CHANGED: Canvas drag default key bindings restored

In the default key bindings, the behavior of `ctrl+left mouse button` is described as follows:
	- If have elements are selected, execute `DnD`
	- If no element is selected, execute `canvas drag`

Author: qindapao

documentation/mdbook_asciio/src/SUMMARY.md

@@ -9,7 +9,7 @@
 - [Installation](guide/installation.md)
 
 - [Asciio's interface](Interface.md)
-    - [Tabs](tabs.md)
+	- [Tabs](tabs.md)
 
 - [Unicode support](unicode_support.md)
 
@@ -42,7 +42,7 @@
 	- [Mouse](editing/mouse.md)
 	- [Cloning](editing/cloning.md)
 	- [Stencils and "Drag and Drop"](editing/drag_drop.md)
-    - [Changing element attributes](editing/changing_element_attributes.md)
+	- [Changing element attributes](editing/changing_element_attributes.md)
 
 - [Export/Save](exporting.md)
 	- [Asciio format](export/asciio.md)
@@ -64,7 +64,7 @@
 	- [Git](modes/git.md)
 	- [Cross](modes/cross.md)
 	- [Slide](modes/slides.md)
-    - [Animation](modes/animations.md)
+	- [Animation](modes/animations.md)
 
 - [Examples](examples.md)
 	- [Class hierarchy](examples/example1.md)
@@ -76,60 +76,60 @@
 
 - [Bindings Reference](bindings_index.md)
 	- [Why vim-like bindings](bindings/vim-like.md)
-    - [Root level bindings](root_level_bindings.md)
+	- [Root level bindings](root_level_bindings.md)
 		- [GUI bindings](bindings/gui.md)
-        - [Tab Management](bindings_group_tabs.md)
-    - [Insert operations](insert_operation.md)
-		- [box variants](bindings_group_insert_box.md)            
-        - [multiple elements](bindings_group_insert_multiple.md)  
-        - [unicode elements](bindings_group_insert_unicode.md)    
-        - [connected elements](bindings_group_insert_connected.md)
-        - [lines](bindings_group_insert_line.md)                  
-        - [stencils](bindings_group_insert_stencil.md)       
-        - [special elements](bindings_group_insert_element.md)    
-        - [rulers](bindings_group_insert_ruler.md)                
-    - [Element manipulation](element_operation.md)
+		- [Tab Management](bindings_group_tabs.md)
+	- [Insert operations](insert_operation.md)
+		- [box variants](bindings_group_insert_box.md)
+		- [multiple elements](bindings_group_insert_multiple.md)
+		- [unicode elements](bindings_group_insert_unicode.md)
+		- [connected elements](bindings_group_insert_connected.md)
+		- [lines](bindings_group_insert_line.md)
+		- [stencils](bindings_group_insert_stencil.md)
+		- [special elements](bindings_group_insert_element.md)
+		- [rulers](bindings_group_insert_ruler.md)
+	- [Element manipulation](element_operation.md)
 		- [Resizing elements](bindings/resizing.md)
-        - [Grouping elements](element_grouping_operation.md)
-        - [Spellchecking](spellchecking_operation.md)
-    - [Arrow manipulation](arrow_operation.md)
-        - [Arrow - Connectors](bindings_group_arrow_connectors.md)
-            - [Start Connector](bindings_group_arrow_connectors_start.md) 
-            - [End Connector](bindings_group_arrow_connectors_end.md)
-            - [Both Connectors](bindings_group_arrow_connectors_both.md)
-            - [Fixed vs dynamic connectors](fixed_vs_dynamic_connectors.md)
-    - [Yank](yank_operations.md)
-    - [Mouse](mouse_operations.md)
-    - [Image box](image_box_operations.md)
-    - [Display option](visual_settings_operation.md)
-        - [Color options](color_operations.md)
-    - [Debug](debug_operations.md)
-    - [Modes](modes_operation.md)
-        - [Clone](clone_mode_operation.md)
-        - [Eraser](eraser_mode.md)
-        - [Pen](pen_mode.md)
-        - [Arrow](arrow_mode.md)
-        - [Find](find_mode.md)
-        - [Git](git_mode.md)
-        - [Selection](selection_mode_operation.md)
-            - [Selection polygon mode](selection_polygon_mode.md)
-        - [Slide](slide_mode.md)
-        - [Animation](animation_mode.md)
-            - [Animation script](animation_script_mode.md)
+		- [Grouping elements](element_grouping_operation.md)
+		- [Spellchecking](spellchecking_operation.md)
+	- [Arrow manipulation](arrow_operation.md)
+		- [Arrow - Connectors](bindings_group_arrow_connectors.md)
+			- [Start Connector](bindings_group_arrow_connectors_start.md) 
+			- [End Connector](bindings_group_arrow_connectors_end.md)
+			- [Both Connectors](bindings_group_arrow_connectors_both.md)
+			- [Fixed vs dynamic connectors](fixed_vs_dynamic_connectors.md)
+	- [Yank](yank_operations.md)
+	- [Mouse](mouse_operations.md)
+	- [Image box](image_box_operations.md)
+	- [Display option](visual_settings_operation.md)
+		- [Color options](color_operations.md)
+	- [Debug](debug_operations.md)
+	- [Modes](modes_operation.md)
+		- [Clone](clone_mode_operation.md)
+		- [Eraser](eraser_mode.md)
+		- [Pen](pen_mode.md)
+		- [Arrow](arrow_mode.md)
+		- [Find](find_mode.md)
+		- [Git](git_mode.md)
+		- [Selection](selection_mode_operation.md)
+			- [Selection polygon mode](selection_polygon_mode.md)
+		- [Slide](slide_mode.md)
+		- [Animation](animation_mode.md)
+			- [Animation script](animation_script_mode.md)
 
