API Reference

Context

The Context is the main drawing surface and entry point for all graphics operations.

Creating Contexts

State Management

// Save and restore drawing state
dc.Push()    // Save current state
// ... drawing operations ...
dc.Pop()     // Restore saved state

// Clear the canvas
dc.Clear()   // Fill with current color
dc.SetRGB(1, 1, 1)
dc.Clear()   // White background

Drawing

Basic Shapes

// Rectangles
dc.DrawRectangle(x, y, width, height)
dc.DrawRoundedRectangle(x, y, width, height, radius)

// Circles and ellipses
dc.DrawCircle(x, y, radius)
dc.DrawEllipse(x, y, rx, ry)

// Lines
dc.DrawLine(x1, y1, x2, y2)

// Polygons
dc.DrawRegularPolygon(sides, x, y, radius, rotation)

Fill and Stroke

// Fill shapes
dc.Fill()           // Fill and clear path
dc.FillPreserve()   // Fill but keep path

// Stroke outlines
dc.Stroke()         // Stroke and clear path
dc.StrokePreserve() // Stroke but keep path

// Combined operations
dc.FillPreserve()
dc.Stroke()         // Fill then stroke

Line Styles

// Line width
dc.SetLineWidth(5.0)

// Line cap styles
dc.SetLineCap(advancegg.LineCapRound)   // Round, Butt, Square

// Line join styles
dc.SetLineJoin(advancegg.LineJoinRound) // Round, Miter, Bevel

// Dash patterns
dc.SetDash(10, 5)                       // 10 on, 5 off
dc.SetDashOffset(2.5)                   // Offset pattern

Paths

Path Operations

// Start new path
dc.NewPath()

// Move without drawing
dc.MoveTo(x, y)

// Draw lines
dc.LineTo(x, y)

// Bézier curves
dc.QuadraticTo(cpx, cpy, x, y)          // Quadratic
dc.CubicTo(cp1x, cp1y, cp2x, cp2y, x, y) // Cubic

// Arcs
dc.Arc(x, y, radius, startAngle, endAngle)
dc.ArcNegative(x, y, radius, startAngle, endAngle)

// Close path
dc.ClosePath()

Path2D Support

// Create Path2D object
path := advancegg.NewPath2D()
path.MoveTo(100, 100)
path.LineTo(200, 200)
path.Arc(150, 150, 50, 0, 2*math.Pi)

// Use with context
dc.DrawPath(path)
dc.Fill()

// Path operations
path.Transform(matrix)
bounds := path.GetBounds()
contains := path.Contains(x, y)

Text

Font Management

// Load fonts
dc.LoadFontFace("fonts/arial.ttf", 24)
dc.LoadFontFaceFromBytes(fontData, 24)

// Font properties
dc.SetFontSize(18)
dc.SetFontFace(fontFace)

Text Rendering

// Basic text
dc.DrawString("Hello World", x, y)

// Anchored text (alignment)
dc.DrawStringAnchored("Centered", x, y, 0.5, 0.5)
// ax, ay: 0=left/top, 0.5=center, 1=right/bottom

// Word wrapping
dc.DrawStringWrapped("Long text that will wrap...", 
    x, y, ax, ay, width, lineSpacing, align)

// Text measurement
w, h := dc.MeasureString("Text")
lines := dc.WordWrap("Text", width)

Advanced Text Features

// Text on path
advancegg.DrawTextOnCircle(dc, "Circular Text", centerX, centerY, radius)
advancegg.DrawTextOnWave(dc, "Wave Text", startX, startY, endX, amplitude, frequency)

// Unicode and emoji
dc.DrawString("Hello 世界 🌍", x, y)  // Automatic support

// Text effects
dc.SetTextShadow(offsetX, offsetY, blur, color)
dc.DrawString("Shadow Text", x, y)

Images

Loading and Saving

// Load images
img := advancegg.LoadPNG("input.png")
img := advancegg.LoadJPEG("input.jpg")
img := advancegg.LoadImage("input.gif") // Auto-detect format

// Save images
dc.SavePNG("output.png")
dc.SaveJPEG("output.jpg", 95)  // 95% quality
dc.SaveGIF("output.gif")

// Get image data
rgba := dc.Image()  // Get underlying RGBA image

Drawing Images

// Draw at position
dc.DrawImage(img, x, y)

// Draw with scaling
dc.DrawImageAnchored(img, x, y, ax, ay)

// Draw with transformation
dc.Push()
dc.Scale(2, 2)
dc.Rotate(math.Pi / 4)
dc.DrawImage(img, x, y)
dc.Pop()

