public/zh/builder/src/echarts/chart/line/LineView.js

/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements.  See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership.  The ASF licenses this file
* to you 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.
*/
// FIXME step not support polar
import { __DEV__ } from '../../config';
import * as zrUtil from 'zrender/src/core/util';
import SymbolDraw from '../helper/SymbolDraw';
import SymbolClz from '../helper/Symbol';
import lineAnimationDiff from './lineAnimationDiff';
import * as graphic from '../../util/graphic';
import * as modelUtil from '../../util/model';
import { Polyline, Polygon } from './poly';
import ChartView from '../../view/Chart';
import { round } from '../../util/number';
import { prepareDataCoordInfo, getStackedOnPoint } from './helper';

function isPointsSame(points1, points2) {
  if (points1.length !== points2.length) {
    return;
  }

  for (var i = 0; i < points1.length; i++) {
    var p1 = points1[i];
    var p2 = points2[i];

    if (p1[0] !== p2[0] || p1[1] !== p2[1]) {
      return;
    }
  }

  return true;
}

function getSmooth(smooth) {
  return typeof smooth === 'number' ? smooth : smooth ? 0.5 : 0;
}

function getAxisExtentWithGap(axis) {
  var extent = axis.getGlobalExtent();

  if (axis.onBand) {
    // Remove extra 1px to avoid line miter in clipped edge
    var halfBandWidth = axis.getBandWidth() / 2 - 1;
    var dir = extent[1] > extent[0] ? 1 : -1;
    extent[0] += dir * halfBandWidth;
    extent[1] -= dir * halfBandWidth;
  }

  return extent;
}
/**
 * @param {module:echarts/coord/cartesian/Cartesian2D|module:echarts/coord/polar/Polar} coordSys
 * @param {module:echarts/data/List} data
 * @param {Object} dataCoordInfo
 * @param {Array.<Array.<number>>} points
 */


function getStackedOnPoints(coordSys, data, dataCoordInfo) {
  if (!dataCoordInfo.valueDim) {
    return [];
  }

  var points = [];

  for (var idx = 0, len = data.count(); idx < len; idx++) {
    points.push(getStackedOnPoint(dataCoordInfo, coordSys, data, idx));
  }

  return points;
}

function createGridClipShape(cartesian, hasAnimation, forSymbol, seriesModel) {
  var xExtent = getAxisExtentWithGap(cartesian.getAxis('x'));
  var yExtent = getAxisExtentWithGap(cartesian.getAxis('y'));
  var isHorizontal = cartesian.getBaseAxis().isHorizontal();
  var x = Math.min(xExtent[0], xExtent[1]);
  var y = Math.min(yExtent[0], yExtent[1]);
  var width = Math.max(xExtent[0], xExtent[1]) - x;
  var height = Math.max(yExtent[0], yExtent[1]) - y; // Avoid float number rounding error for symbol on the edge of axis extent.
  // See #7913 and `test/dataZoom-clip.html`.

  if (forSymbol) {
    x -= 0.5;
    width += 0.5;
    y -= 0.5;
    height += 0.5;
  } else {
    var lineWidth = seriesModel.get('lineStyle.width') || 2; // Expand clip shape to avoid clipping when line value exceeds axis

    var expandSize = seriesModel.get('clipOverflow') ? lineWidth / 2 : Math.max(width, height);

    if (isHorizontal) {
      y -= expandSize;
      height += expandSize * 2;
    } else {
      x -= expandSize;
      width += expandSize * 2;
    }
  }

  var clipPath = new graphic.Rect({
    shape: {
      x: x,
      y: y,
      width: width,
      height: height
    }
  });

  if (hasAnimation) {
    clipPath.shape[isHorizontal ? 'width' : 'height'] = 0;
    graphic.initProps(clipPath, {
      shape: {
        width: width,
        height: height
      }
    }, seriesModel);
  }

  return clipPath;
}

function createPolarClipShape(polar, hasAnimation, forSymbol, seriesModel) {
  var angleAxis = polar.getAngleAxis();
  var radiusAxis = polar.getRadiusAxis();
  var radiusExtent = radiusAxis.getExtent().slice();
  radiusExtent[0] > radiusExtent[1] && radiusExtent.reverse();
  var angleExtent = angleAxis.getExtent();
  var RADIAN = Math.PI / 180; // Avoid float number rounding error for symbol on the edge of axis extent.

