text: // Adds JS functions to augment the CanvasKit interface.
  // For example, if there is a wrapper around the C++ call or logic to allow
  // chaining, it should go here.
  
  // CanvasKit.onRuntimeInitialized is called after the WASM library has loaded.
  // Anything that modifies an exposed class (e.g. SkPath) should be set
  // after onRuntimeInitialized, otherwise, it can happen outside of that scope.
  CanvasKit.onRuntimeInitialized = function() {
    // All calls to 'this' need to go in externs.js so closure doesn't minify them away.
  
    // Add some helpers for matrices. This is ported from SkMatrix.cpp
    // to save complexity and overhead of going back and forth between
    // C++ and JS layers.
    // I would have liked to use something like DOMMatrix, except it
    // isn't widely supported (would need polyfills) and it doesn't
    // have a mapPoints() function (which could maybe be tacked on here).
    // If DOMMatrix catches on, it would be worth re-considering this usage.
    CanvasKit.SkMatrix = {};
    function sdot() { // to be called with an even number of scalar args
      var acc = 0;
      for (var i=0; i < arguments.length-1; i+=2) {
        acc += arguments[i] * arguments[i+1];
      }
      return acc;
    }
  
  
    // Private general matrix functions used in both 3x3s and 4x4s.
    // Return a square identity matrix of size n.
    var identityN = function(n) {
      var size = n*n;
      var m = new Array(size);
      while(size--) {
        m[size] = size%(n+1) == 0 ? 1.0 : 0.0;
      }
      return m;
    }
  
    // Stride, a function for compactly representing several ways of copying an array into another.
    // Write vector `v` into matrix `m`. `m` is a matrix encoded as an array in row-major
    // order. Its width is passed as `width`. `v` is an array with length < (m.length/width).
    // An element of `v` is copied into `m` starting at `offset` and moving `colStride` cols right
    // each row.
    //
    // For example, a width of 4, offset of 3, and stride of -1 would put the vector here.
    // _ _ 0 _
    // _ 1 _ _
    // 2 _ _ _
    // _ _ _ 3
    //
    var stride = function(v, m, width, offset, colStride) {
      for (var i=0; i<v.length; i++) {
        m[i * width + // column
          (i * colStride + offset + width) % width // row
        ] = v[i];
      }
      return m;
    }
  
    CanvasKit.SkMatrix.identity = function() {
      return identityN(3);
    };
  
    // Return the inverse (if it exists) of this matrix.
    // Otherwise, return the identity.
    CanvasKit.SkMatrix.invert = function(m) {
      // Find the determinant by the sarrus rule. https://en.wikipedia.org/wiki/Rule_of_Sarrus
      var det = m[0]*m[4]*m[8] + m[1]*m[5]*m[6] + m[2]*m[3]*m[7]
              - m[2]*m[4]*m[6] - m[1]*m[3]*m[8] - m[0]*m[5]*m[7];
      if (!det) {
        SkDebug('Warning, uninvertible matrix');
        return null;
      }
      // Return the inverse by the formula adj(m)/det.
      // adj (adjugate) of a 3x3 is the transpose of it's cofactor matrix.
      // a cofactor matrix is a matrix where each term is +-det(N) where matrix N is the 2x2 formed
      // by removing the row and column we're currently setting from the source.
      // the sign alternates in a checkerboard pattern with a `+` at the top left.
      // that's all been combined here into one expression.
      return [
        (m[4]*m[8] - m[5]*m[7])/det, (m[2]*m[7] - m[1]*m[8])/det, (m[1]*m[5] - m[2]*m[4])/det,
        (m[5]*m[6] - m[3]*m[8])/det, (m[0]*m[8] - m[2]*m[6])/det, (m[2]*m[3] - m[0]*m[5])/det,
        (m[3]*m[7] - m[4]*m[6])/det, (m[1]*m[6] - m[0]*m[7])/det, (m[0]*m[4] - m[1]*m[3])/det,
      ];
    };
  
    // Maps the given points according to the passed in matrix.
    // Results are done in place.
    // See SkMatrix.h::mapPoints for the docs on the math.
    CanvasKit.SkMatrix.mapPoints = function(matrix, ptArr) {
      if (skIsDebug && (ptArr.length % 2)) {
        throw 'mapPoints requires an even length arr';
      }
      for (var i = 0; i < ptArr.length; i+=2) {
        var x = ptArr[i], y = ptArr[i+1];
        // Gx+Hy+I
        var denom  = matrix[6]*x + matrix[7]*y + matrix[8];
        // Ax+By+C
        var xTrans = matrix[0]*x + matrix[1]*y + matrix[2];
        // Dx+Ey+F
        var yTrans = matrix[3]*x + matrix[4]*y + matrix[5];
        ptArr[i]   = xTrans/denom;
        ptArr[i+1] = yTrans/denom;
      }
      return ptArr;
    };
  
    function isnumber(val) { return val !== NaN; };
  
    // gereralized iterative algorithm for multiplying two matrices.
    function multiply(m1, m2, size) {
  
      if (skIsDebug && (!m1.every(isnumber) || !m2.every(isnumber))) {
        throw 'Some members of matrices are NaN m1='+m1+', m2='+m2+'';
      }
      if (skIsDebug && (m1.length !== m2.length)) {
        throw 'Undefined for matrices of different sizes. m1.length='+m1.length+', m2.length='+m2.length;
      }
      if (skIsDebug && (size*size !== m1.length)) {
        throw 'Undefined for non-square matrices. array size was '+size;
      }
  
      var result = Array(m1.length);
      for (var r = 0; r < size; r++) {
        for (var c = 0; c < size; c++) {
          // accumulate a sum of m1[r,k]*m2[k, c]
          var acc = 0;
          for (var k = 0; k < size; k++) {
            acc += m1[size * r + k] * m2[size * k + c];
          }
          result[r * size + c] = acc;
        }
      }
      return result;
    };
  
    // Accept an integer indicating the size of the matrices being multiplied (3 for 3x3), and any
    // number of matrices following it.
    function multiplyMany(size, listOfMatrices) {
      if (skIsDebug && (listOfMatrices.length < 2)) {
        throw 'multiplication expected two or more matrices';
      }
      var result = multiply(listOfMatrices[0], listOfMatrices[1], size);
      var next = 2;
      while (next < listOfMatrices.length) {
        result = multiply(result, listOfMatrices[next], size);
        next++;
      }
      return result;
    };
  
