1// Note, Skia has a different notion of a "radial" gradient. 2// Skia has a twoPointConical gradient that is the same as the 3// canvas's RadialGradient. 4 5function RadialCanvasGradient(x1, y1, r1, x2, y2, r2) { 6 this._shader = null; 7 this._colors = []; 8 this._pos = []; 9 10 this.addColorStop = function(offset, color) { 11 if (offset < 0 || offset > 1 || !isFinite(offset)) { 12 throw 'offset must be between 0 and 1 inclusively'; 13 } 14 15 color = parseColor(color); 16 // From the spec: If multiple stops are added at the same offset on a 17 // gradient, then they must be placed in the order added, with the first 18 // one closest to the start of the gradient, and each subsequent one 19 // infinitesimally further along towards the end point (in effect 20 // causing all but the first and last stop added at each point to be 21 // ignored). 22 // To implement that, if an offset is already in the list, 23 // we just overwrite its color (since the user can't remove Color stops 24 // after the fact). 25 var idx = this._pos.indexOf(offset); 26 if (idx !== -1) { 27 this._colors[idx] = color; 28 } else { 29 // insert it in sorted order 30 for (idx = 0; idx < this._pos.length; idx++) { 31 if (this._pos[idx] > offset) { 32 break; 33 } 34 } 35 this._pos .splice(idx, 0, offset); 36 this._colors.splice(idx, 0, color); 37 } 38 } 39 40 this._copy = function() { 41 var rcg = new RadialCanvasGradient(x1, y1, r1, x2, y2, r2); 42 rcg._colors = this._colors.slice(); 43 rcg._pos = this._pos.slice(); 44 return rcg; 45 } 46 47 this._dispose = function() { 48 if (this._shader) { 49 this._shader.delete(); 50 this._shader = null; 51 } 52 } 53 54 this._getShader = function(currentTransform) { 55 // From the spec: "The points in the linear gradient must be transformed 56 // as described by the current transformation matrix when rendering." 57 var pts = [x1, y1, x2, y2]; 58 CanvasKit.SkMatrix.mapPoints(currentTransform, pts); 59 var sx1 = pts[0]; 60 var sy1 = pts[1]; 61 var sx2 = pts[2]; 62 var sy2 = pts[3]; 63 64 var sx = currentTransform[0]; 65 var sy = currentTransform[4]; 66 var scaleFactor = (Math.abs(sx) + Math.abs(sy))/2; 67 68 var sr1 = r1 * scaleFactor; 69 var sr2 = r2 * scaleFactor; 70 71 this._dispose(); 72 this._shader = CanvasKit.MakeTwoPointConicalGradientShader( 73 [sx1, sy1], sr1, [sx2, sy2], sr2, this._colors, this._pos, 74 CanvasKit.TileMode.Clamp); 75 return this._shader; 76 } 77}