package basic import "image" import "git.tebibyte.media/sashakoshka/tomo" import "git.tebibyte.media/sashakoshka/tomo/theme" import "git.tebibyte.media/sashakoshka/tomo/artist" import "git.tebibyte.media/sashakoshka/tomo/elements/core" // ScrollContainer is a container that is capable of holding a scrollable // element. type ScrollContainer struct { *core.Core core core.CoreControl selected bool child tomo.Scrollable horizontal struct { enabled bool bounds image.Rectangle } vertical struct { enabled bool bounds image.Rectangle } onSelectionRequest func () (granted bool) onSelectionMotionRequest func (tomo.SelectionDirection) (granted bool) } // NewScrollContainer creates a new scroll container with the specified scroll // bars. func NewScrollContainer (horizontal, vertical bool) (element *ScrollContainer) { element = &ScrollContainer { } element.Core, element.core = core.NewCore(element) element.updateMinimumSize() element.horizontal.enabled = horizontal element.vertical.enabled = vertical return } // Resize resizes the scroll box. func (element *ScrollContainer) Resize (width, height int) { element.core.AllocateCanvas(width, height) element.recalculate() element.child.Resize ( element.vertical.bounds.Min.X, element.horizontal.bounds.Min.Y) element.draw() } // Adopt adds a scrollable element to the scroll container. The container can // only contain one scrollable element at a time, and when a new one is adopted // it replaces the last one. func (element *ScrollContainer) Adopt (child tomo.Scrollable) { // disown previous child if it exists if element.child != nil { element.clearChildEventHandlers(child) } // adopt new child element.child = child if child != nil { child.OnDamage(element.childDamageCallback) child.OnMinimumSizeChange(element.updateMinimumSize) if newChild, ok := child.(tomo.Selectable); ok { newChild.OnSelectionRequest ( element.childSelectionRequestCallback) newChild.OnSelectionMotionRequest ( element.childSelectionMotionRequestCallback) } // TODO: somehow inform the core that we do not in fact want to // redraw the element. element.updateMinimumSize() if element.core.HasImage() { element.recalculate() element.child.Resize ( element.horizontal.bounds.Min.X, element.vertical.bounds.Min.X) element.draw() } } } func (element *ScrollContainer) HandleKeyDown ( key tomo.Key, modifiers tomo.Modifiers, repeated bool, ) { if child, ok := element.child.(tomo.KeyboardTarget); ok { child.HandleKeyDown(key, modifiers, repeated) } } func (element *ScrollContainer) HandleKeyUp (key tomo.Key, modifiers tomo.Modifiers) { if child, ok := element.child.(tomo.KeyboardTarget); ok { child.HandleKeyUp(key, modifiers) } } func (element *ScrollContainer) Selected () (selected bool) { return element.selected } func (element *ScrollContainer) Select () { if element.onSelectionRequest != nil { element.onSelectionRequest() } } func (element *ScrollContainer) HandleSelection ( direction tomo.SelectionDirection, ) ( accepted bool, ) { if child, ok := element.child.(tomo.Selectable); ok { element.selected = true return child.HandleSelection(direction) } else { element.selected = false return false } } func (element *ScrollContainer) HandleDeselection () { if child, ok := element.child.(tomo.Selectable); ok { child.HandleDeselection() } element.selected = false } func (element *ScrollContainer) OnSelectionRequest (callback func () (granted bool)) { element.onSelectionRequest = callback } func (element *ScrollContainer) OnSelectionMotionRequest ( callback func (direction tomo.SelectionDirection) (granted bool), ) { element.onSelectionMotionRequest = callback } func (element *ScrollContainer) childDamageCallback (region tomo.Canvas) { element.core.DamageRegion(artist.Paste(element, region, image.Point { })) } func (element *ScrollContainer) childSelectionRequestCallback () (granted bool) { child, ok := element.child.(tomo.Selectable) if !ok { return false } if element.onSelectionRequest != nil && element.onSelectionRequest() { child.HandleSelection(tomo.SelectionDirectionNeutral) return true } else { return false } } func (element *ScrollContainer) childSelectionMotionRequestCallback ( direction tomo.SelectionDirection, ) ( granted bool, ) { if element.onSelectionMotionRequest == nil { return } return element.onSelectionMotionRequest(direction) } func (element *ScrollContainer) clearChildEventHandlers (child tomo.Element) { child.OnDamage(nil) child.OnMinimumSizeChange(nil) if child0, ok := child.(tomo.Selectable); ok { child0.OnSelectionRequest(nil) child0.OnSelectionMotionRequest(nil) if child0.Selected() { child0.HandleDeselection() } } if child0, ok := child.(tomo.Flexible); ok { child0.OnFlexibleHeightChange(nil) } } func (element *ScrollContainer) recalculate () { horizontal := &element.horizontal vertical := &element.vertical bounds := element.Bounds() thickness := theme.Padding() * 2 // reset bounds horizontal.bounds = image.Rectangle { } vertical.bounds = image.Rectangle { } // if enabled, give substance to the bars if horizontal.enabled { horizontal.bounds.Max.X = bounds.Max.X - thickness horizontal.bounds.Max.Y = thickness } if vertical.enabled { vertical.bounds.Max.X = thickness vertical.bounds.Max.Y = bounds.Max.Y - thickness } // move the bars to the edge of the element horizontal.bounds = horizontal.bounds.Add ( bounds.Max.Sub(horizontal.bounds.Max)) vertical.bounds = vertical.bounds.Add ( bounds.Max.Sub(vertical.bounds.Max)) } func (element *ScrollContainer) draw () { artist.Paste(element.core, element.child, image.Point { }) element.drawHorizontalBar() element.drawVerticalBar() } func (element *ScrollContainer) drawHorizontalBar () { } func (element *ScrollContainer) drawVerticalBar () { } func (element *ScrollContainer) updateMinimumSize () { width := theme.Padding() * 2 height := theme.Padding() * 2 if element.child != nil { childWidth, childHeight := element.child.MinimumSize() width += childWidth height += childHeight } element.core.SetMinimumSize(width, height) }