  if (forSymbol) {
    radiusExtent[0] -= 0.5;
    radiusExtent[1] += 0.5;
  }

  var clipPath = new graphic.Sector({
    shape: {
      cx: round(polar.cx, 1),
      cy: round(polar.cy, 1),
      r0: round(radiusExtent[0], 1),
      r: round(radiusExtent[1], 1),
      startAngle: -angleExtent[0] * RADIAN,
      endAngle: -angleExtent[1] * RADIAN,
      clockwise: angleAxis.inverse
    }
  });

  if (hasAnimation) {
    clipPath.shape.endAngle = -angleExtent[0] * RADIAN;
    graphic.initProps(clipPath, {
      shape: {
        endAngle: -angleExtent[1] * RADIAN
      }
    }, seriesModel);
  }

  return clipPath;
}

function createClipShape(coordSys, hasAnimation, forSymbol, seriesModel) {
  return coordSys.type === 'polar' ? createPolarClipShape(coordSys, hasAnimation, forSymbol, seriesModel) : createGridClipShape(coordSys, hasAnimation, forSymbol, seriesModel);
}

function turnPointsIntoStep(points, coordSys, stepTurnAt) {
  var baseAxis = coordSys.getBaseAxis();
  var baseIndex = baseAxis.dim === 'x' || baseAxis.dim === 'radius' ? 0 : 1;
  var stepPoints = [];

  for (var i = 0; i < points.length - 1; i++) {
    var nextPt = points[i + 1];
    var pt = points[i];
    stepPoints.push(pt);
    var stepPt = [];

    switch (stepTurnAt) {
      case 'end':
        stepPt[baseIndex] = nextPt[baseIndex];
        stepPt[1 - baseIndex] = pt[1 - baseIndex]; // default is start

        stepPoints.push(stepPt);
        break;

      case 'middle':
        // default is start
        var middle = (pt[baseIndex] + nextPt[baseIndex]) / 2;
        var stepPt2 = [];
        stepPt[baseIndex] = stepPt2[baseIndex] = middle;
        stepPt[1 - baseIndex] = pt[1 - baseIndex];
        stepPt2[1 - baseIndex] = nextPt[1 - baseIndex];
        stepPoints.push(stepPt);
        stepPoints.push(stepPt2);
        break;

      default:
        stepPt[baseIndex] = pt[baseIndex];
        stepPt[1 - baseIndex] = nextPt[1 - baseIndex]; // default is start

        stepPoints.push(stepPt);
    }
  } // Last points


  points[i] && stepPoints.push(points[i]);
  return stepPoints;
}

function getVisualGradient(data, coordSys) {
  var visualMetaList = data.getVisual('visualMeta');

  if (!visualMetaList || !visualMetaList.length || !data.count()) {
    // When data.count() is 0, gradient range can not be calculated.
    return;
  }

  if (coordSys.type !== 'cartesian2d') {
    return;
  }

  var coordDim;
  var visualMeta;

  for (var i = visualMetaList.length - 1; i >= 0; i--) {
    var dimIndex = visualMetaList[i].dimension;
    var dimName = data.dimensions[dimIndex];
    var dimInfo = data.getDimensionInfo(dimName);
    coordDim = dimInfo && dimInfo.coordDim; // Can only be x or y

    if (coordDim === 'x' || coordDim === 'y') {
      visualMeta = visualMetaList[i];
      break;
    }
  }

  if (!visualMeta) {
    return;
  } // If the area to be rendered is bigger than area defined by LinearGradient,
  // the canvas spec prescribes that the color of the first stop and the last
  // stop should be used. But if two stops are added at offset 0, in effect
  // browsers use the color of the second stop to render area outside
  // LinearGradient. So we can only infinitesimally extend area defined in
  // LinearGradient to render `outerColors`.


