graphicsstate

package
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 Go to latest Published: Feb 3, 2026 License: MIT Imports: 5 Imported by: 0

Documentation

Overview

Package graphicsstate provides PDF graphics state management.

The PDF graphics state controls how content is rendered, including transformation matrices, colors, line properties, and text state. This package implements the state stack used during content stream processing.

Graphics State

The main type is GraphicsState, which tracks:

  • CTM (Current Transformation Matrix) for coordinate transformations
  • Line properties (width, cap, join)
  • Colors (stroke and fill)
  • Text state (font, size, spacing, matrices)

Example usage: 

gs := graphicsstate.NewGraphicsState()
gs.Save()              // Push state (q operator)
gs.Transform(matrix)   // Modify CTM (cm operator)
gs.SetFont("F1", 12)   // Set font (Tf operator)
gs.Restore()           // Pop state (Q operator)

Text State

Text rendering uses a separate TextState structure that tracks:

  • Font name and size (Tf operator)
  • Character and word spacing (Tc, Tw operators)
  • Horizontal scaling (Tz operator)
  • Leading for line spacing (TL operator)
  • Text and text line matrices (Tm, Td operators)

Path Operations

The package also includes path construction and painting support for extracting line graphics used in table detection:

  • MoveTo, LineTo, CurveTo for path construction
  • Rectangle for rect operator
  • Stroke, Fill for path painting

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

This section is empty.

Types

type ExtractedLine 

type ExtractedLine struct {
	// Start and end points in device space
	Start model.Point
	End   model.Point

	// Line attributes
	Width float64
	Color [3]float64

	// Classification
	IsHorizontal bool
	IsVertical   bool

	// Original bounding box
	BBox model.BBox
}

ExtractedLine represents a line extracted from PDF graphics

type ExtractedRectangle 

type ExtractedRectangle struct {
	// Bounding box in device space
	BBox model.BBox

	// Rectangle attributes
	StrokeWidth float64
	StrokeColor [3]float64
	FillColor   [3]float64
	IsFilled    bool
	IsStroked   bool
}

ExtractedRectangle represents a rectangle extracted from PDF graphics

type GraphicsExtractor 

type GraphicsExtractor struct {

	// Minimum dimensions for filtering
	MinLineLength float64
	MinRectWidth  float64
	MinRectHeight float64
	// contains filtered or unexported fields
}

GraphicsExtractor extracts lines and rectangles from content streams

func NewGraphicsExtractor 

func NewGraphicsExtractor() *GraphicsExtractor

NewGraphicsExtractor creates a new graphics extractor

func (*GraphicsExtractor) ClassifyLines 

func (ge *GraphicsExtractor) ClassifyLines() LineClassification

ClassifyLines classifies lines by orientation

func (*GraphicsExtractor) Clear 

func (ge *GraphicsExtractor) Clear()

Clear resets the extractor for reuse

func (*GraphicsExtractor) Extract 

func (ge *GraphicsExtractor) Extract(operations []contentstream.Operation) error

Extract extracts graphics from content stream operations

func (*GraphicsExtractor) ExtractFromBytes 

func (ge *GraphicsExtractor) ExtractFromBytes(data []byte) error

ExtractFromBytes parses and extracts graphics from raw content stream data

func (*GraphicsExtractor) GetFilteredLines 

func (ge *GraphicsExtractor) GetFilteredLines() []ExtractedLine

GetFilteredLines returns lines meeting the minimum length requirement

func (*GraphicsExtractor) GetFilteredRectangles 

func (ge *GraphicsExtractor) GetFilteredRectangles() []ExtractedRectangle

GetFilteredRectangles returns rectangles meeting the minimum size requirements

func (*GraphicsExtractor) GetGraphicsState 

func (ge *GraphicsExtractor) GetGraphicsState() *GraphicsState

GetGraphicsState returns the current graphics state (useful for debugging)