    // Accept any number 3x3 of matrices as arguments, multiply them together.
    // Matrix multiplication is associative but not commutatieve. the order of the arguments
    // matters, but it does not matter that this implementation multiplies them left to right.
    CanvasKit.SkMatrix.multiply = function() {
      return multiplyMany(3, arguments);
    };
  
    // Return a matrix representing a rotation by n radians.
    // px, py optionally say which point the rotation should be around
    // with the default being (0, 0);
    CanvasKit.SkMatrix.rotated = function(radians, px, py) {
      px = px || 0;
      py = py || 0;
      var sinV = Math.sin(radians);
      var cosV = Math.cos(radians);
      return [
        cosV, -sinV, sdot( sinV, py, 1 - cosV, px),
        sinV,  cosV, sdot(-sinV, px, 1 - cosV, py),
        0,        0,                             1,
      ];
    };
  
    CanvasKit.SkMatrix.scaled = function(sx, sy, px, py) {
      px = px || 0;
      py = py || 0;
      var m = stride([sx, sy], identityN(3), 3, 0, 1);
      return stride([px-sx*px, py-sy*py], m, 3, 2, 0);
    };
  
    CanvasKit.SkMatrix.skewed = function(kx, ky, px, py) {
      px = px || 0;
      py = py || 0;
      var m = stride([kx, ky], identityN(3), 3, 1, -1);
      return stride([-kx*px, -ky*py], m, 3, 2, 0);
    };
  
    CanvasKit.SkMatrix.translated = function(dx, dy) {
      return stride(arguments, identityN(3), 3, 2, 0);
    };
  
    // Functions for manipulating vectors.
    // Loosely based off of SkV3 in SkM44.h but skia also has SkVec2 and Skv4. This combines them and
    // works on vectors of any length.
    CanvasKit.SkVector = {};
    CanvasKit.SkVector.dot = function(a, b) {
      if (skIsDebug && (a.length !== b.length)) {
        throw 'Cannot perform dot product on arrays of different length ('+a.length+' vs '+b.length+')';
      }
      return a.map(function(v, i) { return v*b[i] }).reduce(function(acc, cur) { return acc + cur; });
    }
    CanvasKit.SkVector.lengthSquared = function(v) {
      return CanvasKit.SkVector.dot(v, v);
    }
    CanvasKit.SkVector.length = function(v) {
      return Math.sqrt(CanvasKit.SkVector.lengthSquared(v));
    }
    CanvasKit.SkVector.mulScalar = function(v, s) {
      return v.map(function(i) { return i*s });
    }
    CanvasKit.SkVector.add = function(a, b) {
      return a.map(function(v, i) { return v+b[i] });
    }
    CanvasKit.SkVector.sub = function(a, b) {
      return a.map(function(v, i) { return v-b[i]; });
    }
    CanvasKit.SkVector.dist = function(a, b) {
      return CanvasKit.SkVector.length(CanvasKit.SkVector.sub(a, b));
    }
    CanvasKit.SkVector.normalize = function(v) {
      return CanvasKit.SkVector.mulScalar(v, 1/CanvasKit.SkVector.length(v));
    }
    CanvasKit.SkVector.cross = function(a, b) {
      if (skIsDebug && (a.length !== 3 || a.length !== 3)) {
        throw 'Cross product is only defined for 3-dimensional vectors (a.length='+a.length+', b.length='+b.length+')';
      }
      return [
        a[1]*b[2] - a[2]*b[1],
        a[2]*b[0] - a[0]*b[2],
        a[0]*b[1] - a[1]*b[0],
      ];
    }
  
    // Functions for creating and manipulating 4x4 matrices. Accepted in place of SkM44 in canvas
    // methods, for the same reasons as the 3x3 matrices above.
    // ported from C++ code in SkM44.cpp
    CanvasKit.SkM44 = {};
    // Create a 4x4 identity matrix
    CanvasKit.SkM44.identity = function() {
      return identityN(4);
    }
  
    // Anything named vec below is an array of length 3 representing a vector/point in 3D space.
    // Create a 4x4 matrix representing a translate by the provided 3-vec
    CanvasKit.SkM44.translated = function(vec) {
      return stride(vec, identityN(4), 4, 3, 0);
    }
    // Create a 4x4 matrix representing a scaling by the provided 3-vec
    CanvasKit.SkM44.scaled = function(vec) {
      return stride(vec, identityN(4), 4, 0, 1);
    }
    // Create a 4x4 matrix representing a rotation about the provided axis 3-vec.
    // axis does not need to be normalized.
    CanvasKit.SkM44.rotated = function(axisVec, radians) {
      return CanvasKit.SkM44.rotatedUnitSinCos(
        CanvasKit.SkVector.normalize(axisVec), Math.sin(radians), Math.cos(radians));
    }
    // Create a 4x4 matrix representing a rotation about the provided normalized axis 3-vec.
    // Rotation is provided redundantly as both sin and cos values.
    // This rotate can be used when you already have the cosAngle and sinAngle values
    // so you don't have to atan(cos/sin) to call roatated() which expects an angle in radians.
    // this does no checking! Behavior for invalid sin or cos values or non-normalized axis vectors
    // is incorrect. Prefer rotate().
    CanvasKit.SkM44.rotatedUnitSinCos = function(axisVec, sinAngle, cosAngle) {
      var x = axisVec[0];
      var y = axisVec[1];
      var z = axisVec[2];
      var c = cosAngle;
      var s = sinAngle;
      var t = 1 - c;
      return [
        t*x*x + c,   t*x*y - s*z, t*x*z + s*y, 0,
        t*x*y + s*z, t*y*y + c,   t*y*z - s*x, 0,
        t*x*z - s*y, t*y*z + s*x, t*z*z + c,   0,
        0,           0,           0,           1
      ];
    }
    // Create a 4x4 matrix representing a camera at eyeVec, pointed at centerVec.
    CanvasKit.SkM44.lookat = function(eyeVec, centerVec, upVec) {
      var f = CanvasKit.SkVector.normalize(CanvasKit.SkVector.sub(centerVec, eyeVec));
      var u = CanvasKit.SkVector.normalize(upVec);
      var s = CanvasKit.SkVector.normalize(CanvasKit.SkVector.cross(f, u));
  
