techy2 commented on PR #20829: URL: https://github.com/apache/echarts/pull/20829#issuecomment-2735506603
anchor: is an optional parameter that only applies to 'inside' zooming, if it put in 'option' it has no affect the default behavior of dataZoom with the mouse wheel is : zoom in, move both edges of the data outwards towards the start and end points of the visible window, and move mored data into the window from the start and endpoints of the visible window. anchor: changes that behavior so that if the anchor says anchor: 'end', then that end will not move, only the start of the data will zoom in and out of the chart view window anchor: 'start' pins the oldest data so that only the newest data zooms in and out of the view window. why is this useful. For financial charts that track information over time, (think of stock trading or monthly revenue) the users typically wants to zoom in on the most recent data. pinning the 'end' allows them to do that by zooming the oldest data away to the left to see detail of the anchored/pinned newest data or to see long trends, zooming out brings more of the old data into focus. With the start or end pinned /anchored, the anchored point can still be moved by dragging the chart or using the slider bar by grabbing the handles or slide tab. This is a minimal patch that I think provides a great deal of new flexibility. The reason I made the patch was that I was trying to get this affect using myChart.setOption and event handlers to do it. It can be accomplished that way but it is messy to implement with the event handlers and has a major impact on performance with pixelization and slow rendering during zoom and few other undesirable side effects. I took a look at the echarts code and saw that a simple patch with just a few lines of code would accomplish the objective with no side effects at all, hence the PR Please feel free to ask for any more details if you need them. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
