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feat(转换能力): 增强PDF字形与扫描件转换
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xiaoqidun committed 2026-09-25 00:31:52 +08:00
1 parent 2ae89e54b4
commit 786b1a41c2
14 files changed
+250 -97
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ofdgo_pdf_object.go
+87 -42
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@@ -56,14 +56,22 @@ func (p *pdfImporter) image(mark pdfgo.ImageMark) error {
id = ""
}
if id == "" {
jbig2Original, err := source.JBIG2File()
if err != nil {
return err
}
filter, err := p.reader.Resolve(source.Stream.Dictionary["Filter"])
if err != nil {
return err
}
jpegOriginal := filter == pdfgo.Name("DCTDecode") && len(source.Decode) == 0 && !source.ImageMask && source.ColorSpace != pdfgo.Name("DeviceCMYK") && source.Mask == nil && source.SoftMask == nil
decoded, err := source.DecodeImage()
if err != nil {
return err
space, _ := source.ColorSpace.(pdfgo.Name)
jpegOriginal := filter == pdfgo.Name("DCTDecode") && len(source.Decode) == 0 && !source.ImageMask && (space == "DeviceGray" || space == "DeviceRGB") && source.Mask == nil && source.SoftMask == nil
var decoded image.Image
if len(jbig2Original) == 0 {
decoded, err = source.DecodeImage()
if err != nil {
return err
}
}
if source.ImageMask {
if mark.Style.Fill.CMYK != nil {
@@ -85,7 +93,9 @@ func (p *pdfImporter) image(mark pdfgo.ImageMark) error {
decoded = stencil
}
var encoded bytes.Buffer
if jpegOriginal {
if len(jbig2Original) != 0 {
encoded.Write(jbig2Original)
} else if jpegOriginal {
encoded.Write(source.Stream.Data)
} else {
if err := png.Encode(&encoded, decoded); err != nil {
@@ -112,10 +122,25 @@ func (p *pdfImporter) image(mark pdfgo.ImageMark) error {
return nil
}
// text 保留原字体、字形编号与逐字基线，不重新塑形
// text 保留内嵌字形及逐字基线，外部字体保留名称引用
// 入参: mark PDF文字绘制信息
// 返回: error 错误信息
func (p *pdfImporter) text(mark pdfgo.TextMark) error {
if mark.Font.Subtype == pdfgo.Name("Type3") {
if err := p.flushPath(); err != nil {
return err
}
visitor := pdfgo.Visitor{Path: p.path, Image: p.image}
visitor.Group = func(group pdfgo.GroupMark, walk func(pdfgo.Visitor) error) error {
return p.group(group, walk, visitor)
}
for index := range mark.Glyphs {
if err := p.reader.WalkType3Glyph(p.ctx, mark, index, visitor); err != nil {
return err
}
}
return p.flushPath()
}
if mark.Style.BlendMode == "Multiply" {
return &pdfgo.UnsupportedError{Feature: "multiply text"}
}
@@ -130,44 +155,50 @@ func (p *pdfImporter) text(mark pdfgo.TextMark) error {
if err != nil {
return err
}
if (mark.Mode == 0 || mark.Mode == 2) && mark.Style.FillOverprint && !pdfOpaqueBlack(mark.Style.Fill) || (mark.Mode == 1 || mark.Mode == 2) && mark.Style.StrokeOverprint && !pdfOpaqueBlack(mark.Style.Stroke) {
if (mark.Mode == 0 || mark.Mode == 2) && mark.Style.FillOverprint && pdfOverprintNeedsSeparation(mark.Style.Fill) || (mark.Mode == 1 || mark.Mode == 2) && mark.Style.StrokeOverprint && pdfOverprintNeedsSeparation(mark.Style.Stroke) {
return &pdfgo.UnsupportedError{Feature: "text color separation overprint"}
}
font := mark.Font
if len(font.Program) == 0 {
return &pdfgo.UnsupportedError{Feature: "text without embedded font"}
}
if font.ProgramType != "FontFile2" && font.ProgramType != "OpenType" && font.ProgramType != "Type1C" && font.ProgramType != "CIDFontType0C" {
embedded := len(font.Program) != 0
if embedded && font.ProgramType != "FontFile2" && font.ProgramType != "OpenType" && font.ProgramType != "Type1C" && font.ProgramType != "CIDFontType0C" {
return &pdfgo.UnsupportedError{Feature: "font program " + string(font.ProgramType)}
}
id := p.fontIDs[font]
if id == "" {
var err error
program, err := pdfFontProgram(font)
if err != nil {
return err
if embedded {
program, err := pdfFontProgram(font)
if err != nil {
return err
}
id, err = p.editor.AddFont(FontFile{Name: font.Name + ".ttf", Data: program}, 0)
} else {
id, err = p.editor.AddExternalFont(font.Name)
}
id, err = p.editor.AddFont(FontFile{Name: font.Name + ".ttf", Data: program}, 0)
