starting to experiment with animated pane transitions

0005-animate

@@ -1,8 +1,5 @@
--- A debugging aid to help animate intermediate results within f.
--- Pause animation in the current frame using loiter().
--- Try to only have one such call in your program.
--- You can have multiple, but things might get confusing if one of them indirectly calls the other,
--- or more generally if a single function ever loiters sometimes under the call tree of one and sometimes under the other.
+-- Animate 'f' by smearing its work across multiple frames.
+-- Pause animation in the current frame using end_frame().
 animate = function(f, ...)
 	local args = {...}
 	Error_with_callstack = nil
@@ -17,5 +14,5 @@ animate = function(f, ...)
 	if Error_with_callstack then
 		error(Error_with_callstack)
 	end
-	table.insert(Debug_animations_in_progress, {co=co, next_run=Current_time+0.3})
-end
+	table.insert(Animations_in_progress, {co=co})
+end

0006-loiter

@@ -1,5 +1,5 @@
 -- A debugging aid to animate intermediate results in computations.
--- Can only be called from functions invoked using `animate()`.
+-- Can only be called from functions invoked using `enable_loiter()`.
 loiter = function()
 	coroutine.yield()
-end
+end

0007-save_callstack

@@ -1,7 +1,7 @@
--- Internal helper for animate()
+-- Internal helper for animations.
 -- Records the stack of function calls that led to any error within a debug animation coroutine.
 -- Lua normally prints out errors with callstacks, but coroutines interrupt the stack unless we do some additional work.
 save_callstack = function(err)
 	local callstack = debug.traceback('', --[[stack frame]]2)
 	Error_with_callstack = 'Error: ' .. cleaned_up_frame(tostring(err))..'\n'..cleaned_up_callstack(callstack)
-end
+end

0012-on.draw

@@ -10,4 +10,5 @@ on.draw = function()
 	edit.draw(Current_pane.output_editor_state, Normal_color, --[[hide cursor]] true)
 	draw_scrollbar(Current_pane.output_editor_state)
 	draw_menu()
+	draw_next_frames_of_animations()
 end

0021-draw_menu

@@ -25,6 +25,7 @@ draw_menu = function()
 			onpress1 = function()
 				Current_pane_index = Current_pane_index-1
 				Current_pane = Panes[Current_pane_index]
+				animate(slide_canvas(Current_pane_index+1, 'right'))
 			end,
 		})
 	end
@@ -39,6 +40,7 @@ draw_menu = function()
 				table.insert(Panes, new_pane())
 				Current_pane_index = Current_pane_index+1
 				Current_pane = Panes[Current_pane_index]
+				animate(slide_canvas(Current_pane_index-1, 'left'))
 			end,
 		})
 	else
@@ -50,6 +52,7 @@ draw_menu = function()
 			onpress1 = function()
 				Current_pane_index = Current_pane_index+1
 				Current_pane = Panes[Current_pane_index]
+				animate(slide_canvas(Current_pane_index-1, 'left'))
 			end,
 		})
 	end

0052-enable_loiter

@@ -0,0 +1,21 @@
+-- A debugging aid to help animate intermediate results within f.
+-- Pause animation in the current frame using loiter().
+-- Try to only have one such call in your program.
+-- You can have multiple, but things might get confusing if one of them indirectly calls the other,
+-- or more generally if a single function ever loiters sometimes under the call tree of one and sometimes under the other.
+enable_loiter = function(f, ...)
+	local args = {...}
+	Error_with_callstack = nil
+	local co = coroutine.create(
+						function()
+							xpcall(function()
+											f(unpack(args))
+										end,
+										save_callstack)
+						end)
+	coroutine.resume(co, ...)
+	if Error_with_callstack then
+		error(Error_with_callstack)
+	end
+	table.insert(Debug_animations_in_progress, {co=co, next_run=Current_time+0.3})
+end

0054-Animations_in_progress

@@ -0,0 +1,2 @@
+-- Intermediate state during animations.
+Animations_in_progress = {}

0056-end_frame

@@ -0,0 +1,4 @@
+-- Pause a drawing called by animate().
+end_frame = function()
+	coroutine.yield()
+end

0058-draw_next_frames_of_animations

@@ -0,0 +1,14 @@
+-- update any in-progress animations
+-- return whether any work remains
+draw_next_frames_of_animations = function()
+	local a = Animations_in_progress
+	for i=#a,1,-1 do
+		if coroutine.status(a[i].co) == 'dead' then
+			table.remove(a, i)
+		else
+			local status, err = coroutine.resume(a[i].co)
+			if status == false then error(err) end
+		end
+	end
+	return #a > 0
+end

0059-slide_canvas

@@ -0,0 +1,18 @@
+slide_canvas = function(pane_index, dir)
+	return function()
+		end_frame()
+		if dir == 'right' then
+			for i=1,40 do
+				print(Current_time, i)
+				love.graphics.rectangle('fill', i*10,0, 30, App.screen.height)
+				end_frame()
+			end
+		elseif dir == 'left' then
+			for i=20,1,-1 do
+				print(i)
+				love.graphics.line(i*50,0, i*50, App.screen.height)
+				end_frame()
+			end
+		end
+	end
+end