mirror of
https://github.com/unidoc/unipdf.git
synced 2025-05-09 19:29:34 +08:00
re-ordered font.go functions, public at top
This commit is contained in:
Peter Williams
parent
638c3557ce
commit
539a3be976
@ -29,210 +29,19 @@ type PdfFont struct {
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context fonts.Font // The underlying font: Type0, Type1, Truetype, etc..
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}
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// fontSkeleton represents the fields that are common to all PDF fonts.
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type fontSkeleton struct {
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// All fonts have these fields
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subtype string
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basefont string
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// These are optional fields in the PDF font
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toUnicode PdfObject // The stream containing ucMap. We keep it around for ToPdfObject.
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// These objects are computed from optional fields in the PDF font
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ucMap *cmap.CMap // Computed from "ToUnicode"
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fontDescriptor *PdfFontDescriptor // Computed from "FontDescriptor"
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// This is an internal implementation detail. It is passed to specific font types so they can parse it.
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dict *PdfObjectDictionary
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}
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// toFont returns a PdfObjectDictionary for `skel`.
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// It is for use in font ToPdfObject functions.
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// NOTE: The returned dict's SubType is set to `subtype` if `skel` doesn't have a subtype.
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func (skel fontSkeleton) toDict(subtype string) *PdfObjectDictionary {
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if subtype != "" && skel.subtype != "" {
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common.Log.Debug("ERROR: toDict. Overriding subtype to %#q %s", subtype, skel)
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} else if subtype == "" && skel.subtype == "" {
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common.Log.Debug("ERROR: toDict no subtype. font=%s", skel)
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} else if skel.subtype == "" {
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skel.subtype = subtype
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}
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d := MakeDict()
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d.Set("Type", MakeName("Font"))
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d.Set("Subtype", MakeName(skel.subtype))
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d.Set("BaseFont", MakeName(skel.basefont))
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if skel.fontDescriptor != nil {
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d.Set("FontDescriptor", skel.fontDescriptor.ToPdfObject())
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}
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if skel.toUnicode != nil {
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d.Set("ToUnicode", skel.toUnicode)
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}
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return d
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}
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// String returns a string that describes `font`.
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func (font PdfFont) String() string {
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return fmt.Sprintf("%T %s", font.context, font.fontSkeleton.String())
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}
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// String returns a string that describes `skel`.
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func (skel fontSkeleton) String() string {
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descriptor := ""
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if skel.fontDescriptor != nil {
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descriptor = "(has descriptor)"
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}
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return fmt.Sprintf("%#q %#q %s", skel.subtype, skel.basefont, descriptor)
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// BaseFont returns the font's "BaseFont" field.
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func (font PdfFont) BaseFont() string {
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return font.fontSkeleton.basefont
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}
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// CharcodeBytesToUnicode converts PDF character codes `data` to a Go unicode string.
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//
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// 9.10 Extraction of Text Content (page 292)
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// The process of finding glyph descriptions in OpenType fonts by a conforming reader shall be the following:
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// • For Type 1 fonts using “CFF” tables, the process shall be as described in 9.6.6.2, "Encodings
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// for Type 1 Fonts".
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// • For TrueType fonts using “glyf” tables, the process shall be as described in 9.6.6.4,
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// "Encodings for TrueType Fonts". Since this process sometimes produces ambiguous results,
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// conforming writers, instead of using a simple font, shall use a Type 0 font with an Identity-H
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// encoding and use the glyph indices as character codes, as described following Table 118.
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func (font PdfFont) CharcodeBytesToUnicode(data []byte) string {
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if font.ucMap != nil {
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unicode, ok := font.ucMap.CharcodeBytesToUnicode(data)
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if ok {
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return unicode
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}
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}
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// Fall back to encoding
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charcodes := []uint16{}
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if font.isCIDFont() {
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if len(data) == 1 {
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data = []byte{0, data[0]}
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}
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if len(data)%2 != 0 {
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common.Log.Debug("ERROR: Padding data=%+v to even length", data)
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data = append(data, 0)
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}
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for i := 0; i < len(data); i += 2 {
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b := uint16(data[i])<<8 | uint16(data[i+1])
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charcodes = append(charcodes, b)
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}
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} else {
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for _, b := range data {
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charcodes = append(charcodes, uint16(b))
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}
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}
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if encoder := font.Encoder(); encoder != nil {
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runes := []rune{}
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for _, code := range charcodes {
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r, ok := encoder.CharcodeToRune(code)
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if !ok {
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common.Log.Debug("ERROR: No rune. code=0x%04x font=%s encoding=%s data = [% 02x]=%#q",
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code, font, encoder, data, data)
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r = cmap.MissingCodeRune
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}
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runes = append(runes, r)
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}
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return string(runes)
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}
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common.Log.Debug("ERROR: Couldn't convert to unicode. Using input. data=%#q=[% 02x] font=%s",
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string(data), data, font)
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return string(data)
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}
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// isCIDFont returns true if `skel` is a CID font.
