From f8cf25ca565ba96ea4e84b711d8c1460c1ec69d7 Mon Sep 17 00:00:00 2001
From: Lovell Fuller <github@lovell.info>
Date: Thu, 5 Oct 2023 14:05:36 +0100
Subject: [PATCH] Ensure correct interp of 16-bit raw input #3808

---
 docs/changelog.md |  3 +++
 src/common.cc     |  5 +++--
 test/unit/raw.js  | 38 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/docs/changelog.md b/docs/changelog.md
index 6606c16a..6bbd42c5 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -13,6 +13,9 @@ Requires libvips v8.14.5
 * Make `compression` option of `heif` mandatory to help reduce HEIF vs HEIC confusion.
   [#3740](https://github.com/lovell/sharp/issues/3740)
 
+* Ensure correct interpretation of 16-bit raw input.
+  [#3808](https://github.com/lovell/sharp/issues/3808)
+
 ## v0.32 - *flow*
 
 Requires libvips v8.14.5
diff --git a/src/common.cc b/src/common.cc
index 9e2eacde..3b6b2827 100644
--- a/src/common.cc
+++ b/src/common.cc
@@ -363,12 +363,13 @@ namespace sharp {
     if (descriptor->isBuffer) {
       if (descriptor->rawChannels > 0) {
         // Raw, uncompressed pixel data
+        bool const is8bit = vips_band_format_is8bit(descriptor->rawDepth);
         image = VImage::new_from_memory(descriptor->buffer, descriptor->bufferLength,
           descriptor->rawWidth, descriptor->rawHeight, descriptor->rawChannels, descriptor->rawDepth);
         if (descriptor->rawChannels < 3) {
-          image.get_image()->Type = VIPS_INTERPRETATION_B_W;
+          image.get_image()->Type = is8bit ? VIPS_INTERPRETATION_B_W : VIPS_INTERPRETATION_GREY16;
         } else {
-          image.get_image()->Type = VIPS_INTERPRETATION_sRGB;
+          image.get_image()->Type = is8bit ? VIPS_INTERPRETATION_sRGB : VIPS_INTERPRETATION_RGB16;
         }
         if (descriptor->rawPremultiplied) {
           image = image.unpremultiply();
diff --git a/test/unit/raw.js b/test/unit/raw.js
index 7976ccd4..7ad24012 100644
--- a/test/unit/raw.js
+++ b/test/unit/raw.js
@@ -284,4 +284,42 @@ describe('Raw pixel data', function () {
       );
     }
   });
+
+  describe('16-bit roundtrip', () => {
+    it('grey', async () => {
+      const grey = 42000;
+      const png = await sharp(
+        Uint16Array.from([grey]),
+        { raw: { width: 1, height: 1, channels: 1 } }
+      )
+        .toColourspace('grey16')
+        .png({ compressionLevel: 0 })
+        .toBuffer();
+      const raw = await sharp(png)
+        .toColourspace('grey16')
+        .raw({ depth: 'ushort' })
+        .toBuffer();
+
+      assert.strictEqual(raw.readUint16LE(0), grey);
+    });
+
+    it('RGB', async () => {
+      const rgb = [10946, 28657, 46368];
+      const png = await sharp(
+        Uint16Array.from(rgb),
+        { raw: { width: 1, height: 1, channels: 3 } }
+      )
+        .toColourspace('rgb16')
+        .png({ compressionLevel: 0 })
+        .toBuffer();
+      const raw = await sharp(png)
+        .toColourspace('rgb16')
+        .raw({ depth: 'ushort' })
+        .toBuffer();
+
+      assert.strictEqual(raw.readUint16LE(0), rgb[0]);
+      assert.strictEqual(raw.readUint16LE(2), rgb[1]);
+      assert.strictEqual(raw.readUint16LE(4), rgb[2]);
+    });
+  });
 });