tpl/images: Add images.QR function

Closes #13205

tpl/images/images.go

@@ -16,11 +16,18 @@ package images
 
 import (
 	"errors"
+	"fmt"
 	"image"
+	"path"
 	"sync"
 
 	"github.com/bep/overlayfs"
+	"github.com/gohugoio/hugo/common/hashing"
+	"github.com/gohugoio/hugo/common/hugio"
 	"github.com/gohugoio/hugo/resources/images"
+	"github.com/gohugoio/hugo/resources/resource_factories/create"
+	"github.com/mitchellh/mapstructure"
+	"rsc.io/qr"
 
 	// Importing image codecs for image.DecodeConfig
 	_ "image/gif"
@@ -50,21 +57,22 @@ func New(d *deps.Deps) *Namespace {
 	}
 
 	return &Namespace{
-		readFileFs: readFileFs,
-		Filters:    &images.Filters{},
-		cache:      map[string]image.Config{},
-		deps:       d,
+		readFileFs:   readFileFs,
+		Filters:      &images.Filters{},
+		cache:        map[string]image.Config{},
+		deps:         d,
+		createClient: create.New(d.ResourceSpec),
 	}
 }
 
 // Namespace provides template functions for the "images" namespace.
 type Namespace struct {
 	*images.Filters
-	readFileFs afero.Fs
-	cacheMu    sync.RWMutex
-	cache      map[string]image.Config
-
-	deps *deps.Deps
+	readFileFs   afero.Fs
+	cacheMu      sync.RWMutex
+	cache        map[string]image.Config
+	deps         *deps.Deps
+	createClient *create.Client
 }
 
 // Config returns the image.Config for the specified path relative to the
@@ -117,3 +125,77 @@ func (ns *Namespace) Filter(args ...any) (images.ImageResource, error) {
 
 	return img.Filter(filtersv...)
 }
+
+var qrErrorCorrectionLevels = map[string]qr.Level{
+	"low":      qr.L,
+	"medium":   qr.M,
+	"quartile": qr.Q,
+	"high":     qr.H,
+}
+
+// QR encodes the given text into a QR code using the specified options,
+// returning an image resource.
+func (ns *Namespace) QR(options any) (images.ImageResource, error) {
+	const (
+		qrDefaultErrorCorrectionLevel = "medium"
+		qrDefaultScale                = 4
+	)
+
+	opts := struct {
+		Text      string // text to encode
+		Level     string // error correction level; one of low, medium, quartile, or high
+		Scale     int    // number of image pixels per QR code module
+		TargetDir string // target directory relative to publishDir
+	}{
+		Level: qrDefaultErrorCorrectionLevel,
+		Scale: qrDefaultScale,
+	}
+
+	err := mapstructure.WeakDecode(options, &opts)
+	if err != nil {
+		return nil, err
+	}
+
+	if opts.Text == "" {
+		return nil, errors.New("cannot encode an empty string")
+	}
+
+	level, ok := qrErrorCorrectionLevels[opts.Level]
+	if !ok {
+		return nil, errors.New("error correction level must be one of low, medium, quartile, or high")
+	}
+
+	if opts.Scale < 2 {
+		return nil, errors.New("scale must be an integer greater than or equal to 2")
+	}
+
+	targetPath := path.Join(opts.TargetDir, fmt.Sprintf("qr_%s.png", hashing.HashString(opts)))
+
+	r, err := ns.createClient.FromOpts(
+		create.Options{
+			TargetPath:        targetPath,
+			TargetPathHasHash: true,
+			CreateContent: func() (func() (hugio.ReadSeekCloser, error), error) {
+				code, err := qr.Encode(opts.Text, level)
+				if err != nil {
+					return nil, err
+				}
+				code.Scale = opts.Scale
+				png := code.PNG()
+				return func() (hugio.ReadSeekCloser, error) {
+					return hugio.NewReadSeekerNoOpCloserFromBytes(png), nil
+				}, nil
+			},
+		},
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	ir, ok := r.(images.ImageResource)
+	if !ok {
+		panic("bug: resource is not an image resource")
+	}
+
+	return ir, nil
+}

tpl/images/images_integration_test.go

@@ -14,8 +14,10 @@
 package images_test
 
 import (
+	"strings"
 	"testing"
 
+	qt "github.com/frankban/quicktest"
 	"github.com/gohugoio/hugo/hugolib"
 )
 
@@ -49,3 +51,52 @@ fileExists2 OK: true|
 imageConfig2 OK: 1|
 `)
 }
+
+func TestQR(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- hugo.toml --
+disableKinds = ['page','rss','section','sitemap','taxonomy','term']
+-- layouts/index.html --
+{{- $text := "https://gohugo.io" }}
+{{- $optionMaps := slice
+    (dict "text" $text)
+    (dict "text" $text "level" "medium")
+    (dict "text" $text "level" "medium" "scale" 4)
+    (dict "text" $text "level" "low" "scale" 2)
+    (dict "text" $text "level" "medium" "scale" 3)
+    (dict "text" $text "level" "quartile" "scale" 5)
+    (dict "text" $text "level" "high" "scale" 6)
+    (dict "text" $text "level" "high" "scale" 6 "targetDir" "foo/bar")
+}}
+{{- range $k, $opts := $optionMaps }}
+    {{- with images.QR $opts }}
+<img data-id="{{ $k }}" data-img-hash="{{ .Content | hash.XxHash }}" data-level="{{ $opts.level }}" data-scale="{{ $opts.scale }}" data-targetDir="{{ $opts.targetDir }}" src="{{ .RelPermalink }}">
+    {{- end }}
+{{- end }}
+`
+
+	b := hugolib.Test(t, files)
+	b.AssertFileContent("public/index.html",
+		`<img data-id="0" data-img-hash="6ccacf8056c41475" data-level="" data-scale="" data-targetDir="" src="/qr_3891606335523452031.png">`,
+		`<img data-id="1" data-img-hash="6ccacf8056c41475" data-level="medium" data-scale="" data-targetDir="" src="/qr_3891606335523452031.png">`,
+		`<img data-id="2" data-img-hash="6ccacf8056c41475" data-level="medium" data-scale="4" data-targetDir="" src="/qr_3891606335523452031.png">`,
+		`<img data-id="3" data-img-hash="c29338c3d105b156" data-level="low" data-scale="2" data-targetDir="" src="/qr_2532593520456080065.png">`,
+		`<img data-id="4" data-img-hash="8f7a639cea917b0e" data-level="medium" data-scale="3" data-targetDir="" src="/qr_6630115934366238432.png">`,
+		`<img data-id="5" data-img-hash="2d15d6dcb861b5da" data-level="quartile" data-scale="5" data-targetDir="" src="/qr_14167719016579496966.png">`,
+		`<img data-id="6" data-img-hash="113c45f2c091bc4d" data-level="high" data-scale="6" data-targetDir="" src="/qr_1700475212608554630.png">`,
+		`<img data-id="7" data-img-hash="113c45f2c091bc4d" data-level="high" data-scale="6" data-targetDir="foo/bar" src="/foo/bar/qr_12381230670040458986.png">`,
+	)
+
+	files = strings.ReplaceAll(files, "low", "foo")
+
+	b, err := hugolib.TestE(t, files)
+	b.Assert(err.Error(), qt.Contains, "error correction level must be one of low, medium, quartile, or high")
+
+	files = strings.ReplaceAll(files, "foo", "low")
+	files = strings.ReplaceAll(files, "https://gohugo.io", "")
+
+	b, err = hugolib.TestE(t, files)
+	b.Assert(err.Error(), qt.Contains, "cannot encode an empty string")
+}