added theme system, makes it easier to add more color schemes

src/theme.go

@@ -0,0 +1,123 @@
+package main
+
+import (
+	"image/color"
+
+	"github.com/hajimehoshi/ebiten/v2"
+)
+
+// Color definitions. ColLife could be black or white depending on theme
+const (
+	ColLife = iota
+	ColDead
+	ColOld
+	ColAge1
+	ColAge2
+	ColAge3
+	ColAge4
+	ColGrid
+)
+
+// A Theme defines  how the grid and the cells  are colored. We define
+// the  colors and  the  actual tile  images here,  so  that they  are
+// readily available from play.go
+type Theme struct {
+	Tiles  map[int]*ebiten.Image
+	Colors map[int]color.RGBA
+	Name   string
+}
+
+// create a new theme
+func NewTheme(life, dead, old, age1, age2, age3, age4, grid color.RGBA, cellsize int, name string) Theme {
+	theme := Theme{
+		Name: name,
+		Colors: map[int]color.RGBA{
+			ColLife: life,
+			ColDead: dead,
+			ColGrid: grid,
+			ColAge1: age1,
+			ColAge2: age2,
+			ColAge3: age3,
+			ColAge4: age4,
+			ColOld:  old,
+		},
+	}
+
+	theme.Tiles = make(map[int]*ebiten.Image, 6)
+
+	for cid, col := range theme.Colors {
+		theme.Tiles[cid] = ebiten.NewImage(cellsize, cellsize)
+		FillCell(theme.Tiles[cid], cellsize, col)
+	}
+
+	return theme
+}
+
+// return  the tile  image  for  the requested  color  type. panic  if
+// unknown type is being used, which is ok, since the code is the only
+// user anyway
+func (theme *Theme) Tile(col int) *ebiten.Image {
+	return theme.Tiles[col]
+}
+
+func (theme *Theme) Color(col int) color.RGBA {
+	return theme.Colors[col]
+}
+
+type ThemeManager struct {
+	Theme  string
+	Themes map[string]Theme
+}
+
+// Manager is used to easily switch themes from cli or menu
+func NewThemeManager(initial string, cellsize int) ThemeManager {
+	light := NewTheme(
+		color.RGBA{0, 0, 0, 0xff},       // life
+		color.RGBA{200, 200, 200, 0xff}, // dead
+		color.RGBA{255, 30, 30, 0xff},   // old
+		color.RGBA{255, 195, 97, 0xff},  // age 1..4
+		color.RGBA{255, 211, 140, 0xff},
+		color.RGBA{255, 227, 181, 0xff},
+		color.RGBA{255, 240, 224, 0xff},
+		color.RGBA{128, 128, 128, 0xff}, // grid
+		cellsize,
+		"light",
+	)
+
+	dark := NewTheme(
+		color.RGBA{200, 200, 200, 0xff}, // life
+		color.RGBA{0, 0, 0, 0xff},       // dead
+		color.RGBA{255, 30, 30, 0xff},   // old
+		color.RGBA{82, 38, 0, 0xff},     // age 1..4
+		color.RGBA{66, 35, 0, 0xff},
+		color.RGBA{43, 27, 0, 0xff},
+		color.RGBA{25, 17, 0, 0xff},
+		color.RGBA{128, 128, 128, 0xff}, // grid
+		cellsize,
+		"dark",
+	)
+
+	manager := ThemeManager{
+		Themes: map[string]Theme{
+			"dark":  dark,
+			"light": light,
+		},
+		Theme: initial,
+	}
+
+	return manager
+}
+
+func (manager *ThemeManager) GetCurrentTheme() Theme {
+	return manager.Themes[manager.Theme]
+}
+
+func (manager *ThemeManager) GetCurrentThemeName() string {
+	return manager.Theme
+}
+
+func (manager *ThemeManager) SetCurrentTheme(theme string) {
+	if Exists(manager.Themes, theme) {
+		manager.Theme = theme
+	}
+}