Optionally snap slider to range (#74)

Also require Julia 1.10, update CI and require TestImages 1.9 for tests.

Author: jwahlstrand

.github/workflows/CI.yml

@@ -15,7 +15,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest, macOS-latest]
-        version: ['1.6', '1', 'nightly']
+        version: ['1', 'nightly']
         arch: [x64, x86]
         include:
           - os: ubuntu-latest
@@ -29,9 +29,8 @@ jobs:
         with:
           version: ${{ matrix.version }}
           arch: ${{ matrix.arch }}
-      - uses: julia-actions/cache@v1
-      - uses: julia-actions/julia-buildpkg@latest
-      - uses: julia-actions/julia-runtest@latest
+      - uses: julia-actions/cache@v2
+      - uses: julia-actions/julia-runtest@master
         with:
           prefix: ${{ matrix.prefix }}
       - uses: julia-actions/julia-processcoverage@latest

Project.toml

@@ -1,6 +1,6 @@
 name = "GtkObservables"
 uuid = "8710efd8-4ad6-11eb-33ea-2d5ceb25a41c"
-version = "2.1.4"
+version = "2.2.0"
 
 [deps]
 Cairo = "159f3aea-2a34-519c-b102-8c37f9878175"
@@ -19,7 +19,7 @@ RoundingIntegers = "d5f540fe-1c90-5db3-b776-2e2f362d9394"
 [compat]
 Cairo = "1"
 Colors = "0.12, 0.13"
-Dates = "1.6"
+Dates = "1.10"
 FixedPointNumbers = "0.8"
 Graphics = "1"
 Gtk4 = "0.6, 0.7"
@@ -29,15 +29,5 @@ Observables = "0.4, 0.5"
 PrecompileTools = "1"
 Reexport = "0.2, 1"
 RoundingIntegers = "0.2, 1"
-julia = "1.6"
+julia = "1.10"
 
-[extras]
-Cairo = "159f3aea-2a34-519c-b102-8c37f9878175"
-FileIO = "5789e2e9-d7fb-5bc7-8068-2c6fae9b9549"
-IdentityRanges = "bbac6d45-d8f3-5730-bfe4-7a449cd117ca"
-ImageIO = "82e4d734-157c-48bb-816b-45c225c6df19"
-Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
-TestImages = "5e47fb64-e119-507b-a336-dd2b206d9990"
-
-[targets]
-test = ["FileIO", "IdentityRanges", "ImageIO", "Cairo", "Test", "TestImages"]

