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[Linux] Keep the frame at the top of a resizing subsurface - #192408
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This pull request adjusts the Linux subsurface EGL platform code to correctly position frames when the EGL surface size differs from the frame size, addressing the vertical origin discrepancy between OpenGL and Wayland. It queries surface dimensions after resizing and applies a vertical offset during framebuffer blitting or viewport configuration, supported by new unit tests and mock updates. The feedback recommends resolving potential signed/unsigned mismatch warnings by using explicit type casts and safe comparisons when calculating and applying the vertical offset.
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OpenGL places the origin at the bottom left of the window surface but Wayland places it at the top left, so while a resize has the surface and the frame at different heights the two disagree about which rows line up. Presenting the frame at the OpenGL origin lined up the bottom rows, so the contents jumped vertically for as long as the sizes differed: down, leaving a stale strip at the top, when the surface was taller than the frame, and up, dropping the top rows, when it was shorter. Line up the top row of the frame with the top row of the surface instead, which keeps the contents still and drops anything that doesn't fit off the bottom, where the window is being clipped in Wayland's coordinates. A width difference only clips harmlessly at the right hand edge, which is why this was only visible when resizing vertically.
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Yup, that would make sense 👍
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autosubmit label was removed for flutter/flutter/192408, because - The status or check suite Dashboard Checks has failed. Please fix the issues identified (or deflake) before re-applying this label. |
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Roll Flutter from 63b9518f16bc to 2553f89be1ef (62 revisions) flutter/flutter@63b9518...2553f89 2026-09-12 [email protected] Roll clang to 07d67299a15ce03b053736e2d31a668ee0576987 (flutter/flutter#192607) 2026-09-12 [email protected] Roll Dart SDK from b24b352c29db to 7863887acbfb (3 revisions) (flutter/flutter#192665) 2026-09-12 [email protected] fix(tree): et format --all (flutter/flutter#192669) 2026-09-12 [email protected] Support activity-alias in Android launcher activity detection (flutter/flutter#187251) 2026-09-12 [email protected] fix: regenerate gradle lockfiles for external_textures integration test (flutter/flutter#192657) 2026-09-12 [email protected] Roll Skia from 51aa02b2c195 to e5e96533b732 (4 revisions) (flutter/flutter#192646) 2026-09-12 [email protected] [WebParagraph] Fix text pixelation, glyph clipping, and snapping offsets to avoid subpixel raster caching (flutter/flutter#191736) 2026-09-12 [email protected] fix(tests): Add ruby dep to Mac windowing_test (flutter/flutter#192656) 2026-09-12 [email protected] Remove some `unawaited_futures` outdated ignores (flutter/flutter#192026) 2026-09-11 [email protected] Bump Dart to 3.13, reformat, re-enable formatting check (flutter/flutter#192649) 2026-09-11 [email protected] [android] Isolate API-34 high contrast listener in AccessibilityBridge behind Api34Impl (flutter/flutter#192502) 2026-09-11 [email protected] Update style guide for Dart 3.13 (flutter/flutter#192639) 2026-09-11 [email protected] ci(bringups): remove bringup from these tests (flutter/flutter#192637) 2026-09-11 [email protected] Unmark new_gallery_windows_impeller__transition_perf as bringup (flutter/flutter#192633) 2026-09-11 [email protected] Unmark new_gallery_windows_skia__transition_perf as bringup (flutter/flutter#192635) 2026-09-11 [email protected] Roll Skia from f446aec4ce9e to 51aa02b2c195 (2 revisions) (flutter/flutter#192631) 2026-09-11 [email protected] fix(ci): mac verify binaries still racing (flutter/flutter#192634) 2026-09-11 [email protected] Roll Packages from 8a35b16 to 9caa77c (8 revisions) (flutter/flutter#192630) 2026-09-11 [email protected] Roll Dart SDK from a76fee2722e0 to b24b352c29db (2 revisions) (flutter/flutter#192627) 2026-09-11 [email protected] [tool] Migrate PackagesCommand and Pub to modular dependency injection (flutter/flutter#192460) 2026-09-11 [email protected] [tool] Migrate Darwin framework commands to modular dependency injection (flutter/flutter#192252) 2026-09-11 [email protected] [tool] Migrate Upgrade, Downgrade, and UpdatePackages commands to modular dependency injection (flutter/flutter#190787) 2026-09-11 [email protected] Roll Skia from b3fa80a0e168 to f446aec4ce9e (55 revisions) (flutter/flutter#192620) 2026-09-11 [email protected] Roll Dart SDK from d20d59cfa664 to a76fee2722e0 (2 revisions) (flutter/flutter#192616) 2026-09-11 [email protected] remove deeplink integration tests from bringup (flutter/flutter#192459) 2026-09-11 [email protected] Revert: [devicelab] Clean up Chrome profile directories and trap abort signals in web benchmarks (flutter/flutter#192615) 2026-09-11 [email protected] Roll Fuchsia Linux SDK from C0j8F-_Iy-OQZ6YyI... to m69nfK-wnHaMTe8P9... 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OpenGL places the origin at the bottom left of the window surface but Wayland places it at the top left, so while a resize has the surface and the frame at different heights the two disagree about which rows line up. Presenting the frame at the OpenGL origin lined up the bottom rows, so the contents jumped vertically for as long as the sizes differed: down, leaving a stale strip at the top, when the surface was taller than the frame, and up, dropping the top rows, when it was shorter.
Line up the top row of the frame with the top row of the surface instead, which keeps the contents still and drops anything that doesn't fit off the bottom, where the window is being clipped in Wayland's coordinates.
A width difference only clips harmlessly at the right hand edge, which is why this was only visible when resizing vertically.