Color API - AdvanceGG

Color Creation

SetRGB(r, g, b float64)
Sets the current color using RGB values (0.0 to 1.0)

SetRGBA(r, g, b, a float64)
Sets the current color using RGBA values with alpha transparency

SetHSL(h, s, l float64)
Sets the current color using HSL values (Hue, Saturation, Lightness)

SetHex(hex string)
Sets the current color using hex color string (#RRGGBB or #RGB)

// RGB colors
dc.SetRGB(1.0, 0.5, 0.2)  // Orange
dc.SetRGBA(0.2, 0.8, 0.4, 0.7)  // Semi-transparent green

// HSL colors
dc.SetHSL(240, 1.0, 0.5)  // Pure blue

// Hex colors
dc.SetHex("#FF6B35")  // Orange
dc.SetHex("#3498DB")  // Blue

Color Spaces

RGB Color Space

Red, Green, Blue additive color model

RGB(255, 0, 0)

RGB(0, 255, 0)

RGB(0, 0, 255)

HSL Color Space

Hue, Saturation, Lightness intuitive color model

HSL(0°, 100%, 50%)

HSL(120°, 100%, 50%)

HSL(240°, 100%, 50%)

Gradients

NewLinearGradient(x0, y0, x1, y1 float64) *LinearGradient
Creates a linear gradient between two points

NewRadialGradient(x0, y0, r0, x1, y1, r1 float64) *RadialGradient
Creates a radial gradient between two circles

AddColorStop(offset float64, color color.Color)
Adds a color stop to the gradient at the specified offset (0.0 to 1.0)

// Linear gradient
gradient := advancegg.NewLinearGradient(0, 0, 200, 0)
gradient.AddColorStop(0, color.RGBA{255, 0, 0, 255})    // Red
gradient.AddColorStop(0.5, color.RGBA{255, 255, 0, 255}) // Yellow
gradient.AddColorStop(1, color.RGBA{0, 255, 0, 255})    // Green

dc.SetFillStyle(gradient)
dc.DrawRectangle(0, 0, 200, 100)
dc.Fill()

// Radial gradient
radial := advancegg.NewRadialGradient(100, 100, 0, 100, 100, 50)
radial.AddColorStop(0, color.RGBA{255, 255, 255, 255})  // White center
radial.AddColorStop(1, color.RGBA{0, 0, 0, 255})        // Black edge

dc.SetFillStyle(radial)
dc.DrawCircle(100, 100, 50)
dc.Fill()

Color Manipulation

Lighten(color color.Color, amount float64) color.Color
Lightens a color by the specified amount (0.0 to 1.0)

Darken(color color.Color, amount float64) color.Color
Darkens a color by the specified amount (0.0 to 1.0)

Saturate(color color.Color, amount float64) color.Color
Increases color saturation by the specified amount

Desaturate(color color.Color, amount float64) color.Color
Decreases color saturation by the specified amount

// Color manipulation
baseColor := color.RGBA{100, 150, 200, 255}

// Lighten and darken
lighter := advancegg.Lighten(baseColor, 0.3)
darker := advancegg.Darken(baseColor, 0.3)

// Saturate and desaturate
saturated := advancegg.Saturate(baseColor, 0.5)
desaturated := advancegg.Desaturate(baseColor, 0.5)

// Mix colors
mixed := advancegg.MixColors(baseColor, color.RGBA{255, 0, 0, 255}, 0.5)

Color Palettes

Material Design

#F44336

#2196F3

#4CAF50

Flat UI

#E74C3C

#3498DB

#2ECC71

Pastel

#FFB3BA

#BAFFC9

#BAE1FF

Complete Examples

// Rainbow gradient
func createRainbow(dc *advancegg.Context) {
    gradient := advancegg.NewLinearGradient(0, 0, 400, 0)
    gradient.AddColorStop(0.0, color.RGBA{255, 0, 0, 255})    // Red
    gradient.AddColorStop(0.17, color.RGBA{255, 165, 0, 255}) // Orange
    gradient.AddColorStop(0.33, color.RGBA{255, 255, 0, 255}) // Yellow
    gradient.AddColorStop(0.5, color.RGBA{0, 255, 0, 255})    // Green
    gradient.AddColorStop(0.67, color.RGBA{0, 0, 255, 255})   // Blue
    gradient.AddColorStop(0.83, color.RGBA{75, 0, 130, 255})  // Indigo
    gradient.AddColorStop(1.0, color.RGBA{238, 130, 238, 255}) // Violet
    
    dc.SetFillStyle(gradient)
    dc.DrawRectangle(0, 0, 400, 100)
    dc.Fill()
}

// Color wheel
func createColorWheel(dc *advancegg.Context) {
    centerX, centerY := 200.0, 200.0
    radius := 100.0
    
    for angle := 0.0; angle < 360.0; angle += 1.0 {
        hue := angle
        saturation := 1.0
        lightness := 0.5
        
        dc.SetHSL(hue, saturation, lightness)
        
        x1 := centerX + math.Cos(angle*math.Pi/180) * radius * 0.8
        y1 := centerY + math.Sin(angle*math.Pi/180) * radius * 0.8
        x2 := centerX + math.Cos(angle*math.Pi/180) * radius
        y2 := centerY + math.Sin(angle*math.Pi/180) * radius
        
        dc.SetLineWidth(2)
        dc.MoveTo(x1, y1)
        dc.LineTo(x2, y2)
        dc.Stroke()
    }
}

Color API Reference