blob: 431bbc504e9135ad8e26ac6977e11638b7ff4cd2 [file] [log] [blame]
// Note, Skia has a different notion of a "radial" gradient.
// Skia has a twoPointConical gradient that is the same as the
// canvas's RadialGradient.
function RadialCanvasGradient(x1, y1, r1, x2, y2, r2) {
this._shader = null;
this._colors = [];
this._pos = [];
this.addColorStop = function(offset, color) {
if (offset < 0 || offset > 1 || !isFinite(offset)) {
throw 'offset must be between 0 and 1 inclusively';
}
color = parseColor(color);
// From the spec: If multiple stops are added at the same offset on a
// gradient, then they must be placed in the order added, with the first
// one closest to the start of the gradient, and each subsequent one
// infinitesimally further along towards the end point (in effect
// causing all but the first and last stop added at each point to be
// ignored).
// To implement that, if an offset is already in the list,
// we just overwrite its color (since the user can't remove Color stops
// after the fact).
var idx = this._pos.indexOf(offset);
if (idx !== -1) {
this._colors[idx] = color;
} else {
// insert it in sorted order
for (idx = 0; idx < this._pos.length; idx++) {
if (this._pos[idx] > offset) {
break;
}
}
this._pos .splice(idx, 0, offset);
this._colors.splice(idx, 0, color);
}
}
this._copy = function() {
var rcg = new RadialCanvasGradient(x1, y1, r1, x2, y2, r2);
rcg._colors = this._colors.slice();
rcg._pos = this._pos.slice();
return rcg;
}
this._dispose = function() {
if (this._shader) {
this._shader.delete();
this._shader = null;
}
}
this._getShader = function(currentTransform) {
// From the spec: "The points in the linear gradient must be transformed
// as described by the current transformation matrix when rendering."
var pts = [x1, y1, x2, y2];
CanvasKit.SkMatrix.mapPoints(currentTransform, pts);
var sx1 = pts[0];
var sy1 = pts[1];
var sx2 = pts[2];
var sy2 = pts[3];
var sx = currentTransform[0];
var sy = currentTransform[4];
var scaleFactor = (Math.abs(sx) + Math.abs(sy))/2;
var sr1 = r1 * scaleFactor;
var sr2 = r2 * scaleFactor;
this._dispose();
this._shader = CanvasKit.MakeTwoPointConicalGradientShader(
[sx1, sy1], sr1, [sx2, sy2], sr2, this._colors, this._pos,
CanvasKit.TileMode.Clamp);
return this._shader;
}
}