func (*GraphicsExtractor) GetGridLines 

func (ge *GraphicsExtractor) GetGridLines() GridLines

GetGridLines returns horizontal and vertical lines suitable for table detection

func (*GraphicsExtractor) GetHorizontalLines 

func (ge *GraphicsExtractor) GetHorizontalLines() []ExtractedLine

GetHorizontalLines returns only horizontal lines

func (*GraphicsExtractor) GetLines 

func (ge *GraphicsExtractor) GetLines() []ExtractedLine

GetLines returns all extracted lines

func (*GraphicsExtractor) GetRectangles 

func (ge *GraphicsExtractor) GetRectangles() []ExtractedRectangle

GetRectangles returns all extracted rectangles

func (*GraphicsExtractor) GetStatistics 

func (ge *GraphicsExtractor) GetStatistics() GraphicsStatistics

GetStatistics returns statistics about extracted graphics

func (*GraphicsExtractor) GetVerticalLines 

func (ge *GraphicsExtractor) GetVerticalLines() []ExtractedLine

GetVerticalLines returns only vertical lines

func (*GraphicsExtractor) ToModelLines 

func (ge *GraphicsExtractor) ToModelLines() []model.Line

ToModelLines converts extracted lines to model.Line objects

func (*GraphicsExtractor) ToModelRectangles 

func (ge *GraphicsExtractor) ToModelRectangles() []model.Line

ToModelRectangles converts extracted rectangles to model.Line objects (with IsRect=true)

type GraphicsState 

type GraphicsState struct {
	// Current Transformation Matrix
	CTM model.Matrix

	// Text state
	Text TextState

	// Line attributes
	LineWidth float64

	// Color (simplified - just RGB for now)
	StrokeColor [3]float64
	FillColor   [3]float64
	// contains filtered or unexported fields
}

GraphicsState represents the PDF graphics state

func NewGraphicsState 

func NewGraphicsState() *GraphicsState

NewGraphicsState creates a new graphics state with default values

func (*GraphicsState) BeginText 

func (gs *GraphicsState) BeginText()

BeginText initializes text state (BT operator)

func (*GraphicsState) Clone 

func (gs *GraphicsState) Clone() *GraphicsState

Clone creates a deep copy of the graphics state

func (*GraphicsState) EndText 

func (gs *GraphicsState) EndText()

EndText does nothing for now (ET operator)

func (*GraphicsState) GetEffectiveFontSize 

func (gs *GraphicsState) GetEffectiveFontSize() float64

GetEffectiveFontSize returns the font size accounting for text matrix transformations The text matrix can scale the font even when the Tf operator uses size=1

func (*GraphicsState) GetFontName 

func (gs *GraphicsState) GetFontName() string

GetFontName returns the current font name

func (*GraphicsState) GetFontSize 

func (gs *GraphicsState) GetFontSize() float64

GetFontSize returns the current font size

func (*GraphicsState) GetTextMatrix 

func (gs *GraphicsState) GetTextMatrix() model.Matrix

GetTextMatrix returns the current text matrix

func (*GraphicsState) GetTextPosition 

func (gs *GraphicsState) GetTextPosition() (x, y float64)

GetTextPosition returns the current text position in device space

func (*GraphicsState) NextLine 

func (gs *GraphicsState) NextLine()

NextLine moves to next line (T* operator)

func (*GraphicsState) Restore 

func (gs *GraphicsState) Restore() error

Restore pops a graphics state from the stack (Q operator)

func (*GraphicsState) Save 

func (gs *GraphicsState) Save()

Save pushes the current graphics state onto the stack (q operator)

func (*GraphicsState) SetCharSpacing 

func (gs *GraphicsState) SetCharSpacing(spacing float64)

SetCharSpacing sets character spacing (Tc operator)

func (*GraphicsState) SetFillColorRGB 

func (gs *GraphicsState) SetFillColorRGB(r, g, b float64)

SetFillColorRGB sets the fill color (rg operator)

func (*GraphicsState) SetFont 

func (gs *GraphicsState) SetFont(name string, size float64)

SetFont sets the current font (Tf operator)

func (*GraphicsState) SetHorizontalScaling 

func (gs *GraphicsState) SetHorizontalScaling(scale float64)

SetHorizontalScaling sets horizontal scaling (Tz operator)

func (*GraphicsState) SetLeading 

func (gs *GraphicsState) SetLeading(leading float64)

SetLeading sets text leading (TL operator)

func (*GraphicsState) SetLineWidth 

func (gs *GraphicsState) SetLineWidth(width float64)

SetLineWidth sets the line width (w operator)

func (*GraphicsState) SetRenderingMode 

func (gs *GraphicsState) SetRenderingMode(mode int)

SetRenderingMode sets text rendering mode (Tr operator)

func (*GraphicsState) SetStrokeColorRGB 

func (gs *GraphicsState) SetStrokeColorRGB(r, g, b float64)

SetStrokeColorRGB sets the stroke color (RG operator)

func (*GraphicsState) SetTextMatrix 

func (gs *GraphicsState) SetTextMatrix(m model.Matrix)

SetTextMatrix sets the text matrix (Tm operator)

func (*GraphicsState) SetTextRise 

func (gs *GraphicsState) SetTextRise(rise float64)

