# Knobman sliders

**URL:** <https://forum.cabbageaudio.com/t/knobman-sliders/390>\
**Category:** Cabbage recipes\
**Created:** [1 January 2017 16:18 UTC](https://forum.cabbageaudio.com/t/knobman-sliders/390 "2017-01-01T16:18:15Z")\
**Posts on this page:** 1\
**Showing post:** 7

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**Author:** ![rorywalsh](https://forum.cabbageaudio.com/user_avatar/forum.cabbageaudio.com/rorywalsh/32/165_2.png) [@rorywalsh](https://forum.cabbageaudio.com/u/rorywalsh)\
**Post date:** [25 April 2017 15:33 UTC](https://forum.cabbageaudio.com/t/knobman-sliders/390/7 "2017-04-25T15:33:08Z")

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I’ve now have this implemented by adding a crop() identifier to the image widget. I went with the image widget rather than the slider to make things a little more generic. In the example shown below, I place a slider with alpha 0 on top of each image widget. The crop identifier forces the image widget to display only a small part of the source image. It’s then quite simple to dynamically set which part of the image to show using identifier channels().

![](https://forum.cabbageaudio.com/uploads/default/original/1X/9f42c36977d747d509771db978a268cb3a43d0c1.gif)

Note that I would probably wrap this logic into a UDO if I was developing GUIs using this method. Note this is only implemented for .pngs for now.

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