go-chart/drawing/stack_graphic_context.go
2016-07-09 09:04:30 -07:00

212 lines
5.4 KiB
Go

package drawing
import (
"image"
"image/color"
"github.com/golang/freetype/truetype"
)
// StackGraphicContext is a context that does thngs.
type StackGraphicContext struct {
current *ContextStack
}
// ContextStack is a graphic context implementation.
type ContextStack struct {
Tr Matrix
Path *Path
LineWidth float64
Dash []float64
DashOffset float64
StrokeColor color.Color
FillColor color.Color
FillRule FillRule
Cap LineCap
Join LineJoin
FontSizePoints float64
Font *truetype.Font
Scale float64
Previous *ContextStack
}
// NewStackGraphicContext Create a new Graphic context from an image
func NewStackGraphicContext() *StackGraphicContext {
gc := &StackGraphicContext{}
gc.current = new(ContextStack)
gc.current.Tr = NewIdentityMatrix()
gc.current.Path = new(Path)
gc.current.LineWidth = 1.0
gc.current.StrokeColor = image.Black
gc.current.FillColor = image.White
gc.current.Cap = RoundCap
gc.current.FillRule = FillRuleEvenOdd
gc.current.Join = RoundJoin
gc.current.FontSizePoints = 10
return gc
}
// GetMatrixTransform returns the matrix transform.
func (gc *StackGraphicContext) GetMatrixTransform() Matrix {
return gc.current.Tr
}
// SetMatrixTransform sets the matrix transform.
func (gc *StackGraphicContext) SetMatrixTransform(tr Matrix) {
gc.current.Tr = tr
}
// ComposeMatrixTransform composes a transform into the current transform.
func (gc *StackGraphicContext) ComposeMatrixTransform(tr Matrix) {
gc.current.Tr.Compose(tr)
}
// Rotate rotates the matrix transform by an angle in degrees.
func (gc *StackGraphicContext) Rotate(angle float64) {
gc.current.Tr.Rotate(angle)
}
// Translate translates a transform.
func (gc *StackGraphicContext) Translate(tx, ty float64) {
gc.current.Tr.Translate(tx, ty)
}
// Scale scales a transform.
func (gc *StackGraphicContext) Scale(sx, sy float64) {
gc.current.Tr.Scale(sx, sy)
}
// SetStrokeColor sets the stroke color.
func (gc *StackGraphicContext) SetStrokeColor(c color.Color) {
gc.current.StrokeColor = c
}
// SetFillColor sets the fill color.
func (gc *StackGraphicContext) SetFillColor(c color.Color) {
gc.current.FillColor = c
}
// SetFillRule sets the fill rule.
func (gc *StackGraphicContext) SetFillRule(f FillRule) {
gc.current.FillRule = f
}
// SetLineWidth sets the line width.
func (gc *StackGraphicContext) SetLineWidth(lineWidth float64) {
gc.current.LineWidth = lineWidth
}
// SetLineCap sets the line cap.
func (gc *StackGraphicContext) SetLineCap(cap LineCap) {
gc.current.Cap = cap
}
// SetLineJoin sets the line join.
func (gc *StackGraphicContext) SetLineJoin(join LineJoin) {
gc.current.Join = join
}
// SetLineDash sets the line dash.
func (gc *StackGraphicContext) SetLineDash(dash []float64, dashOffset float64) {
gc.current.Dash = dash
gc.current.DashOffset = dashOffset
}
// SetFontSize sets the font size.
func (gc *StackGraphicContext) SetFontSize(fontSizePoints float64) {
gc.current.FontSizePoints = fontSizePoints
}
// GetFontSize gets the font size.
func (gc *StackGraphicContext) GetFontSize() float64 {
return gc.current.FontSizePoints
}
// SetFont sets the current font.
func (gc *StackGraphicContext) SetFont(f *truetype.Font) {
gc.current.Font = f
}
// GetFont returns the font.
func (gc *StackGraphicContext) GetFont() *truetype.Font {
return gc.current.Font
}
// BeginPath starts a new path.
func (gc *StackGraphicContext) BeginPath() {
gc.current.Path.Clear()
}
// IsEmpty returns if the path is empty.
func (gc *StackGraphicContext) IsEmpty() bool {
return gc.current.Path.IsEmpty()
}
// LastPoint returns the last point on the path.
func (gc *StackGraphicContext) LastPoint() (x float64, y float64) {
return gc.current.Path.LastPoint()
}
// MoveTo moves the cursor for a path.
func (gc *StackGraphicContext) MoveTo(x, y float64) {
gc.current.Path.MoveTo(x, y)
}
// LineTo draws a line.
func (gc *StackGraphicContext) LineTo(x, y float64) {
gc.current.Path.LineTo(x, y)
}
// QuadCurveTo draws a quad curve.
func (gc *StackGraphicContext) QuadCurveTo(cx, cy, x, y float64) {
gc.current.Path.QuadCurveTo(cx, cy, x, y)
}
// CubicCurveTo draws a cubic curve.
func (gc *StackGraphicContext) CubicCurveTo(cx1, cy1, cx2, cy2, x, y float64) {
gc.current.Path.CubicCurveTo(cx1, cy1, cx2, cy2, x, y)
}
// ArcTo draws an arc.
func (gc *StackGraphicContext) ArcTo(cx, cy, rx, ry, startAngle, angle float64) {
gc.current.Path.ArcTo(cx, cy, rx, ry, startAngle, angle)
}
// Close closes a path.
func (gc *StackGraphicContext) Close() {
gc.current.Path.Close()
}
// Save pushes a context onto the stack.
func (gc *StackGraphicContext) Save() {
context := new(ContextStack)
context.FontSizePoints = gc.current.FontSizePoints
context.Font = gc.current.Font
context.LineWidth = gc.current.LineWidth
context.StrokeColor = gc.current.StrokeColor
context.FillColor = gc.current.FillColor
context.FillRule = gc.current.FillRule
context.Dash = gc.current.Dash
context.DashOffset = gc.current.DashOffset
context.Cap = gc.current.Cap
context.Join = gc.current.Join
context.Path = gc.current.Path.Copy()
context.Font = gc.current.Font
context.Scale = gc.current.Scale
copy(context.Tr[:], gc.current.Tr[:])
context.Previous = gc.current
gc.current = context
}
// Restore restores the previous context.
func (gc *StackGraphicContext) Restore() {
if gc.current.Previous != nil {
oldContext := gc.current
gc.current = gc.current.Previous
oldContext.Previous = nil
}
}