init

internal/engine/config.go

@@ -0,0 +1,175 @@
+package engine
+
+import "math"
+
+// ColorConfig represents the configuration for color generation
+type ColorConfig struct {
+	// Saturation settings
+	ColorSaturation     float64 // Saturation for normal colors [0, 1]
+	GrayscaleSaturation float64 // Saturation for grayscale colors [0, 1]
+	
+	// Lightness ranges
+	ColorLightness     LightnessRange // Lightness range for normal colors
+	GrayscaleLightness LightnessRange // Lightness range for grayscale colors
+	
+	// Hue restrictions
+	Hues []float64 // Allowed hues in degrees [0, 360] or range [0, 1]. Empty means no restriction
+	
+	// Background color
+	BackColor *Color // Background color (nil for transparent)
+	
+	// Icon padding
+	IconPadding float64 // Padding as percentage of icon size [0, 1]
+}
+
+// LightnessRange represents a range of lightness values
+type LightnessRange struct {
+	Min float64 // Minimum lightness [0, 1]
+	Max float64 // Maximum lightness [0, 1]
+}
+
+// GetLightness returns a lightness value for the given position in range [0, 1]
+// where 0 returns Min and 1 returns Max
+func (lr LightnessRange) GetLightness(value float64) float64 {
+	// Clamp value to [0, 1] range
+	value = clamp(value, 0, 1)
+	
+	// Linear interpolation between min and max
+	result := lr.Min + value*(lr.Max-lr.Min)
+	
+	// Clamp result to valid lightness range
+	return clamp(result, 0, 1)
+}
+
+// DefaultColorConfig returns the default configuration matching the JavaScript implementation
+func DefaultColorConfig() ColorConfig {
+	return ColorConfig{
+		ColorSaturation:     0.5,
+		GrayscaleSaturation: 0.0,
+		ColorLightness:      LightnessRange{Min: 0.4, Max: 0.8},
+		GrayscaleLightness:  LightnessRange{Min: 0.3, Max: 0.9},
+		Hues:               nil, // No hue restriction
+		BackColor:          nil, // Transparent background
+		IconPadding:        0.08,
+	}
+}
+
+// RestrictHue applies hue restrictions to the given hue value
+// Returns the restricted hue in range [0, 1]
+func (c ColorConfig) RestrictHue(originalHue float64) float64 {
+	// Normalize hue to [0, 1) range
+	hue := math.Mod(originalHue, 1.0)
+	if hue < 0 {
+		hue += 1.0
+	}
+	
+	// If no hue restrictions, return original
+	if len(c.Hues) == 0 {
+		return hue
+	}
+	
+	// Find the closest allowed hue
+	// originalHue is in range [0, 1], multiply by 0.999 to get range [0, 1)
+	// then truncate to get index
+	index := int((0.999 * hue * float64(len(c.Hues))))
+	if index >= len(c.Hues) {
+		index = len(c.Hues) - 1
+	}
+	
+	restrictedHue := c.Hues[index]
+	
+	// Convert from degrees to turns in range [0, 1)
+	// Handle any turn - e.g. 746° is valid
+	result := math.Mod(restrictedHue/360.0, 1.0)
+	if result < 0 {
+		result += 1.0
+	}
+	
+	return result
+}
+
+// ValidateConfig validates and corrects a ColorConfig to ensure all values are within valid ranges
+func (c *ColorConfig) Validate() {
+	// Clamp saturation values
+	c.ColorSaturation = clamp(c.ColorSaturation, 0, 1)
+	c.GrayscaleSaturation = clamp(c.GrayscaleSaturation, 0, 1)
+	
+	// Validate lightness ranges
+	c.ColorLightness.Min = clamp(c.ColorLightness.Min, 0, 1)
+	c.ColorLightness.Max = clamp(c.ColorLightness.Max, 0, 1)
+	if c.ColorLightness.Min > c.ColorLightness.Max {
+		c.ColorLightness.Min, c.ColorLightness.Max = c.ColorLightness.Max, c.ColorLightness.Min
+	}
+	
+	c.GrayscaleLightness.Min = clamp(c.GrayscaleLightness.Min, 0, 1)
+	c.GrayscaleLightness.Max = clamp(c.GrayscaleLightness.Max, 0, 1)
+	if c.GrayscaleLightness.Min > c.GrayscaleLightness.Max {
+		c.GrayscaleLightness.Min, c.GrayscaleLightness.Max = c.GrayscaleLightness.Max, c.GrayscaleLightness.Min
+	}
+	
+	// Clamp icon padding
+	c.IconPadding = clamp(c.IconPadding, 0, 1)
+	
+	// Validate hues (no need to clamp as RestrictHue handles normalization)
+}
+
+// ColorConfigBuilder provides a fluent interface for building ColorConfig
+type ColorConfigBuilder struct {
+	config ColorConfig
+}
+
+// NewColorConfigBuilder creates a new builder with default values
+func NewColorConfigBuilder() *ColorConfigBuilder {
+	return &ColorConfigBuilder{
+		config: DefaultColorConfig(),
+	}
+}
+
+// WithColorSaturation sets the color saturation
+func (b *ColorConfigBuilder) WithColorSaturation(saturation float64) *ColorConfigBuilder {
+	b.config.ColorSaturation = saturation
+	return b
+}
+
+// WithGrayscaleSaturation sets the grayscale saturation
+func (b *ColorConfigBuilder) WithGrayscaleSaturation(saturation float64) *ColorConfigBuilder {
+	b.config.GrayscaleSaturation = saturation
+	return b
+}
+
+// WithColorLightness sets the color lightness range
+func (b *ColorConfigBuilder) WithColorLightness(min, max float64) *ColorConfigBuilder {
+	b.config.ColorLightness = LightnessRange{Min: min, Max: max}
+	return b
+}
+
+// WithGrayscaleLightness sets the grayscale lightness range
+func (b *ColorConfigBuilder) WithGrayscaleLightness(min, max float64) *ColorConfigBuilder {
+	b.config.GrayscaleLightness = LightnessRange{Min: min, Max: max}
+	return b
+}
+
+// WithHues sets the allowed hues in degrees
+func (b *ColorConfigBuilder) WithHues(hues ...float64) *ColorConfigBuilder {
+	b.config.Hues = make([]float64, len(hues))
+	copy(b.config.Hues, hues)
+	return b
+}
+
+// WithBackColor sets the background color
+func (b *ColorConfigBuilder) WithBackColor(color Color) *ColorConfigBuilder {
+	b.config.BackColor = &color
+	return b
+}
+
+// WithIconPadding sets the icon padding
+func (b *ColorConfigBuilder) WithIconPadding(padding float64) *ColorConfigBuilder {
+	b.config.IconPadding = padding
+	return b
+}
+
+// Build returns the configured ColorConfig after validation
+func (b *ColorConfigBuilder) Build() ColorConfig {
+	b.config.Validate()
+	return b.config
+}