  var axis = coordSys.getAxis(coordDim); // dataToCoor mapping may not be linear, but must be monotonic.

  var colorStops = zrUtil.map(visualMeta.stops, function (stop) {
    return {
      coord: axis.toGlobalCoord(axis.dataToCoord(stop.value)),
      color: stop.color
    };
  });
  var stopLen = colorStops.length;
  var outerColors = visualMeta.outerColors.slice();

  if (stopLen && colorStops[0].coord > colorStops[stopLen - 1].coord) {
    colorStops.reverse();
    outerColors.reverse();
  }

  var tinyExtent = 10; // Arbitrary value: 10px

  var minCoord = colorStops[0].coord - tinyExtent;
  var maxCoord = colorStops[stopLen - 1].coord + tinyExtent;
  var coordSpan = maxCoord - minCoord;

  if (coordSpan < 1e-3) {
    return 'transparent';
  }

  zrUtil.each(colorStops, function (stop) {
    stop.offset = (stop.coord - minCoord) / coordSpan;
  });
  colorStops.push({
    offset: stopLen ? colorStops[stopLen - 1].offset : 0.5,
    color: outerColors[1] || 'transparent'
  });
  colorStops.unshift({
    // notice colorStops.length have been changed.
    offset: stopLen ? colorStops[0].offset : 0.5,
    color: outerColors[0] || 'transparent'
  }); // zrUtil.each(colorStops, function (colorStop) {
  //     // Make sure each offset has rounded px to avoid not sharp edge
  //     colorStop.offset = (Math.round(colorStop.offset * (end - start) + start) - start) / (end - start);
  // });

  var gradient = new graphic.LinearGradient(0, 0, 0, 0, colorStops, true);
  gradient[coordDim] = minCoord;
  gradient[coordDim + '2'] = maxCoord;
  return gradient;
}

function getIsIgnoreFunc(seriesModel, data, coordSys) {
  var showAllSymbol = seriesModel.get('showAllSymbol');
  var isAuto = showAllSymbol === 'auto';

  if (showAllSymbol && !isAuto) {
    return;
  }

  var categoryAxis = coordSys.getAxesByScale('ordinal')[0];

  if (!categoryAxis) {
    return;
  } // Note that category label interval strategy might bring some weird effect
  // in some scenario: users may wonder why some of the symbols are not
  // displayed. So we show all symbols as possible as we can.


  if (isAuto // Simplify the logic, do not determine label overlap here.
  && canShowAllSymbolForCategory(categoryAxis, data)) {
    return;
  } // Otherwise follow the label interval strategy on category axis.


  var categoryDataDim = data.mapDimension(categoryAxis.dim);
  var labelMap = {};
  zrUtil.each(categoryAxis.getViewLabels(), function (labelItem) {
    labelMap[labelItem.tickValue] = 1;
  });
  return function (dataIndex) {
    return !labelMap.hasOwnProperty(data.get(categoryDataDim, dataIndex));
  };
}

function canShowAllSymbolForCategory(categoryAxis, data) {
  // In mose cases, line is monotonous on category axis, and the label size
  // is close with each other. So we check the symbol size and some of the
  // label size alone with the category axis to estimate whether all symbol
  // can be shown without overlap.
  var axisExtent = categoryAxis.getExtent();
  var availSize = Math.abs(axisExtent[1] - axisExtent[0]) / categoryAxis.scale.count();
  isNaN(availSize) && (availSize = 0); // 0/0 is NaN.
  // Sampling some points, max 5.

