84 lines
2 KiB
Go
84 lines
2 KiB
Go
package d2latex
|
|
|
|
import (
|
|
_ "embed"
|
|
"fmt"
|
|
"math"
|
|
"regexp"
|
|
"strconv"
|
|
|
|
"oss.terrastruct.com/d2/lib/jsrunner"
|
|
"oss.terrastruct.com/util-go/xdefer"
|
|
)
|
|
|
|
var pxPerEx = 8
|
|
|
|
//go:embed polyfills.js
|
|
var polyfillsJS string
|
|
|
|
//go:embed setup.js
|
|
var setupJS string
|
|
|
|
//go:embed mathjax.js
|
|
var mathjaxJS string
|
|
|
|
// Matches this
|
|
// <svg style="background: white;" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="563" height="326" viewBox="-100 -100 563 326"><style type="text/css">
|
|
var svgRe = regexp.MustCompile(`<svg[^>]+width="([0-9\.]+)ex" height="([0-9\.]+)ex"[^>]+>`)
|
|
|
|
func Render(s string) (_ string, err error) {
|
|
defer xdefer.Errorf(&err, "latex failed to parse")
|
|
runner := jsrunner.NewJSRunner()
|
|
|
|
if _, err := runner.RunString(polyfillsJS); err != nil {
|
|
return "", err
|
|
}
|
|
|
|
if _, err := runner.RunString(mathjaxJS); err != nil {
|
|
// Known issue that a harmless error occurs in JS: https://github.com/mathjax/MathJax/issues/3289
|
|
if runner.Engine() == jsrunner.Goja {
|
|
return "", err
|
|
}
|
|
}
|
|
|
|
if _, err := runner.RunString(setupJS); err != nil {
|
|
return "", err
|
|
}
|
|
|
|
val, err := runner.RunString(fmt.Sprintf(`adaptor.innerHTML(html.convert(`+"`"+"%s`"+`, {
|
|
em: %d,
|
|
ex: %d,
|
|
}))`, s, pxPerEx*2, pxPerEx))
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
|
|
return val.String(), nil
|
|
}
|
|
|
|
func Measure(s string) (width, height int, err error) {
|
|
defer xdefer.Errorf(&err, "latex failed to parse")
|
|
svg, err := Render(s)
|
|
if err != nil {
|
|
return 0, 0, err
|
|
}
|
|
|
|
dims := svgRe.FindAllStringSubmatch(svg, -1)
|
|
if len(dims) != 1 || len(dims[0]) != 3 {
|
|
return 0, 0, fmt.Errorf("svg parsing failed for latex: %v", svg)
|
|
}
|
|
|
|
wEx := dims[0][1]
|
|
hEx := dims[0][2]
|
|
|
|
wf, err := strconv.ParseFloat(wEx, 64)
|
|
if err != nil {
|
|
return 0, 0, fmt.Errorf("svg parsing failed for latex: %v", svg)
|
|
}
|
|
hf, err := strconv.ParseFloat(hEx, 64)
|
|
if err != nil {
|
|
return 0, 0, fmt.Errorf("svg parsing failed for latex: %v", svg)
|
|
}
|
|
|
|
return int(math.Ceil(wf * float64(pxPerEx))), int(math.Ceil(hf * float64(pxPerEx))), nil
|
|
}
|