Skip to content

Fix iOS pixel format label for default byte order #159

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
mrousavy wants to merge 2 commits into
base: main
Choose a base branch
from
Open

Fix iOS pixel format label for default byte order #159

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
24005d0
fix: label iOS pixel format correctly for default byte order
mrousavy Jul 23, 2026
a1cb6d5
Merge branch 'main' into fix/ios-pixel-format-byte-order
mrousavy Jul 23, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
13 changes: 9 additions & 4 deletions packages/react-native-nitro-image/ios/Extensions/CGImage+getPixelFormat.swift
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -12,8 +12,11 @@ extension CGImage {
private var isLittleEndian: Bool {
switch self.byteOrderInfo {
case .orderDefault:
// iOS uses little endian by default
return true
// The "default" byte order has big-endian semantics: components are stored
// in memory in exactly the order alphaInfo names them - e.g. premultipliedLast
// + orderDefault is physically [R, G, B, A] bytes. This is a property of the
// Core Graphics format description, unrelated to the host CPU's endianness.
return false
case .order16Little, .order32Little:
return true
case .order16Big, .order32Big:
Expand All @@ -37,10 +40,12 @@ extension CGImage {
// ___A
return self.isLittleEndian ? .abgr : .rgba
case .noneSkipFirst:
// X___
// X___ - the padding byte is reported as alpha on purpose: Apple's decoders
// and renderers fill it with 0xFF, so the bytes read correctly as opaque alpha,
// and consumers don't need to special-case the X formats.
return self.isLittleEndian ? .bgra : .argb
case .noneSkipLast:
// ___X
// ___X - see above, reported as alpha on purpose.
return self.isLittleEndian ? .abgr : .rgba
case .none:
// ___
Expand Down
Loading