Fail to render with OTF font

[nobe4]

Hi 👋

I couldn't make a simple program working with an OTF font.

I used: https://velvetyne.fr/download/?font=karrik

Code sample:

package main

import (
	"fmt"

	"github.com/go-pdf/fpdf"
)

func main() {
	pdf := fpdf.New("P", "mm", "A4", ".")
	pdf.AddUTF8Font("f", "B", "./Karrik-Regular.otf")

	pdf.AddPage()
	pdf.SetFont("f", "B", 20)
	pdf.Write(10, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz")

	err := pdf.OutputFileAndClose("hello.pdf")
	if err != nil {
		fmt.Printf("Error: %#v\n", err)
	}
}

I get the following error:

panic: runtime error: index out of range [65] with length 0                                       
                                                                                                  
goroutine 1 [running]:                                                                            
github.com/go-pdf/fpdf.(*Fpdf).write(0xc00013c008, 0x4024000000000000, {0x573ba3?, 0x5a4ee0?}, 0x0
, {0x0, 0x0})                                                                                     
        /home/n/go/pkg/mod/github.com/go-pdf/fpdf@v0.9.0/fpdf.go:3074 +0xb9f                      
github.com/go-pdf/fpdf.(*Fpdf).Write(...)                                                         
        /home/n/go/pkg/mod/github.com/go-pdf/fpdf@v0.9.0/fpdf.go:3136                             
main.main()                                                                                       
        /home/n/dev/fontly/main.go:15 +0xf8                                                       
exit status 2                                                                                     
                                                                                                  
shell returned 1

Which corresponds to:

fpdf/fpdf.go

Line 3077 in 9e977fe

l += float64(cw[int(c)])

(the line number is different locally, but it's this one)

Using delve to step through the program, it seems that arriving here, the cw is empty:

(dlv) l
> [Breakpoint 1] github.com/go-pdf/fpdf.(*Fpdf).write() /home/n/go/pkg/mod/github.com/go-pdf/fpdf@v0.9.0/fpdf.go:3074 (hits goroutine(1):1 total:1) (PC: 0x58c1f8)
  3069:				continue
  3070:			}
  3071:			if c == ' ' {
  3072:				sep = i
  3073:			}
=>3074:			l += float64(cw[int(c)])
  3075:			if l > wmax {
  3076:				// Automatic line break
  3077:				if sep == -1 {
  3078:					if f.x > f.lMargin {
  3079:						// Move to next line
(dlv) p c 
65
(dlv) p cw
[]int len: 0, cap: 0, nil

cw is just a copy of f.currentFont.Cw, so the current font character width.

fpdf/fpdf.go

Line 3028 in 9e977fe

cw := f.currentFont.Cw

If I instead use pdf.SetFont("Arial", "B", 16) or a random TTF font:

(dlv) p cw
[]int len: 256, cap: 256, [278,278,278,278,278,278,278,278,278,278,278,278,278,278,278,278,278,278,278,278,278,278,278,278,278,278,278,278,278,278,278,278,278,333,474,556,556,889,722,238,333,333,389,584,278,333,278,278,556,556,556,556,556,556,556,556,556,556,333,333,584,584,584,611,...+192 more]

Can you have a look as to why this (and other OTF) font aren't loaded correctly?

[nobe4]

Ah, after looking at the error, it seems that I get a generic message:

	pdf.AddUTF8Font("f", "B", "./Karrik-Regular.otf")
	if pdf.Error() != nil {
		fmt.Printf("Error: %#v\n", pdf.Error())
	}

Error:

Error: &errors.errorString{s:"not supported\n "}

🤔

Does that mean that I need first to run makefont before I load an OTF font?

[nobe4]

New try with the cp1252.map found in this repo:

func main() {
	err := fpdf.MakeFont("./Karrik-Regular.otf", "./cp1252.map", "./font-out", os.Stdout, false)
	if err != nil {
		panic(err)
	}
}

result:

panic: fonts based on PostScript outlines are not supported