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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 | 6x 6x 6x 2x 4x 4x 3200x 3200x 3200x 800x 1x 1x 1x 400x 400x 400x 400x 400x 400x 400x 400x 1x 1x 400x 400x 400x 400x 6x | const Point = require('./Point')
const uint32 = require('./uint32')
const util = require('./util')
class CanvasGradient {
constructor() {
this.stops = []
}
addColorStop(t,colorstring) {
const color = util.colorStringToUint32(colorstring)
this.stops.push({t:t,color:color})
}
_lerpStops(t) {
const first = uint32.getBytesBigEndian(this.stops[0].color).map(b=>b/255);
const second = uint32.getBytesBigEndian(this.stops[1].color).map(b=>b/255);
const fc = first.map((f,i) => util.lerp(f,second[i],t)).map(c=>c*255)
return uint32.fromBytesBigEndian(fc[0],fc[1],fc[2],0xFF)
}
}
class LinearGradient extends CanvasGradient {
constructor(x0,y0,x1,y1) {
super()
this.start = new Point(x0,y0)
this.end = new Point(x1,y1)
}
colorAt(x,y) {
const pc = new Point(x,y) //convert to a point
//calculate V
let V = this.end.subtract(this.start) // subtract
const d = V.magnitude() // get magnitude
V = V.divide(d) // normalize
//calculate V0
const V0 = pc.subtract(this.start)
//project V0 onto V
let t = V0.dotProduct(V)
//convert to t value and clamp
t = util.clamp(t/d,0,1)
return this._lerpStops(t)
}
}
class RadialGradient extends CanvasGradient {
constructor(x0, y0, x1, y1) {
super()
this.start = new Point(x0,y0)
}
colorAt(x,y) {
const pc = new Point(x, y) //convert to a point
const dist = pc.distance(this.start)
let t = util.clamp(dist/10,0,1)
return this._lerpStops(t)
}
}
module.exports = {
CanvasGradient: CanvasGradient,
LinearGradient: LinearGradient,
RadialGradient: RadialGradient,
} |