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func (skel fontSkeleton) isCIDFont() bool {
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if skel.subtype == "" {
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common.Log.Debug("ERROR: isCIDFont. context is nil. font=%s", skel)
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}
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isCID := false
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switch skel.subtype {
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case "Type0", "CIDFontType0", "CIDFontType2":
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isCID = true
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}
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common.Log.Trace("isCIDFont: isCID=%t font=%s", isCID, skel)
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return isCID
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}
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// actualFont returns the Font in font.context
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func (font PdfFont) actualFont() fonts.Font {
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if font.context == nil {
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common.Log.Debug("ERROR: actualFont. context is nil. font=%s", font)
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}
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switch t := font.context.(type) {
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case *pdfFontSimple:
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return t
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case *pdfFontType0:
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return t
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case *pdfCIDFontType0:
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return t
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case *pdfCIDFontType2:
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return t
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case fonts.FontCourier:
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return t
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case fonts.FontCourierBold:
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return t
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case fonts.FontCourierBoldOblique:
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return t
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case fonts.FontCourierOblique:
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return t
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case fonts.FontHelvetica:
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return t
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case fonts.FontHelveticaBold:
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return t
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case fonts.FontHelveticaBoldOblique:
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return t
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case fonts.FontHelveticaOblique:
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return t
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case fonts.FontTimesRoman:
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return t
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case fonts.FontTimesBold:
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return t
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case fonts.FontTimesBoldItalic:
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return t
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case fonts.FontTimesItalic:
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return t
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case fonts.FontSymbol:
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return t
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case fonts.FontZapfDingbats:
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return t
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default:
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common.Log.Debug("ERROR: actualFont. Unknown font type %t. font=%s", t, font)
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return nil
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}
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}
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// Encoder returns the font's text encoder.
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func (font PdfFont) Encoder() textencoding.TextEncoder {
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t := font.actualFont()
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if t == nil {
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common.Log.Debug("ERROR: Encoder not implemented for font type=%#T", font.context)
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// XXX: Should we return a default encoding?
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return nil
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}
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return t.Encoder()
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}
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// SetEncoder sets the encoding for the underlying font.
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// !@#$ Is this only possible for simple fonts?
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func (font PdfFont) SetEncoder(encoder textencoding.TextEncoder) {
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t := font.actualFont()
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if t == nil {
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common.Log.Debug("ERROR: SetEncoder. Not implemented for font type=%#T", font.context)
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return
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}
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t.SetEncoder(encoder)
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}
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// GetGlyphCharMetrics returns the specified char metrics for a specified glyph name.
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func (font PdfFont) GetGlyphCharMetrics(glyph string) (fonts.CharMetrics, bool) {
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t := font.actualFont()
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if t == nil {
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common.Log.Debug("ERROR: GetGlyphCharMetrics Not implemented for font type=%#T", font.context)
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return fonts.CharMetrics{}, false
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}
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return t.GetGlyphCharMetrics(glyph)
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// Subtype returns the font's "Subtype" field.
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func (font PdfFont) Subtype() string {
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return font.fontSkeleton.subtype
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}
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// NewPdfFontFromPdfObject loads a PdfFont from the dictionary `fontObj`. If there is a problem an
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@ -297,6 +106,217 @@ func newPdfFontFromPdfObject(fontObj PdfObject, allowType0 bool) (*PdfFont, erro
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return font, nil
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}
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// CharcodeBytesToUnicode converts PDF character codes `data` to a Go unicode string.
