# Rendering : avoid re-render pixels that did not change

**URL:** <https://discourse.julialang.org/t/rendering-avoid-re-render-pixels-that-did-not-change/82599>\
**Category:** General Usage\
**Tags:** makie, glmakie\
**Created:** [June 11, 2022, 12:12pm UTC](https://discourse.julialang.org/t/rendering-avoid-re-render-pixels-that-did-not-change/82599 "2022-06-11T12:12:20Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Francois](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/francois/32/42434_2.png) [@Francois](https://discourse.julialang.org/u/Francois)\
**Post date:** [June 11, 2022, 12:12pm UTC](https://discourse.julialang.org/t/rendering-avoid-re-render-pixels-that-did-not-change/82599/1 "2022-06-11T12:12:20Z")

</div>

I’m trying to render a very big cellular automaton. I use image!(ax, Matrix{RGB}, …) to render the first image, then I change the Observable at each step of my simulation with the updated matrix. Few cells change from one step to the other. Is there a more efficient way to do the rendering than recomputing the complete image ?