function progress(params, data) {
                var segCount = params.end - params.start;
                var points = isLargeRender && new Float32Array(segCount * dimLen);

                for (var i = params.start, offset = 0, tmpIn = [], tmpOut = []; i < params.end; i++) {
                    var point;

                    if (dimLen === 1) {
                        var x = data.get(dims[0], i);
                        point = !isNaN(x) && coordSys.dataToPoint(x, null, tmpOut);
                    }
                    else {
                        var x = tmpIn[0] = data.get(dims[0], i);
                        var y = tmpIn[1] = data.get(dims[1], i);
                        // Also {Array.<number>}, not undefined to avoid if...else... statement
                        point = !isNaN(x) && !isNaN(y) && coordSys.dataToPoint(tmpIn, null, tmpOut);
                    }

                    if (isLargeRender) {
                        points[offset++] = point ? point[0] : NaN;
                        points[offset++] = point ? point[1] : NaN;
                    }
                    else {
                        data.setItemLayout(i, (point && point.slice()) || [NaN, NaN]);
                    }
                }

                isLargeRender && data.setLayout('symbolPoints', points);
            }
@alias module:echarts/coord/Cartesian
@constructor