scratchfoundation/paper.js
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Clean up and improve Path drawing commands.

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This commit is contained in:
Jürg Lehni 2011-03-19 23:09:17 +00:00
parent 1267f41559
commit 2c9d168224
1 changed files with 13 additions and 17 deletions
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30
src/path/Path.js
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@ -389,9 +389,7 @@ var Path = this.Path = PathItem.extend({
handle1.x - current._point.x,
handle1.y - current._point.y));
// And add the new segment, with handleIn set to c2
this._add(
new Segment(to, handle2.subtract(to), new Point())
);
this._add(new Segment(to, handle2.subtract(to), new Point()));
},
/**
@ -399,14 +397,14 @@ var Path = this.Path = PathItem.extend({
* to point.
*/
quadraticCurveTo: function(handle, to) {
handle = Point.read(arguments, 0, 1);
to = Point.read(arguments, 1, 1);
// This is exact:
// If we have the three quad points: A E D,
// and the cubic is A B C D,
// B = E + 1/3 (A - E)
// C = E + 1/3 (D - E)
var current = getCurrentSegment(this),
x1 = current._point.x,
y1 = current._point.y;
var current = getCurrentSegment(this);
this.cubicCurveTo(
handle.add(current._point.subtract(handle).multiply(1/3)),
handle.add(to.subtract(handle).multiply(1/3)),
@ -415,22 +413,20 @@ var Path = this.Path = PathItem.extend({
},
curveTo: function(through, to, parameter) {
through = new Point(through);
to = new Point(to);
if (parameter == null)
parameter = 0.5;
through = Point.read(arguments, 0, 1);
to = Point.read(arguments, 1, 1);
var t = parameter;
if (t == null)
t = 0.5;
var current = getCurrentSegment(this)._point;
// handle = (through - (1 - t)^2 * current - t^2 * to) /
// (2 * (1 - t) * t)
var t1 = 1 - parameter;
var handle = through.subtract(
current.multiply(t1 * t1)).subtract(
to.multiply(parameter * parameter)).divide(
2.0 * parameter * t1);
var t1 = 1 - t;
var handle = through.subtract(current.multiply(t1 * t1)).subtract(
to.multiply(t * t)).divide(2 * t * t1);
if (handle.isNaN())
throw new Error(
"Cannot put a curve through points with parameter="
+ parameter);
"Cannot put a curve through points with parameter=" + t);
this.quadraticCurveTo(handle, to);
},