def.go

/*
 * Copyright (c) 2013-2014 Kurt Jung (Gmail: kurt.w.jung)
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

package gofpdf

import (
	"bytes"
	"crypto/sha1"
	"encoding/gob"
	"encoding/json"
	"fmt"
	"io"
	"time"
)

// Version of FPDF from which this package is derived
const (
	cnFpdfVersion = "1.7"
)

type blendModeType struct {
	strokeStr, fillStr, modeStr string
	objNum                      int
}

type gradientType struct {
	tp                int // 2: linear, 3: radial
	clr1Str, clr2Str  string
	x1, y1, x2, y2, r float64
	objNum            int
}

const (
	// OrientationPortrait represents the portrait orientation.
	OrientationPortrait = "portrait"

	// OrientationLandscape represents the landscape orientation.
	OrientationLandscape = "landscape"
)

const (
	// UnitPoint represents the size unit point
	UnitPoint = "pt"
	// UnitMillimeter represents the size unit millimeter
	UnitMillimeter = "mm"
	// UnitCentimeter represents the size unit centimeter
	UnitCentimeter = "cm"
	// UnitInch represents the size unit inch
	UnitInch = "inch"
)

const (
	// PageSizeA3 represents DIN/ISO A3 page size
	PageSizeA3 = "A3"
	// PageSizeA4 represents DIN/ISO A4 page size
	PageSizeA4 = "A4"
	// PageSizeA5 represents DIN/ISO A5 page size
	PageSizeA5 = "A5"
	// PageSizeLetter represents US Letter page size
	PageSizeLetter = "Letter"
	// PageSizeLegal represents US Legal page size
	PageSizeLegal = "Legal"
)

const (
	// BorderNone set no border
	BorderNone = ""
	// BorderFull sets a full border
	BorderFull = "1"
	// BorderLeft sets the border on the left side
	BorderLeft = "L"
	// BorderTop sets the border at the top
	BorderTop = "T"
	// BorderRight sets the border on the right side
	BorderRight = "R"
	// BorderBottom sets the border on the bottom
	BorderBottom = "B"
)

const (
	// LineBreakNone disables linebreak
	LineBreakNone = 0
	// LineBreakNormal enables normal linebreak
	LineBreakNormal = 1
	// LineBreakBelow enables linebreak below
	LineBreakBelow = 2
)

const (
	// AlignLeft left aligns the cell
	AlignLeft = "L"
	// AlignRight right aligns the cell
	AlignRight = "R"
	// AlignCenter centers the cell
	AlignCenter = "C"
	// AlignTop aligns the cell to the top
	AlignTop = "T"
	// AlignBottom aligns the cell to the bottom
	AlignBottom = "B"
	// AlignMiddle aligns the cell to the middle
	AlignMiddle = "M"
	// AlignBaseline aligns the cell to the baseline
	AlignBaseline = "B"
)

type colorMode int

const (
	colorModeRGB colorMode = iota
	colorModeSpot
	colorModeCMYK
)

type colorType struct {
	r, g, b    float64
	ir, ig, ib int
	mode       colorMode
	spotStr    string // name of current spot color
	gray       bool
	str        string
}

// SpotColorType specifies a named spot color value
type spotColorType struct {
	id, objID int
	val       cmykColorType
}

// CMYKColorType specifies an ink-based CMYK color value
type cmykColorType struct {
	c, m, y, k byte // 0% to 100%
}

// SizeType fields Wd and Ht specify the horizontal and vertical extents of a
// document element such as a page.
type SizeType struct {
	Wd, Ht float64
}

// PointType fields X and Y specify the horizontal and vertical coordinates of
// a point, typically used in drawing.
type PointType struct {
	X, Y float64
}

// XY returns the X and Y components of the receiver point.
func (p PointType) XY() (float64, float64) {
	return p.X, p.Y
}

