# Feature request: something like \onslide and \only in text objects #258

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opened this issue Aug 27, 2019 · 1 comment

### lorenzhs commented Aug 27, 2019

 Let me begin with saying that this might have some overlap with #135. When working on presentations, I sometimes want to modify a text object between views. Currently, the way to do this is to duplicate the object onto a second layer, which is only shown in the second view (or to cover the bits that should only appear later with an opaque box). But this quickly gets cumbersome when revealing the contents over multiple views. Beamer solves this by providing the \only and \onslide commands along with a syntax for specifying the desired views, supporting both manual ranges like <2-> or <3-5> and automatic ones like \item<+>. The expedience of such reveals in general notwithstanding, I'd love to be able to have something like it in Ipe. Would you say that this is something that Ipe could support (cf #135) or that should be solved in a LaTeX package? In the latter case, does Ipe evaluate the text element for each view that it is visible on, or once and then place it on each page of the resulting pdf? For the former behaviour would be needed to make this work, requiring at least the option to have an object rendered separately for each view it appears on. I hope I didn't miss an answer to why this is complicated / not supported when searching for existing issues and mailing list discussions.
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### otfried commented Aug 28, 2019

 Yes, I wanted to have something like this for a long time. As you noticed, it's not so easy, because Ipe reuses the same PDF for the text object on each view where it is present. To make this possible, a somewhat more complicated mechanism is needed that runs latex for each view in which the text object appears (so this is somewhat more complicated than #135, which I plan to implement soon). By the way, the \item<+> of beamer is rather easy to simulate by simply making separate text boxes (using F10) with style item. So my use case for this is rather where you have a text that will be modified on the next slide, or perhaps highlighted in a different color.