mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-29 17:27:08 +08:00
330 lines
11 KiB
Go
330 lines
11 KiB
Go
// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package ofdgo
|
|
|
|
import (
|
|
"bytes"
|
|
"encoding/binary"
|
|
"fmt"
|
|
"image"
|
|
"image/color"
|
|
"image/png"
|
|
"math"
|
|
"strconv"
|
|
"unicode/utf16"
|
|
"unicode/utf8"
|
|
|
|
"github.com/xiaoqidun/pdfgo"
|
|
)
|
|
|
|
// image 转换图像样本，不将整页或其他对象栅格化
|
|
// 入参: mark PDF图像绘制信息
|
|
// 返回: error 错误信息
|
|
func (p *pdfImporter) image(mark pdfgo.ImageMark) error {
|
|
if err := p.flushPath(); err != nil {
|
|
return err
|
|
}
|
|
if mark.Image.ImageMask && mark.Style.Fill.Axial != nil {
|
|
return &pdfgo.UnsupportedError{Feature: "gradient stencil image"}
|
|
}
|
|
var err error
|
|
mark.Style, err = p.maskStyle(mark.Style)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if mark.Style.FillOverprint {
|
|
return &pdfgo.UnsupportedError{Feature: "image color separation overprint"}
|
|
}
|
|
source := mark.Image
|
|
id := p.imageIDs[source.Stream]
|
|
if source.ImageMask {
|
|
id = ""
|
|
}
|
|
if id == "" {
|
|
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
|
|
}
|
|
if source.ImageMask {
|
|
if mark.Style.Fill.CMYK != nil {
|
|
return &pdfgo.UnsupportedError{Feature: "CMYK stencil image"}
|
|
}
|
|
stencil := image.NewNRGBA64(image.Rect(0, 0, source.Width, source.Height))
|
|
fill := mark.Style.Fill.RGB
|
|
for y := 0; y < source.Height; y++ {
|
|
for x := 0; x < source.Width; x++ {
|
|
gray, _, _, _ := decoded.At(x, y).RGBA()
|
|
stencil.SetNRGBA64(x, y, color.NRGBA64{
|
|
R: uint16(math.Round(fill[0] * 65535)),
|
|
G: uint16(math.Round(fill[1] * 65535)),
|
|
B: uint16(math.Round(fill[2] * 65535)),
|
|
A: uint16(65535 - gray),
|
|
})
|
|
}
|
|
}
|
|
decoded = stencil
|
|
}
|
|
var encoded bytes.Buffer
|
|
if jpegOriginal {
|
|
encoded.Write(source.Stream.Data)
|
|
} else {
|
|
if err := png.Encode(&encoded, decoded); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
id, err = p.editor.AddImage(encoded.Bytes())
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if !source.ImageMask {
|
|
if p.imageIDs == nil {
|
|
p.imageIDs = map[*pdfgo.Stream]string{}
|
|
}
|
|
p.imageIDs[source.Stream] = id
|
|
}
|
|
}
|
|
m := p.matrix.Mul(mark.Matrix).Mul(pdfgo.Matrix{1, 0, 0, -1, 0, 1})
|
|
box := pdfBounds([]pdfgo.Point{m.Apply(pdfgo.Point{}), m.Apply(pdfgo.Point{X: 1}), m.Apply(pdfgo.Point{Y: 1}), m.Apply(pdfgo.Point{X: 1, Y: 1})})
|
|
alpha := int(math.Round(mark.Style.Fill.Alpha * 255))
|
|
object := ImageObject{Boundary: pdfBoundary(box), ResourceID: id, CTM: pdfNumbers(m[0], m[1], m[2], m[3], m[4]-box.X, m[5]-box.Y), Alpha: &alpha, Clips: p.clips(mark.Style.Clips, box)}
|
|
p.objects = append(p.objects, GraphicObject{Type: "ImageObject", ImageObject: object})
|
|
p.report.ImageObjects++
|
|
return nil
|
|
}
|
|
|
|
// text 保留原字体、字形编号与逐字基线，不重新塑形
|
|
// 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 err := p.flushPath(); err != nil {
