# Add points to scatter plot by Mouse.down click using GLMakie
**URL:** https://discourse.julialang.org/t/add-points-to-scatter-plot-by-mouse-down-click-using-glmakie/89740
**Category:** Visualization
**Tags:** question, plotting, makie, glmakie
**Created:** [November 3, 2022, 9:56pm UTC](https://discourse.julialang.org/t/add-points-to-scatter-plot-by-mouse-down-click-using-glmakie/89740 "2022-11-03T21:56:51Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@mgalenb](https://discourse.julialang.org/u/mgalenb)
#### Post date: [November 3, 2022, 9:56pm UTC](https://discourse.julialang.org/t/add-points-to-scatter-plot-by-mouse-down-click-using-glmakie/89740/1 "2022-11-03T21:56:52Z")
Id like to add points to a GLMakie plot when holding down the keyboard letter “a” and then holding down the left mouse button. The docs have a good demo on how to do this with a click ([Point Picking](https://docs.makie.org/v0.18.2/documentation/events/index.html#point_picking)). However when I change `Mouse.press` to `Mouse.down` the zoom action occurs. Any idea how to turn off the zoom action?
Here is my code:
```julia
using GLMakie
positions = Observable(rand(Point2f, 10))
fig, ax, p = scatter(positions)
on(events(fig).mousebutton, priority = 2) do event
if event.button == Mouse.left && event.action == Mouse.down
if Keyboard.d in events(fig).keyboardstate
# Delete marker
plt, i = pick(fig)
if plt == p
deleteat!(positions[], i)
notify(positions)
return Consume(true)
end
elseif Keyboard.a in events(fig).keyboardstate
# Add marker
push!(positions[], mouseposition(ax))
notify(positions)
return Consume(true)
end
end
return Consume(false)
end
```
---
### Author:  [@jules](https://discourse.julialang.org/u/jules)
#### Post date: [November 3, 2022, 10:26pm UTC](https://discourse.julialang.org/t/add-points-to-scatter-plot-by-mouse-down-click-using-glmakie/89740/2 "2022-11-03T22:26:52Z")
[https://docs.makie.org/stable/examples/blocks/axis/#registering\_and\_deregistering\_interactions](https://docs.makie.org/stable/examples/blocks/axis/#registering_and_deregistering_interactions)
---
### Author:  [@mgalenb](https://discourse.julialang.org/u/mgalenb)
#### Post date: [November 4, 2022, 5:15am UTC](https://discourse.julialang.org/t/add-points-to-scatter-plot-by-mouse-down-click-using-glmakie/89740/3 "2022-11-04T05:15:15Z")
Thanks @jules . I have another question. id like continually add new points to the plot when the mouse button is pressed. Basically I am trying to paint over pixels in a 2D image. I have tried change Mouse.press to Mouse.pressed but that doesn’t seem to work.
---
### Author:  [@mgalenb](https://discourse.julialang.org/u/mgalenb)
#### Post date: [November 4, 2022, 7:10am UTC](https://discourse.julialang.org/t/add-points-to-scatter-plot-by-mouse-down-click-using-glmakie/89740/4 "2022-11-04T07:10:05Z")
Update: Look at the dragging example in the docs, duh. [Point Picking](https://docs.makie.org/v0.18.2/documentation/events/index.html#point_picking)
Changed the bottom dragging function to this,
```julia
if dragging
#positions[][idx] = mouseposition(ax)
push!(positions[], mouseposition(ax))
notify(positions)
return Consume(true)
end
return Consume(false)
end
```
---
### Author:  [@jules](https://discourse.julialang.org/u/jules)
#### Post date: [November 4, 2022, 8:51am UTC](https://discourse.julialang.org/t/add-points-to-scatter-plot-by-mouse-down-click-using-glmakie/89740/5 "2022-11-04T08:51:21Z")
I would not use `dragging` state directly, because this will still fire if you drag the mouse over the axis from somewhere else. This often happens with sliders etc. You can just use the precomputed mouse events accessible via the axis interactions as explained here [https://docs.makie.org/stable/examples/blocks/axis/#function\_interaction](https://docs.makie.org/stable/examples/blocks/axis/#function_interaction)
For example (I didn’t test this)
```julia
register_interaction!(ax, :painting_scatters) do event::MouseEvent, axis
if event.type === MouseEventTypes.leftdrag
# do your picking logic etc here
end
end
```