Mouse events

Several kinds of mouse events can be generated for the View

Event	Constant	Description
"mouse-down"	MouseDown	The mouse button was pressed.
"mouse-up"	MouseUp	The mouse button has been released.
"mouse-move"	MouseMove	Mouse cursor moved
"mouse-out"	MouseOut	The mouse cursor has moved outside the View, or entered the child View
"mouse-over"	MouseOver	The mouse cursor has moved within the area of View
"click-event"	ClickEvent	There was a mouse click
"double-click-event"	DoubleClickEvent	There was a double mouse click
"context-menu-event"	ContextMenuEvent	The key for calling the context menu (right mouse button) is pressed

The main event data listener has the following format:


func(View, MouseEvent)

where the second argument describes the parameters of the mouse event. The MouseEvent structure has the following fields:

Field	Type	Description
TimeStamp	uint64	The time the event was created (in milliseconds). The starting point depends on the browser implementation (EPOCH, browser launch, etc.).
Button	int	The number of the mouse button clicked on which triggered the event
Buttons	int	Bitmask showing which mouse buttons were pressed when the event occurred
X	float64	The horizontal position of the mouse relative to the origin View
Y	float64	The vertical position of the mouse relative to the origin View
ClientX	float64	Horizontal position of the mouse relative to the upper left corner of the application
ClientY	float64	The vertical position of the mouse relative to the upper left corner of the application
ScreenX	float64	Horizontal position of the mouse relative to the upper left corner of the screen
ScreenY	float64	Vertical position of the mouse relative to the upper left corner of the screen
CtrlKey	bool	The Ctrl key was active when the event occurred.
ShiftKey	bool	The Shift key was active when the event occurred.
AltKey	bool	The Alt (Option or ⌥ in OS X) key was active when the event occurred.
MetaKey	bool	The Meta key (for Mac this is the ⌘ Command key, for Windows is the Windows key ⊞) was active when the event occurred.

Button field can take the following values

Value	Constant	Description
<0		No buttons pressed
0	PrimaryMouseButton	Main button. Usually the left mouse button (can be changed in the OS settings)
1	AuxiliaryMouseButton	Auxiliary button (wheel or middle mouse button)
2	SecondaryMouseButton	Secondary button. Usually the right mouse button (can be changed in the OS settings)
3	MouseButton4	Fourth mouse button. Usually the browser's Back button
4	MouseButton5	Fifth mouse button. Usually the browser button Forward

The Button field is a bit mask combining (using OR) the following values

Value	Constant	Description
1	PrimaryMouseMask	Main button
2	SecondaryMouseMask	Secondary button
4	AuxiliaryMouseMask	Auxiliary button
8	MouseMask4	Fourth button
16	MouseMask5	Fifth button

You can also use listeners in the following formats:

func(MouseEvent)
func(View)
func()

You can get lists of listeners for mouse events using the functions:

func GetMouseDownListeners(view View, subviewID ...string) []func(View, MouseEvent)
func GetMouseUpListeners(view View, subviewID ...string) []func(View, MouseEvent)
func GetMouseMoveListeners(view View, subviewID ...string) []func(View, MouseEvent)
func GetMouseOverListeners(view View, subviewID ...string) []func(View, MouseEvent)
func GetMouseOutListeners(view View, subviewID ...string) []func(View, MouseEvent)
func GetClickListeners(view View, subviewID ...string) []func(View, MouseEvent)
func GetDoubleClickListeners(view View, subviewID ...string) []func(View, MouseEvent)
func GetContextMenuListeners(view View, subviewID ...string) []func(View, MouseEvent)