lots changes:

- renamed scene files
- fixed options back using scene.Prev
- fixed initial zooming (finally)
- fixed reset zoom (key r)
- fixed initial size, now works with state loading as well

TODO.md

@@ -2,16 +2,3 @@
 
 - changing options mid-game has no effect in most cases, even after a restart
 
-- Statefile loading does not work correclty anymore. With larger grids
-  everything  is empty.  With square  grids part  of the  grid is  cut
-  off. Smaller grids load though
-  
-- Also  when loading a state  file, centering doesn't work  anymore, I
-  think the geom calculation is overthrown by the parser func. So, put
-  this calc into its own func and  always call. Or - as stated below -
-  put it onto camera.go and call from Init().
-  
-- Zoom 0 on reset only  works when world<screen.  otherwise zoom would
-  be negative So, on Init() memoize  centered camera position or add a
-  Center() function  to camera.go.  Then on  reset calculate  the zoom
-  level so that the world fits into the screen.

camera.go

@@ -1,3 +1,5 @@
+// this comes from the camera example but I enhanced it a little bit
+
 package main
 
 import (
@@ -9,9 +11,12 @@ import (
 )
 
 type Camera struct {
-	ViewPort   f64.Vec2
-	Position   f64.Vec2
-	ZoomFactor int
+	ViewPort          f64.Vec2
+	Position          f64.Vec2
+	ZoomFactor        int
+	InitialZoomFactor int
+	InitialPosition   f64.Vec2
+	ZoomOutFactor     int
 }
 
 func (c *Camera) String() string {
@@ -32,15 +37,17 @@ func (c *Camera) worldMatrix() ebiten.GeoM {
 	m := ebiten.GeoM{}
 	m.Translate(-c.Position[0], -c.Position[1])
 
+	viewportCenter := c.viewportCenter()
+
 	// We want to scale and rotate around center of image / screen
-	m.Translate(-c.viewportCenter()[0], -c.viewportCenter()[1])
+	m.Translate(-viewportCenter[0], -viewportCenter[1])
 
 	m.Scale(
 		math.Pow(1.01, float64(c.ZoomFactor)),
 		math.Pow(1.01, float64(c.ZoomFactor)),
 	)
 
-	m.Translate(c.viewportCenter()[0], c.viewportCenter()[1])
+	m.Translate(viewportCenter[0], viewportCenter[1])
 	return m
 }
 
@@ -61,8 +68,14 @@ func (c *Camera) ScreenToWorld(posX, posY int) (float64, float64) {
 	}
 }
 
-func (c *Camera) Reset() {
-	c.Position[0] = 0
-	c.Position[1] = 0
-	c.ZoomFactor = 0
+func (c *Camera) Setup() {
+	c.Position[0] = c.InitialPosition[0]
+	c.Position[1] = c.InitialPosition[1]
+	c.ZoomFactor = c.InitialZoomFactor
+}
+
+func (c *Camera) Reset() {
+	c.Position[0] = c.InitialPosition[0]
+	c.Position[1] = c.InitialPosition[1]
+	c.ZoomFactor = c.ZoomOutFactor
 }

config.go

@@ -30,6 +30,7 @@ type Config struct {
 	Restart, RestartGrid, RestartCache     bool
 	StartWithMenu                          bool
 	Zoomfactor                             int
+	ZoomOutFactor                          int
 	InitialCamPos                          []float64
 	DelayedStart                           bool // if true game, we wait. like pause but program induced
 
@@ -51,6 +52,40 @@ const (
 	DEFAULT_GEOM        = "640x384"
 )
 