|
|
return err
|
|
}
|
|
if mark.Style.Fill.Axial != nil || mark.Style.Stroke.Axial != nil {
|
|
return &pdfgo.UnsupportedError{Feature: "gradient text paint"}
|
|
}
|
|
var err error
|
|
mark.Style, err = p.maskStyle(mark.Style)
|
|
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) {
|
|
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" {
|
|
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
|
|
}
|
|
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 err error
|
|
metrics, err = p.editor.backends.Fonts.OpenFont(p.editor.fonts[id].Data)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
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})
|
|
var points []pdfgo.Point
|
|
object := TextObject{Font: id, Size: mark.Size * unit, HScale: mark.HorizontalScale}
|
|
position := 0
|
|
for n, glyph := range mark.Glyphs {
|
|
gid := glyph.ID
|
|
if glyph.Text == "" && glyph.HasID {
|
|
character := getUnicodeFromName(glyph.Name)
|
|
if character == 0 {
|
|
character = packedGlyphRune(gid)
|
|
}
|
|
glyph.Text = string(character)
|
|
}
|
|
if !glyph.HasID {
|
|
if utf8.RuneCountInString(glyph.Text) != 1 {
|
|
return &pdfgo.UnsupportedError{Feature: "simple font glyph ligature mapping"}
|
|
}
|
|
char, _ := utf8.DecodeRuneInString(glyph.Text)
|
|
gid = metrics.GlyphIndex(char)
|
|
if gid == 0 && char != 0 {
|
|
return fmt.Errorf("missing PDF glyph for %U", char)
|
|
}
|
|
}
|
|
if gid >= metrics.NumGlyphs() {
|
|
return fmt.Errorf("PDF glyph index outside embedded font")
|
|
}
|
|
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}))
|
|
}
|
|
}
|
|
box := pdfBounds(points)
|
|
fill, stroke, visible := mark.Mode == 0 || mark.Mode == 2, mark.Mode == 1 || mark.Mode == 2, mark.Mode != 3
|
|
if stroke {
|
|
margin := mark.Style.LineWidth * unit * math.Hypot(m[0], m[1]) / 2 * math.Max(1, mark.Style.MiterLimit)
|
|
box = Box{box.X - margin, box.Y - margin, box.W + 2*margin, box.H + 2*margin}
|
|
color := StrokeColor(*p.color(mark.Style.Stroke))
|
|
object.StrokeColor = &color
|
|
object.LineWidth = mark.Style.LineWidth * unit
|
|
object.LineWidthSet = object.LineWidth == 0
|
|
object.Join = []string{"Miter", "Round", "Bevel"}[mark.Style.Join]
|
|
object.MiterLimit = mark.Style.MiterLimit
|
|
if len(mark.Style.Dash) > 0 {
|
|
return &pdfgo.UnsupportedError{Feature: "dashed text stroke"}
|
|
}
|
|
}
|
|
object.Boundary = pdfBoundary(box)
|
|
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
|
|
object.Visible = &visible
|
|
object.FillColor = p.color(mark.Style.Fill)
|
|
object.Clips = p.clips(mark.Style.Clips, box)
|
|
p.objects = append(p.objects, GraphicObject{Type: "TextObject", TextObject: object})
|
|
p.report.TextObjects++
|
|
return nil
|
|
}
|
|
|
|
// pdfFontProgram 为PDF子集字体补齐封装表，保留字形轮廓和编号
|
|
// 入参: source PDF字体
|
|
// 返回: []byte 封装后的字体数据, error 错误信息
|
|
func pdfFontProgram(source *pdfgo.Font) ([]byte, error) {
|
|
program := source.Program
|
|
if source.ProgramType == "Type1C" || source.ProgramType == "CIDFontType0C" {