      var m = CanvasKit.SkM44.identity();
      // set each column's top three numbers
      stride(s,                                 m, 4, 0, 0);
      stride(CanvasKit.SkVector.cross(s, f),      m, 4, 1, 0);
      stride(CanvasKit.SkVector.mulScalar(f, -1), m, 4, 2, 0);
      stride(eyeVec,                            m, 4, 3, 0);
  
      var m2 = CanvasKit.SkM44.invert(m);
      if (m2 === null) {
        return CanvasKit.SkM44.identity();
      }
      return m2;
    }
    // Create a 4x4 matrix representing a perspective. All arguments are scalars.
    // angle is in radians.
    CanvasKit.SkM44.perspective = function(near, far, angle) {
      if (skIsDebug && (far <= near)) {
        throw "far must be greater than near when constructing SkM44 using perspective.";
      }
      var dInv = 1 / (far - near);
      var halfAngle = angle / 2;
      var cot = Math.cos(halfAngle) / Math.sin(halfAngle);
      return [
        cot, 0,   0,               0,
        0,   cot, 0,               0,
        0,   0,   (far+near)*dInv, 2*far*near*dInv,
        0,   0,   -1,              1,
      ];
    }
    // Returns the number at the given row and column in matrix m.
    CanvasKit.SkM44.rc = function(m, r, c) {
      return m[r*4+c];
    }
    // Accepts any number of 4x4 matrix arguments, multiplies them left to right.
    CanvasKit.SkM44.multiply = function() {
      return multiplyMany(4, arguments);
    }
  
    // Invert the 4x4 matrix if it is invertible and return it. if not, return null.
    // taken from SkM44.cpp (altered to use row-major order)
    // m is not altered.
    CanvasKit.SkM44.invert = function(m) {
      if (skIsDebug && !m.every(isnumber)) {
        throw 'some members of matrix are NaN m='+m;
      }
  
      var a00 = m[0];
      var a01 = m[4];
      var a02 = m[8];
      var a03 = m[12];
      var a10 = m[1];
      var a11 = m[5];
      var a12 = m[9];
      var a13 = m[13];
      var a20 = m[2];
      var a21 = m[6];
      var a22 = m[10];
      var a23 = m[14];
      var a30 = m[3];
      var a31 = m[7];
      var a32 = m[11];
      var a33 = m[15];
  
      var b00 = a00 * a11 - a01 * a10;
      var b01 = a00 * a12 - a02 * a10;
      var b02 = a00 * a13 - a03 * a10;
      var b03 = a01 * a12 - a02 * a11;
      var b04 = a01 * a13 - a03 * a11;
      var b05 = a02 * a13 - a03 * a12;
      var b06 = a20 * a31 - a21 * a30;
      var b07 = a20 * a32 - a22 * a30;
      var b08 = a20 * a33 - a23 * a30;
      var b09 = a21 * a32 - a22 * a31;
      var b10 = a21 * a33 - a23 * a31;
      var b11 = a22 * a33 - a23 * a32;
  
      // calculate determinate
      var det = b00 * b11 - b01 * b10 + b02 * b09 + b03 * b08 - b04 * b07 + b05 * b06;
      var invdet = 1.0 / det;
  
      // bail out if the matrix is not invertible
      if (det === 0 || invdet === Infinity) {
        SkDebug('Warning, uninvertible matrix');
        return null;
      }
  
      b00 *= invdet;
      b01 *= invdet;
      b02 *= invdet;
      b03 *= invdet;
      b04 *= invdet;
      b05 *= invdet;
      b06 *= invdet;
      b07 *= invdet;
      b08 *= invdet;
      b09 *= invdet;
      b10 *= invdet;
      b11 *= invdet;
  
      // store result in row major order
      var tmp = [
        a11 * b11 - a12 * b10 + a13 * b09,
        a12 * b08 - a10 * b11 - a13 * b07,
        a10 * b10 - a11 * b08 + a13 * b06,
        a11 * b07 - a10 * b09 - a12 * b06,
  
        a02 * b10 - a01 * b11 - a03 * b09,
        a00 * b11 - a02 * b08 + a03 * b07,
        a01 * b08 - a00 * b10 - a03 * b06,
        a00 * b09 - a01 * b07 + a02 * b06,
  
        a31 * b05 - a32 * b04 + a33 * b03,
        a32 * b02 - a30 * b05 - a33 * b01,
        a30 * b04 - a31 * b02 + a33 * b00,
        a31 * b01 - a30 * b03 - a32 * b00,
  
        a22 * b04 - a21 * b05 - a23 * b03,
        a20 * b05 - a22 * b02 + a23 * b01,
        a21 * b02 - a20 * b04 - a23 * b00,
        a20 * b03 - a21 * b01 + a22 * b00,
      ];
  
  
      if (!tmp.every(function(val) { return val !== NaN && val !== Infinity && val !== -Infinity; })) {
        SkDebug('inverted matrix contains infinities or NaN '+tmp);
        return null;
      }
      return tmp;
    }
  
    CanvasKit.SkM44.transpose = function(m) {
      return [
        m[0], m[4], m[8], m[12],
        m[1], m[5], m[9], m[13],
        m[2], m[6], m[10], m[14],
        m[3], m[7], m[11], m[15],
      ];
    }
  
    // An SkColorMatrix is a 4x4 color matrix that transforms the 4 color channels
    //  with a 1x4 matrix that post-translates those 4 channels.
    // For example, the following is the layout with the scale (S) and post-transform
    // (PT) items indicated.
    // RS,  0,  0,  0 | RPT
    //  0, GS,  0,  0 | GPT
    //  0,  0, BS,  0 | BPT
    //  0,  0,  0, AS | APT
    //
    // Much of this was hand-transcribed from SkColorMatrix.cpp, because it's easier to
    // deal with a Float32Array of length 20 than to try to expose the SkColorMatrix object.
  
    var rScale = 0;
    var gScale = 6;
    var bScale = 12;
    var aScale = 18;
  
    var rPostTrans = 4;
    var gPostTrans = 9;
    var bPostTrans = 14;
    var aPostTrans = 19;
  
    CanvasKit.SkColorMatrix = {};
    CanvasKit.SkColorMatrix.identity = function() {
      var m = new Float32Array(20);
      m[rScale] = 1;
      m[gScale] = 1;
      m[bScale] = 1;
      m[aScale] = 1;
      return m;
    }
  
