Add theme setting nonsense

internal/system/box.go

@@ -20,6 +20,9 @@ type box struct {
 	outer  anyBox
 
 	role           tomo.Role
+	styleCookie    event.Cookie
+	lastStyleNonce int
+	lastIconsNonce int
 
 	bounds              image.Rectangle
 	minSize             image.Point
@@ -57,6 +60,8 @@ type box struct {
 		scroll      event.Broadcaster[func (float64, float64)]
 		keyDown     event.Broadcaster[func (input.Key, bool)]
 		keyUp       event.Broadcaster[func (input.Key, bool)]
+		styleChange event.FuncBroadcaster
+		iconsChange event.FuncBroadcaster
 	}
 }
 
@@ -282,6 +287,12 @@ func (this *box) OnKeyDown (callback func(key input.Key, numberPad bool)) event.
 func (this *box) OnKeyUp (callback func(key input.Key, numberPad bool)) event.Cookie {
 	return this.on.keyUp.Connect(callback)
 }
+func (this *box) OnStyleChange (callback func()) event.Cookie {
+	return this.on.styleChange.Connect(callback)
+}
+func (this *box) OnIconsChange (callback func()) event.Cookie {
+	return this.on.iconsChange.Connect(callback)
+}
 func (this *box) handleFocusEnter () {
 	this.on.focusEnter.Broadcast()
 }
@@ -451,7 +462,7 @@ func (this *box) doLayout () {
 	// laycnt ++
 	
 	this.innerClippingBounds = this.borderSum().Apply(this.bounds)
-	this.loseCanvas()
+	this.outer.recursiveLoseCanvas()
 }
 
 func (this *box) setParent (parent parent) {
@@ -481,7 +492,7 @@ func (this *box) recursiveRedo () {
 	this.doDraw()
 }
 
-func (this *box) loseCanvas () {
+func (this *box) recursiveLoseCanvas () {
 	this.canvas.InvalidateTo(nil)
 }
 
@@ -506,6 +517,28 @@ func (this *box) invalidateMinimum () {
 	}
 }
 
+func (this *box) recursiveReApply () {
+	// re-apply styling, icons *if needed*
+
+	// style
+	hierarchyStyleNonce := this.getStyleNonce()
+	if this.lastStyleNonce != hierarchyStyleNonce {
+		this.lastStyleNonce = hierarchyStyleNonce
+		if this.styleCookie != nil {
+			this.styleCookie.Close()
+		}
+		this.styleCookie = this.getStyle().Apply(this.outer)
+		this.on.styleChange.Broadcast()
+	}
+
+	// icons
+	hierarchyIconsNonce := this.getIconsNonce()
+	if this.lastIconsNonce != hierarchyIconsNonce {
+		this.lastIconsNonce = hierarchyIconsNonce
+		this.on.iconsChange.Broadcast()
+	}
+}
+
 func (this *box) canBeFocused () bool {
 	return this.focusable
 }
@@ -539,7 +572,23 @@ func (this *box) getWindow () tomo.Window {
 	return hierarchy.getWindow()
 }
 
+func (this *box) getStyle () tomo.Style {
+	hierarchy := this.getHierarchy()
+	if hierarchy == nil { return nil }
+	return hierarchy.getStyle()
+}
+
 func (this *box) getHierarchy () *Hierarchy {
 	if this.parent == nil { return nil }
 	return this.parent.getHierarchy()
 }
+
+func (this *box) getStyleNonce () int {
+	// should panic if not in the tree
+	return this.getHierarchy().getStyleNonce()
+}
+
+func (this *box) getIconsNonce () int {
+	// should panic if not in the tree
+	return this.getHierarchy().getIconsNonce()
+}

internal/system/containerbox.go

@@ -335,6 +335,20 @@ func (this *containerBox) recursiveRedo () {
 	}
 }
 
+func (this *containerBox) recursiveLoseCanvas () {
+	this.box.recursiveLoseCanvas()
+	for _, child := range this.children {
+		child.(anyBox).recursiveLoseCanvas()
+	}
+}
+
+func (this *containerBox) recursiveReApply () {
+	this.box.recursiveReApply()
+	for _, child := range this.children {
+		child.(anyBox).recursiveReApply()
+	}
+}
+
 func (this *containerBox) boxUnder (point image.Point, category eventCategory) anyBox {
 	if !point.In(this.bounds) { return nil }
 

internal/system/hierarchy.go

@@ -13,6 +13,10 @@ type Hierarchy struct {
 	system *System
 	canvas canvas.Canvas
 
