aligning_guidelines.js

/**
 * Should objects be aligned by a bounding box?
 * [Bug] Scaled objects sometimes can not be aligned by edges
 *
 */
function initAligningGuidelines(canvas) {

  var ctx = canvas.getSelectionContext(),
      aligningLineOffset = 5,
      aligningLineMargin = 4,
      aligningLineWidth = 1,
      aligningLineColor = 'rgb(0,255,0)',
      viewportTransform,
      zoom = 1;

  function drawVerticalLine(coords) {
    drawLine(
      coords.x + 0.5,
      coords.y1 > coords.y2 ? coords.y2 : coords.y1,
      coords.x + 0.5,
      coords.y2 > coords.y1 ? coords.y2 : coords.y1);
  }

  function drawHorizontalLine(coords) {
    drawLine(
      coords.x1 > coords.x2 ? coords.x2 : coords.x1,
      coords.y + 0.5,
      coords.x2 > coords.x1 ? coords.x2 : coords.x1,
      coords.y + 0.5);
  }

  function drawLine(x1, y1, x2, y2) {
    ctx.save();
    ctx.lineWidth = aligningLineWidth;
    ctx.strokeStyle = aligningLineColor;
    ctx.beginPath();
    ctx.moveTo(((x1+viewportTransform[4])*zoom), ((y1+viewportTransform[5])*zoom));
    ctx.lineTo(((x2+viewportTransform[4])*zoom), ((y2+viewportTransform[5])*zoom));
    ctx.stroke();
    ctx.restore();
  }

  function isInRange(value1, value2) {
    value1 = Math.round(value1);
    value2 = Math.round(value2);
    for (var i = value1 - aligningLineMargin, len = value1 + aligningLineMargin; i <= len; i++) {
      if (i === value2) {
        return true;
      }
    }
    return false;
  }

  var verticalLines = [],
      horizontalLines = [];

  canvas.on('mouse:down', function () {
    viewportTransform = canvas.viewportTransform;
    zoom = canvas.getZoom();
  });

  canvas.on('object:moving', function(e) {

    var activeObject = e.target,
        canvasObjects = canvas.getObjects(),
        activeObjectCenter = activeObject.getCenterPoint(),
        activeObjectLeft = activeObjectCenter.x,
        activeObjectTop = activeObjectCenter.y,
        activeObjectBoundingRect = activeObject.getBoundingRect(),
        activeObjectHeight = activeObjectBoundingRect.height / viewportTransform[3],