// ImageInfoType contains size, color and other information about an image.
// Changes to this structure should be reflected in its GobEncode and GobDecode
// methods.
type ImageInfoType struct {
	data  []byte  // Raw image data
	smask []byte  // Soft Mask, an 8bit per-pixel transparency mask
	n     int     // Image object number
	w     float64 // Width
	h     float64 // Height
	cs    string  // Color space
	pal   []byte  // Image color palette
	bpc   int     // Bits Per Component
	f     string  // Image filter
	dp    string  // DecodeParms
	trns  []int   // Transparency mask
	scale float64 // Document scale factor
	dpi   float64 // Dots-per-inch found from image file (png only)
	i     string  // SHA-1 checksum of the above values.
}

func generateImageID(info *ImageInfoType) (string, error) {
	b, err := info.GobEncode()
	return fmt.Sprintf("%x", sha1.Sum(b)), err
}

// GobEncode encodes the receiving image to a byte slice.
func (info *ImageInfoType) GobEncode() (buf []byte, err error) {
	fields := []any{
		info.data, info.smask, info.n, info.w, info.h, info.cs,
		info.pal, info.bpc, info.f, info.dp, info.trns, info.scale, info.dpi,
	}
	w := new(bytes.Buffer)
	encoder := gob.NewEncoder(w)
	for j := 0; j < len(fields) && err == nil; j++ {
		err = encoder.Encode(fields[j])
	}
	if err == nil {
		buf = w.Bytes()
	}
	return
}

// GobDecode decodes the specified byte buffer (generated by GobEncode) into
// the receiving image.
func (info *ImageInfoType) GobDecode(buf []byte) (err error) {
	fields := []any{
		&info.data, &info.smask, &info.n, &info.w, &info.h,
		&info.cs, &info.pal, &info.bpc, &info.f, &info.dp, &info.trns, &info.scale, &info.dpi,
	}
	r := bytes.NewBuffer(buf)
	decoder := gob.NewDecoder(r)
	for j := 0; j < len(fields) && err == nil; j++ {
		err = decoder.Decode(fields[j])
	}

	info.i, err = generateImageID(info)
	return
}

// PointConvert returns the value of pt, expressed in points (1/72 inch), as a
// value expressed in the unit of measure specified in New(). Since font
// management in Fpdf uses points, this method can help with line height
// calculations and other methods that require user units.
func (f *Fpdf) PointConvert(pt float64) (u float64) {
	return pt / f.k
}

// PointToUnitConvert is an alias for PointConvert.
func (f *Fpdf) PointToUnitConvert(pt float64) (u float64) {
	return pt / f.k
}

// UnitToPointConvert returns the value of u, expressed in the unit of measure
// specified in New(), as a value expressed in points (1/72 inch). Since font
// management in Fpdf uses points, this method can help with setting font sizes
// based on the sizes of other non-font page elements.
func (f *Fpdf) UnitToPointConvert(u float64) (pt float64) {
	return u * f.k
}

// Extent returns the width and height of the image in the units of the Fpdf
// object.
func (info *ImageInfoType) Extent() (wd, ht float64) {
	return info.Width(), info.Height()
}

// Width returns the width of the image in the units of the Fpdf object.
func (info *ImageInfoType) Width() float64 {
	return info.w / (info.scale * info.dpi / 72)
}

// Height returns the height of the image in the units of the Fpdf object.
func (info *ImageInfoType) Height() float64 {
	return info.h / (info.scale * info.dpi / 72)
}

// SetDpi sets the dots per inch for an image. PNG images MAY have their dpi
// set automatically, if the image specifies it. DPI information is not
// currently available automatically for JPG and GIF images, so if it's
// important to you, you can set it here. It defaults to 72 dpi.
func (info *ImageInfoType) SetDpi(dpi float64) {
	info.dpi = dpi
}

type fontFileType struct {
	length1, length2 int64
	n                int
	embedded         bool
	content          []byte
	fontType         string
}

type linkType struct {
	x, y, wd, ht float64
	link         int    // Auto-generated internal link ID or...
	linkStr      string // ...application-provided external link string
}

type intLinkType struct {
	page int
	y    float64
}

// outlineType is used for a sidebar outline of bookmarks
type outlineType struct {
	text                                   string
	level, parent, first, last, next, prev int
	y                                      float64
	p                                      int
}