SetTextRise sets text rise (Ts operator)

func (*GraphicsState) SetWordSpacing 

func (gs *GraphicsState) SetWordSpacing(spacing float64)

SetWordSpacing sets word spacing (Tw operator)

func (*GraphicsState) ShowText 

func (gs *GraphicsState) ShowText(text string) (dx, dy float64)

ShowText updates position after showing text (Tj operator) Returns the displacement caused by the text

func (*GraphicsState) ShowTextArray 

func (gs *GraphicsState) ShowTextArray(array []interface{}) (dx, dy float64)

ShowTextArray shows text with positioning adjustments (TJ operator) Returns the displacement caused by the text

func (*GraphicsState) ShowTextWithWidth 

func (gs *GraphicsState) ShowTextWithWidth(text string, width float64) (dx, dy float64)

ShowTextWithWidth updates position after showing text with a known width width should be the total width of the text glyphs in user space units

func (*GraphicsState) Transform 

func (gs *GraphicsState) Transform(m model.Matrix)

Transform applies a transformation matrix to CTM (cm operator)

func (*GraphicsState) TranslateText 

func (gs *GraphicsState) TranslateText(tx, ty float64)

TranslateText translates the text matrix (Td operator)

func (*GraphicsState) TranslateTextSetLeading 

func (gs *GraphicsState) TranslateTextSetLeading(tx, ty float64)

TranslateTextSetLeading translates text and sets leading (TD operator)

type GraphicsStatistics 

type GraphicsStatistics struct {
	TotalLines        int
	HorizontalLines   int
	VerticalLines     int
	DiagonalLines     int
	TotalRectangles   int
	FilledRectangles  int
	StrokedRectangles int
}

Statistics provides statistics about extracted graphics

type GridLines 

type GridLines struct {
	Horizontals []ExtractedLine
	Verticals   []ExtractedLine
}

GridLines represents horizontal and vertical lines that could form a table grid

type LineClassification 

type LineClassification struct {
	HorizontalLines []ExtractedLine
	VerticalLines   []ExtractedLine
	DiagonalLines   []ExtractedLine
}

LineClassification provides classification of extracted lines

type Path 

type Path struct {
	// Segments contains all the path segments
	Segments []PathSegment

	// CurrentPoint is the current point in user space
	CurrentPoint model.Point

	// SubpathStart is the start of the current subpath (for closepath)
	SubpathStart model.Point

	// HasCurrentPoint indicates if a current point has been set
	HasCurrentPoint bool
}

Path represents a graphics path being constructed

func NewPath 

func NewPath() *Path

NewPath creates a new empty path

func (*Path) Clear 

func (p *Path) Clear()

Clear resets the path

func (*Path) ClosePath 

func (p *Path) ClosePath()

ClosePath closes the current subpath (h operator)

func (*Path) CurveTo 

func (p *Path) CurveTo(x1, y1, x2, y2, x3, y3 float64)

CurveTo appends a cubic Bézier curve (c operator) Control points (x1, y1) and (x2, y2), end point (x3, y3)

func (*Path) CurveToV 

func (p *Path) CurveToV(x2, y2, x3, y3 float64)

CurveToV appends a cubic Bézier curve with first control point = current point (v operator)

func (*Path) CurveToY 

func (p *Path) CurveToY(x1, y1, x3, y3 float64)

CurveToY appends a cubic Bézier curve with second control point = end point (y operator)

func (*Path) IsEmpty 

func (p *Path) IsEmpty() bool

IsEmpty returns true if the path has no segments

func (*Path) LineTo 

func (p *Path) LineTo(x, y float64)

LineTo appends a line segment from current point to (x, y) (l operator)

func (*Path) MoveTo 

func (p *Path) MoveTo(x, y float64)

MoveTo starts a new subpath at the specified point (m operator)

func (*Path) Rectangle 

func (p *Path) Rectangle(x, y, width, height float64)

Rectangle appends a rectangle as a complete subpath (re operator)

type PathExtractor 

type PathExtractor struct {
	// Collected graphics elements
	Lines      []ExtractedLine
	Rectangles []ExtractedRectangle

	// Tolerance for horizontal/vertical classification (in points)
	AngleTolerance float64
	// contains filtered or unexported fields
}

PathExtractor extracts lines and rectangles from paths

func NewPathExtractor 

func NewPathExtractor(gs *GraphicsState) *PathExtractor

NewPathExtractor creates a new path extractor

func (*PathExtractor) Clear 

func (pe *PathExtractor) Clear()

Clear clears all extracted elements and the current path

func (*PathExtractor) CloseAndStroke 

func (pe *PathExtractor) CloseAndStroke()

