context

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 Go to latest Published: Jun 10, 2024 License: MIT Imports: 9 Imported by: 0

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Constants

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Variables

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Functions

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Types

type Context 

type Context interface {

	// Push adds the current context state on the stack.
	Push()

	// Pop removes the most recent context state from the stack.
	Pop()

	// Matrix returns the current transformation matrix.
	Matrix() transform.Matrix

	// SetMatrix modifies the transformation matrix.
	SetMatrix(m transform.Matrix)

	// Translate updates the current matrix with a translation.
	Translate(x, y float64)

	// Scale updates the current matrix with a scaling factor.
	// Scaling occurs about the origin.
	Scale(x, y float64)

	// Rotate updates the current matrix with a anticlockwise rotation.
	// Rotation occurs about the origin. Angle is specified in radians.
	Rotate(angle float64)

	// MoveTo starts a new subpath within the current path starting at
	// the specified point.
	MoveTo(x, y float64)

	// LineTo adds a line segment to the current path starting at the current
	// point.
	LineTo(x, y float64)

	// CubicTo adds a cubic bezier curve to the current path starting at the
	// current point.
	CubicTo(x1, y1, x2, y2, x3, y3 float64)

	// QuadraticTo adds a quadratic bezier curve to the current path starting
	// at the current point.
	QuadraticTo(x1, y1, x2, y2 float64)

	// NewSubPath starts a new subpath within the current path.
	NewSubPath()

	// ClosePath adds a line segment from the current point to the beginning
	// of the current subpath.
	ClosePath()

	// ClearPath clears the current path.
	ClearPath()

	// Clip updates the clipping region by intersecting the current
	// clipping region with the current path as it would be filled by Fill().
	// The path is cleared after this operation.
	Clip()

	// ClipPreserve updates the clipping region by intersecting the current
	// clipping region with the current path as it would be filled by Fill().
	// The path is preserved after this operation.
	ClipPreserve()

	// ResetClip clears the clipping region.
	ResetClip()

	// LineWidth returns the current line width.
	LineWidth() float64

	// SetLineWidth sets the line width.
	SetLineWidth(lineWidth float64)

	// SetLineCap sets the line cap style.
	SetLineCap(lineCap LineCap)

	// SetLineJoin sets the line join style.
	SetLineJoin(lineJoin LineJoin)

	// SetDash sets the line dash pattern.
	SetDash(dashes ...float64)

	// SetDashOffset sets the initial offset into the dash pattern to use when
	// stroking dashed paths.
	SetDashOffset(offset float64)

	// Fill fills the current path with the current color. Open subpaths
	// are implicity closed.
	Fill()

	// FillPreserve fills the current path with the current color. Open subpaths
	// are implicity closed. The path is preserved after this operation.
	FillPreserve()

	// Stroke strokes the current path with the current color, line width,
	// line cap, line join and dash settings. The path is cleared after this
	// operation.
	Stroke()

	// StrokePreserve strokes the current path with the current color,
	// line width, line cap, line join and dash settings. The path is preserved
	// after this operation.
	StrokePreserve()

	// SetRGBA sets the both the fill and stroke colors.
	// r, g, b, a values should be in range 0-1.
	SetRGBA(r, g, b, a float64)

	// SetRGBA sets the fill color.
	// r, g, b, a values should be in range 0-1.
	SetFillRGBA(r, g, b, a float64)

	// SetStrokeStyle sets current fill pattern.
	SetFillStyle(pattern Pattern)

	// SetFillRule sets the fill rule.
	SetFillRule(fillRule FillRule)

	// SetRGBA sets the stroke color.
	// r, g, b, a values should be in range 0-1.
	SetStrokeRGBA(r, g, b, a float64)

	// SetStrokeStyle sets current stroke pattern.
	SetStrokeStyle(pattern Pattern)

	// TextState returns the current text state.
	TextState() *TextState

	// DrawString renders the specified string and the specified position.
	DrawString(s string, x, y float64)

	// Measure string returns the width and height of the specified string.
	MeasureString(s string) (w, h float64)

	// DrawRectangle draws the specified rectangle.
	DrawRectangle(x, y, w, h float64)

	// DrawImage draws the specified image at the specified point.
	DrawImage(image image.Image, x, y int)

	// DrawImageAnchored draws the specified image at the specified anchor point.
	// The anchor point is x - w * ax, y - h * ay, where w, h is the size of the
	// image. Use ax=0.5, ay=0.5 to center the image at the specified point.
	DrawImageAnchored(image image.Image, x, y int, ax, ay float64)

	// Width returns the width of the rendering area.
	Height() int

	// Height returns the height of the rendering area.
	Width() int
}

Context defines operations for rendering to a particular target.

type FillRule 

type FillRule int

FillRule represents the fill style used by a context instance. 

const (
	FillRuleWinding FillRule = iota
	FillRuleEvenOdd
)

Fill rules.

type Gradient 

type Gradient interface {
	Pattern
	AddColorStop(offset float64, color color.Color)
}

Gradient represents a gradient pattern which can be rendered by a context instance.

type LineCap 

type LineCap int

LineCap represents the line cap style used by a context instance. 

const (
	LineCapRound LineCap = iota
	LineCapButt
	LineCapSquare
)

Line cap styles.

