[GSoC'21] Different morphing modes

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Javis.jl - Changelog
 
+## Unreleased
+- Add a manim-like :long morhping mode
+
 ## v0.5.3 (26th of July 2021)
 - Allow all kinds of iterable ways in the `act!` function such that `act!(::Matrix, ::Action)` also works
 - Updated `anim_translate`

src/Shape.jl

@@ -221,7 +221,7 @@ function print_basic(s::Shape)
 end
 
 
-function prepare_to_interpolate(from_shape, to_shape)
+function prepare_to_interpolate(from_shape, to_shape, style)
     # match number of points for outer polygon
     from_outer, to_outer = match_num_points(from_shape.points, to_shape.points)
 
@@ -239,6 +239,11 @@ function prepare_to_interpolate(from_shape, to_shape)
     rotate_i, _ = compute_shortest_morphing_dist(from_outer, to_outer)
     new_from_outer = circshift(from_outer, -rotate_i + 1)
 
+    if style == :long
+        new_from_outer =
+            circshift(reverse!(new_from_outer), floor(-length(new_from_outer) / 2.6)) # found this to work best
+    end
+
     new_from_holes = Vector{Vector{Point}}()
 
     # rotate holes

src/morphs.jl

@@ -1,7 +1,7 @@
 include("Shape.jl")
 
 """
-    morph_to(to_func::Function; object=:stroke)
+    morph_to(to_func::Function; style=:short, object=:stroke)
 
 A closure for the [`_morph_to`](@ref) function.
 This makes it easier to write the function inside an `Object`.
@@ -11,6 +11,7 @@ It especially does not work with functions which produce more than one polygon
 or which produce filled polygons.
 Blending between fills of polygons is definitely coming at a later stage.
 
+To get a more visually appealing morphing one can try setting `style = :long`.
 **Important:** The functions itself should not draw the polygon
 i.e. use `circle(Point(100,100), 50)` instead of `circle(Point(100,100), 50, :stroke)`
 
@@ -19,6 +20,7 @@ i.e. use `circle(Point(100,100), 50)` instead of `circle(Point(100,100), 50, :st
                        which will be displayed at the end of the Object
 
 # Keywords
+- `style::Symbol` Sets the style of morphing
 - `do_action::Symbol` defines whether the object has a fill or just a stroke. Defaults to `:stroke`.
 
 # Example
@@ -37,13 +39,20 @@ circle_obj = Object(11:20, acirc)
 act!(circle_obj, Action(:same, morph_to(astar)))
 ```
 """
-function morph_to(to_func::Function; do_action = :stroke)
-    return (video, object, action, frame) ->
-        _morph_to(video, object, action, frame, to_func; do_action = do_action)
+function morph_to(to_func::Function; style = :short, do_action = :stroke)
+    return (video, object, action, frame) -> _morph_to(
+        video,
+        object,
+        action,
+        frame,
+        to_func;
+        style = style,
+        do_action = do_action,
+    )
 end
 
 """
-    _morph_to(video::Video, object::Object, action::Action, frame, to_func::Function; do_action=:stroke)
+    _morph_to(video::Video, object::Object, action::Action, frame, to_func::Function; style=:short, do_action=:stroke)
 
 Internal version of [`morph_to`](@ref) but described there.
 """
@@ -53,6 +62,7 @@ function _morph_to(
     action::Action,
     frame,
     to_func::Function;
+    style = :short,
     do_action = :stroke,
 )
     if frame == last(get_frames(action))
@@ -78,6 +88,7 @@ function _morph_to(
             frame,
             from_polys,
             to_polys;
+            style = style,
             do_action = do_action,
         )
     end
@@ -86,7 +97,7 @@ end
 """
     morph_between(video::Video, action::Action, frame,
         from_polys::Vector{Vector{Point}}, to_polys::Vector{Vector{Point}};
-        do_action=:stroke)
+        style=:short, do_action=:stroke)
 
 Internal version of [`morph_to`](@ref) after the from poly is defined.
 """
@@ -96,14 +107,15 @@ function morph_between(
     frame,
     from_polys::Vector{Vector{Point}},
     to_polys::Vector{Vector{Point}};
+    style = :short,
     do_action = :stroke,
 )
     cs = get_current_setting()
     cs.show_object = false
 
     # computation of the polygons and the best way to morph in the first frame
     if frame == first(get_frames(action))
-        save_morph_polygons!(action, from_polys, to_polys)
+        save_morph_polygons!(action, from_polys, to_polys, style)
     end
 
     # obtain the computed polygons. These polygons have the same number of points.
@@ -227,7 +239,7 @@ end
 
 """
     save_morph_polygons!(action::Action, from_func::Vector{Vector{Point}},
-                                         to_func::Vector{Vector{Point}})
+                                         to_func::Vector{Vector{Point}}, style::Symbol)
 
 Calls the functions to polygons and calls [`match_num_points`](@ref)
 such that both polygons have the same number of points.
@@ -240,6 +252,7 @@ function save_morph_polygons!(
     action::Action,
     from_polys::Vector{Vector{Point}},
     to_polys::Vector{Vector{Point}},
+    style::Symbol,
 )
     # delete polygons with less than 2 points
     for i in length(from_polys):-1:1
@@ -291,7 +304,7 @@ function save_morph_polygons!(
                 )
             end
         else
-            from_shape, to_shape = prepare_to_interpolate(from_shape, to_shape)
+            from_shape, to_shape = prepare_to_interpolate(from_shape, to_shape, style)
 
             push!(action.defs[:from_shape], from_shape)
             push!(action.defs[:to_shape], to_shape)

test/morphing.jl

@@ -157,6 +157,7 @@ end
     end
 end
 
+
 @testset "Morphing mutates the object" begin
     function ground(args...)
         background("black")
@@ -215,3 +216,30 @@ end
         rm("images/$(lpad(i, 10, "0")).png")
     end
 end
+
+@testset "Morphing modes" begin
+    function ground(args...)
+        background("black")
+        sethue("white")
+    end
+
+    astar(args...; do_action = :stroke) = star(O, 50, 5, 0.5, 0, do_action)
+    abox(args...; do_action = :stroke) = rect(-150, -150, 100, 100, do_action)
+    acirc(args...; do_action = :stroke) = circle(Point(0, 0), 50, do_action)
+
+    video = Video(500, 500)
+    back = Background(1:50, ground)
+    star_obj = Object(1:50, astar)
+    box_obj = Object(1:50, abox)
+    act!(star_obj, Action(5:20, morph_to(acirc, style = :long)))
+    act!(box_obj, Action(30:50, morph_to(astar, style = :long)))
+    render(video; tempdirectory = "images", pathname = "")
+
+    for i in [5, 10, 15, 19, 20, 21, 30, 35, 40, 45, 49, 50]
+        @test_reference "refs/morph_modes$i.png" load("images/$(lpad(i, 10, "0")).png")
+    end
+
+    for i in 1:50
+        rm("images/$(lpad(i, 10, "0")).png")
+    end
+end