  var dataLen = data.count();
  var step = Math.max(1, Math.round(dataLen / 5));

  for (var dataIndex = 0; dataIndex < dataLen; dataIndex += step) {
    if (SymbolClz.getSymbolSize(data, dataIndex // Only for cartesian, where `isHorizontal` exists.
    )[categoryAxis.isHorizontal() ? 1 : 0] // Empirical number
    * 1.5 > availSize) {
      return false;
    }
  }

  return true;
}

export default ChartView.extend({
  type: 'line',
  init: function () {
    var lineGroup = new graphic.Group();
    var symbolDraw = new SymbolDraw();
    this.group.add(symbolDraw.group);
    this._symbolDraw = symbolDraw;
    this._lineGroup = lineGroup;
  },
  render: function (seriesModel, ecModel, api) {
    var coordSys = seriesModel.coordinateSystem;
    var group = this.group;
    var data = seriesModel.getData();
    var lineStyleModel = seriesModel.getModel('lineStyle');
    var areaStyleModel = seriesModel.getModel('areaStyle');
    var points = data.mapArray(data.getItemLayout);
    var isCoordSysPolar = coordSys.type === 'polar';
    var prevCoordSys = this._coordSys;
    var symbolDraw = this._symbolDraw;
    var polyline = this._polyline;
    var polygon = this._polygon;
    var lineGroup = this._lineGroup;
    var hasAnimation = seriesModel.get('animation');
    var isAreaChart = !areaStyleModel.isEmpty();
    var valueOrigin = areaStyleModel.get('origin');
    var dataCoordInfo = prepareDataCoordInfo(coordSys, data, valueOrigin);
    var stackedOnPoints = getStackedOnPoints(coordSys, data, dataCoordInfo);
    var showSymbol = seriesModel.get('showSymbol');
    var isIgnoreFunc = showSymbol && !isCoordSysPolar && getIsIgnoreFunc(seriesModel, data, coordSys); // Remove temporary symbols

    var oldData = this._data;
    oldData && oldData.eachItemGraphicEl(function (el, idx) {
      if (el.__temp) {
        group.remove(el);
        oldData.setItemGraphicEl(idx, null);
      }
    }); // Remove previous created symbols if showSymbol changed to false

    if (!showSymbol) {
      symbolDraw.remove();
    }

    group.add(lineGroup); // FIXME step not support polar

    var step = !isCoordSysPolar && seriesModel.get('step'); // Initialization animation or coordinate system changed

    if (!(polyline && prevCoordSys.type === coordSys.type && step === this._step)) {
      showSymbol && symbolDraw.updateData(data, {
        isIgnore: isIgnoreFunc,
        clipShape: createClipShape(coordSys, false, true, seriesModel)
      });

      if (step) {
        // TODO If stacked series is not step
        points = turnPointsIntoStep(points, coordSys, step);
        stackedOnPoints = turnPointsIntoStep(stackedOnPoints, coordSys, step);
      }

      polyline = this._newPolyline(points, coordSys, hasAnimation);

      if (isAreaChart) {
        polygon = this._newPolygon(points, stackedOnPoints, coordSys, hasAnimation);
      }

      lineGroup.setClipPath(createClipShape(coordSys, true, false, seriesModel));
    } else {
      if (isAreaChart && !polygon) {
        // If areaStyle is added
        polygon = this._newPolygon(points, stackedOnPoints, coordSys, hasAnimation);
      } else if (polygon && !isAreaChart) {
        // If areaStyle is removed
        lineGroup.remove(polygon);
        polygon = this._polygon = null;
      } // Update clipPath


      lineGroup.setClipPath(createClipShape(coordSys, false, false, seriesModel)); // Always update, or it is wrong in the case turning on legend
      // because points are not changed

      showSymbol && symbolDraw.updateData(data, {
        isIgnore: isIgnoreFunc,
        clipShape: createClipShape(coordSys, false, true, seriesModel)
      }); // Stop symbol animation and sync with line points
      // FIXME performance?