+	style tomo.Style
+	styleNonce int
+	iconsNonce int
+	
 	root    anyBox
 	focused anyBox
 	hovered anyBox
@@ -56,6 +60,7 @@ func (this *System) NewHierarchy (link WindowLink) *Hierarchy {
 		needLayout:  make(util.Set[anyBox]),
 		needDraw:    make(util.Set[anyBox]),
 	}
+	this.hierarchies.Add(hierarchy)
 	return hierarchy
 }
 
@@ -85,7 +90,7 @@ func (this *Hierarchy) Empty () bool {
 // draw to. The Hierarchy will use the canvas.Canvas's bounds to lay itself out.
 func (this *Hierarchy) SetCanvas (can canvas.Canvas) {
 	this.canvas = can
-	if this.root != nil { this.root.loseCanvas() }
+	if this.root != nil { this.root.recursiveLoseCanvas() }
 	this.needRedo = true
 }
 
@@ -135,6 +140,23 @@ func (this *Hierarchy) AfterEvent () {
 	}
 }
 
+// Close closes the Hierarchy. This should be called when the Window that
+// contains it has been closed.
+func (this *Hierarchy) Close () {
+	this.system.removeHierarchy(this)
+}
+
+func (this *Hierarchy) setStyle (style tomo.Style) {
+	this.style = style
+	this.styleNonce ++
+	if this.root != nil { this.root.recursiveReApply() }
+}
+
+func (this *Hierarchy) setIcons (icons tomo.Icons) {
+	this.iconsNonce ++
+	if this.root != nil { this.root.recursiveReApply() }
+}
+
 func (this *Hierarchy) getHierarchy () *Hierarchy {
 	return this
 }
@@ -143,6 +165,18 @@ func (this *Hierarchy) getWindow () tomo.Window {
 	return this.link.GetWindow()
 }
 
+func (this *Hierarchy) getStyle () tomo.Style {
+	return this.style
+}
+
+func (this *Hierarchy) getStyleNonce () int {
+	return this.styleNonce
+}
+
+func (this *Hierarchy) getIconsNonce () int {
+	return this.iconsNonce
+}
+
 func (this *Hierarchy) getCanvas () canvas.Canvas {
 	return this.canvas
 }

internal/system/internal-iface.go

@@ -57,7 +57,11 @@ type anyBox interface {
 	recursiveRedo       ()
 	// loseCanvas causes this anyBox and its children (if applicable) to
 	// lose their canvases and re-cut them as needed.
-	loseCanvas       ()
+	recursiveLoseCanvas ()
+	// recursiveReAppply causes this anyBox and its children (if applicable)
+	// to check whether they have an outdated style or icon set, and if so,
+	// update it and trigger the appropriate event broadcasters.
+	recursiveReApply    ()
 	
 	// contentMinimum returns the minimum dimensions of this box's content
 	contentMinimum   () image.Point

internal/system/system.go

@@ -2,12 +2,15 @@ package system
 
 import "io"
 import "image"
+import "git.tebibyte.media/tomo/tomo"
 import "git.tebibyte.media/tomo/tomo/canvas"
+import "git.tebibyte.media/tomo/backend/internal/util"
 
 // System is coupled to a tomo.Backend implementation, and manages Hierarchies
 // and Boxes.
 type System struct {
 	link        BackendLink
+	hierarchies util.Set[*Hierarchy]
 }
 
 // BackendLink allows the System to call up into the tomo.Backend implementation
@@ -31,5 +34,25 @@ type SurfaceLink interface {
 func New (link BackendLink) *System {
 	return &System {
 		link:        link,
+		hierarchies: make(util.Set[*Hierarchy]),
 	}
 }
+
+// SetStyle sets the tomo.Style that is applied to objects, and notifies them
+// that the style has changed.
+func (this *System) SetStyle (style tomo.Style) {
+	for hierarchy := range this.hierarchies {
+		hierarchy.setStyle(style)
+	}
+}
+
+// SetIcons notifies objects that the icons have changed.
+func (this *System) SetIcons (icons tomo.Icons) {
+	for hierarchy := range this.hierarchies {
+		hierarchy.setIcons(icons)
+	}
+}
+
+func (this *System) removeHierarchy (hierarchy *Hierarchy) {
+	delete(this.hierarchies, hierarchy)
+}