is it possible to show magnification in slider widget, how to do that

[zhusihan-python]

hello.

is it possible to show magnification in slider widget, how to do that if yes

like 20x when slide to level 5, 40x when slide to level 10, and show the 20x/40x when scroll the slider bar

[manthey]

Not directly, but it wouldn't be hard: for instance, you could use map.geoOn(geo.event.zoom, () => {<some code to update a DOM element with the scale>}).

[zhusihan-python]

thanks for the reply sir. i can't figure out what DOM element i can update to achieve that after reading the sliderWidget so i modified the geo.js, add a d3 text like this

m_level = svg.append('text')
  .text('20')
  .attr('x', m_xscale(0))
  .attr('y', m_yscale(0.5) - m_nubSize)
  .attr('width', m_width/2)
  .attr('height', m_nubSize)
  .attr('font-size', 12)
  .style('dominant-baseline', 'central')
  .style('text-anchor', 'middle');

then update the y and text

this._update = function (obj) {
  var map = m_this.layer().map(),
    zoomRange = map.zoomRange(),
    zoom = map.zoom(),
    zoomScale = d3.scale.linear();
  obj = obj || {};
  zoom = obj.value || zoom;
  zoomScale.domain([zoomRange.min, zoomRange.max]).range([1, 0]).clamp(true);
  m_nub.attr('y', m_yscale(zoomScale(zoom)) - m_nubSize / 2);
  m_level.attr('y', m_yscale(zoomScale(zoom)) - m_nubSize);
  m_level.text(((parseInt(zoom)+1)*5).toString());
}; 

now it looks like this i got an magnification text which can change with the zoom event, but it can only locate upon the nub, as the text will be covered when i change the m_level x bigger than m_xscale(4)

i guess its a bad idea to modify the source code right, do you have any suggestions to do it in an elegant way