      data.eachItemGraphicEl(function (el) {
        el.stopAnimation(true);
      }); // In the case data zoom triggerred refreshing frequently
      // Data may not change if line has a category axis. So it should animate nothing

      if (!isPointsSame(this._stackedOnPoints, stackedOnPoints) || !isPointsSame(this._points, points)) {
        if (hasAnimation) {
          this._updateAnimation(data, stackedOnPoints, coordSys, api, step, valueOrigin);
        } else {
          // Not do it in update with animation
          if (step) {
            // TODO If stacked series is not step
            points = turnPointsIntoStep(points, coordSys, step);
            stackedOnPoints = turnPointsIntoStep(stackedOnPoints, coordSys, step);
          }

          polyline.setShape({
            points: points
          });
          polygon && polygon.setShape({
            points: points,
            stackedOnPoints: stackedOnPoints
          });
        }
      }
    }

    var visualColor = getVisualGradient(data, coordSys) || data.getVisual('color');
    polyline.useStyle(zrUtil.defaults( // Use color in lineStyle first
    lineStyleModel.getLineStyle(), {
      fill: 'none',
      stroke: visualColor,
      lineJoin: 'bevel'
    }));
    var smooth = seriesModel.get('smooth');
    smooth = getSmooth(seriesModel.get('smooth'));
    polyline.setShape({
      smooth: smooth,
      smoothMonotone: seriesModel.get('smoothMonotone'),
      connectNulls: seriesModel.get('connectNulls')
    });

    if (polygon) {
      var stackedOnSeries = data.getCalculationInfo('stackedOnSeries');
      var stackedOnSmooth = 0;
      polygon.useStyle(zrUtil.defaults(areaStyleModel.getAreaStyle(), {
        fill: visualColor,
        opacity: 0.7,
        lineJoin: 'bevel'
      }));

      if (stackedOnSeries) {
        stackedOnSmooth = getSmooth(stackedOnSeries.get('smooth'));
      }

      polygon.setShape({
        smooth: smooth,
        stackedOnSmooth: stackedOnSmooth,
        smoothMonotone: seriesModel.get('smoothMonotone'),
        connectNulls: seriesModel.get('connectNulls')
      });
    }

    this._data = data; // Save the coordinate system for transition animation when data changed

    this._coordSys = coordSys;
    this._stackedOnPoints = stackedOnPoints;
    this._points = points;
    this._step = step;
    this._valueOrigin = valueOrigin;
  },
  dispose: function () {},
  highlight: function (seriesModel, ecModel, api, payload) {
    var data = seriesModel.getData();
    var dataIndex = modelUtil.queryDataIndex(data, payload);

    if (!(dataIndex instanceof Array) && dataIndex != null && dataIndex >= 0) {
      var symbol = data.getItemGraphicEl(dataIndex);

      if (!symbol) {
        // Create a temporary symbol if it is not exists
        var pt = data.getItemLayout(dataIndex);

        if (!pt) {
          // Null data
          return;
        }

        symbol = new SymbolClz(data, dataIndex);
        symbol.position = pt;
        symbol.setZ(seriesModel.get('zlevel'), seriesModel.get('z'));
        symbol.ignore = isNaN(pt[0]) || isNaN(pt[1]);
        symbol.__temp = true;
        data.setItemGraphicEl(dataIndex, symbol); // Stop scale animation

        symbol.stopSymbolAnimation(true);
        this.group.add(symbol);
      }

      symbol.highlight();
    } else {
      // Highlight whole series
      ChartView.prototype.highlight.call(this, seriesModel, ecModel, api, payload);
    }
  },
  downplay: function (seriesModel, ecModel, api, payload) {
    var data = seriesModel.getData();
    var dataIndex = modelUtil.queryDataIndex(data, payload);

    if (dataIndex != null && dataIndex >= 0) {
      var symbol = data.getItemGraphicEl(dataIndex);

      if (symbol) {
        if (symbol.__temp) {
          data.setItemGraphicEl(dataIndex, null);
          this.group.remove(symbol);
        } else {
          symbol.downplay();
        }
      }
    } else {
      // FIXME
      // can not downplay completely.
      // Downplay whole series
      ChartView.prototype.downplay.call(this, seriesModel, ecModel, api, payload);
    }
  },