    CanvasKit.SkColorMatrix.scaled = function(rs, gs, bs, as) {
      var m = new Float32Array(20);
      m[rScale] = rs;
      m[gScale] = gs;
      m[bScale] = bs;
      m[aScale] = as;
      return m;
    }
  
    var rotateIndices = [
      [6, 7, 11, 12],
      [0, 10, 2, 12],
      [0, 1,  5,  6],
    ];
    // axis should be 0, 1, 2 for r, g, b
    CanvasKit.SkColorMatrix.rotated = function(axis, sine, cosine) {
      var m = CanvasKit.SkColorMatrix.identity();
      var indices = rotateIndices[axis];
      m[indices[0]] = cosine;
      m[indices[1]] = sine;
      m[indices[2]] = -sine;
      m[indices[3]] = cosine;
      return m;
    }
  
    // m is a SkColorMatrix (i.e. a Float32Array), and this sets the 4 "special"
    // params that will translate the colors after they are multiplied by the 4x4 matrix.
    CanvasKit.SkColorMatrix.postTranslate = function(m, dr, dg, db, da) {
      m[rPostTrans] += dr;
      m[gPostTrans] += dg;
      m[bPostTrans] += db;
      m[aPostTrans] += da;
      return m;
    }
  
    // concat returns a new SkColorMatrix that is the result of multiplying outer*inner;
    CanvasKit.SkColorMatrix.concat = function(outer, inner) {
      var m = new Float32Array(20);
      var index = 0;
      for (var j = 0; j < 20; j += 5) {
          for (var i = 0; i < 4; i++) {
              m[index++] =  outer[j + 0] * inner[i + 0] +
                            outer[j + 1] * inner[i + 5] +
                            outer[j + 2] * inner[i + 10] +
                            outer[j + 3] * inner[i + 15];
          }
          m[index++] =  outer[j + 0] * inner[4] +
                        outer[j + 1] * inner[9] +
                        outer[j + 2] * inner[14] +
                        outer[j + 3] * inner[19] +
                        outer[j + 4];
      }
  
      return m;
    }
  
    CanvasKit.SkPath.prototype.addArc = function(oval, startAngle, sweepAngle) {
      // see arc() for the HTMLCanvas version
      // note input angles are degrees.
      this._addArc(oval, startAngle, sweepAngle);
      return this;
    };
  
    CanvasKit.SkPath.prototype.addOval = function(oval, isCCW, startIndex) {
      if (startIndex === undefined) {
        startIndex = 1;
      }
      this._addOval(oval, !!isCCW, startIndex);
      return this;
    };
  
    CanvasKit.SkPath.prototype.addPath = function() {
      // Takes 1, 2, 7, or 10 required args, where the first arg is always the path.
      // The last arg is optional and chooses between add or extend mode.
      // The options for the remaining args are:
      //   - an array of 6 or 9 parameters (perspective is optional)
      //   - the 9 parameters of a full matrix or
      //     the 6 non-perspective params of a matrix.
      var args = Array.prototype.slice.call(arguments);
      var path = args[0];
      var extend = false;
      if (typeof args[args.length-1] === "boolean") {
        extend = args.pop();
      }
      if (args.length === 1) {
        // Add path, unchanged.  Use identity matrix
        this._addPath(path, 1, 0, 0,
                            0, 1, 0,
                            0, 0, 1,
                            extend);
      } else if (args.length === 2) {
        // User provided the 9 params of a full matrix as an array.
        var a = args[1];
        this._addPath(path, a[0],      a[1],      a[2],
                            a[3],      a[4],      a[5],
                            a[6] || 0, a[7] || 0, a[8] || 1,
                            extend);
      } else if (args.length === 7 || args.length === 10) {
        // User provided the 9 params of a (full) matrix directly.
        // (or just the 6 non perspective ones)
        // These are in the same order as what Skia expects.
        var a = args;
        this._addPath(path, a[1],      a[2],      a[3],
                            a[4],      a[5],      a[6],
                            a[7] || 0, a[8] || 0, a[9] || 1,
                            extend);
      } else {
        SkDebug('addPath expected to take 1, 2, 7, or 10 required args. Got ' + args.length);
        return null;
      }
      return this;
    };
  
    // points is either an array of [x, y] where x and y are numbers or
    // a typed array from Malloc where the even indices will be treated
    // as x coordinates and the odd indices will be treated as y coordinates.
    CanvasKit.SkPath.prototype.addPoly = function(points, close) {
      var ptr;
      var n;
      // This was created with CanvasKit.Malloc, so assume the user has
      // already been filled with data.
      if (points['_ck']) {
        ptr = points.byteOffset;
        n = points.length/2;
      } else {
        ptr = copy2dArray(points, CanvasKit.HEAPF32);
        n = points.length;
      }
      this._addPoly(ptr, n, close);
      CanvasKit._free(ptr);
      return this;
    };
  
    CanvasKit.SkPath.prototype.addRect = function() {
      // Takes 1, 2, 4 or 5 args
      //  - SkRect
      //  - SkRect, isCCW
      //  - left, top, right, bottom
      //  - left, top, right, bottom, isCCW
      if (arguments.length === 1 || arguments.length === 2) {
        var r = arguments[0];
        var ccw = arguments[1] || false;
        this._addRect(r.fLeft, r.fTop, r.fRight, r.fBottom, ccw);
      } else if (arguments.length === 4 || arguments.length === 5) {
        var a = arguments;
        this._addRect(a[0], a[1], a[2], a[3], a[4] || false);
      } else {
        SkDebug('addRect expected to take 1, 2, 4, or 5 args. Got ' + arguments.length);
        return null;
      }
      return this;
    };
  
