blob: fc75fb3d46d4e69a93dbf3a4508e1e42910181bb [file] [log] [blame]
function LinearCanvasGradient(x1, y1, x2, y2) {
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 lcg = new LinearCanvasGradient(x1, y1, x2, y2);
lcg._colors = this._colors.slice();
lcg._pos = this._pos.slice();
return lcg;
}
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];
this._dispose();
this._shader = CanvasKit.MakeLinearGradientShader([sx1, sy1], [sx2, sy2],
this._colors, this._pos, CanvasKit.TileMode.Clamp);
return this._shader;
}
}