  /**
   * @param {module:zrender/container/Group} group
   * @param {Array.<Array.<number>>} points
   * @private
   */
  _newPolyline: function (points) {
    var polyline = this._polyline; // Remove previous created polyline

    if (polyline) {
      this._lineGroup.remove(polyline);
    }

    polyline = new Polyline({
      shape: {
        points: points
      },
      silent: true,
      z2: 10
    });

    this._lineGroup.add(polyline);

    this._polyline = polyline;
    return polyline;
  },

  /**
   * @param {module:zrender/container/Group} group
   * @param {Array.<Array.<number>>} stackedOnPoints
   * @param {Array.<Array.<number>>} points
   * @private
   */
  _newPolygon: function (points, stackedOnPoints) {
    var polygon = this._polygon; // Remove previous created polygon

    if (polygon) {
      this._lineGroup.remove(polygon);
    }

    polygon = new Polygon({
      shape: {
        points: points,
        stackedOnPoints: stackedOnPoints
      },
      silent: true
    });

    this._lineGroup.add(polygon);

    this._polygon = polygon;
    return polygon;
  },

  /**
   * @private
   */
  // FIXME Two value axis
  _updateAnimation: function (data, stackedOnPoints, coordSys, api, step, valueOrigin) {
    var polyline = this._polyline;
    var polygon = this._polygon;
    var seriesModel = data.hostModel;
    var diff = lineAnimationDiff(this._data, data, this._stackedOnPoints, stackedOnPoints, this._coordSys, coordSys, this._valueOrigin, valueOrigin);
    var current = diff.current;
    var stackedOnCurrent = diff.stackedOnCurrent;
    var next = diff.next;
    var stackedOnNext = diff.stackedOnNext;

    if (step) {
      // TODO If stacked series is not step
      current = turnPointsIntoStep(diff.current, coordSys, step);
      stackedOnCurrent = turnPointsIntoStep(diff.stackedOnCurrent, coordSys, step);
      next = turnPointsIntoStep(diff.next, coordSys, step);
      stackedOnNext = turnPointsIntoStep(diff.stackedOnNext, coordSys, step);
    } // `diff.current` is subset of `current` (which should be ensured by
    // turnPointsIntoStep), so points in `__points` can be updated when
    // points in `current` are update during animation.


    polyline.shape.__points = diff.current;
    polyline.shape.points = current;
    graphic.updateProps(polyline, {
      shape: {
        points: next
      }
    }, seriesModel);

    if (polygon) {
      polygon.setShape({
        points: current,
        stackedOnPoints: stackedOnCurrent
      });
      graphic.updateProps(polygon, {
        shape: {
          points: next,
          stackedOnPoints: stackedOnNext
        }
      }, seriesModel);
    }

    var updatedDataInfo = [];
    var diffStatus = diff.status;

    for (var i = 0; i < diffStatus.length; i++) {
      var cmd = diffStatus[i].cmd;

      if (cmd === '=') {
        var el = data.getItemGraphicEl(diffStatus[i].idx1);

        if (el) {
          updatedDataInfo.push({
            el: el,
            ptIdx: i // Index of points

          });
        }
      }
    }

    if (polyline.animators && polyline.animators.length) {
      polyline.animators[0].during(function () {
        for (var i = 0; i < updatedDataInfo.length; i++) {
          var el = updatedDataInfo[i].el;
          el.attr('position', polyline.shape.__points[updatedDataInfo[i].ptIdx]);
        }
      });
    }
  },
  remove: function (ecModel) {
    var group = this.group;
    var oldData = this._data;

    this._lineGroup.removeAll();

    this._symbolDraw.remove(true); // Remove temporary created elements when highlighting


    oldData && oldData.eachItemGraphicEl(function (el, idx) {
      if (el.__temp) {
        group.remove(el);
        oldData.setItemGraphicEl(idx, null);
      }
    });
    this._polyline = this._polygon = this._coordSys = this._points = this._stackedOnPoints = this._data = null;
  }
});