From 6db13c8f4639a47fbe13e1e5718bae7440f74c3f Mon Sep 17 00:00:00 2001
From: Sander Schobers <sander@schobers.eu>
Date: Fri, 15 May 2020 16:02:54 +0200
Subject: [PATCH] Added overlays.

---
 ui/context.go  |  7 ++++-
 ui/overlays.go | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++
 ui/ui.go       |  5 ++--
 3 files changed, 80 insertions(+), 3 deletions(-)
 create mode 100644 ui/overlays.go

diff --git a/ui/context.go b/ui/context.go
index 2282b52..a4a41ee 100644
--- a/ui/context.go
+++ b/ui/context.go
@@ -4,6 +4,7 @@ type Context interface {
 	Animate()
 	Fonts() *Fonts
 	HasQuit() bool
+	Overlays() *Overlays
 	Quit()
 	Renderer() Renderer
 	Style() *Style
@@ -18,6 +19,7 @@ type context struct {
 	quit     chan struct{}
 	renderer Renderer
 	view     Control
+	overlays *Overlays
 	fonts    *Fonts
 	textures *Textures
 	style    *Style
@@ -29,6 +31,7 @@ func newContext(r Renderer, s *Style, view Control) *context {
 		renderer: r,
 		style:    s,
 		view:     view,
+		overlays: NewOverlays(view),
 		fonts:    NewFonts(r),
 		textures: NewTextures(r)}
 }
@@ -51,6 +54,8 @@ func (c *context) HasQuit() bool {
 	}
 }
 
+func (c *context) Overlays() *Overlays { return c.overlays }
+
 func (c *context) Renderer() Renderer { return c.renderer }
 
 func (c *context) Style() *Style { return c.style }
@@ -71,5 +76,5 @@ func (c *context) Handle(e Event) {
 		c.Quit()
 		return
 	}
-	c.view.Handle(c, e)
+	c.overlays.Handle(c, e)
 }
diff --git a/ui/overlays.go b/ui/overlays.go
new file mode 100644
index 0000000..e292328
--- /dev/null
+++ b/ui/overlays.go
@@ -0,0 +1,71 @@
+package ui
+
+import "opslag.de/schobers/geom"
+
+var _ Control = &Overlays{}
+
+type Overlays struct {
+	Proxy
+
+	overlays map[string]Control
+	order    []string
+	visible  map[string]bool
+}
+
+func NewOverlays(over Control) *Overlays {
+	return &Overlays{
+		Proxy: Proxy{Content: over},
+
+		overlays: map[string]Control{},
+		visible:  map[string]bool{},
+	}
+}
+
+func (o *Overlays) AddOnTop(name string, control Control, visible bool) {
+	o.order = append(o.order, name)
+	o.overlays[name] = control
+	o.visible[name] = visible
+}
+
+func (o *Overlays) AddOnBottom(name string, control Control, visible bool) {
+	o.order = append([]string{name}, o.order...)
+	o.overlays[name] = control
+	o.visible[name] = visible
+}
+
+func (o *Overlays) Arrange(ctx Context, bounds geom.RectangleF32, offset geom.PointF32, parent Control) {
+	o.Proxy.Arrange(ctx, bounds, offset, parent)
+	for _, overlay := range o.overlays {
+		overlay.Arrange(ctx, bounds, offset, parent)
+	}
+}
+
+func (o *Overlays) Handle(ctx Context, e Event) {
+	for overlay, visible := range o.visible {
+		if visible {
+			o.overlays[overlay].Handle(ctx, e)
+		}
+	}
+	o.Proxy.Handle(ctx, e)
+}
+
+func (o *Overlays) Hide(name string) {
+	o.visible[name] = false
+}
+
+func (o *Overlays) Render(ctx Context) {
+	o.Proxy.Render(ctx)
+	for overlay, visible := range o.visible {
+		if visible {
+			o.overlays[overlay].Render(ctx)
+		}
+	}
+}
+
+func (o *Overlays) Show(name string) {
+	o.visible[name] = true
+}
+
+func (o *Overlays) Toggle(name string) {
+	o.visible[name] = !o.visible[name]
+}
diff --git a/ui/ui.go b/ui/ui.go
index 42039f7..6a8a103 100644
--- a/ui/ui.go
+++ b/ui/ui.go
@@ -39,12 +39,13 @@ func RunWait(r Renderer, s *Style, view Control, wait bool) error {
 	}()
 	defer anim.Stop()
 
+	overlays := ctx.Overlays()
 	ctx.Renderer().Refresh()
 	for !ctx.HasQuit() {
 		var size = r.Size()
 		var bounds = geom.RectF32(0, 0, size.X, size.Y)
-		view.Arrange(ctx, bounds, geom.ZeroPtF32, nil)
-		view.Render(ctx)
+		overlays.Arrange(ctx, bounds, geom.ZeroPtF32, nil)
+		overlays.Render(ctx)
 		if ctx.HasQuit() {
 			return nil
 		}