var _constants = require("../../graphic/constants");

var mathRound = _constants.mathRound;
var mathMax = _constants.mathMax;

/**
 * Sub-pixel optimize for canvas rendering, prevent from blur
 * when rendering a thin vertical/horizontal line.
 */

/**
 * Sub pixel optimize line for canvas
 *
 * @param {Object} outputShape The modification will be performed on `outputShape`.
 *                 `outputShape` and `inputShape` can be the same object.
 *                 `outputShape` object can be used repeatly, because all of
 *                 the `x1`, `x2`, `y1`, `y2` will be assigned in this method.
 * @param {Object} [inputShape]
 * @param {Number} [inputShape.x1]
 * @param {Number} [inputShape.y1]
 * @param {Number} [inputShape.x2]
 * @param {Number} [inputShape.y2]
 * @param {Object} [style]
 * @param {Number} [style.lineWidth]
 */
function subPixelOptimizeLine(outputShape, inputShape, style) {
  var lineWidth = style && style.lineWidth;

  if (!inputShape || !lineWidth) {
    return;
  }

  var x1 = inputShape.x1;
  var x2 = inputShape.x2;
  var y1 = inputShape.y1;
  var y2 = inputShape.y2;

  if (mathRound(x1 * 2) === mathRound(x2 * 2)) {
    outputShape.x1 = outputShape.x2 = subPixelOptimize(x1, lineWidth, true);
  } else {
    outputShape.x1 = x1;
    outputShape.x2 = x2;
  }

  if (mathRound(y1 * 2) === mathRound(y2 * 2)) {
    outputShape.y1 = outputShape.y2 = subPixelOptimize(y1, lineWidth, true);
  } else {
    outputShape.y1 = y1;
    outputShape.y2 = y2;
  }
}
/**
 * Sub pixel optimize rect for canvas
 *
 * @param {Object} outputShape The modification will be performed on `outputShape`.
 *                 `outputShape` and `inputShape` can be the same object.
 *                 `outputShape` object can be used repeatly, because all of
 *                 the `x`, `y`, `width`, `height` will be assigned in this method.
 * @param {Object} [inputShape]
 * @param {Number} [inputShape.x]
 * @param {Number} [inputShape.y]
 * @param {Number} [inputShape.width]
 * @param {Number} [inputShape.height]
 * @param {Object} [style]
 * @param {Number} [style.lineWidth]
 */


function subPixelOptimizeRect(outputShape, inputShape, style) {
  var lineWidth = style && style.lineWidth;

  if (!inputShape || !lineWidth) {
    return;
  }

  var originX = inputShape.x;
  var originY = inputShape.y;
  var originWidth = inputShape.width;
  var originHeight = inputShape.height;
  outputShape.x = subPixelOptimize(originX, lineWidth, true);
  outputShape.y = subPixelOptimize(originY, lineWidth, true);
  outputShape.width = mathMax(subPixelOptimize(originX + originWidth, lineWidth, false) - outputShape.x, originWidth === 0 ? 0 : 1);
  outputShape.height = mathMax(subPixelOptimize(originY + originHeight, lineWidth, false) - outputShape.y, originHeight === 0 ? 0 : 1);
}
/**
 * Sub pixel optimize for canvas
 *
 * @param {Number} position Coordinate, such as x, y
 * @param {Number} lineWidth Should be nonnegative integer.
 * @param {boolean=} positiveOrNegative Default false (negative).
 * @return {Number} Optimized position.
 */


function subPixelOptimize(position, lineWidth, positiveOrNegative) {
  // Assure that (position + lineWidth / 2) is near integer edge,
  // otherwise line will be fuzzy in canvas.
  var doubledPosition = mathRound(position * 2);
  return (doubledPosition + mathRound(lineWidth)) % 2 === 0 ? doubledPosition / 2 : (doubledPosition + (positiveOrNegative ? 1 : -1)) / 2;
}

exports.subPixelOptimizeLine = subPixelOptimizeLine;
exports.subPixelOptimizeRect = subPixelOptimizeRect;
exports.subPixelOptimize = subPixelOptimize;