CloseAndStroke handles the s operator (close path and stroke)

func (*PathExtractor) CloseFillAndStroke 

func (pe *PathExtractor) CloseFillAndStroke()

CloseFillAndStroke handles the b operator

func (*PathExtractor) CloseFillAndStrokeEvenOdd 

func (pe *PathExtractor) CloseFillAndStrokeEvenOdd()

CloseFillAndStrokeEvenOdd handles the b* operator

func (*PathExtractor) ClosePath 

func (pe *PathExtractor) ClosePath()

ClosePath handles the h operator

func (*PathExtractor) CurveTo 

func (pe *PathExtractor) CurveTo(x1, y1, x2, y2, x3, y3 float64)

CurveTo handles the c operator

func (*PathExtractor) CurveToV 

func (pe *PathExtractor) CurveToV(x2, y2, x3, y3 float64)

CurveToV handles the v operator

func (*PathExtractor) CurveToY 

func (pe *PathExtractor) CurveToY(x1, y1, x3, y3 float64)

CurveToY handles the y operator

func (*PathExtractor) EndPath 

func (pe *PathExtractor) EndPath()

EndPath handles the n operator (end path without filling or stroking)

func (*PathExtractor) Fill 

func (pe *PathExtractor) Fill()

Fill handles the f/F operator (fill path)

func (*PathExtractor) FillAndStroke 

func (pe *PathExtractor) FillAndStroke()

FillAndStroke handles the B operator (fill and stroke)

func (*PathExtractor) FillAndStrokeEvenOdd 

func (pe *PathExtractor) FillAndStrokeEvenOdd()

FillAndStrokeEvenOdd handles the B* operator

func (*PathExtractor) FillEvenOdd 

func (pe *PathExtractor) FillEvenOdd()

FillEvenOdd handles the f* operator (fill with even-odd rule)

func (*PathExtractor) FilterLinesByLength 

func (pe *PathExtractor) FilterLinesByLength(minLength float64) []ExtractedLine

FilterLinesByLength filters lines by minimum length

func (*PathExtractor) FilterRectanglesBySize 

func (pe *PathExtractor) FilterRectanglesBySize(minWidth, minHeight float64) []ExtractedRectangle

FilterRectanglesBySize filters rectangles by minimum dimensions

func (*PathExtractor) GetHorizontalLines 

func (pe *PathExtractor) GetHorizontalLines() []ExtractedLine

GetHorizontalLines returns only horizontal lines

func (*PathExtractor) GetLines 

func (pe *PathExtractor) GetLines() []ExtractedLine

GetLines returns all extracted lines

func (*PathExtractor) GetRectangles 

func (pe *PathExtractor) GetRectangles() []ExtractedRectangle

GetRectangles returns all extracted rectangles

func (*PathExtractor) GetVerticalLines 

func (pe *PathExtractor) GetVerticalLines() []ExtractedLine

GetVerticalLines returns only vertical lines

func (*PathExtractor) LineTo 

func (pe *PathExtractor) LineTo(x, y float64)

LineTo handles the l operator

func (*PathExtractor) MoveTo 

func (pe *PathExtractor) MoveTo(x, y float64)

MoveTo handles the m operator

func (*PathExtractor) Rectangle 

func (pe *PathExtractor) Rectangle(x, y, width, height float64)

Rectangle handles the re operator

func (*PathExtractor) Stroke 

func (pe *PathExtractor) Stroke()

Stroke handles the S operator (stroke path)

type PathSegment 

type PathSegment struct {
	Type PathSegmentType

	// For MoveTo and LineTo: single point
	// For CurveTo: control point 1, control point 2, end point
	Points []model.Point
}

PathSegment represents a single segment of a path

type PathSegmentType 

type PathSegmentType int

PathSegmentType defines the type of path segment 

const (
	// PathMoveTo starts a new subpath
	PathMoveTo PathSegmentType = iota
	// PathLineTo draws a line to a point
	PathLineTo
	// PathCurveTo draws a cubic Bézier curve
	PathCurveTo
	// PathClosePath closes the current subpath
	PathClosePath
)

type TextState 

type TextState struct {
	// Font and size
	FontName string
	FontSize float64

	// Character and word spacing
	CharSpacing float64
	WordSpacing float64

	// Horizontal scaling (percentage)
	HorizontalScaling float64

	// Leading (line spacing)
	Leading float64

	// Text rendering mode
	RenderingMode int

	// Text rise
	Rise float64

	// Text matrices
	TextMatrix     model.Matrix
	TextLineMatrix model.Matrix
}

TextState represents text-specific state

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