// InitType is used with NewCustom() to customize an Fpdf instance.
// OrientationStr, UnitStr, SizeStr and FontDirStr correspond to the arguments
// accepted by New(). If the Wd and Ht fields of Size are each greater than
// zero, Size will be used to set the default page size rather than SizeStr. Wd
// and Ht are specified in the units of measure indicated by UnitStr.
type InitType struct {
	OrientationStr string
	UnitStr        string
	SizeStr        string
	Size           SizeType
	FontDirStr     string
}

// FontLoader is used to read fonts (JSON font specification and zlib compressed font binaries)
// from arbitrary locations (e.g. files, zip files, embedded font resources).
//
// Open provides an io.Reader for the specified font file (.json or .z). The file name
// never includes a path. Open returns an error if the specified file cannot be opened.
type FontLoader interface {
	Open(name string) (io.Reader, error)
}

// PageBox defines the coordinates and extent of the various page box types
type PageBox struct {
	SizeType
	PointType
}

// Fpdf is the principal structure for creating a single PDF document
type Fpdf struct {
	isCurrentUTF8    bool                       // is current font used in utf-8 mode
	isRTL            bool                       // is is right to left mode enabled
	page             int                        // current page number
	n                int                        // current object number
	offsets          []int                      // array of object offsets
	templates        map[string]Template        // templates used in this document
	templateObjects  map[string]int             // template object IDs within this document
	importedObjs     map[string][]byte          // imported template objects (gofpdi)
	importedObjPos   map[string]map[int]string  // imported template objects hashes and their positions (gofpdi)
	importedTplObjs  map[string]string          // imported template names and IDs (hashed) (gofpdi)
	importedTplIDs   map[string]int             // imported template ids hash to object id int (gofpdi)
	buffer           fmtBuffer                  // buffer holding in-memory PDF
	pages            []*bytes.Buffer            // slice[page] of page content; 1-based
	state            int                        // current document state
	compress         bool                       // compression flag
	k                float64                    // scale factor (number of points in user unit)
	defOrientation   string                     // default orientation
	curOrientation   string                     // current orientation
	stdPageSizes     map[string]SizeType        // standard page sizes
	defPageSize      SizeType                   // default page size
	defPageBoxes     map[string]PageBox         // default page size
	curPageSize      SizeType                   // current page size
	pageSizes        map[int]SizeType           // used for pages with non default sizes or orientations
	pageBoxes        map[int]map[string]PageBox // used to define the crop, trim, bleed and art boxes
	unitStr          string                     // unit of measure for all rendered objects except fonts
	wPt, hPt         float64                    // dimensions of current page in points
	w, h             float64                    // dimensions of current page in user unit
	lMargin          float64                    // left margin
	tMargin          float64                    // top margin
	rMargin          float64                    // right margin
	bMargin          float64                    // page break margin
	cMargin          float64                    // cell margin
	x, y             float64                    // current position in user unit
	lasth            float64                    // height of last printed cell
	lineWidth        float64                    // line width in user unit
	fontpath         string                     // path containing fonts
	fontLoader       FontLoader                 // used to load font files from arbitrary locations
	coreFonts        map[string]bool            // array of core font names
	fonts            map[string]fontDefType     // array of used fonts
	fontFiles        map[string]fontFileType    // array of font files
	diffs            []string                   // array of encoding differences
	fontFamily       string                     // current font family
	fontStyle        string                     // current font style
	underline        bool                       // underlining flag
	strikeout        bool                       // strike out flag
	currentFont      fontDefType                // current font info
	fontSizePt       float64                    // current font size in points
	fontSize         float64                    // current font size in user unit
	ws               float64                    // word spacing
	images           map[string]*ImageInfoType  // array of used images
	aliasMap         map[string]string          // map of alias->replacement
	pageLinks        [][]linkType               // pageLinks[page][link], both 1-based
	links            []intLinkType              // array of internal links
	attachments      []Attachment               // slice of content to embed globally
	pageAttachments  [][]annotationAttach       // 1-based array of annotation for file attachments (per page)
	outlines         []outlineType              // array of outlines
	outlineRoot      int                        // root of outlines