type LineJoin 

type LineJoin int

LineJoin represents the line join style used by a context instance. 

const (
	LineJoinRound LineJoin = iota
	LineJoinBevel
)

Line join styles.

type Pattern 

type Pattern interface {
	ColorAt(x, y int) color.Color
}

Pattern represents a pattern which can be rendered by a context instance.

type TextFont 

type TextFont struct {
	Font *model.PdfFont
	Face font.Face
	Size float64
	// contains filtered or unexported fields
}

TextFont represents a font used to draw text to a target, through a rendering context.

func NewTextFont 

func NewTextFont(font *model.PdfFont, size float64) (*TextFont, error)

NewTextFont returns a new text font instance based on the specified PDF font and the specified font size.

func NewTextFontFromPath 

func NewTextFontFromPath(filePath string, size float64) (*TextFont, error)

NewTextFontFromPath returns a new text font instance based on the specified font file and the specified font size.

func (*TextFont) BytesToCharcodes 

func (tf *TextFont) BytesToCharcodes(data []byte) []textencoding.CharCode

BytesToCharcodes converts the specified byte data to character codes, using the encapsulated PDF font instance.

func (*TextFont) CharcodesToUnicode 

func (tf *TextFont) CharcodesToUnicode(charcodes []textencoding.CharCode) []rune

CharcodesToUnicode converts the specified character codes to a slice of runes, using the encapsulated PDF font instance.

func (*TextFont) GetCharMetrics 

func (tf *TextFont) GetCharMetrics(code textencoding.CharCode) (float64, float64, bool)

GetCharMetrics returns the metrics of the specified character code. The character metrics are calculated by the internal PDF font.

func (*TextFont) GetRuneMetrics 

func (tf *TextFont) GetRuneMetrics(r rune) (float64, float64, bool)

GetRuneMetrics returns the metrics of the specified rune. The character metrics are calculated by the internal PDF font.

func (*TextFont) WithSize 

func (tf *TextFont) WithSize(size float64, originalFont *model.PdfFont) *TextFont

WithSize returns a new text font instance based on the current text font, with the specified font size.

type TextState 

type TextState struct {
	Tc  float64          // Character spacing.
	Tw  float64          // Word spacing.
	Th  float64          // Horizontal scaling.
	Tl  float64          // Leading.
	Tf  *TextFont        // Font
	Ts  float64          // Text rise.
	Tm  transform.Matrix // Text matrix.
	Tlm transform.Matrix // Text line matrix.
}

TextState holds a representation of a PDF text state. The text state processes different text related operations which may occur in PDF content streams. It is used as a part of a renderding context in order to manipulate and display text.

func NewTextState 

func NewTextState() *TextState

NewTextState returns a new TextState instance.

func (*TextState) ProcDQ 

func (ts *TextState) ProcDQ(data []byte, aw, ac float64, ctx Context)

ProcDQ processes a `"` operation, which advances the text state to a new line and then displays a text string using aw and ac as word and character spacing.

See section 9.4.3 "Text Showing Operators" and Table 209 (pp. 258-259 PDF32000_2008).

func (*TextState) ProcQ 

func (ts *TextState) ProcQ(data []byte, ctx Context)

ProcQ processes a `'` operation, which advances the text state to a new line and then displays a text string.

See section 9.4.3 "Text Showing Operators" and Table 209 (pp. 258-259 PDF32000_2008).

func (*TextState) ProcTD 

func (ts *TextState) ProcTD(tx, ty float64)

ProcTD processes a `TD` operation, which advances the text state to a new line with offsets `tx`,`ty`.

See section 9.4.2 "Text Positioning Operators" and Table 108 (pp. 257-258 PDF32000_2008).

func (*TextState) ProcTStar 

func (ts *TextState) ProcTStar()

ProcTStar processes a `T*` operation, which advances the text state to a new line.

See section 9.4.2 "Text Positioning Operators" and Table 108 (pp. 257-258 PDF32000_2008).

func (*TextState) ProcTd 

func (ts *TextState) ProcTd(tx, ty float64)

ProcTd processes a `Td` operation, which advances the text state to a new line with offsets `tx`,`ty`.

See section 9.4.2 "Text Positioning Operators" and Table 108 (pp. 257-258 PDF32000_2008).

func (*TextState) ProcTf 

func (ts *TextState) ProcTf(font *TextFont)

ProcTf processes a `Tf` operation which sets the font and its size.

See section 9.3 "Text State Parameters and Operators" and Table 105 (pp. 251-252 PDF32000_2008).

func (*TextState) ProcTj 

func (ts *TextState) ProcTj(data []byte, ctx Context)

ProcTj processes a `Tj` operation, which displays a text string.

See section 9.4.3 "Text Showing Operators" and Table 209 (pp. 258-259 PDF32000_2008).

func (*TextState) ProcTm 

func (ts *TextState) ProcTm(a, b, c, d, e, f float64)

ProcTm processes a `Tm` operation, which sets the current text matrix.

See section 9.4.2 "Text Positioning Operators" and Table 108 (pp. 257-258 PDF32000_2008).

func (*TextState) Reset 

func (ts *TextState) Reset()

Reset resets both the text matrix and the line matrix.

func (*TextState) Translate 

func (ts *TextState) Translate(tx, ty float64)

Translate translates the current text matrix with `tx`,`ty`.

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