+func (config *Config) SetupCamera() {
+	config.Zoomfactor = DEFAULT_ZOOMFACTOR
+
+	// calculate the initial cam pos. It is negative if the total grid
+	// size  is smaller than  the screen  in a centered  position, but
+	// it's zero if it's equal or larger than the screen.
+	config.InitialCamPos = make([]float64, 2)
+
+	config.InitialCamPos[0] = float64(((config.ScreenWidth - (config.Width * config.Cellsize)) / 2) * -1)
+	if config.Width*config.Cellsize >= config.ScreenWidth {
+		// must be positive if world wider than screen
+		config.InitialCamPos[0] = math.Abs(config.InitialCamPos[0])
+	}
+
+	// for Y we need only positive (really?)
+	if config.Height*config.Cellsize > config.ScreenHeight {
+		config.InitialCamPos[1] = math.Abs(
+			float64(((config.ScreenHeight - (config.Height * config.Cellsize)) / 2)))
+	}
+
+	// Calculate  zoom out factor, which  shows 100% of the  world. We
+	// need to reverse math.Pow(1.01,  $zoomfactor) to get the correct
+	// percentage of  the world to show.  I.e: with  a ScreenHeight of
+	// 384px and a world of 800px the factor to show 100% of the world
+	// is  -75: math.Log(384/800) / math.Log(1.01).  The 1.01 constant
+	// is being used in camera.go:worldMatrix().
+
+	// FIXME: determine if the diff is larger on width, then calc with
+	// widh instead of height
+	config.ZoomOutFactor = int(
+		math.Log(float64(config.ScreenHeight)/(float64(config.Height)*float64(config.Cellsize))) /
+			math.Log(1.01))
+}
+
 // parse given window geometry and adjust game settings according to it
 func (config *Config) ParseGeom(geom string) error {
 	// force a geom
@@ -73,22 +108,6 @@ func (config *Config) ParseGeom(geom string) error {
 	config.ScreenHeight = height
 
 	config.Cellsize = DEFAULT_CELLSIZE
-	config.Zoomfactor = DEFAULT_ZOOMFACTOR
-
-	// calculate the initial cam pos. It is negative if the total grid
-	// size  is smaller than  the screen  in a centered  position, but
-	// it's zero if it's equal or larger than the screen.
-	config.InitialCamPos = make([]float64, 2)
-
-	config.InitialCamPos[0] = float64(((config.ScreenWidth - (config.Width * config.Cellsize)) / 2) * -1)
-	if config.Width*config.Cellsize >= config.ScreenWidth {
-		// must be positive if world wider than screen
-		config.InitialCamPos[0] = math.Abs(config.InitialCamPos[0])
-	}
-
-	if config.Height*config.Cellsize > config.ScreenHeight {
-		config.InitialCamPos[1] = math.Abs(float64(((config.ScreenHeight - (config.Height * config.Cellsize)) / 2)))
-	}
 
 	return nil
 }
@@ -145,7 +164,6 @@ func (config *Config) ParseStatefile() error {
 
 	config.Width = grid.Width
 	config.Height = grid.Height
-	config.Cellsize = config.ScreenWidth / config.Width
 	config.StateGrid = grid
 
 	return nil
@@ -225,6 +243,8 @@ func ParseCommandline() (*Config, error) {
 		config.Rule = ParseGameRule(rule)
 	}
 
+	config.SetupCamera()
+
 	//repr.Println(config)
 	return &config, nil
 }

game.go

@@ -53,6 +53,7 @@ func (game *Game) Update() error {
 
 	next := scene.GetNext()
 	if next != game.CurrentScene {
+		game.Scenes[next].SetPrevious(game.CurrentScene)
 		scene.ResetNext()
 		game.CurrentScene = next
 	}

menu.go

@@ -14,6 +14,7 @@ type SceneMenu struct {
 	Game      *Game
 	Config    *Config
 	Next      SceneName
+	Prev      SceneName
 	Whoami    SceneName
 	Ui        *ebitenui.UI
 	FontColor color.RGBA
@@ -38,6 +39,10 @@ func (scene *SceneMenu) GetNext() SceneName {
 	return scene.Next
 }
 
+func (scene *SceneMenu) SetPrevious(prev SceneName) {
+	scene.Prev = prev
+}
+
 func (scene *SceneMenu) ResetNext() {
 	scene.Next = scene.Whoami
 }
@@ -99,9 +104,9 @@ func (scene *SceneMenu) Init() {
 			scene.SetNext(Options)
 		})
 