 # Configuration
 
 - [Configuration](configuration.md)
 	- [Configuration Format](config/config_format.md)
-    - [Bindings Format](config/binding_format.md)
+	- [Bindings Format](config/binding_format.md)
 		- [Binding override](config/user_bindings/binding_override.md)
 
 # Developer Guide
 
 - [For Developers](for_developers/README.md)
 	- [Scripting](for_developers/scripting.md)
-	    - [Execute](for_developers/scripting_execute.md)
-	    - [Simplified API](for_developers/scripting_api.md)
+		- [Execute](for_developers/scripting_execute.md)
+		- [Simplified API](for_developers/scripting_api.md)
 	- [Modifying Asciio](for_developers/modify_Asciio.md)
 		- [Bindings](for_developers/bindings.md)
 		- [Capturing groups with overlay](config/user_bindings/capturing_groups_overlay.md)

documentation/mdbook_asciio/src/editing/mouse.md

@@ -66,3 +66,13 @@ You can quickly create boxes and section by combining ***quick link*** and ***qu
 
 ![quick box and section](quick_box_and_section.gif)
 
+## Mouse dragging canvas
+
+If no element is selected, you can use the mouse to drag the canvas.
+
+If at least one element is selected, other operations are performed. See [drag_drop](drag_drop.md).
+
+***Binding:*** control + left click + drag
+
+![mouse drag canvas](mouse_drag_canvas.gif)
+

documentation/mdbook_asciio/src/editing/mouse_drag_canvas.gif

@@ -825,7 +825,10 @@ if($self->{PREVIOUS_X} != $x || $self->{PREVIOUS_Y} != $y)
 
 	$self->run_actions(["${modifiers}motion_notify", $event]) if $self->exists_action("${modifiers}motion_notify") ;
 
-	($self->{PREVIOUS_X}, $self->{PREVIOUS_Y}) = ($self->{MOUSE_X}, $self->{MOUSE_Y}) = ($x, $y) ;
+	unless($self->{SKIP_COORDINATE_UPDATE})
+		{
+		($self->{PREVIOUS_X}, $self->{PREVIOUS_Y}) = ($self->{MOUSE_X}, $self->{MOUSE_Y}) = ($x, $y) ;
+		}
 	}
 