Image Processing

// Apply filters
blurred := advancegg.ApplyBlur(img, 5.0)
sharpened := advancegg.ApplySharpen(img, 1.5)
grayscale := advancegg.ApplyGrayscale(img)

// Brightness and contrast
bright := advancegg.ApplyBrightness(img, 1.2)
contrast := advancegg.ApplyContrast(img, 1.5)

// Color adjustments
saturated := advancegg.ApplySaturation(img, 1.3)
hueShifted := advancegg.ApplyHueRotate(img, 30) // degrees

Colors

Setting Colors

// RGB colors
dc.SetRGB(1, 0, 0)        // Red (values 0-1)
dc.SetRGBA(1, 0, 0, 0.5)  // Semi-transparent red
dc.SetRGB255(255, 0, 0)   // RGB with 0-255 values

// Hex colors
dc.SetHexColor("#FF5733")
dc.SetHexColor("#F53")    // Short form

// Color objects
dc.SetColor(color.RGBA{255, 0, 0, 255})

Color Spaces

// CMYK (for print)
dc.SetCMYK(0, 1, 1, 0)    // Cyan=0, Magenta=100%, Yellow=100%, Black=0

// HSV (Hue, Saturation, Value)
dc.SetHSV(240, 1, 1)      // Blue: H=240°, S=100%, V=100%

// HSL (Hue, Saturation, Lightness)
dc.SetHSL(240, 1, 0.5)    // Blue: H=240°, S=100%, L=50%

// LAB color space
dc.SetLAB(50, 20, -30)    // L=50, a=20, b=-30

Gradients

// Linear gradient
gradient := advancegg.NewLinearGradient(0, 0, 100, 0)
gradient.AddColorStop(0, color.RGBA{255, 0, 0, 255})    // Red at start
gradient.AddColorStop(1, color.RGBA{0, 0, 255, 255})    // Blue at end
dc.SetFillStyle(gradient)

// Radial gradient
radial := advancegg.NewRadialGradient(50, 50, 0, 50, 50, 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)

Transformations

// Translation
dc.Translate(dx, dy)

// Scaling
dc.Scale(sx, sy)          // Different X and Y scaling
dc.Scale(s, s)            // Uniform scaling

// Rotation
dc.Rotate(angle)          // Angle in radians
dc.RotateAbout(angle, x, y) // Rotate about point

// Shearing
dc.Shear(sx, sy)

// Matrix transformations
matrix := advancegg.Identity()
matrix = matrix.Scale(2, 2)
matrix = matrix.Rotate(math.Pi / 4)
dc.SetMatrix(matrix)

// Reset transformation
dc.Identity()

Layer System

// Create layer manager
layerManager := advancegg.NewLayerManager(800, 600)

// Add layers
background := layerManager.AddLayer("bg")
foreground := layerManager.AddLayer("fg")

// Draw on layers
background.SetRGB(0.2, 0.2, 0.4)
background.Clear()

foreground.SetRGB(1, 1, 0)
foreground.DrawCircle(400, 300, 100)
foreground.Fill()

// Layer properties
foreground.SetOpacity(0.8)
foreground.SetBlendMode(advancegg.BlendModeMultiply)
foreground.SetVisible(true)

// Composite layers
result := layerManager.Flatten()
result.SavePNG("layered.png")

Image Filters

Advanced Strokes

// Dashed strokes
dc.DrawDashedLine(x1, y1, x2, y2, []float64{10, 5, 2, 5})

// Gradient strokes
stops := []advancegg.StrokeGradientStop{
    {Position: 0.0, Color: color.RGBA{255, 0, 0, 255}},
    {Position: 1.0, Color: color.RGBA{0, 0, 255, 255}},
}
dc.DrawGradientLine(x1, y1, x2, y2, stops)

// Tapered strokes
dc.DrawTaperedLine(x1, y1, x2, y2, startWidth, endWidth)

Performance

// Enable performance optimizations
dc.SetSIMDEnabled(true)        // Use SIMD instructions
dc.SetMemoryPooling(true)      // Enable memory pooling
dc.SetBatchMode(true)          // Batch operations

// Debug and profiling
dc.SetDebugMode(true)          // Visual debugging
dc.EnableProfiling(true)       // Performance profiling
stats := dc.GetPerformanceStats()

// Caching
dc.EnableCaching(true)         // Cache rendered elements
dc.ClearCache()                // Clear cache manually

Quick Reference

// Basic setup
dc := advancegg.NewContext(800, 600)
dc.SetRGB(1, 1, 1)
dc.Clear()

// Draw with style
dc.SetRGB(1, 0, 0)
dc.SetLineWidth(3)
dc.DrawCircle(400, 300, 100)
dc.Stroke()

// Save result
dc.SavePNG("output.png")