -- returns new coordinates object function rotateAboutPoint( point, centre, degrees, round ) local pt = { x=point.x - centre.x, y=point.y - centre.y } pt = rotatePoint( pt, degrees ) pt.x, pt.y = pt.x + centre.x, pt.y + centre.y if (round) then pt.x = math.round(pt.x) pt.y = math.round(pt.y) end return pt end -- calculates the average centre of a list of points local function calcAvgCentre( points ) local x, y = 0, 0 for i=1, #points do local pt = points[i] x = x + pt.x y = y + pt.y end return { x = x / #points, y = y / #points } end -- calculate each tracking dot's distance and angle from the midpoint local function updateTracking( centre, points ) for i=1, #points do local point = points[i] point.prevAngle = point.angle point.prevDistance = point.distance point.angle = angleBetweenPoints( centre, point ) point.distance = lengthOf( centre, point ) end end -- calculates rotation amount based on the average change in tracking point rotation local function calcAverageRotation( points ) local total = 0 for i=1, #points do local point = points[i] total = total + smallestAngleDiff( point.angle, point.prevAngle ) end return total / #points end -- calculates scaling amount based on the average change in tracking point distances local function calcAverageScaling( points ) local total = 0 for i=1, #points do local point = points[i] total = total + point.distance / point.prevDistance end return total / #points end circle={} -- creates an object to be moved function newTrackDot(e) -- keep reference to the rectangle rect = e.target -- create a user interface object if rect.Numdots==0 then nameC="circle\_"..rect.nombre.."\_1" else nameC="circle\_"..rect.nombre.."\_2" end circle[nameC] = display.newCircle( e.x, e.y, 30 ) circle[nameC].dots={} circle[nameC].numero=rect.Numdots+1 circle[nameC].nombre=nameC circle[nameC].alpha = .5 -- standard multi-touch event listener function touchC(e) -- get the object which received the touch event local target = circle[nameC] -- store the parent object in the event e.parent = rect -- handle each phase of the touch event life cycle... if (e.phase == "began") then -- tell corona that following touches come to this display object display.getCurrentStage():setFocus(target, e.id) -- remember that this object has the focus target.hasFocus = true -- indicate the event was handled return true elseif (target.hasFocus) then -- this object is handling touches if (e.phase == "moved") then -- move the display object with the touch (or whatever) target.x, target.y = e.x, e.y else -- "ended" and "cancelled" phases -- stop being responsible for touches display.getCurrentStage():setFocus(target, nil) -- remember this object no longer has the focus target.hasFocus = false end -- send the event parameter to the rect object startDrag(e) -- indicate that we handled the touch and not to propagate it return true end -- if the target is not responsible for this touch event return false return false end -- listen for touches starting on the touch layer circle[nameC]:addEventListener("touch",touchC) -- listen for a tap when running in the simulator function tapC(e) if (e.numTaps == 2) then -- set the parent e.parent = rect -- call touch to remove the tracking dot startDrag(e) end return true end -- only attach tap listener in the simulator if (not isDevice) then circle[nameC]:addEventListener("tap",tapC) end -- pass the began phase to the tracking dot touchC(e) -- return the object for use return circle[nameC] end -- advanced multi-touch event listener function startDrag( e) -- get the object which received the touch event local target = e.target -- handle began phase of the touch event life cycle... if (e.phase == "began") then print( e.phase, e.x, e.y ) -- create a tracking dot local dot = newTrackDot(e) -- add the new dot to the list rect.dots[#rect.dots+1] = dot -- pre-store the average centre position of all touch points rect.prevCentre = calcAvgCentre( rect.dots ) -- pre-store the tracking dot scale and rotation values updateTracking( rect.prevCentre, rect.dots ) -- we handled the began phase return true elseif (e.parent == rect) then if (e.phase == "moved") then print( e.phase, e.x, e.y ) -- declare working variables local centre, scale, rotate = {}, 1, 0 -- calculate the average centre position of all touch points centre = calcAvgCentre( rect.dots ) -- refresh tracking dot scale and rotation values updateTracking( rect.prevCentre, rect.dots ) -- if there is more than one tracking dot, calculate the rotation and scaling if (#rect.dots \> 1) then -- calculate the average rotation of the tracking dots rotate = calcAverageRotation( rect.dots ) -- calculate the average scaling of the tracking dots scale = calcAverageScaling( rect.dots ) -- apply rotation to rect rect.rotation = rect.rotation + rotate -- apply scaling to rect rect.xScale, rect.yScale = rect.xScale \* scale, rect.yScale \* scale end -- declare working point for the rect location local pt = {} -- translation relative to centre point move pt.x = rect.x + (centre.x - rect.prevCentre.x) pt.y = rect.y + (centre.y - rect.prevCentre.y) -- scale around the average centre of the pinch -- (centre of the tracking dots, not the rect centre) pt.x = centre.x + ((pt.x - centre.x) \* scale) pt.y = centre.y + ((pt.y - centre.y) \* scale) -- rotate the rect centre around the pinch centre -- (same rotation as the rect is rotated!) pt = rotateAboutPoint( pt, centre, rotate, false ) -- apply pinch translation, scaling and rotation to the rect centre rect.x, rect.y = pt.x, pt.y -- store the centre of all touch points rect.prevCentre = centre else -- "ended" and "cancelled" phases print( e.phase, e.x, e.y ) -- remove the tracking dot from the list if (isDevice or e.numTaps == 2) then -- get index of dot to be removed local index = table.indexOf( rect.dots, e.target ) -- remove dot from list table.remove( rect.dots, index ) rect.Numdots=0 -- remove tracking dot from the screen e.target:removeSelf() -- store the new centre of all touch points rect.prevCentre = calcAvgCentre( rect.dots ) -- refresh tracking dot scale and rotation values updateTracking( rect.prevCentre, rect.dots ) end end return true end -- if the target is not responsible for this touch event return false return false end function creaNuevoPersonaje(personaje) rect=display.newImage(personaje..".png",200,200) rect.nombre=personaje -- keep a list of the tracking dots rect.dots = { } rect.Nomdots = { } rect.Numdots =0 rect:addEventListener( "touch",startDrag) return true end timer.performWithDelay( 100, creaNuevoPersonaje("leon") ) timer.performWithDelay( 200, creaNuevoPersonaje("sol") )