Implemented text clipboard system instead of the old one (#693)

* add limit change with brush

* Delete Draw.gd

* Delete BaseTool.gd

* added error calculation

* revert last commit

* Implemented OS.clipboard (using var2str())

* some sanity checks

* formatting

* use text system instead of os clibboard

src/UI/Canvas/Selection.gd

@@ -4,7 +4,6 @@ enum SelectionOperation { ADD, SUBTRACT, INTERSECT }
 
 const KEY_MOVE_ACTION_NAMES := ["ui_up", "ui_down", "ui_left", "ui_right"]
 
-var clipboard := Clipboard.new()
 var is_moving_content := false
 var arrow_key_move := false
 var is_pasting := false
@@ -33,13 +32,6 @@ var clear_in_selected_cels := true
 onready var marching_ants_outline: Sprite = $MarchingAntsOutline
 
 
-class Clipboard:
-	var image := Image.new()
-	var selection_bitmap := BitMap.new()
-	var big_bounding_rectangle := Rect2()
-	var selection_offset := Vector2.ZERO
-
-
 class Gizmo:
 	enum Type { SCALE, ROTATE }
 
@@ -658,6 +650,11 @@ func cut() -> void:
 
 func copy() -> void:
 	var project: Project = Global.current_project
+	var cl_image := Image.new()
+	var cl_selection_bitmap = BitMap.new()
+	var cl_big_bounding_rectangle := Rect2()
+	var cl_selection_offset := Vector2.ZERO
+
 	if !project.has_selection:
 		return
 	var image: Image = project.frames[project.current_frame].cels[project.current_layer].image
@@ -666,7 +663,7 @@ func copy() -> void:
 		to_copy.copy_from(preview_image)
 		var selected_bitmap_copy := project.selection_bitmap.duplicate()
 		project.move_bitmap_values(selected_bitmap_copy, false)
-		clipboard.selection_bitmap = selected_bitmap_copy
+		cl_selection_bitmap = selected_bitmap_copy
 	else:
 		to_copy = image.get_rect(big_bounding_rectangle)
 		to_copy.lock()
@@ -682,10 +679,22 @@ func copy() -> void:
 				if not project.selection_bitmap.get_bit(pos + offset_pos):
 					to_copy.set_pixelv(pos, Color(0))
 		to_copy.unlock()
-		clipboard.selection_bitmap = project.selection_bitmap.duplicate()
+		cl_selection_bitmap = project.selection_bitmap.duplicate()
-	clipboard.image = to_copy
+	cl_image = to_copy
-	clipboard.big_bounding_rectangle = big_bounding_rectangle
+	cl_big_bounding_rectangle = big_bounding_rectangle
-	clipboard.selection_offset = project.selection_offset
+	cl_selection_offset = project.selection_offset
+
+	var transfer_clipboard = {
+		"image": cl_image,
+		"selection_bitmap": cl_selection_bitmap,
+		"big_bounding_rectangle": cl_big_bounding_rectangle,
+		"selection_offset": cl_selection_offset,
+	}
+	# Store to ".clipboard.txt" file
+	var clipboard_file = File.new()
+	clipboard_file.open("user://clipboard.txt", File.WRITE)
+	clipboard_file.store_var(transfer_clipboard, true)
+	clipboard_file.close()
 
 	if !to_copy.is_empty():
 		var pattern: Patterns.Pattern = Global.patterns_popup.get_pattern(0)
@@ -697,6 +706,21 @@ func copy() -> void:
 
 
 func paste() -> void:
+	# Read from the ".clipboard.txt" file
+	var clipboard_file = File.new()
+	if !clipboard_file.file_exists("user://clipboard.txt"):
+		return
+	clipboard_file.open("user://clipboard.txt", File.READ)
+	var clipboard = clipboard_file.get_var(true)
+	clipboard_file.close()
+
+	if typeof(clipboard) == TYPE_DICTIONARY:
+		# A sanity check
+		if not clipboard.has_all(
+			["image", "selection_bitmap", "big_bounding_rectangle", "selection_offset"]
+		):
+			return
+
 		if clipboard.image.is_empty():
 			return
 		clear_selection()
@@ -771,6 +795,13 @@ func new_brush() -> void:
 		brush.copy_from(preview_image)
 		var selected_bitmap_copy := project.selection_bitmap.duplicate()
 		project.move_bitmap_values(selected_bitmap_copy, false)
+		var clipboard = str2var(OS.get_clipboard())
+		if typeof(clipboard) == TYPE_DICTIONARY:
+			# A sanity check
+			if not clipboard.has_all(
+				["image", "selection_bitmap", "big_bounding_rectangle", "selection_offset"]
+			):
+				return
 			clipboard.selection_bitmap = selected_bitmap_copy
 	else:
 		brush = image.get_rect(big_bounding_rectangle)