    CanvasKit.SkPath.prototype.addRoundRect = function() {
      // Takes 3, 4, 6 or 7 args
      //  - SkRect, radii, ccw
      //  - SkRect, rx, ry, ccw
      //  - left, top, right, bottom, radii, ccw
      //  - left, top, right, bottom, rx, ry, ccw
      var args = arguments;
      if (args.length === 3 || args.length === 6) {
        var radii = args[args.length-2];
      } else if (args.length === 6 || args.length === 7){
        // duplicate the given (rx, ry) pairs for each corner.
        var rx = args[args.length-3];
        var ry = args[args.length-2];
        var radii = [rx, ry, rx, ry, rx, ry, rx, ry];
      } else {
        SkDebug('addRoundRect expected to take 3, 4, 6, or 7 args. Got ' + args.length);
        return null;
      }
      if (radii.length !== 8) {
        SkDebug('addRoundRect needs 8 radii provided. Got ' + radii.length);
        return null;
      }
      var rptr = copy1dArray(radii, CanvasKit.HEAPF32);
      if (args.length === 3 || args.length === 4) {
        var r = args[0];
        var ccw = args[args.length - 1];
        this._addRoundRect(r.fLeft, r.fTop, r.fRight, r.fBottom, rptr, ccw);
      } else if (args.length === 6 || args.length === 7) {
        var a = args;
        this._addRoundRect(a[0], a[1], a[2], a[3], rptr, ccw);
      }
      CanvasKit._free(rptr);
      return this;
    };
  
    CanvasKit.SkPath.prototype.arc = function(x, y, radius, startAngle, endAngle, ccw) {
      // emulates the HTMLCanvas behavior.  See addArc() for the SkPath version.
      // Note input angles are radians.
      var bounds = CanvasKit.LTRBRect(x-radius, y-radius, x+radius, y+radius);
      var sweep = radiansToDegrees(endAngle - startAngle) - (360 * !!ccw);
      var temp = new CanvasKit.SkPath();
      temp.addArc(bounds, radiansToDegrees(startAngle), sweep);
      this.addPath(temp, true);
      temp.delete();
      return this;
    };
  
    CanvasKit.SkPath.prototype.arcTo = function() {
      // takes 4, 5 or 7 args
      // - 5 x1, y1, x2, y2, radius
      // - 4 oval (as Rect), startAngle, sweepAngle, forceMoveTo
      // - 7 rx, ry, xAxisRotate, useSmallArc, isCCW, x, y
      var args = arguments;
      if (args.length === 5) {
        this._arcTo(args[0], args[1], args[2], args[3], args[4]);
      } else if (args.length === 4) {
        this._arcTo(args[0], args[1], args[2], args[3]);
      } else if (args.length === 7) {
        this._arcTo(args[0], args[1], args[2], !!args[3], !!args[4], args[5], args[6]);
      } else {
        throw 'Invalid args for arcTo. Expected 4, 5, or 7, got '+ args.length;
      }
  
      return this;
    };
  
    CanvasKit.SkPath.prototype.close = function() {
      this._close();
      return this;
    };
  
    CanvasKit.SkPath.prototype.conicTo = function(x1, y1, x2, y2, w) {
      this._conicTo(x1, y1, x2, y2, w);
      return this;
    };
  
    CanvasKit.SkPath.prototype.cubicTo = function(cp1x, cp1y, cp2x, cp2y, x, y) {
      this._cubicTo(cp1x, cp1y, cp2x, cp2y, x, y);
      return this;
    };
  
    CanvasKit.SkPath.prototype.dash = function(on, off, phase) {
      if (this._dash(on, off, phase)) {
        return this;
      }
      return null;
    };
  
    CanvasKit.SkPath.prototype.lineTo = function(x, y) {
      this._lineTo(x, y);
      return this;
    };
  
    CanvasKit.SkPath.prototype.moveTo = function(x, y) {
      this._moveTo(x, y);
      return this;
    };
  
    CanvasKit.SkPath.prototype.offset = function(dx, dy) {
      this._transform(1, 0, dx,
                      0, 1, dy,
                      0, 0, 1);
      return this;
    };
  
    CanvasKit.SkPath.prototype.quadTo = function(cpx, cpy, x, y) {
      this._quadTo(cpx, cpy, x, y);
      return this;
    };
  
   CanvasKit.SkPath.prototype.rArcTo = function(rx, ry, xAxisRotate, useSmallArc, isCCW, dx, dy) {
      this._rArcTo(rx, ry, xAxisRotate, useSmallArc, isCCW, dx, dy);
      return this;
    };
  
    CanvasKit.SkPath.prototype.rConicTo = function(dx1, dy1, dx2, dy2, w) {
      this._rConicTo(dx1, dy1, dx2, dy2, w);
      return this;
    };
  
    // These params are all relative
    CanvasKit.SkPath.prototype.rCubicTo = function(cp1x, cp1y, cp2x, cp2y, x, y) {
      this._rCubicTo(cp1x, cp1y, cp2x, cp2y, x, y);
      return this;
    };
  
    CanvasKit.SkPath.prototype.rLineTo = function(dx, dy) {
      this._rLineTo(dx, dy);
      return this;
    };
  
    CanvasKit.SkPath.prototype.rMoveTo = function(dx, dy) {
      this._rMoveTo(dx, dy);
      return this;
    };
  
    // These params are all relative
    CanvasKit.SkPath.prototype.rQuadTo = function(cpx, cpy, x, y) {
      this._rQuadTo(cpx, cpy, x, y);
      return this;
    };
  
    CanvasKit.SkPath.prototype.stroke = function(opts) {
      // Fill out any missing values with the default values.
      /**
       * See externs.js for this definition
       * @type {StrokeOpts}
       */
      opts = opts || {};
      opts.width = opts.width || 1;
      opts.miter_limit = opts.miter_limit || 4;
      opts.cap = opts.cap || CanvasKit.StrokeCap.Butt;
      opts.join = opts.join || CanvasKit.StrokeJoin.Miter;
      opts.precision = opts.precision || 1;
      if (this._stroke(opts)) {
        return this;
      }
      return null;
    };
  
    CanvasKit.SkPath.prototype.transform = function() {
      // Takes 1 or 9 args
      if (arguments.length === 1) {
        // argument 1 should be a 6 or 9 element array.
        var a = arguments[0];
        this._transform(a[0], a[1], a[2],
                        a[3], a[4], a[5],
                        a[6] || 0, a[7] || 0, a[8] || 1);
      } else if (arguments.length === 6 || arguments.length === 9) {
        // these arguments are the 6 or 9 members of the matrix
        var a = arguments;
        this._transform(a[0], a[1], a[2],
                        a[3], a[4], a[5],
                        a[6] || 0, a[7] || 0, a[8] || 1);
      } else {
        throw 'transform expected to take 1 or 9 arguments. Got ' + arguments.length;
      }
      return this;
    };
    // isComplement is optional, defaults to false
    CanvasKit.SkPath.prototype.trim = function(startT, stopT, isComplement) {
      if (this._trim(startT, stopT, !!isComplement)) {
        return this;
      }
      return null;
    };
  
