package rui import ( "strconv" "strings" ) const ( // TouchStart is the constant for "touch-start" property tag. // The "touch-start" event is fired when one or more touch points are placed on the touch surface. // The main listener format: func(View, TouchEvent). // The additional listener formats: func(TouchEvent), func(View), and func(). TouchStart = "touch-start" // TouchEnd is the constant for "touch-end" property tag. // The "touch-end" event fires when one or more touch points are removed from the touch surface. // The main listener format: func(View, TouchEvent). // The additional listener formats: func(TouchEvent), func(View), and func(). TouchEnd = "touch-end" // TouchMove is the constant for "touch-move" property tag. // The "touch-move" event is fired when one or more touch points are moved along the touch surface. // The main listener format: func(View, TouchEvent). // The additional listener formats: func(TouchEvent), func(View), and func(). TouchMove = "touch-move" // TouchCancel is the constant for "touch-cancel" property tag. // The "touch-cancel" event is fired when one or more touch points have been disrupted // in an implementation-specific manner (for example, too many touch points are created). // The main listener format: func(View, TouchEvent). // The additional listener formats: func(TouchEvent), func(View), and func(). TouchCancel = "touch-cancel" ) // Touch contains parameters of a single touch of a touch event type Touch struct { // Identifier is a unique identifier for this Touch object. A given touch point (say, by a finger) // will have the same identifier for the duration of its movement around the surface. // This lets you ensure that you're tracking the same touch all the time. Identifier int // X provides the horizontal coordinate within the view's viewport. X float64 // Y provides the vertical coordinate within the view's viewport. Y float64 // ClientX provides the horizontal coordinate within the application's viewport at which the event occurred. ClientX float64 // ClientY provides the vertical coordinate within the application's viewport at which the event occurred. ClientY float64 // ScreenX provides the horizontal coordinate (offset) of the touch pointer in global (screen) coordinates. ScreenX float64 // ScreenY provides the vertical coordinate (offset) of the touch pointer in global (screen) coordinates. ScreenY float64 // RadiusX is the X radius of the ellipse that most closely circumscribes the area of contact with the screen. // The value is in pixels of the same scale as screenX. RadiusX float64 // RadiusY is the Y radius of the ellipse that most closely circumscribes the area of contact with the screen. // The value is in pixels of the same scale as screenX. RadiusY float64 // RotationAngle is the angle (in degrees) that the ellipse described by radiusX and radiusY must be rotated, // clockwise, to most accurately cover the area of contact between the user and the surface. RotationAngle float64 // Force is the amount of pressure being applied to the surface by the user, as a float // between 0.0 (no pressure) and 1.0 (maximum pressure). Force float64 } // TouchEvent contains parameters of a touch event type TouchEvent struct { // TimeStamp is the time at which the event was created (in milliseconds). // This value is time since epoch—but in reality, browsers' definitions vary. TimeStamp uint64 // Touches is the array of all the Touch objects representing all current points // of contact with the surface, regardless of target or changed status. Touches []Touch // CtrlKey == true if the control key was down when the event was fired. false otherwise. CtrlKey bool // ShiftKey == true if the shift key was down when the event was fired. false otherwise. ShiftKey bool // AltKey == true if the alt key was down when the event was fired. false otherwise. AltKey bool // MetaKey == true if the meta key was down when the event was fired. false otherwise. MetaKey bool } var touchEvents = map[string]struct{ jsEvent, jsFunc string }{ TouchStart: {jsEvent: "ontouchstart", jsFunc: "touchStartEvent"}, TouchEnd: {jsEvent: "ontouchend", jsFunc: "touchEndEvent"}, TouchMove: {jsEvent: "ontouchmove", jsFunc: "touchMoveEvent"}, TouchCancel: {jsEvent: "ontouchcancel", jsFunc: "touchCancelEvent"}, } func (view *viewData) setTouchListener(tag string, value any) bool { listeners, ok := valueToEventListeners[View, TouchEvent](value) if !ok { notCompatibleType(tag, value) return false } if listeners == nil { view.removeTouchListener(tag) } else if js, ok := touchEvents[tag]; ok { view.properties[tag] = listeners if view.created { updateProperty(view.htmlID(), js.jsEvent, js.jsFunc+"(this, event)", view.Session()) } } else { return false } return true } func (view *viewData) removeTouchListener(tag string) { delete(view.properties, tag) if view.created { if js, ok := touchEvents[tag]; ok { removeProperty(view.htmlID(), js.jsEvent, view.Session()) } } } func touchEventsHtml(view View, buffer *strings.Builder) { for tag, js := range touchEvents { if value := view.getRaw(tag); value != nil { if listeners, ok := value.([]func(View, TouchEvent)); ok && len(listeners) > 0 { buffer.WriteString(js.jsEvent + `="` + js.jsFunc + `(this, event)" `) } } } } func (event *TouchEvent) init(data DataObject) { event.Touches = []Touch{} event.TimeStamp = getTimeStamp(data) if node := data.PropertyWithTag("touches"); node != nil && node.Type() == ArrayNode { for i := 0; i < node.ArraySize(); i++ { if element := node.ArrayElement(i); element != nil && element.IsObject() { if obj := element.Object(); obj != nil { var touch Touch if value, ok := obj.PropertyValue("identifier"); ok { touch.Identifier, _ = strconv.Atoi(value) } touch.X = dataFloatProperty(obj, "x") touch.Y = dataFloatProperty(obj, "y") touch.ClientX = dataFloatProperty(obj, "clientX") touch.ClientY = dataFloatProperty(obj, "clientY") touch.ScreenX = dataFloatProperty(obj, "screenX") touch.ScreenY = dataFloatProperty(obj, "screenY") touch.RadiusX = dataFloatProperty(obj, "radiusX") touch.RadiusY = dataFloatProperty(obj, "radiusY") touch.RotationAngle = dataFloatProperty(obj, "rotationAngle") touch.Force = dataFloatProperty(obj, "force") event.Touches = append(event.Touches, touch) } } } } event.CtrlKey = dataBoolProperty(data, "ctrlKey") event.ShiftKey = dataBoolProperty(data, "shiftKey") event.AltKey = dataBoolProperty(data, "altKey") event.MetaKey = dataBoolProperty(data, "metaKey") } func handleTouchEvents(view View, tag string, data DataObject) { listeners := getEventListeners[View, TouchEvent](view, "", tag) if len(listeners) == 0 { return } var event TouchEvent event.init(data) for _, listener := range listeners { listener(view, event) } } // GetTouchStartListeners returns the "touch-start" listener list. If there are no listeners then the empty list is returned. // If the second argument (subviewID) is "" then a value from the first argument (view) is returned. func GetTouchStartListeners(view View, subviewID string) []func(View, TouchEvent) { return getEventListeners[View, TouchEvent](view, subviewID, TouchStart) } // GetTouchEndListeners returns the "touch-end" listener list. If there are no listeners then the empty list is returned. // If the second argument (subviewID) is "" then a value from the first argument (view) is returned. func GetTouchEndListeners(view View, subviewID string) []func(View, TouchEvent) { return getEventListeners[View, TouchEvent](view, subviewID, TouchEnd) } // GetTouchMoveListeners returns the "touch-move" listener list. If there are no listeners then the empty list is returned. // If the second argument (subviewID) is "" then a value from the first argument (view) is returned. func GetTouchMoveListeners(view View, subviewID string) []func(View, TouchEvent) { return getEventListeners[View, TouchEvent](view, subviewID, TouchMove) } // GetTouchCancelListeners returns the "touch-cancel" listener list. If there are no listeners then the empty list is returned. // If the second argument (subviewID) is "" then a value from the first argument (view) is returned. func GetTouchCancelListeners(view View, subviewID string) []func(View, TouchEvent) { return getEventListeners[View, TouchEvent](view, subviewID, TouchCancel) }