|
|
var err error
|
|
program, _, err = wrapCFFToOTF(source.Program)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
tables, err := fontFileTables(program, 0)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if len(tables["head"]) < 54 || len(tables["maxp"]) < 6 || len(tables["hhea"]) < 36 || len(tables["hmtx"]) == 0 {
|
|
return nil, fmt.Errorf("embedded PDF font lacks required metrics")
|
|
}
|
|
count := binary.BigEndian.Uint16(tables["maxp"][4:6])
|
|
if count == 0 {
|
|
return nil, fmt.Errorf("embedded PDF font has no glyphs")
|
|
}
|
|
changed := false
|
|
metrics := int(binary.BigEndian.Uint16(tables["hhea"][34:36]))
|
|
if metrics == 0 || metrics > int(count) {
|
|
return nil, fmt.Errorf("invalid embedded PDF font metric count")
|
|
}
|
|
metricLength := 4*metrics + 2*(int(count)-metrics)
|
|
if len(tables["hmtx"]) < metricLength {
|
|
return nil, fmt.Errorf("incomplete embedded PDF font metrics")
|
|
}
|
|
if len(tables["hmtx"]) > metricLength {
|
|
tables["hmtx"] = tables["hmtx"][:metricLength]
|
|
changed = true
|
|
}
|
|
if len(tables["cmap"]) == 0 {
|
|
mapping := map[rune]uint16{}
|
|
for code := range source.Unicode {
|
|
glyphs, err := source.Decode([]byte(code))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if len(glyphs) != 1 || !glyphs[0].HasID {
|
|
return nil, &pdfgo.UnsupportedError{Feature: "font without explicit glyph mapping"}
|
|
}
|
|
glyph := glyphs[0]
|
|
if utf8.RuneCountInString(glyph.Text) == 1 {
|
|
char, _ := utf8.DecodeRuneInString(glyph.Text)
|
|
if _, exists := mapping[char]; !exists {
|
|
mapping[char] = glyph.ID
|
|
}
|
|
}
|
|
}
|
|
addPackedGlyphMapping(mapping, count)
|
|
tables["cmap"] = buildCmapTable(count, mapping)
|
|
changed = true
|
|
}
|
|
if len(fontNamesFromTable(tables["name"])) == 0 {
|
|
name := utf16.Encode([]rune(source.Name))
|
|
if len(name) == 0 || len(name) > 32767 {
|
|
return nil, fmt.Errorf("PDF font name missing or excessive")
|
|
}
|
|
data := make([]byte, 42+len(name)*2)
|
|
binary.BigEndian.PutUint16(data[2:], 3)
|
|
binary.BigEndian.PutUint16(data[4:], 42)
|
|
for n, id := range []uint16{1, 4, 6} {
|
|
record := data[6+n*12:]
|
|
binary.BigEndian.PutUint16(record, 3)
|
|
binary.BigEndian.PutUint16(record[2:], 1)
|
|
binary.BigEndian.PutUint16(record[4:], 0x409)
|
|
binary.BigEndian.PutUint16(record[6:], id)
|
|
binary.BigEndian.PutUint16(record[8:], uint16(len(name)*2))
|
|
}
|
|
for n, v := range name {
|
|
binary.BigEndian.PutUint16(data[42+n*2:], v)
|
|
}
|
|
tables["name"] = data
|
|
changed = true
|
|
}
|
|
if len(tables["post"]) == 0 {
|
|
tables["post"] = buildPostTable()
|
|
changed = true
|
|
}
|
|
if len(tables["OS/2"]) == 0 {
|
|
hhea := tables["hhea"]
|
|
tables["OS/2"] = buildOS2TableWithMetrics(int16(binary.BigEndian.Uint16(hhea[4:6])), int16(binary.BigEndian.Uint16(hhea[6:8])))
|
|
changed = true
|
|
}
|
|
if !changed {
|
|
return program, nil
|
|
}
|
|
return serializeOTF(tables)
|
|
}
|