if err != nil {
return err
}
p.fontIDs[font] = id
}
metrics := p.fontMetrics[id]
if metrics == nil {
if p.editor.backends.Fonts == nil {
return fmt.Errorf("PDF font backend unavailable")
var metrics FontMetrics
var outline FontOutlines
if embedded {
metrics = p.fontMetrics[id]
if metrics == nil {
if p.editor.backends.Fonts == nil {
return fmt.Errorf("PDF font backend unavailable")
}
metrics, err = p.editor.backends.Fonts.OpenFont(p.editor.fonts[id].Data)
if err != nil {
return err
}
p.fontMetrics[id] = metrics
}
var err error
metrics, err = p.editor.backends.Fonts.OpenFont(p.editor.fonts[id].Data)
if err != nil {
return err
var ok bool
outline, ok = metrics.(FontOutlines)
if !ok {
return fmt.Errorf("PDF font backend does not provide glyph outlines")
}
p.fontMetrics[id] = metrics
}
outline, ok := metrics.(FontOutlines)
if !ok {
return fmt.Errorf("PDF font backend does not provide glyph outlines")
}
const unit = 25.4 / 72
m := p.matrix.Mul(mark.Matrix).Mul(pdfgo.Matrix{1 / unit, 0, 0, -1 / unit, 0, 0})
@@ -183,7 +214,7 @@ func (p *pdfImporter) text(mark pdfgo.TextMark) error {
}
glyph.Text = string(character)
}
if !glyph.HasID {
if embedded && !glyph.HasID {
if utf8.RuneCountInString(glyph.Text) != 1 {
return &pdfgo.UnsupportedError{Feature: "simple font glyph ligature mapping"}
}
@@ -193,23 +224,34 @@ func (p *pdfImporter) text(mark pdfgo.TextMark) error {
return fmt.Errorf("missing PDF glyph for %U", char)
}
}
if gid >= metrics.NumGlyphs() {
if embedded && gid >= metrics.NumGlyphs() {
return fmt.Errorf("PDF glyph index outside embedded font")
}
if !embedded && glyph.Text == "" {
return &pdfgo.UnsupportedError{Feature: "unmapped external font character"}
}
origin := mark.Positions[n]
object.TextCode = append(object.TextCode, TextCode{X: pdfNumbers(origin.X * unit), Y: pdfNumbers(-origin.Y * unit), Value: glyph.Text})
object.CGTransform = append(object.CGTransform, CGTransform{CodePosition: position, CodeCount: utf8.RuneCountInString(glyph.Text), GlyphCount: 1, Glyphs: strconv.Itoa(int(gid))})
position += utf8.RuneCountInString(glyph.Text)
path, err := outline.GlyphOutline(gid, object.Size)
if err != nil {
return err
}
bounds, err := path.Bounds()
if err != nil {
return err
}
for _, point := range []pdfgo.Point{{X: bounds.X, Y: bounds.Y}, {X: bounds.X + bounds.W, Y: bounds.Y}, {X: bounds.X, Y: bounds.Y + bounds.H}, {X: bounds.X + bounds.W, Y: bounds.Y + bounds.H}} {
points = append(points, m.Apply(pdfgo.Point{X: origin.X*unit + point.X*mark.HorizontalScale, Y: -origin.Y*unit + point.Y}))
if embedded {
count := utf8.RuneCountInString(glyph.Text)
object.CGTransform = append(object.CGTransform, CGTransform{CodePosition: position, CodeCount: count, GlyphCount: 1, Glyphs: strconv.Itoa(int(gid))})
position += count
path, err := outline.GlyphOutline(gid, object.Size)
if err != nil {
return err
}
bounds, err := path.Bounds()
if err != nil {
return err
}
for _, point := range []pdfgo.Point{{X: bounds.X, Y: bounds.Y}, {X: bounds.X + bounds.W, Y: bounds.Y}, {X: bounds.X, Y: bounds.Y + bounds.H}, {X: bounds.X + bounds.W, Y: bounds.Y + bounds.H}} {
points = append(points, m.Apply(pdfgo.Point{X: origin.X*unit + point.X*mark.HorizontalScale, Y: -origin.Y*unit + point.Y}))
}
} else {
width := glyph.Width / 1000 * object.Size * mark.HorizontalScale
for _, point := range []pdfgo.Point{{X: 0, Y: -object.Size}, {X: width, Y: -object.Size}, {X: 0, Y: object.Size / 4}, {X: width, Y: object.Size / 4}} {
points = append(points, m.Apply(pdfgo.Point{X: origin.X*unit + point.X, Y: -origin.Y*unit + point.Y}))
}
}
}
box := pdfBounds(points)
@@ -232,6 +274,9 @@ func (p *pdfImporter) text(mark pdfgo.TextMark) error {
}
}
object.Boundary = pdfBoundary(box)
if box.X >= p.pageWidth || box.Y >= p.pageHeight || box.X+box.W <= 0 || box.Y+box.H <= 0 {
visible = false
}
object.CTM = pdfNumbers(m[0], m[1], m[2], m[3], m[4]-box.X, m[5]-box.Y)
object.Fill = &fill
object.Stroke = &stroke