 }

lib/App/Asciio.pm

@@ -6,6 +6,7 @@ use App::Asciio::Actions::ElementAttributes ;
 #----------------------------------------------------------------------------------------------
 
 use List::MoreUtils qw(any minmax first_value) ;
+use List::Util qw(max) ;
 use Readonly ;
 
 use App::Asciio::stripes::section_wirl_arrow ;
@@ -407,10 +408,19 @@ sub mouse_drag_canvas
 {
 my ($self, $event) = @_ ;
 
+# If have elements are selected, DnD is executed.
+# If no element is selected, canvas drag is executed.
+return if $self->any_selected_elements() ;
+
 my ($x, $y) = @{$event->{COORDINATES}}[0, 1] ;
 
+($self->{PREVIOUS_X}, $self->{PREVIOUS_Y}) = ($x, $y) if ($event->{STATE} eq 'button1-press') ;
+
 if($event->{STATE} eq 'dragging-button1' && ($self->{PREVIOUS_X} != $x || $self->{PREVIOUS_Y} != $y))
 	{
+	# The coordinates cannot be updated during the dragging process, otherwise
+	# the source and target coordinates will be incorrect.
+	$self->{SKIP_COORDINATE_UPDATE} = 1 ;
 	my ($character_width, $character_height) = $self->get_character_size() ;
 
 	my $h_value = $self->{hadjustment}->get_value() ;
@@ -419,29 +429,14 @@ if($event->{STATE} eq 'dragging-button1' && ($self->{PREVIOUS_X} != $x || $self-
 	my $new_h_value = $h_value - (($x - $self->{PREVIOUS_X}) * $character_width) ;
 	my $new_v_value = $v_value - (($y - $self->{PREVIOUS_Y}) * $character_height) ;
 
-	if($new_h_value >= 0)
-		{
-		$self->{hadjustment}->set_value($new_h_value) ;
-		}
-	else
-		{
-		# scrollbar reached top
-		}
-	
-	if($new_v_value >= 0)
-		{
-		$self->{vadjustment}->set_value($new_v_value) ;
-		}
-	else
-		{
-		# scrollbar reached top
-		}
-	}
-else
-	{
-	($self->{PREVIOUS_X}, $self->{PREVIOUS_Y}) = ($self->{MOUSE_X}, $self->{MOUSE_Y}) ;
-	($self->{MOUSE_X}, $self->{MOUSE_Y}) = ($x, $y) ;
+	# when <=0 scrollbar reached top
+	$self->{hadjustment}->set_value(max($new_h_value, 0)) ;
+	$self->{vadjustment}->set_value(max($new_v_value, 0)) ;
+	return ;
 	}
+
+delete $self->{SKIP_COORDINATE_UPDATE} ;
+($self->{PREVIOUS_X}, $self->{PREVIOUS_Y}) = ($self->{MOUSE_X}, $self->{MOUSE_Y}) = ($x, $y) ;
 }
 
 #----------------------------------------------------------------------------------------------

lib/App/Asciio/Actions/Mouse.pm

@@ -129,6 +129,7 @@
 
 'Mouse motion'                 => ['000-motion_notify',                  \&App::Asciio::Actions::Mouse::mouse_motion, undef, { HIDE => 1}        ],
 'Mouse motion 2'               => ['0AS-motion_notify',                  \&App::Asciio::Actions::Mouse::mouse_motion, undef, { HIDE => 1}        ],
+'Mouse drag canvas'            => ['C00-motion_notify',                  \&App::Asciio::Actions::Mouse::mouse_drag_canvas                        ],
 
 # mouse emulation
 'Mouse emulation toggle'           => [['000-apostrophe', "'"], \&App::Asciio::Actions::Mouse::toggle_mouse                ],