-	separator1 := NewSeparator()
-	separator2 := NewSeparator()
-	separator3 := NewSeparator()
+	separator1 := NewSeparator(3)
+	separator2 := NewSeparator(3)
+	separator3 := NewSeparator(10)
 
 	cancel := NewMenuButton("Back",
 		func(args *widget.ButtonClickedEventArgs) {

options.go

@@ -13,6 +13,7 @@ type SceneOptions struct {
 	Game      *Game
 	Config    *Config
 	Next      SceneName
+	Prev      SceneName
 	Whoami    SceneName
 	Ui        *ebitenui.UI
 	FontColor color.RGBA
@@ -36,6 +37,10 @@ func (scene *SceneOptions) GetNext() SceneName {
 	return scene.Next
 }
 
+func (scene *SceneOptions) SetPrevious(prev SceneName) {
+	scene.Prev = prev
+}
+
 func (scene *SceneOptions) ResetNext() {
 	scene.Next = scene.Whoami
 }
@@ -100,11 +105,11 @@ func (scene *SceneOptions) Init() {
 		})
 	scene.SetInitialValue(gridlines, scene.Config.ShowGrid)
 
-	separator := NewSeparator()
+	separator := NewSeparator(3)
 
 	cancel := NewMenuButton("Close",
 		func(args *widget.ButtonClickedEventArgs) {
-			scene.SetNext(Menu)
+			scene.SetNext(scene.Prev)
 		})
 
 	rowContainer.AddChild(pause)

play.go

@@ -26,6 +26,7 @@ type ScenePlay struct {
 	Game   *Game
 	Config *Config
 	Next   SceneName
+	Prev   SceneName
 	Whoami SceneName
 
 	Clear bool
@@ -73,6 +74,10 @@ func (scene *ScenePlay) GetNext() SceneName {
 	return scene.Next
 }
 
+func (scene *ScenePlay) SetPrevious(prev SceneName) {
+	scene.Prev = prev
+}
+
 func (scene *ScenePlay) ResetNext() {
 	scene.Next = scene.Whoami
 }
@@ -166,6 +171,10 @@ func (scene *ScenePlay) CheckInput() {
 		scene.SetNext(Menu)
 	}
 
+	if inpututil.IsKeyJustPressed(ebiten.KeyO) {
+		scene.SetNext(Options)
+	}
+
 	if inpututil.IsKeyJustPressed(ebiten.KeyC) {
 		fmt.Println("mark mode on")
 		scene.Config.Markmode = true
@@ -625,6 +634,12 @@ func (scene *ScenePlay) Init() {
 			float64(scene.Config.ScreenWidth),
 			float64(scene.Config.ScreenHeight),
 		},
+		InitialZoomFactor: scene.Config.Zoomfactor,
+		InitialPosition: f64.Vec2{
+			scene.Config.InitialCamPos[0],
+			scene.Config.InitialCamPos[1],
+		},
+		ZoomOutFactor: scene.Config.ZoomOutFactor,
 	}
 
 	scene.World = ebiten.NewImage(
@@ -659,8 +674,7 @@ func (scene *ScenePlay) Init() {
 		scene.Camera.ZoomFactor = scene.Config.Zoomfactor
 	}
 
-	scene.Camera.Position[0] = scene.Config.InitialCamPos[0]
-	scene.Camera.Position[1] = scene.Config.InitialCamPos[1]
+	scene.Camera.Setup()
 }
 
 // count the living neighbors of a cell

scene.go

@@ -13,6 +13,7 @@ type SceneName int
 type Scene interface {
 	SetNext(SceneName)
 	GetNext() SceneName
+	SetPrevious(SceneName)
 	ResetNext()
 	Update() error
 	Draw(screen *ebiten.Image)

widgets.go

@@ -64,12 +64,12 @@ func NewCheckbox(
 	)
 }
 
-func NewSeparator() widget.PreferredSizeLocateableWidget {
+func NewSeparator(padding int) widget.PreferredSizeLocateableWidget {
 	c := widget.NewContainer(
 		widget.ContainerOpts.Layout(widget.NewRowLayout(
 			widget.RowLayoutOpts.Direction(widget.DirectionVertical),
 			widget.RowLayoutOpts.Padding(widget.Insets{
-				Top:    3,
+				Top:    padding,
 				Bottom: 0,
 			}))),
 		widget.ContainerOpts.WidgetOpts(