    // bones should be a 3d array.
    // Each bone is a 3x2 transformation matrix in column major order:
    // | scaleX   skewX transX |
    // |  skewY  scaleY transY |
    // and bones is an array of those matrices.
    // Returns a copy of this (SkVertices) with the bones applied.
    CanvasKit.SkVertices.prototype.applyBones = function(bones) {
      var bPtr = copy3dArray(bones, CanvasKit.HEAPF32);
      var vert = this._applyBones(bPtr, bones.length);
      CanvasKit._free(bPtr);
      return vert;
    }
  
    CanvasKit.SkImage.prototype.encodeToData = function() {
      if (!arguments.length) {
        return this._encodeToData();
      }
  
      if (arguments.length === 2) {
        var a = arguments;
        return this._encodeToDataWithFormat(a[0], a[1]);
      }
  
      throw 'encodeToData expected to take 0 or 2 arguments. Got ' + arguments.length;
    }
  
    CanvasKit.SkImage.prototype.makeShader = function(xTileMode, yTileMode, localMatrix) {
      if (localMatrix) {
        // Add perspective args if not provided.
        if (localMatrix.length === 6) {
          localMatrix.push(0, 0, 1);
        }
        return this._makeShader(xTileMode, yTileMode, localMatrix);
      } else {
        return this._makeShader(xTileMode, yTileMode);
      }
    }
  
    CanvasKit.SkImage.prototype.readPixels = function(imageInfo, srcX, srcY) {
      var rowBytes;
      // Important to use ["string"] notation here, otherwise the closure compiler will
      // minify away the colorType.
      switch (imageInfo["colorType"]) {
        case CanvasKit.ColorType.RGBA_8888:
          rowBytes = imageInfo.width * 4; // 1 byte per channel == 4 bytes per pixel in 8888
          break;
        case CanvasKit.ColorType.RGBA_F32:
          rowBytes = imageInfo.width * 16; // 4 bytes per channel == 16 bytes per pixel in F32
          break;
        default:
          SkDebug("Colortype not yet supported");
          return;
      }
      var pBytes = rowBytes * imageInfo.height;
      var pPtr = CanvasKit._malloc(pBytes);
  
      if (!this._readPixels(imageInfo, pPtr, rowBytes, srcX, srcY)) {
        SkDebug("Could not read pixels with the given inputs");
        return null;
      }
  
      // Put those pixels into a typed array of the right format and then
      // make a copy with slice() that we can return.
      var retVal = null;
      switch (imageInfo["colorType"]) {
        case CanvasKit.ColorType.RGBA_8888:
          retVal = new Uint8Array(CanvasKit.HEAPU8.buffer, pPtr, pBytes).slice();
          break;
        case CanvasKit.ColorType.RGBA_F32:
          retVal = new Float32Array(CanvasKit.HEAPU8.buffer, pPtr, pBytes).slice();
          break;
      }
  
      // Free the allocated pixels in the WASM memory
      CanvasKit._free(pPtr);
      return retVal;
  
    }
  
    // atlas is an SkImage, e.g. from CanvasKit.MakeImageFromEncoded
    // srcRects and dstXforms should be CanvasKit.SkRectBuilder and CanvasKit.RSXFormBuilder
    // or just arrays of floats in groups of 4.
    // colors, if provided, should be a CanvasKit.SkColorBuilder or array of SkColor
    // (from CanvasKit.Color)
    CanvasKit.SkCanvas.prototype.drawAtlas = function(atlas, srcRects, dstXforms, paint,
                                         /*optional*/ blendMode, colors) {
      if (!atlas || !paint || !srcRects || !dstXforms) {
        SkDebug('Doing nothing since missing a required input');
        return;
      }
      if (srcRects.length !== dstXforms.length || (colors && colors.length !== dstXforms.length)) {
        SkDebug('Doing nothing since input arrays length mismatches');
      }
      if (!blendMode) {
        blendMode = CanvasKit.BlendMode.SrcOver;
      }
  
      var srcRectPtr;
      if (srcRects.build) {
        srcRectPtr = srcRects.build();
      } else {
        srcRectPtr = copy1dArray(srcRects, CanvasKit.HEAPF32);
      }
  
      var dstXformPtr;
      if (dstXforms.build) {
        dstXformPtr = dstXforms.build();
      } else {
        dstXformPtr = copy1dArray(dstXforms, CanvasKit.HEAPF32);
      }
  
      var colorPtr = 0; // enscriptem doesn't like undefined for nullptr
      if (colors) {
        if (colors.build) {
          colorPtr = colors.build();
        } else {
          colorPtr = copy1dArray(colors, CanvasKit.HEAPU32);
        }
      }
  
      this._drawAtlas(atlas, dstXformPtr, srcRectPtr, colorPtr, dstXforms.length,
                      blendMode, paint);
  
      if (srcRectPtr && !srcRects.build) {
        CanvasKit._free(srcRectPtr);
      }
      if (dstXformPtr && !dstXforms.build) {
        CanvasKit._free(dstXformPtr);
      }
      if (colorPtr && !colors.build) {
        CanvasKit._free(colorPtr);
      }
  
    }
  
    // points is either an array of [x, y] where x and y are numbers or
    // a typed array from Malloc where the even indices will be treated
    // as x coordinates and the odd indices will be treated as y coordinates.
    CanvasKit.SkCanvas.prototype.drawPoints = function(mode, points, paint) {
      var ptr;
      var n;
      // This was created with CanvasKit.Malloc, so assume the user has
      // already been filled with data.
      if (points['_ck']) {
        ptr = points.byteOffset;
        n = points.length/2;
      } else {
        ptr = copy2dArray(points, CanvasKit.HEAPF32);
        n = points.length;
      }
      this._drawPoints(mode, ptr, n, paint);
      CanvasKit._free(ptr);
    }
  
    // returns Uint8Array
    CanvasKit.SkCanvas.prototype.readPixels = function(x, y, w, h, alphaType,
                                                       colorType, dstRowBytes) {
      // supply defaults (which are compatible with HTMLCanvas's getImageData)
      alphaType = alphaType || CanvasKit.AlphaType.Unpremul;
      colorType = colorType || CanvasKit.ColorType.RGBA_8888;
      dstRowBytes = dstRowBytes || (4 * w);
  
      var len = h * dstRowBytes
      var pptr = CanvasKit._malloc(len);
      var ok = this._readPixels({
        'width': w,
        'height': h,
        'colorType': colorType,
        'alphaType': alphaType,
      }, pptr, dstRowBytes, x, y);
      if (!ok) {
        CanvasKit._free(pptr);
        return null;
      }
  
