line path expressions

4 line expressions for After Effects TOC

• line path with length, angle, anchorpoint, position
  Easy to link this line expression up to expression controls or other properties. Link it up to determine length, angle, position of the anchorpoint along the line and it's position.
• straight line path with controlpoints
  Easy to link up two controlpoints to this line.
• curved line path with controlpoints
  A curved line between two controlpoints.
• arrow with controlpoints
  A single arrow line between two controlpoints.

line path with length, angle, anchorpoint, position

var lineLength = 200;
var anchorAtMiddleOrEnd = 100; //100 is middle and 0 is end of line
var myPosition = [0,0];
var angle = degreesToRadians( -90 );
//pointAndTangents grouped as: point, inTangent, outTangent
var pointsAndTangents = [
            [[myPosition[0] + Math.sin(angle) * lineLength * (anchorAtMiddleOrEnd * .005),
              myPosition[1] - Math.cos(angle) * lineLength * (anchorAtMiddleOrEnd * .005)],
             [0,0], [0,0]],
            [[myPosition[0] - Math.sin(angle) * lineLength * (1 - anchorAtMiddleOrEnd * .005),
              myPosition[1] + Math.cos(angle) * lineLength * (1 - anchorAtMiddleOrEnd * .005)],
             [0,0], [0,0]]
            ];

var myPoints = [];
var myinTangents = [];
var myoutTangents = [];
for(var i = 0;i<2;i++){
    myPoints.push(pointsAndTangents[i][0]);
    myinTangents.push(pointsAndTangents[i][1]);
    myoutTangents.push(pointsAndTangents[i][2]);
}
myIs_closed = false;
createPath(myPoints, myinTangents, myoutTangents, myIs_closed);

straight line path with controlpoints

// straight line between two expression control points
try{                var linePoint1 =    
                        effect("SLT point 1")("Point") 
                        - transform.position + transform.anchorPoint;
    }catch(error){  var linePoint1 = [-100,0];  };
try{                var linePoint2 = 
                        effect("SLT point 2")("Point") 
                        - transform.position + transform.anchorPoint;
    }catch(error){  var linePoint2 = [100,0];   };
//pointAndTangents grouped as: point, inTangent, outTangent
var pointsAndTangents = [
            [linePoint1,
             [0,0], [0,0]],
            [linePoint2,
             [0,0], [0,0]]
            ];
var myPoints = [];
var myinTangents = [];
var myoutTangents = [];
for(var i = 0;i<2;i++){
    myPoints.push(pointsAndTangents[i][0]);
    myinTangents.push(pointsAndTangents[i][1]);
    myoutTangents.push(pointsAndTangents[i][2]);
}
myIs_closed = false;
createPath(myPoints, myinTangents, myoutTangents, myIs_closed);

curved line path with controlpoints

// curved line between two expression control points
try{                var linePoint1 =    
                        effect("SLT point 1")("Point") 
                        - transform.position + transform.anchorPoint;
    }catch(error){  var linePoint1 = [-100,0];  };
try{                var linePoint2 = 
                        effect("SLT point 2")("Point") 
                        - transform.position + transform.anchorPoint;
    }catch(error){  var linePoint2 = [100,0];   };

var delta = linePoint2[0] - linePoint1[0];
var factor = .5;

//pointAndTangents grouped as: point, inTangent, outTangent
var pointsAndTangents = [
            [linePoint1,
             [0,0], [delta*factor,0]],
            [linePoint2,
             [-delta*factor,0], [0,0]]
            ];
var myPoints = [];
var myinTangents = [];
var myoutTangents = [];
for(var i = 0;i<2;i++){
    myPoints.push(pointsAndTangents[i][0]);
    myinTangents.push(pointsAndTangents[i][1]);
    myoutTangents.push(pointsAndTangents[i][2]);
}
myIs_closed = false;
createPath(myPoints, myinTangents, myoutTangents, myIs_closed);

arrow with controlpoints

// arrow between two expression control points
try{                var linePoint1 =    
                        effect("SLT point 1")("Point") 
                        - transform.position + transform.anchorPoint;
    }catch(error){  var linePoint1 = [-100,0];  };
try{                var linePoint2 = 
                        effect("SLT point 2")("Point") 
                        - transform.position + transform.anchorPoint;
    }catch(error){  var linePoint2 = [100,0];   };

var delta = linePoint2[0] - linePoint1[0];
var factor = .5;
var vector = linePoint2 - linePoint1;
var anglePoint = Math.atan2(vector[1], vector[0]) + degreesToRadians(90);
var trianglepoints = [[0,0],[17.3,-30],[-17.3,-30]];

function rotatePoint(i, angle){
    rotatedpointx = trianglepoints[i][0] * Math.cos(angle) 
                    - trianglepoints[i][1] * Math.sin(angle);
    rotatedpointy = trianglepoints[i][0] * Math.sin(angle) 
                    + trianglepoints[i][1] * Math.cos(angle);
    return [rotatedpointx,rotatedpointy]
}

//pointAndTangents grouped as: point, inTangent, outTangent
var pointsAndTangents = [
            [rotatePoint(0, anglePoint) + linePoint1,
             [0,0], [0,0]],
            [rotatePoint(1, anglePoint) + linePoint1,
             [0,0], [0,0]],
            [rotatePoint(2, anglePoint) + linePoint1,
             [0,0], [0,0]],
            [linePoint1,
             [0,0], [0,0]],
            [linePoint2,
             [0,0], [0,0]]
            ];
var myPoints = [];
var myinTangents = [];
var myoutTangents = [];
for(var i = 0;i<5;i++){
    myPoints.push(pointsAndTangents[i][0]);
    myinTangents.push(pointsAndTangents[i][1]);
    myoutTangents.push(pointsAndTangents[i][2]);
}
myIs_closed = false;
createPath(myPoints, myinTangents, myoutTangents, myIs_closed);