Implement visualization for DEMA

README.md

@@ -88,7 +88,7 @@ golden_cross_chart |> visualize |> lwc_show
 - [ ] ChandeKrollStop
 - [ ] CHOP
 - [ ] CoppockCurve
-- [ ] DEMA
+- [x] DEMA
 - [ ] DonchianChannels
 - [ ] DPO
 - [x] EMA

src/DEMA.jl

@@ -0,0 +1,23 @@
+denominated_price(dema::DEMA) = true
+
+"""$(TYPEDSIGNATURES)
+
+Visualize DEMA using 1 lwc_line.
+"""
+function visualize(dema::DEMA, opts::Union{AbstractDict,Nothing}, df::DataFrame)
+    name = indicator_fields(dema)[1]
+    start = findfirst(!ismissing, df[!, name])
+    kwargs = Dict(
+        :label_name => "DEMA $(dema.period)",
+        :line_color => "#058ED9",
+        :line_width => 2
+    )
+    if opts !== nothing
+        merge!(kwargs, opts)
+    end
+    return lwc_line(
+        df.ts[start:end],
+        [df[!, name][start:end]...];
+        kwargs...
+    )
+end

src/TechnicalIndicatorCharts.jl

@@ -478,6 +478,7 @@ function visualize(chart::Chart;
 end
 
 include("BB.jl")
+include("DEMA.jl")
 include("EMA.jl")
 include("HMA.jl")
 include("RSI.jl")

test/DEMA.jl

@@ -0,0 +1,18 @@
+using TechnicalIndicatorCharts
+
+@testset "DEMA" begin
+    if !isdefined(Main, :sample_candles)
+        include("helper/main.jl")
+    end
+    chart = Chart(
+        "TEST", Minute(1),
+        indicators=[DEMA{Float64}(;period=8)],
+        visuals=[nothing]
+    )
+    candles = sample_candles()
+    for c in candles
+        update!(chart, c)
+    end
+    @test visualize(chart) isa Any
+    # If it gets this far, we can instantiate, update, and visualize.
+end