      // The first typed array is just a view into memory. Because we will
      // be free-ing that, we call slice to make a persistent copy.
      var pixels = new Uint8Array(CanvasKit.HEAPU8.buffer, pptr, len).slice();
      CanvasKit._free(pptr);
      return pixels;
    }
  
    // pixels is a TypedArray. No matter the input size, it will be treated as
    // a Uint8Array (essentially, a byte array).
    CanvasKit.SkCanvas.prototype.writePixels = function(pixels, srcWidth, srcHeight,
                                                        destX, destY, alphaType, colorType) {
      if (pixels.byteLength % (srcWidth * srcHeight)) {
        throw 'pixels length must be a multiple of the srcWidth * srcHeight';
      }
      var bytesPerPixel = pixels.byteLength / (srcWidth * srcHeight);
      // supply defaults (which are compatible with HTMLCanvas's putImageData)
      alphaType = alphaType || CanvasKit.AlphaType.Unpremul;
      colorType = colorType || CanvasKit.ColorType.RGBA_8888;
      var srcRowBytes = bytesPerPixel * srcWidth;
  
      var pptr = CanvasKit._malloc(pixels.byteLength);
      CanvasKit.HEAPU8.set(pixels, pptr);
  
      var ok = this._writePixels({
        'width': srcWidth,
        'height': srcHeight,
        'colorType': colorType,
        'alphaType': alphaType,
      }, pptr, srcRowBytes, destX, destY);
  
      CanvasKit._free(pptr);
      return ok;
    }
  
    // colorMatrix is an SkColorMatrix (e.g. Float32Array of length 20)
    CanvasKit.SkColorFilter.MakeMatrix = function(colorMatrix) {
      if (!colorMatrix || colorMatrix.length !== 20) {
        SkDebug('ignoring invalid color matrix');
        return;
      }
      var fptr = copy1dArray(colorMatrix, CanvasKit.HEAPF32);
      // We know skia memcopies the floats, so we can free our memory after the call returns.
      var m = CanvasKit.SkColorFilter._makeMatrix(fptr);
      CanvasKit._free(fptr);
      return m;
    }
  
    CanvasKit.SkShader.Blend = function(mode, dst, src, localMatrix) {
      if (!localMatrix) {
        return this._Blend(mode, dst, src);
      }
      return this._Blend(mode, dst, src, localMatrix);
    }
  
    CanvasKit.SkShader.Lerp = function(t, dst, src, localMatrix) {
      if (!localMatrix) {
        return this._Lerp(t, dst, src);
      }
      return this._Lerp(t, dst, src, localMatrix);
    }
  
    CanvasKit.SkSurface.prototype.captureFrameAsSkPicture = function(drawFrame) {
      // Set up SkPictureRecorder
      var spr = new CanvasKit.SkPictureRecorder();
      var canvas = spr.beginRecording(
                      CanvasKit.LTRBRect(0, 0, this.width(), this.height()));
      drawFrame(canvas);
      var pic = spr.finishRecordingAsPicture();
      spr.delete();
      // TODO: do we need to clean up the memory for canvas?
      // If we delete it here, saveAsFile doesn't work correctly.
      return pic;
    }
  
    CanvasKit.SkSurface.prototype.requestAnimationFrame = function(callback, dirtyRect) {
      if (!this._cached_canvas) {
        this._cached_canvas = this.getCanvas();
      }
      window.requestAnimationFrame(function() {
        if (this._context !== undefined) {
          CanvasKit.setCurrentContext(this._context);
        }
  
        callback(this._cached_canvas);
  
        // We do not dispose() of the SkSurface here, as the client will typically
        // call requestAnimationFrame again from within the supplied callback.
        // For drawing a single frame, prefer drawOnce().
        this.flush();
      }.bind(this));
    }
  
    // drawOnce will dispose of the surface after drawing the frame using the provided
    // callback.
    CanvasKit.SkSurface.prototype.drawOnce = function(callback, dirtyRect) {
      if (!this._cached_canvas) {
        this._cached_canvas = this.getCanvas();
      }
      window.requestAnimationFrame(function() {
        if (this._context !== undefined) {
          CanvasKit.setCurrentContext(this._context);
        }
        callback(this._cached_canvas);
  
        this.flush();
        this.dispose();
      }.bind(this));
    }
  
    // Run through the JS files that are added at compile time.
    if (CanvasKit._extraInitializations) {
      CanvasKit._extraInitializations.forEach(function(init) {
        init();
      });
    }
  }; // end CanvasKit.onRuntimeInitialized, that is, anything changing prototypes or dynamic.
  
  CanvasKit.LTRBRect = function(l, t, r, b) {
    return {
      fLeft: l,
      fTop: t,
      fRight: r,
      fBottom: b,
    };
  }
  
  CanvasKit.XYWHRect = function(x, y, w, h) {
    return {
      fLeft: x,
      fTop: y,
      fRight: x+w,
      fBottom: y+h,
    };
  }
  
  // RRectXY returns an RRect with the given rect and a radiusX and radiusY for
  // all 4 corners.
  CanvasKit.RRectXY = function(rect, rx, ry) {
    return {
      rect: rect,
      rx1: rx,
      ry1: ry,
      rx2: rx,
      ry2: ry,
      rx3: rx,
      ry3: ry,
      rx4: rx,
      ry4: ry,
    };
  }
  
  CanvasKit.MakePathFromCmds = function(cmds) {
    var ptrLen = loadCmdsTypedArray(cmds);
    var path = CanvasKit._MakePathFromCmds(ptrLen[0], ptrLen[1]);
    CanvasKit._free(ptrLen[0]);
    return path;
  }
  
  CanvasKit.MakeSkDashPathEffect = function(intervals, phase) {
    if (!phase) {
      phase = 0;
    }
    if (!intervals.length || intervals.length % 2 === 1) {
      throw 'Intervals array must have even length';
    }
    var ptr = copy1dArray(intervals, CanvasKit.HEAPF32);
    var dpe = CanvasKit._MakeSkDashPathEffect(ptr, intervals.length, phase);
    CanvasKit._free(ptr);
    return dpe;
  }
  