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//
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// 9.10 Extraction of Text Content (page 292)
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// The process of finding glyph descriptions in OpenType fonts by a conforming reader shall be the following:
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// • For Type 1 fonts using “CFF” tables, the process shall be as described in 9.6.6.2, "Encodings
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// for Type 1 Fonts".
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// • For TrueType fonts using “glyf” tables, the process shall be as described in 9.6.6.4,
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// "Encodings for TrueType Fonts". Since this process sometimes produces ambiguous results,
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// conforming writers, instead of using a simple font, shall use a Type 0 font with an Identity-H
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// encoding and use the glyph indices as character codes, as described following Table 118.
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func (font PdfFont) CharcodeBytesToUnicode(data []byte) string {
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if font.ucMap != nil {
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unicode, ok := font.ucMap.CharcodeBytesToUnicode(data)
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if ok {
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return unicode
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}
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}
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// Fall back to encoding
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charcodes := []uint16{}
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if font.isCIDFont() {
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if len(data) == 1 {
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data = []byte{0, data[0]}
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}
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if len(data)%2 != 0 {
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common.Log.Debug("ERROR: Padding data=%+v to even length", data)
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data = append(data, 0)
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}
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for i := 0; i < len(data); i += 2 {
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b := uint16(data[i])<<8 | uint16(data[i+1])
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charcodes = append(charcodes, b)
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}
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} else {
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for _, b := range data {
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charcodes = append(charcodes, uint16(b))
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}
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}
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if encoder := font.Encoder(); encoder != nil {
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runes := []rune{}
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for _, code := range charcodes {
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r, ok := encoder.CharcodeToRune(code)
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if !ok {
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common.Log.Debug("ERROR: No rune. code=0x%04x font=%s encoding=%s data = [% 02x]=%#q",
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code, font, encoder, data, data)
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r = cmap.MissingCodeRune
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}
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runes = append(runes, r)
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}
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return string(runes)
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}
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common.Log.Debug("ERROR: Couldn't convert to unicode. Using input. data=%#q=[% 02x] font=%s",
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string(data), data, font)
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return string(data)
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}
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// ToPdfObject converts the PdfFont object to its PDF representation.
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func (font PdfFont) ToPdfObject() PdfObject {
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if t := font.actualFont(); t != nil {
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return t.ToPdfObject()
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}
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common.Log.Debug("ERROR: ToPdfObject Not implemented for font type=%#T. Returning null object",
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font.context)
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return MakeNull()
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}
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// Encoder returns the font's text encoder.
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func (font PdfFont) Encoder() textencoding.TextEncoder {
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t := font.actualFont()
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if t == nil {
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common.Log.Debug("ERROR: Encoder not implemented for font type=%#T", font.context)
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// XXX: Should we return a default encoding?
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return nil
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}
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return t.Encoder()
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}
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// SetEncoder sets the encoding for the underlying font.
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// !@#$ Is this only possible for simple fonts?
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func (font PdfFont) SetEncoder(encoder textencoding.TextEncoder) {
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t := font.actualFont()
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if t == nil {
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common.Log.Debug("ERROR: SetEncoder. Not implemented for font type=%#T", font.context)
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return
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}
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t.SetEncoder(encoder)
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}
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// GetGlyphCharMetrics returns the specified char metrics for a specified glyph name.
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func (font PdfFont) GetGlyphCharMetrics(glyph string) (fonts.CharMetrics, bool) {
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t := font.actualFont()
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if t == nil {
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common.Log.Debug("ERROR: GetGlyphCharMetrics Not implemented for font type=%#T", font.context)
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return fonts.CharMetrics{}, false
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}
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return t.GetGlyphCharMetrics(glyph)
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}
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// actualFont returns the Font in font.context
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func (font PdfFont) actualFont() fonts.Font {
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if font.context == nil {
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common.Log.Debug("ERROR: actualFont. context is nil. font=%s", font)
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}
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switch t := font.context.(type) {
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case *pdfFontSimple:
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return t
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case *pdfFontType0:
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return t
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case *pdfCIDFontType0:
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return t
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case *pdfCIDFontType2:
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return t
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case fonts.FontCourier:
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return t
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case fonts.FontCourierBold:
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return t
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case fonts.FontCourierBoldOblique:
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return t
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case fonts.FontCourierOblique:
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return t
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case fonts.FontHelvetica:
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return t
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case fonts.FontHelveticaBold:
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return t
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case fonts.FontHelveticaBoldOblique:
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return t
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case fonts.FontHelveticaOblique:
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return t
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case fonts.FontTimesRoman:
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return t
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case fonts.FontTimesBold:
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return t
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case fonts.FontTimesBoldItalic:
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return t
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case fonts.FontTimesItalic:
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return t
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case fonts.FontSymbol:
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return t
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case fonts.FontZapfDingbats:
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return t
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default:
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common.Log.Debug("ERROR: actualFont. Unknown font type %t. font=%s", t, font)
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return nil
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}
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}
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// fontSkeleton represents the fields that are common to all PDF fonts.
