From 513d2ae9063440ca1d44288f783732c2133f55f9 Mon Sep 17 00:00:00 2001
From: David Vogel <Dadido3@aol.com>
Date: Tue, 4 Nov 2025 23:17:17 +0100
Subject: [PATCH] Add ability to encode raw byte slices as Typst images

---
 README.md           |   3 ++-
 image.go            |  25 ++++++++++++++++++++++++-
 image_test.go       |  27 +++++++++++++++++++++++++++
 test-files/test.png | Bin 0 -> 405 bytes
 4 files changed, 53 insertions(+), 2 deletions(-)
 create mode 100644 test-files/test.png

diff --git a/README.md b/README.md
index 5a88616..57762a6 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,8 @@ Use at your own discretion for production systems.
 
 - PDF, SVG and PNG generation.
 - All Typst parameters are discoverable and documented in [cli-options.go](cli-options.go).
-- Go-to-Typst Value Encoder: Seamlessly inject any Go values (Including `image.Image` with a [wrapper](image.go)) into Typst documents via the provided encoder.
+- Go-to-Typst Value Encoder: Seamlessly inject any Go values.
+- Encode and inject images as a Typst markup simply by [wrapping](image.go) `image.Image` types or byte slices with raw JPEG or PNG data.
 - Errors from Typst CLI are returned as structured Go error objects with detailed information, such as line numbers and file paths.
 - Uses stdio; No temporary files will be created.
 - Good unit test coverage.
diff --git a/image.go b/image.go
index 4d0263c..7024a59 100644
--- a/image.go
+++ b/image.go
@@ -15,7 +15,10 @@ import (
 
 // Image can be used to encode any image.Image into a Typst image.
 //
-// For this, just wrap any image.Image with this type before passing it to MarshalValue or a ValueEncoder.
+// For this, just wrap any image.Image with this type before passing it to MarshalValue or a ValueEncoder:
+//
+//	typstImage := typst.Image{img}
+//	typst.InjectValues(&r, map[string]any{"TestImage": typstImage})
 type Image struct{ image.Image }
 
 func (i Image) MarshalTypstValue() ([]byte, error) {
@@ -38,3 +41,23 @@ func (i Image) MarshalTypstValue() ([]byte, error) {
 
 	return buf.Bytes(), nil
 }
+
+// ImageRaw can be used to pass the raw data of any image to Typst.
+// This will pass the raw byte values of a PNG, JPEG or any other image format that is supported by Typst.
+//
+// For this, just wrap any byte slice with this type before passing it to MarshalValue or a ValueEncoder:
+//
+//	typstImage := typst.ImageRaw(bufferPNG)
+//	typst.InjectValues(&r, map[string]any{"TestImage": typstImage})
+type ImageRaw []byte
+
+func (i ImageRaw) MarshalTypstValue() ([]byte, error) {
+	var buf bytes.Buffer
+	buf.WriteString("image.decode(bytes((") // TODO: Pass bytes directly to image once Typst 0.12.0 is not supported anymore
+	for _, b := range i {
+		buf.WriteString(strconv.FormatUint(uint64(b), 10) + ",")
+	}
+	buf.WriteString(")))")
+
+	return buf.Bytes(), nil
+}
diff --git a/image_test.go b/image_test.go
index 1a35826..3089fad 100644
--- a/image_test.go
+++ b/image_test.go
@@ -7,6 +7,7 @@ package typst_test
 
 import (
 	"bytes"
+	_ "embed"
 	"image"
 	"image/color"
 	"io"
@@ -61,3 +62,29 @@ func TestImage(t *testing.T) {
 		t.Fatalf("Failed to compile document: %v.", err)
 	}
 }
+
+//go:embed test-files/test.png
+var testPNG []byte
+
+func TestImageRaw(t *testing.T) {
+	// Wrap image.
+	typstImage := typst.ImageRaw(testPNG)
+
+	cli := typst.CLI{}
+
+	var r bytes.Buffer
+
+	if err := typst.InjectValues(&r, map[string]any{"TestImage": typstImage}); err != nil {
+		t.Fatalf("Failed to inject values into Typst markup: %v.", err)
+	}
+
+	r.WriteString(`= Image test
+
+#TestImage
+
+#assert(type(TestImage) == content, message: "TestImage is not of expected type: got " + str(type(TestImage)) + ", want content")`) // TODO: Add another assertion for the image width and height as soon as it's possible to query that
+
+	if err := cli.Compile(&r, io.Discard, nil); err != nil {
+		t.Fatalf("Failed to compile document: %v.", err)
+	}
+}
diff --git a/test-files/test.png b/test-files/test.png
new file mode 100644
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GIT binary patch
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