scratchfoundation/paper.js
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Restructure Path#getBounds() code so Curve bounds calculations can be moved to Curve.

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This commit is contained in:
Jürg Lehni 2012-12-27 15:19:42 +01:00
parent 2673991620
commit 3a1f2eec3f
1 changed files with 24 additions and 26 deletions
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50
src/path/Path.js
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@ -1889,25 +1889,8 @@ statics: {
segment._transformCoordinates(matrix, coords, false);
for (var i = 0; i < 2; i++) {
var v0 = prevCoords[i], // prev.point
v1 = prevCoords[i + 4], // prev.handleOut
v2 = coords[i + 2], // segment.handleIn
v3 = coords[i]; // segment.point
function add(value, t) {
var padding = 0;
if (value == null) {
// Calculate bezier polynomial at t
var u = 1 - t;
value = u * u * u * v0
+ 3 * u * u * t * v1
+ 3 * u * t * t * v2
+ t * t * t * v3;
// Only add strokeWidth to bounds for points which lie
// within 0 < t < 1. The corner cases for cap and join
// are handled in getStrokeBounds()
padding = strokePadding ? strokePadding[i] : 0;
}
function add(value, padding) {
var left = value - padding,
right = value + padding;
if (left < min[i])
@ -1916,21 +1899,36 @@ statics: {
max[i] = right;
}
add(v3, null);
// Calculate derivative of our bezier polynomial, divided by 3.
// Dividing by 3 allows for simpler calculations of a, b, c and
// leads to the same quadratic roots.
var a = 3 * (v1 - v2) - v0 + v3,
var v0 = prevCoords[i], // prev.point
v1 = prevCoords[i + 4], // prev.handleOut
v2 = coords[i + 2], // segment.handleIn
v3 = coords[i], // segment.point
// Calculate derivative of our bezier polynomial, divided by
// 3. Doing so allows for simpler calculations of a, b, c
// and leads to the same quadratic roots.
a = 3 * (v1 - v2) - v0 + v3,
b = 2 * (v0 + v2) - 4 * v1,
c = v1 - v0;
count = Numerical.solveQuadratic(a, b, c, roots,
Numerical.TOLERANCE);
Numerical.TOLERANCE);
// Only add strokeWidth to bounds for points which lie within
// 0 < t < 1. The corner cases for cap and join are handled in
// getStrokeBounds()
add(v3, 0);
for (var j = 0; j < count; j++) {
var t = roots[j];
var t = roots[j],
u = 1 - t;
// Test for good roots and only add to bounds if good.
if (tMin < t && t < tMax)
add(null, t);
// Calculate bezier polynomial at t
add(u * u * u * v0
+ 3 * u * u * t * v1
+ 3 * u * t * t * v2
+ t * t * t * v3,
strokePadding ? strokePadding[i] : 0);
}
}
// Swap coordinate buffers.