albert-svg/src/Line.js

Dynamic SVG generation using Cassowary constraints

// Copyright 2019 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import { Expression } from "cassowary";
import { createElement, omit } from "./utils";
import { variable } from "./helpers";

export default class Line {
  constructor(attributes = {}) {
    this.attributes_ = omit(attributes, ["x1", "y1", "x2", "y2"]);

    const idPrefix = attributes.id ? attributes.id + ":" : "";
    this.x1 = variable(idPrefix + "line.x1", attributes.x1);
    this.y1 = variable(idPrefix + "line.y1", attributes.y1);
    this.x2 = variable(idPrefix + "line.x2", attributes.x2);
    this.y2 = variable(idPrefix + "line.y2", attributes.y2);

    this.centerX = new Expression(this.x1).plus(this.x2).divide(2);
    this.centerY = new Expression(this.y1).plus(this.y2).divide(2);
  }

  render() {
    const el = createElement("line", this.attributes_);

    el.setAttributeNS(null, "x1", this.x1.value);
    el.setAttributeNS(null, "y1", this.y1.value);
    el.setAttributeNS(null, "x2", this.x2.value);
    el.setAttributeNS(null, "y2", this.y2.value);

    return el;
  }
}