1 files changed, 389 insertions, 0 deletions
diff --git a/toolkit/modules/Geometry.sys.mjs b/toolkit/modules/Geometry.sys.mjs
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+++ b/toolkit/modules/Geometry.sys.mjs
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+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Simple Point class.
+ *
+ * Any method that takes an x and y may also take a point.
+ */
+export function Point(x, y) {
+  this.set(x, y);
+}
+
+Point.prototype = {
+  clone: function clone() {
+    return new Point(this.x, this.y);
+  },
+
+  set: function set(x, y) {
+    this.x = x;
+    this.y = y;
+    return this;
+  },
+
+  equals: function equals(x, y) {
+    return this.x == x && this.y == y;
+  },
+
+  toString: function toString() {
+    return "(" + this.x + "," + this.y + ")";
+  },
+
+  map: function map(f) {
+    this.x = f.call(this, this.x);
+    this.y = f.call(this, this.y);
+    return this;
+  },
+
+  add: function add(x, y) {
+    this.x += x;
+    this.y += y;
+    return this;
+  },
+
+  subtract: function subtract(x, y) {
+    this.x -= x;
+    this.y -= y;
+    return this;
+  },
+
+  scale: function scale(s) {
+    this.x *= s;
+    this.y *= s;
+    return this;
+  },
+
+  isZero() {
+    return this.x == 0 && this.y == 0;
+  },
+};
+
+(function () {
+  function takePointOrArgs(f) {
+    return function (arg1, arg2) {
+      if (arg2 === undefined) {
+        return f.call(this, arg1.x, arg1.y);
+      }
+      return f.call(this, arg1, arg2);
+    };
+  }
+
+  for (let f of ["add", "subtract", "equals", "set"]) {
+    Point.prototype[f] = takePointOrArgs(Point.prototype[f]);
+  }
+})();
+
+/**
+ * Rect is a simple data structure for representation of a rectangle supporting
+ * many basic geometric operations.
+ *
+ * NOTE: Since its operations are closed, rectangles may be empty and will report
+ * non-positive widths and heights in that case.
+ */
+
+export function Rect(x, y, w, h) {
+  this.left = x;
+  this.top = y;
+  this.right = x + w;
+  this.bottom = y + h;
+}
+
+Rect.fromRect = function fromRect(r) {
+  return new Rect(r.left, r.top, r.right - r.left, r.bottom - r.top);
+};
+
+Rect.prototype = {
+  get x() {
+    return this.left;
+  },
+  get y() {
+    return this.top;
+  },
+  get width() {
+    return this.right - this.left;
+  },
+  get height() {
+    return this.bottom - this.top;
+  },
+  set x(v) {
+    let diff = this.left - v;
+    this.left = v;
+    this.right -= diff;
+  },
+  set y(v) {
+    let diff = this.top - v;
+    this.top = v;
+    this.bottom -= diff;
+  },
+  set width(v) {
+    this.right = this.left + v;
+  },
+  set height(v) {
+    this.bottom = this.top + v;
+  },
+
+  isEmpty: function isEmpty() {
+    return this.left >= this.right || this.top >= this.bottom;
+  },
+
+  setRect(x, y, w, h) {
+    this.left = x;
+    this.top = y;
+    this.right = x + w;
+    this.bottom = y + h;
+
+    return this;
+  },
+
+  setBounds(l, t, r, b) {
+    this.top = t;
+    this.left = l;
+    this.bottom = b;
+    this.right = r;
+
+    return this;
+  },
+
+  equals: function equals(other) {
+    return (
+      other != null &&
+      ((this.isEmpty() && other.isEmpty()) ||
+        (this.top == other.top &&
+          this.left == other.left &&
+          this.bottom == other.bottom &&
+          this.right == other.right))
+    );
+  },
+
+  clone: function clone() {
+    return new Rect(
+      this.left,
+      this.top,
+      this.right - this.left,
+      this.bottom - this.top
+    );
+  },
+
+  center: function center() {
+    if (this.isEmpty()) {
+      throw new Error("Empty rectangles do not have centers");
+    }
+    return new Point(
+      this.left + (this.right - this.left) / 2,
+      this.top + (this.bottom - this.top) / 2
+    );
+  },
+
+  copyFrom(other) {
+    this.top = other.top;
+    this.left = other.left;
+    this.bottom = other.bottom;
+    this.right = other.right;
+
+    return this;
+  },
+
+  translate(x, y) {
+    this.left += x;
+    this.right += x;
+    this.top += y;
+    this.bottom += y;
+
+    return this;
+  },
+
+  toString() {
+    return (
+      "[" + this.x + "," + this.y + "," + this.width + "," + this.height + "]"
+    );
+  },
+
+  /** return a new rect that is the union of that one and this one */
+  union(other) {
+    return this.clone().expandToContain(other);
+  },
+
+  contains(other) {
+    if (other.isEmpty()) {
+      return true;
+    }
+    if (this.isEmpty()) {
+      return false;
+    }
+
+    return (
+      other.left >= this.left &&
+      other.right <= this.right &&
+      other.top >= this.top &&
+      other.bottom <= this.bottom
+    );
+  },
+
+  intersect(other) {
+    return this.clone().restrictTo(other);
+  },
+
+  intersects(other) {
+    if (this.isEmpty() || other.isEmpty()) {
+      return false;
+    }
+
+    let x1 = Math.max(this.left, other.left);
+    let x2 = Math.min(this.right, other.right);
+    let y1 = Math.max(this.top, other.top);
+    let y2 = Math.min(this.bottom, other.bottom);
+    return x1 < x2 && y1 < y2;
+  },
+
+  /** Restrict area of this rectangle to the intersection of both rectangles. */
+  restrictTo: function restrictTo(other) {
+    if (this.isEmpty() || other.isEmpty()) {
+      return this.setRect(0, 0, 0, 0);
+    }
+
+    let x1 = Math.max(this.left, other.left);
+    let x2 = Math.min(this.right, other.right);
+    let y1 = Math.max(this.top, other.top);
+    let y2 = Math.min(this.bottom, other.bottom);
+    // If width or height is 0, the intersection was empty.
