Fix cursor color swap from wrong XCursor pixel format#49
Merged
malbiruk merged 2 commits intomalbiruk:mainfrom Apr 20, 2026
Merged
Fix cursor color swap from wrong XCursor pixel format#49malbiruk merged 2 commits intomalbiruk:mainfrom
malbiruk merged 2 commits intomalbiruk:mainfrom
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The xcursor crate's `Image::pixels_rgba` field is misleadingly named: bytes come straight from the XCursor file, which stores pixels as uint32 ARGB little-endian — i.e. [B, G, R, A] in memory. The matching DRM fourcc for that byte order is Argb8888 (smithay maps it to GL BGRA_EXT), not Abgr8888 (which maps to GL RGBA and causes R/B to swap on screen). niri uses the correct pairing at src/cursor.rs:255-257. Adopt the same.
The field name suggests RGBA but the bytes are in [B, G, R, A] memory order (XCursor file layout). Record the trap so future contributors don't reintroduce the Fourcc mismatch that caused cursor R/B swap.
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Changes
In
load_xcursor, tag theMemoryRenderBufferwithFourcc::Argb8888instead ofAbgr8888. Also add a CAVEATS note on thexcursor::pixels_rgbamisnomer so the trap doesn't come back.Purpose
The
xcursorcrate'spixels_rgbafield is misleadingly named — bytes are actually in[B, G, R, A]memory order (XCursor file layout: uint32 ARGB little-endian). Pairing that withFourcc::Abgr8888makes smithay upload the texture as GL(RGBA, UNSIGNED_BYTE), swapping R and B on screen. niri pairspixels_rgbawithFourcc::Argb8888insrc/cursor.rs:255-257; adopt the same.Reproduced on two machines with different GPUs/drivers. Verified after the fix against yellow/red/lavender themes — all render correctly.
Fixes #48