themes and styles

client/world/theme.go

@@ -0,0 +1,93 @@
+package world
+
+import (
+	"image"
+	"image/color"
+)
+
+// BackgroundTileMode defines how the background image is tiled.
+type BackgroundTileMode uint8
+
+const (
+	BackgroundTileNone BackgroundTileMode = iota
+	BackgroundTileRepeat
+)
+
+// BackgroundAnchorMode defines whether the background image scrolls with the world or stays fixed to viewport.
+type BackgroundAnchorMode uint8
+
+const (
+	BackgroundAnchorWorld BackgroundAnchorMode = iota
+	BackgroundAnchorViewport
+)
+
+// BackgroundScaleMode defines how the background image is scaled.
+// (Step 1: defined for API completeness; used later when rendering background image.)
+type BackgroundScaleMode uint8
+
+const (
+	BackgroundScaleNone BackgroundScaleMode = iota
+	BackgroundScaleFit
+	BackgroundScaleFill
+)
+
+// StyleTheme describes a cohesive style set (theme) for rendering.
+// Step 1: we store it in World and use it for background and default base styles.
+// Step 2+: theme-relative overrides and background image drawing.
+type StyleTheme interface {
+	ID() string
+	Name() string
+
+	BackgroundColor() color.Color
+	BackgroundImage() image.Image
+
+	BackgroundTileMode() BackgroundTileMode
+	BackgroundScaleMode() BackgroundScaleMode
+	BackgroundAnchorMode() BackgroundAnchorMode
+
+	PointStyle() Style
+	LineStyle() Style
+	CircleStyle() Style
+
+	// Class overrides (relative to base kind style).
+	// Return (override, true) when class is supported; (zero, false) means "no override".
+	PointClassOverride(class PointClassID) (StyleOverride, bool)
+	LineClassOverride(class LineClassID) (StyleOverride, bool)
+	CircleClassOverride(class CircleClassID) (StyleOverride, bool)
+}
+
+// DefaultTheme is a conservative theme matching built-in default styles.
+type DefaultTheme struct{}
+
+func (DefaultTheme) ID() string   { return "default" }
+func (DefaultTheme) Name() string { return "Default" }
+
+func (DefaultTheme) BackgroundColor() color.Color { return color.RGBA{A: 255} }
+func (DefaultTheme) BackgroundImage() image.Image { return nil }
+
+func (DefaultTheme) BackgroundTileMode() BackgroundTileMode     { return BackgroundTileNone }
+func (DefaultTheme) BackgroundScaleMode() BackgroundScaleMode   { return BackgroundScaleNone }
+func (DefaultTheme) BackgroundAnchorMode() BackgroundAnchorMode { return BackgroundAnchorWorld }
+
+func (DefaultTheme) PointStyle() Style {
+	s, _ := NewStyleTable().Get(StyleIDDefaultPoint)
+	return s
+}
+func (DefaultTheme) LineStyle() Style {
+	s, _ := NewStyleTable().Get(StyleIDDefaultLine)
+	return s
+}
+func (DefaultTheme) CircleStyle() Style {
+	s, _ := NewStyleTable().Get(StyleIDDefaultCircle)
+	return s
+}
+
+func (DefaultTheme) PointClassOverride(PointClassID) (StyleOverride, bool) {
+	return StyleOverride{}, false
+}
+func (DefaultTheme) LineClassOverride(LineClassID) (StyleOverride, bool) {
+	return StyleOverride{}, false
+}
+func (DefaultTheme) CircleClassOverride(CircleClassID) (StyleOverride, bool) {
+	return StyleOverride{}, false
+}