+    return this.setRect(x1, y1, Math.max(0, x2 - x1), Math.max(0, y2 - y1));
+  },
+
+  /** Expand this rectangle to the union of both rectangles. */
+  expandToContain: function expandToContain(other) {
+    if (this.isEmpty()) {
+      return this.copyFrom(other);
+    }
+    if (other.isEmpty()) {
+      return this;
+    }
+
+    let l = Math.min(this.left, other.left);
+    let r = Math.max(this.right, other.right);
+    let t = Math.min(this.top, other.top);
+    let b = Math.max(this.bottom, other.bottom);
+    return this.setRect(l, t, r - l, b - t);
+  },
+
+  /**
+   * Expands to the smallest rectangle that contains original rectangle and is bounded
+   * by lines with integer coefficients.
+   */
+  expandToIntegers: function round() {
+    this.left = Math.floor(this.left);
+    this.top = Math.floor(this.top);
+    this.right = Math.ceil(this.right);
+    this.bottom = Math.ceil(this.bottom);
+    return this;
+  },
+
+  scale: function scale(xscl, yscl) {
+    this.left *= xscl;
+    this.right *= xscl;
+    this.top *= yscl;
+    this.bottom *= yscl;
+    return this;
+  },
+
+  map: function map(f) {
+    this.left = f.call(this, this.left);
+    this.top = f.call(this, this.top);
+    this.right = f.call(this, this.right);
+    this.bottom = f.call(this, this.bottom);
+    return this;
+  },
+
+  /** Ensure this rectangle is inside the other, if possible. Preserves w, h. */
+  translateInside: function translateInside(other) {
+    let offsetX = 0;
+    if (this.left <= other.left) {
+      offsetX = other.left - this.left;
+    } else if (this.right > other.right) {
+      offsetX = other.right - this.right;
+    }
+
+    let offsetY = 0;
+    if (this.top <= other.top) {
+      offsetY = other.top - this.top;
+    } else if (this.bottom > other.bottom) {
+      offsetY = other.bottom - this.bottom;
+    }
+
+    return this.translate(offsetX, offsetY);
+  },
+
+  /** Subtract other area from this. Returns array of rects whose union is this-other. */
+  subtract: function subtract(other) {
+    let r = new Rect(0, 0, 0, 0);
+    let result = [];
+    other = other.intersect(this);
+    if (other.isEmpty()) {
+      return [this.clone()];
+    }
+
+    // left strip
+    r.setBounds(this.left, this.top, other.left, this.bottom);
+    if (!r.isEmpty()) {
+      result.push(r.clone());
+    }
+    // inside strip
+    r.setBounds(other.left, this.top, other.right, other.top);
+    if (!r.isEmpty()) {
+      result.push(r.clone());
+    }
+    r.setBounds(other.left, other.bottom, other.right, this.bottom);
+    if (!r.isEmpty()) {
+      result.push(r.clone());
+    }
+    // right strip
+    r.setBounds(other.right, this.top, this.right, this.bottom);
+    if (!r.isEmpty()) {
+      result.push(r.clone());
+    }
+
+    return result;
+  },
+
+  /**
+   * Blends two rectangles together.
+   * @param rect Rectangle to blend this one with
+   * @param scalar Ratio from 0 (returns a clone of this rect) to 1 (clone of rect).
+   * @return New blended rectangle.
+   */
+  blend: function blend(rect, scalar) {
+    return new Rect(
+      this.left + (rect.left - this.left) * scalar,
+      this.top + (rect.top - this.top) * scalar,
+      this.width + (rect.width - this.width) * scalar,
+      this.height + (rect.height - this.height) * scalar
+    );
+  },
+
+  /**
+   * Grows or shrinks the rectangle while keeping the center point.
+   * Accepts single multipler, or separate for both axes.
+   */
+  inflate: function inflate(xscl, yscl) {
+    let xAdj = (this.width * xscl - this.width) / 2;
+    let s = arguments.length > 1 ? yscl : xscl;
+    let yAdj = (this.height * s - this.height) / 2;
+    this.left -= xAdj;
+    this.right += xAdj;
+    this.top -= yAdj;
+    this.bottom += yAdj;
+    return this;
+  },
+
+  /**
+   * Grows or shrinks the rectangle by fixed amount while keeping the center point.
+   * Accepts single fixed amount
+   */
+  inflateFixed: function inflateFixed(fixed) {
+    this.left -= fixed;
+    this.right += fixed;
+    this.top -= fixed;
+    this.bottom += fixed;
+    return this;
+  },
+};