	autoPageBreak    bool                       // automatic page breaking
	acceptPageBreak  func() bool                // returns true to accept page break
	pageBreakTrigger float64                    // threshold used to trigger page breaks
	inHeader         bool                       // flag set when processing header
	headerFnc        func()                     // function provided by app and called to write header
	headerHomeMode   bool                       // set position to home after headerFnc is called
	inFooter         bool                       // flag set when processing footer
	footerFnc        func()                     // function provided by app and called to write footer
	footerFncLpi     func(bool)                 // function provided by app and called to write footer with last page flag
	zoomMode         string                     // zoom display mode
	layoutMode       string                     // layout display mode
	xmp              []byte                     // XMP metadata
	producer         string                     // producer
	title            string                     // title
	subject          string                     // subject
	author           string                     // author
	keywords         string                     // keywords
	creator          string                     // creator
	creationDate     time.Time                  // override for document CreationDate value
	modDate          time.Time                  // override for document ModDate value
	aliasNbPagesStr  string                     // alias for total number of pages
	pdfVersion       string                     // PDF version number
	fontDirStr       string                     // location of font definition files
	capStyle         int                        // line cap style: butt 0, round 1, square 2
	joinStyle        int                        // line segment join style: miter 0, round 1, bevel 2
	dashArray        []float64                  // dash array
	dashPhase        float64                    // dash phase
	blendList        []blendModeType            // slice[idx] of alpha transparency modes, 1-based
	blendMap         map[string]int             // map into blendList
	blendMode        string                     // current blend mode
	alpha            float64                    // current transpacency
	gradientList     []gradientType             // slice[idx] of gradient records
	clipNest         int                        // Number of active clipping contexts
	transformNest    int                        // Number of active transformation contexts
	err              error                      // Set if error occurs during life cycle of instance
	protect          protectType                // document protection structure
	layer            layerRecType               // manages optional layers in document
	catalogSort      bool                       // sort resource catalogs in document
	nJs              int                        // JavaScript object number
	javascript       *string                    // JavaScript code to include in the PDF
	colorFlag        bool                       // indicates whether fill and text colors are different
	color            struct {
		// Composite values of colors
		draw, fill, text colorType
	}
	spotColorMap           map[string]spotColorType // Map of named ink-based colors
	userUnderlineThickness float64                  // A custom user underline thickness multiplier.
}

type encType struct {
	uv   int
	name string
}

type encListType [256]encType

type fontBoxType struct {
	Xmin, Ymin, Xmax, Ymax int
}

// Font flags for FontDescType.Flags as defined in the pdf specification.
const (
	// FontFlagFixedPitch is set if all glyphs have the same width (as
	// opposed to proportional or variable-pitch fonts, which have
	// different widths).
	FontFlagFixedPitch = 1 << 0
	// FontFlagSerif is set if glyphs have serifs, which are short
	// strokes drawn at an angle on the top and bottom of glyph stems.
	// (Sans serif fonts do not have serifs.)
	FontFlagSerif = 1 << 1
	// FontFlagSymbolic is set if font contains glyphs outside the
	// Adobe standard Latin character set. This flag and the
	// Nonsymbolic flag shall not both be set or both be clear.
	FontFlagSymbolic = 1 << 2
	// FontFlagScript is set if glyphs resemble cursive handwriting.
	FontFlagScript = 1 << 3
	// FontFlagNonsymbolic is set if font uses the Adobe standard
	// Latin character set or a subset of it.
	FontFlagNonsymbolic = 1 << 5
	// FontFlagItalic is set if glyphs have dominant vertical strokes
	// that are slanted.
	FontFlagItalic = 1 << 6
	// FontFlagAllCap is set if font contains no lowercase letters;
	// typically used for display purposes, such as for titles or
	// headlines.
	FontFlagAllCap = 1 << 16
	// SmallCap is set if font contains both uppercase and lowercase
	// letters. The uppercase letters are similar to those in the
	// regular version of the same typeface family. The glyphs for the
	// lowercase letters have the same shapes as the corresponding
	// uppercase letters, but they are sized and their proportions
	// adjusted so that they have the same size and stroke weight as
	// lowercase glyphs in the same typeface family.
	SmallCap = 1 << 18
	// ForceBold determines whether bold glyphs shall be painted with
	// extra pixels even at very small text sizes by a conforming
	// reader. If the ForceBold flag is set, features of bold glyphs
	// may be thickened at small text sizes.
	ForceBold = 1 << 18
)

