From ee4abe25fdf0d056b5586ff33deea8979ccf761d Mon Sep 17 00:00:00 2001
From: Twan Koolen <koolen.twan@gmail.com>
Date: Thu, 11 Oct 2018 11:47:10 -0400
Subject: [PATCH] Fix error when position bounds are negative.

---
 src/manipulate.jl | 3 ++-
 test/runtests.jl  | 8 ++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/manipulate.jl b/src/manipulate.jl
index ea3401e..8b0daaa 100644
--- a/src/manipulate.jl
+++ b/src/manipulate.jl
@@ -28,8 +28,9 @@ function sliders(joint::Joint, values=clamp.(zeros(num_positions(joint)), positi
                  resolution=0.01, prefix="")
     map(bounds, labels, values) do b, label, value
         num_steps = ceil(Int, (upper(b) - lower(b)) / resolution)
+        r = range(lower(b), stop=upper(b), length=num_steps)
         slider(range(lower(b), stop=upper(b), length=num_steps),
-               value=value,
+               value=clamp(value, first(r), last(r)),
                label=string(prefix, label))
     end
 end
diff --git a/test/runtests.jl b/test/runtests.jl
index f513bf8..708ffa1 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -104,6 +104,14 @@ vis = Visualizer()
         widget = manipulate!(mvis)
     end
 
+    @testset "manipulation - negative bounds issue" begin
+        mechanism = rand_chain_mechanism(Float64, Revolute{Float64})
+        joint = first(joints(mechanism))
+        joint.position_bounds .= RigidBodyDynamics.Bounds(-2.0, -1.0)
+        mvis = MechanismVisualizer(mechanism)
+        widget = manipulate!(mvis)
+    end
+
     @testset "examples" begin
         dir = joinpath(@__DIR__, "..", "examples")
         for file in readdir(dir)