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type fontSkeleton struct {
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// All fonts have these fields
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basefont string // The font's "BaseFont" field.
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subtype string // The font's "Subtype" field.
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// These are optional fields in the PDF font
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toUnicode PdfObject // The stream containing ucMap. We keep it around for ToPdfObject.
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// These objects are computed from optional fields in the PDF font
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ucMap *cmap.CMap // Computed from "ToUnicode"
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fontDescriptor *PdfFontDescriptor // Computed from "FontDescriptor"
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// This is an internal implementation detail. It is passed to specific font types so they can parse it.
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dict *PdfObjectDictionary
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}
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// toFont returns a PdfObjectDictionary for `skel`.
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// It is for use in font ToPdfObject functions.
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// NOTE: The returned dict's "Subtype" field is set to `subtype` if `skel` doesn't have a subtype.
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func (skel fontSkeleton) toDict(subtype string) *PdfObjectDictionary {
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if subtype != "" && skel.subtype != "" {
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common.Log.Debug("ERROR: toDict. Overriding subtype to %#q %s", subtype, skel)
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} else if subtype == "" && skel.subtype == "" {
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common.Log.Debug("ERROR: toDict no subtype. font=%s", skel)
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} else if skel.subtype == "" {
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skel.subtype = subtype
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}
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d := MakeDict()
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d.Set("Type", MakeName("Font"))
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d.Set("BaseFont", MakeName(skel.basefont))
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d.Set("Subtype", MakeName(skel.subtype))
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if skel.fontDescriptor != nil {
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d.Set("FontDescriptor", skel.fontDescriptor.ToPdfObject())
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}
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if skel.toUnicode != nil {
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d.Set("ToUnicode", skel.toUnicode)
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}
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return d
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}
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// String returns a string that describes `skel`.
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func (skel fontSkeleton) String() string {
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descriptor := ""
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if skel.fontDescriptor != nil {
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descriptor = "(has descriptor)"
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}
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return fmt.Sprintf("%#q %#q %s", skel.subtype, skel.basefont, descriptor)
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}
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// isCIDFont returns true if `skel` is a CID font.
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func (skel fontSkeleton) isCIDFont() bool {
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if skel.subtype == "" {
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common.Log.Debug("ERROR: isCIDFont. context is nil. font=%s", skel)
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}
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isCID := false
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switch skel.subtype {
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case "Type0", "CIDFontType0", "CIDFontType2":
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isCID = true
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}
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common.Log.Trace("isCIDFont: isCID=%t font=%s", isCID, skel)
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return isCID
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}
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// newFontSkeletonFromPdfObject loads a fontSkeleton from a dictionary. If there is a problem an
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// error is returned.
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// The fontSkeleton is the group of fields common to all PDF fonts.
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@ -358,16 +378,6 @@ func newFontSkeletonFromPdfObject(fontObj PdfObject) (*fontSkeleton, error) {
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return font, nil
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}
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// ToPdfObject converts the PdfFont object to its PDF representation.
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func (font PdfFont) ToPdfObject() PdfObject {
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if t := font.actualFont(); t != nil {
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return t.ToPdfObject()
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}
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common.Log.Debug("ERROR: ToPdfObject Not implemented for font type=%#T. Returning null object",
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font.context)
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return MakeNull()
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}
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// toUnicodeToCmap returns a CMap of `toUnicode` if it exists
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// 9.10.3 toUnicode CMaps (page 29)
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// The CMap defined in the toUnicode entry of the font dictionary shall follow the syntax for CMaps
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