1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
|
// Copyright 2021 Nick White.
// Use of this source code is governed by the GPLv3
// license that can be found in the LICENSE file.
package bookpipeline
import (
"bytes"
"compress/zlib"
"errors"
"fmt"
"html"
"image"
"image/jpeg"
"image/png"
"io/ioutil"
"os"
//"github.com/phpdave11/gofpdf"
"github.com/nickjwhite/gofpdf" // adds SetCellStretchToFit function
"golang.org/x/image/draw"
"rescribe.xyz/utils/pkg/hocr"
)
// TODO: maybe set this in Fpdf struct
const pageWidth = 5.8 // pageWidth in inches - 5.8" is A5
const scaleSmaller = 3 // amount the width and height are divided by
// pxToPt converts a pixel value into a pt value (72 pts per inch)
// This uses pageWidth to determine the appropriate value
func pxToPt(i int) float64 {
return float64(i) / pageWidth
}
// Fpdf abstracts the gofpdf.Fpdf adding some useful methods
type Fpdf struct {
fpdf *gofpdf.Fpdf
}
// Setup creates a new PDF with appropriate settings and fonts
func (p *Fpdf) Setup() error {
p.fpdf = gofpdf.New("P", "pt", "A5", "")
// Even though it's invisible, we need to add a font which can do
// UTF-8 so that text renders correctly.
// We embed the font directly in the binary, compressed with zlib
c := bytes.NewBuffer(dejavucondensed)
r, err := zlib.NewReader(c)
defer r.Close()
if err != nil {
return errors.New(fmt.Sprintf("Could not open compressed font: %v", err))
}
var b bytes.Buffer
_, err = b.ReadFrom(r)
if err != nil {
return errors.New(fmt.Sprintf("Could not read compressed font: %v", err))
}
p.fpdf.AddUTF8FontFromBytes("dejavu", "", b.Bytes())
p.fpdf.SetFont("dejavu", "", 10)
p.fpdf.SetAutoPageBreak(false, float64(0))
return p.fpdf.Error()
}
// AddPage adds a page to the pdf with an image and (invisible)
// text from an hocr file
func (p *Fpdf) AddPage(imgpath, hocrpath string, smaller bool) error {
file, err := ioutil.ReadFile(hocrpath)
if err != nil {
return errors.New(fmt.Sprintf("Could not read file %s: %v", hocrpath, err))
}
h, err := hocr.Parse(file)
if err != nil {
return errors.New(fmt.Sprintf("Could not parse hocr in file %s: %v", hocrpath, err))
}
imgf, err := os.Open(imgpath)
defer imgf.Close()
if err != nil {
return errors.New(fmt.Sprintf("Could not open file %s: %v", imgpath, err))
}
img, imgtype, err := image.Decode(imgf)
if err != nil {
return errors.New(fmt.Sprintf("Could not decode image: %v", err))
}
b := img.Bounds()
if smaller {
r := image.Rect(0, 0, b.Max.X/scaleSmaller, b.Max.Y/scaleSmaller)
smimg := image.NewRGBA(r)
draw.ApproxBiLinear.Scale(smimg, r, img, b, draw.Over, nil)
img = smimg
}
var buf bytes.Buffer
if imgtype == "jpeg" {
err = jpeg.Encode(&buf, img, &jpeg.Options{Quality: jpeg.DefaultQuality})
} else {
err = png.Encode(&buf, img)
}
if err != nil {
return err
}
p.fpdf.AddPageFormat("P", gofpdf.SizeType{Wd: pxToPt(b.Dx()), Ht: pxToPt(b.Dy())})
_ = p.fpdf.RegisterImageOptionsReader(imgpath, gofpdf.ImageOptions{ImageType: imgtype}, &buf)
p.fpdf.ImageOptions(imgpath, 0, 0, pxToPt(b.Dx()), pxToPt(b.Dy()), false, gofpdf.ImageOptions{}, 0, "")
p.fpdf.SetTextRenderingMode(3)
for _, l := range h.Lines {
linecoords, err := hocr.BoxCoords(l.Title)
if err != nil {
continue
}
lineheight := pxToPt(linecoords[3] - linecoords[1])
for _, w := range l.Words {
coords, err := hocr.BoxCoords(w.Title)
if err != nil {
continue
}
p.fpdf.SetXY(pxToPt(coords[0]), pxToPt(linecoords[1]))
p.fpdf.SetCellMargin(0)
p.fpdf.SetFontSize(lineheight)
cellW := pxToPt(coords[2] - coords[0])
cellText := html.UnescapeString(w.Text)
p.fpdf.SetCellStretchToFit(cellW, cellText)
// Adding a space after each word causes fewer line breaks to
// be erroneously inserted when copy pasting from the PDF, for
// some reason.
p.fpdf.CellFormat(cellW, lineheight, cellText + " ", "", 0, "T", false, 0, "")
}
}
return p.fpdf.Error()
}
// Save saves the PDF to the file at path
func (p *Fpdf) Save(path string) error {
return p.fpdf.OutputFileAndClose(path)
}
|