docs/src/controls.md

@@ -29,7 +29,7 @@ At present, this slider is not affiliated with any window. Let's
 create one and add the slider to the window. We'll put it inside a
 `Box` so that we can later add more things to this GUI (this
 illustrates usage of some of
-[Gtk's layout tools](https://juliagtk.github.io/Gtk4.jl/dev/manual/layout/):
+[Gtk4's layout tools](https://juliagtk.github.io/Gtk4.jl/dev/manual/layout/):
 
 ```jldoctest demo1
 julia> win = GtkWindow("Testing"); win[] = bx = GtkBox(:v);  # a window containing a vertical Box for layout
@@ -74,6 +74,11 @@ end
 
 Now if you check the window, you'll see that the slider is at 1.
 
+Note: The `slider` function used above to construct a slider widget by default does not
+snap to elements in the provided range (except in some circumstances). By setting
+the keyword argument `snap` to `true`, the `GtkScale` should reliably snap to
+elements of the range. This does not affect observable's `setindex!` method.
+
 Realistic GUIs may have many different widgets. Let's add a second way
 to adjust the value of that observable, by allowing the user to type a
 value into a textbox:

examples/snap_slider.jl

@@ -0,0 +1,13 @@
+using GtkObservables, Gtk4
+
+r=1:10:91
+#r=0.1:0.05:10 also works
+n = slider(r; snap=true)
+
+mainwin = GtkWindow("GtkObservables", 300, 200)
+vbox = GtkBox(:v)
+push!(vbox, GtkLabel("Demonstrates slider that snaps to $(r)"))
+push!(vbox, n)
+push!(mainwin, vbox)
+show(mainwin)
+

src/widgets.jl

@@ -95,38 +95,65 @@ struct Slider{T<:Number} <: InputWidget{T}
     observable::Observable{T}
     widget::GtkScaleLeaf
     id::Culong
+    snap_handler_id::Ref{Culong}
     preserved::Vector{Any}
 
-    function Slider{T}(observable::Observable{T}, widget, id, preserved) where T
-        obj = new{T}(observable, widget, id, preserved)
+    function Slider{T}(observable::Observable{T}, widget, id, snap_id, preserved) where T
+        obj = new{T}(observable, widget, id, snap_id, preserved)
         gc_preserve(widget, obj)
         obj
     end
 end
-Slider(observable::Observable{T}, widget::GtkScale, id, preserved) where {T} =
-    Slider{T}(observable, widget, id, preserved)
+Slider(observable::Observable{T}, widget::GtkScale, id, snap_id, preserved) where {T} =
+    Slider{T}(observable, widget, id, snap_id, preserved)
 
 medianidx(r) = (ax = axes(r)[1]; return (first(ax)+last(ax))÷2)
 # differs from median(r) in that it always returns an element of the range
 medianelement(r::AbstractRange) = r[medianidx(r)]
 
-slider(observable::Observable, widget::GtkScale, id, preserved = []) =
-    Slider(observable, widget, id, preserved)
+# simplified version of function in https://github.com/joshday/SearchSortedNearest.jl
+function searchsortednearest(a, x)
+    i = searchsortedfirst(a, x)
+    if i == 1
+    elseif i > length(a)
+        i = length(a)
+    elseif a[i] == x
+    else
+        i = isless(abs(a[i] - x), abs(a[i - 1] - x)) ? i : i - 1
+    end
+    return i
+end
+
+@guarded Cint(0) function slider_changevalue_cb(ptr::Ptr, scroll, value::Float64, user_data)
+    scale = convert(GtkScale, ptr)
+    r, idr = user_data
+    i = searchsortednearest(r, value)
+    signal_handler_block(scale, idr[])
+    signal_emit(scale, "change-value", Bool, Gtk4.ScrollType(scroll), Float64(r[i]))
+    signal_handler_unblock(scale, idr[])
+    return Cint(1)
+end
+
+
+slider(observable::Observable, widget::GtkScale, id, snap_id, preserved = []) =
+    Slider(observable, widget, id, snap_id, preserved)
 
 """
-    slider(range; widget=nothing, value=nothing, observable=nothing, orientation="horizontal")
+    slider(range; widget=nothing, value=nothing, observable=nothing, orientation="horizontal", snap=false)
 
 Create a slider widget with the specified `range`. Optionally provide:
   - the GtkScale `widget` (by default, creates a new one)
   - the starting `value` (defaults to the median of `range`)
   - the (Observables.jl) `observable` coupled to this slider (by default, creates a new observable)
   - the `orientation` of the slider.
+  - whether to `snap` the slider value to an element of `range`.
 """
 function slider(range::AbstractRange;
                 widget=nothing,
                 value=nothing,
                 observable=nothing,
                 orientation="horizontal",
+                snap=false,
                 syncsig=true,
                 own=nothing)
     obsin = observable
@@ -155,6 +182,11 @@ function slider(range::AbstractRange;
         observable[] = defaultgetter(w)
     end
 
+    ref_snap_id = Ref{Culong}(0)
+    if snap
+        ref_snap_id[] = Gtk4.on_change_value(slider_changevalue_cb, widget, (range,ref_snap_id))
+    end
+
     ## observable -> widget
     preserved = []
     if syncsig
@@ -164,7 +196,7 @@ function slider(range::AbstractRange;
         ondestroy(widget, preserved)
     end
 
-    Slider(observable, widget, id, preserved)
+    Slider(observable, widget, id, ref_snap_id, preserved)
 end
 
 # Adjust the range on a slider

test/Project.toml

@@ -0,0 +1,18 @@
+[deps]
+Cairo = "159f3aea-2a34-519c-b102-8c37f9878175"
+Colors = "5ae59095-9a9b-59fe-a467-6f913c188581"
+Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"
+FileIO = "5789e2e9-d7fb-5bc7-8068-2c6fae9b9549"
+FixedPointNumbers = "53c48c17-4a7d-5ca2-90c5-79b7896eea93"
+Graphics = "a2bd30eb-e257-5431-a919-1863eab51364"
+Gtk4 = "9db2cae5-386f-4011-9d63-a5602296539b"
+IdentityRanges = "bbac6d45-d8f3-5730-bfe4-7a449cd117ca"
+ImageIO = "82e4d734-157c-48bb-816b-45c225c6df19"
+IntervalSets = "8197267c-284f-5f27-9208-e0e47529a953"
+Observables = "510215fc-4207-5dde-b226-833fc4488ee2"
+RoundingIntegers = "d5f540fe-1c90-5db3-b776-2e2f362d9394"
+Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
+TestImages = "5e47fb64-e119-507b-a336-dd2b206d9990"
+
+[compat]
+TestImages = "=1.9"

test/runtests.jl

@@ -142,6 +142,13 @@ Gtk4.GLib.start_main_loop()
     @test s[] == 5
     sleep(0.1)
 
+    # Snap to range element
+    s = slider(0.1:0.05:10.0; snap = true)
+    sleep(0.01)
+    signal_emit(widget(s),"change-value",Bool, Gtk4.ScrollType(0), 0.16)
+    sleep(0.01)
+    @test s[] == 0.15
+
     ## dropdown
     dd = dropdown(("Strawberry", "Vanilla", "Chocolate"))
     @test dd[] === "Strawberry"