  // data is a TypedArray or ArrayBuffer e.g. from fetch().then(resp.arrayBuffer())
  CanvasKit.MakeAnimatedImageFromEncoded = function(data) {
    data = new Uint8Array(data);
  
    var iptr = CanvasKit._malloc(data.byteLength);
    CanvasKit.HEAPU8.set(data, iptr);
    var img = CanvasKit._decodeAnimatedImage(iptr, data.byteLength);
    if (!img) {
      SkDebug('Could not decode animated image');
      return null;
    }
    return img;
  }
  
  // data is a TypedArray or ArrayBuffer e.g. from fetch().then(resp.arrayBuffer())
  CanvasKit.MakeImageFromEncoded = function(data) {
    data = new Uint8Array(data);
  
    var iptr = CanvasKit._malloc(data.byteLength);
    CanvasKit.HEAPU8.set(data, iptr);
    var img = CanvasKit._decodeImage(iptr, data.byteLength);
    if (!img) {
      SkDebug('Could not decode image');
      return null;
    }
    return img;
  }
  
  // pixels must be a Uint8Array with bytes representing the pixel values
  // (e.g. each set of 4 bytes could represent RGBA values for a single pixel).
  CanvasKit.MakeImage = function(pixels, width, height, alphaType, colorType) {
    var bytesPerPixel = pixels.length / (width * height);
    var info = {
      'width': width,
      'height': height,
      'alphaType': alphaType,
      'colorType': colorType,
    };
    var pptr = copy1dArray(pixels, CanvasKit.HEAPU8);
    // No need to _free pptr, Image takes it with SkData::MakeFromMalloc
  
    return CanvasKit._MakeImage(info, pptr, pixels.length, width * bytesPerPixel);
  }
  
  CanvasKit.MakeLinearGradientShader = function(start, end, colors, pos, mode, localMatrix, flags) {
    var colorPtr = copy1dArray(colors, CanvasKit.HEAPU32);
    var posPtr =   copy1dArray(pos,    CanvasKit.HEAPF32);
    flags = flags || 0;
  
    if (localMatrix) {
      // Add perspective args if not provided.
      if (localMatrix.length === 6) {
        localMatrix.push(0, 0, 1);
      }
      var lgs = CanvasKit._MakeLinearGradientShader(start, end, colorPtr, posPtr,
                                                    colors.length, mode, flags, localMatrix);
    } else {
      var lgs = CanvasKit._MakeLinearGradientShader(start, end, colorPtr, posPtr,
                                                    colors.length, mode, flags);
    }
  
    CanvasKit._free(colorPtr);
    CanvasKit._free(posPtr);
    return lgs;
  }
  
  CanvasKit.MakeRadialGradientShader = function(center, radius, colors, pos, mode, localMatrix, flags) {
    var colorPtr = copy1dArray(colors, CanvasKit.HEAPU32);
    var posPtr =   copy1dArray(pos,    CanvasKit.HEAPF32);
    flags = flags || 0;
  
    if (localMatrix) {
      // Add perspective args if not provided.
      if (localMatrix.length === 6) {
        localMatrix.push(0, 0, 1);
      }
      var rgs = CanvasKit._MakeRadialGradientShader(center, radius, colorPtr, posPtr,
                                                    colors.length, mode, flags, localMatrix);
    } else {
      var rgs = CanvasKit._MakeRadialGradientShader(center, radius, colorPtr, posPtr,
                                                    colors.length, mode, flags);
    }
  
    CanvasKit._free(colorPtr);
    CanvasKit._free(posPtr);
    return rgs;
  }
  
  CanvasKit.MakeTwoPointConicalGradientShader = function(start, startRadius, end, endRadius,
                                                         colors, pos, mode, localMatrix, flags) {
    var colorPtr = copy1dArray(colors, CanvasKit.HEAPU32);
    var posPtr =   copy1dArray(pos,    CanvasKit.HEAPF32);
    flags = flags || 0;
  
    if (localMatrix) {
      // Add perspective args if not provided.
      if (localMatrix.length === 6) {
        localMatrix.push(0, 0, 1);
      }
      var rgs = CanvasKit._MakeTwoPointConicalGradientShader(
                          start, startRadius, end, endRadius,
                          colorPtr, posPtr, colors.length, mode, flags, localMatrix);
    } else {
      var rgs = CanvasKit._MakeTwoPointConicalGradientShader(
                          start, startRadius, end, endRadius,
                          colorPtr, posPtr, colors.length, mode, flags);
    }
  
    CanvasKit._free(colorPtr);
    CanvasKit._free(posPtr);
    return rgs;
  }
  
  CanvasKit.MakeSkVertices = function(mode, positions, textureCoordinates, colors,
                                      boneIndices, boneWeights, indices, isVolatile) {
    // Default isVolitile to true if not set
    isVolatile = isVolatile === undefined ? true : isVolatile;
    var idxCount = (indices && indices.length) || 0;
  
    var flags = 0;
    // These flags are from SkVertices.h and should be kept in sync with those.
    if (textureCoordinates && textureCoordinates.length) {
      flags |= (1 << 0);
    }
    if (colors && colors.length) {
      flags |= (1 << 1);
    }
    if (boneIndices && boneIndices.length) {
      flags |= (1 << 2);
    }
    if (!isVolatile) {
      flags |= (1 << 3);
    }
  
    var builder = new CanvasKit._SkVerticesBuilder(mode,  positions.length, idxCount, flags);
  
    copy2dArray(positions,            CanvasKit.HEAPF32, builder.positions());
    if (builder.texCoords()) {
      copy2dArray(textureCoordinates, CanvasKit.HEAPF32, builder.texCoords());
    }
    if (builder.colors()) {
      copy1dArray(colors,             CanvasKit.HEAPU32, builder.colors());
    }
    if (builder.boneIndices()) {
      copy2dArray(boneIndices,        CanvasKit.HEAP32, builder.boneIndices());
    }
    if (builder.boneWeights()) {
      copy2dArray(boneWeights,        CanvasKit.HEAPF32, builder.boneWeights());
    }
    if (builder.indices()) {
      copy1dArray(indices,            CanvasKit.HEAPU16, builder.indices());
    }
  
    var idxCount = (indices && indices.length) || 0;
    // Create the vertices, which owns the memory that the builder had allocated.
    return builder.detach();
  };
  