// FontDescType (font descriptor) specifies metrics and other
// attributes of a font, as distinct from the metrics of individual
// glyphs (as defined in the pdf specification).
type FontDescType struct {
	// The maximum height above the baseline reached by glyphs in this
	// font (for example for "S"). The height of glyphs for accented
	// characters shall be excluded.
	Ascent int
	// The maximum depth below the baseline reached by glyphs in this
	// font. The value shall be a negative number.
	Descent int
	// The vertical coordinate of the top of flat capital letters,
	// measured from the baseline (for example "H").
	CapHeight int
	// A collection of flags defining various characteristics of the
	// font. (See the FontFlag* constants.)
	Flags int
	// A rectangle, expressed in the glyph coordinate system, that
	// shall specify the font bounding box. This should be the smallest
	// rectangle enclosing the shape that would result if all of the
	// glyphs of the font were placed with their origins coincident
	// and then filled.
	FontBBox fontBoxType
	// The angle, expressed in degrees counterclockwise from the
	// vertical, of the dominant vertical strokes of the font. (The
	// 9-o’clock position is 90 degrees, and the 3-o’clock position
	// is –90 degrees.) The value shall be negative for fonts that
	// slope to the right, as almost all italic fonts do.
	ItalicAngle int
	// The thickness, measured horizontally, of the dominant vertical
	// stems of glyphs in the font.
	StemV int
	// The width to use for character codes whose widths are not
	// specified in a font dictionary’s Widths array. This shall have
	// a predictable effect only if all such codes map to glyphs whose
	// actual widths are the same as the value of the MissingWidth
	// entry. (Default value: 0.)
	MissingWidth int
}

type fontDefType struct {
	Tp           string        // "Core", "TrueType", ...
	Name         string        // "Courier-Bold", ...
	Desc         FontDescType  // Font descriptor
	Up           int           // Underline position
	Ut           int           // Underline thickness
	Cw           []int         // Character width by ordinal
	Enc          string        // "cp1252", ...
	Diff         string        // Differences from reference encoding
	File         string        // "Redressed.z"
	Size1, Size2 int           // Type1 values
	OriginalSize int           // Size of uncompressed font file
	N            int           // Set by font loader
	DiffN        int           // Position of diff in app array, set by font loader
	i            string        // 1-based position in font list, set by font loader, not this program
	utf8File     *utf8FontFile // UTF-8 font
	usedRunes    map[int]int   // Array of used runes
}

// generateFontID generates a font Id from the font definition
func generateFontID(fdt fontDefType) (string, error) {
	// file can be different if generated in different instance
	fdt.File = ""
	b, err := json.Marshal(&fdt)
	return fmt.Sprintf("%x", sha1.Sum(b)), err
}

type fontInfoType struct {
	Data               []byte
	File               string
	OriginalSize       int
	FontName           string
	Bold               bool
	IsFixedPitch       bool
	UnderlineThickness int
	UnderlinePosition  int
	Widths             []int
	Size1, Size2       uint32
	Desc               FontDescType
}