feat: SG-41979: Add hotkey and env var for no sequence formation during drag and drop

[chenlj1]

SG-41979: [RV] Add alt/option hotkey and env var with a pattern to prevent RV from loading images as an image sequence

Summarize your change.

Added an Alt/Option hotkey for drag-and-drop: holding Alt while dropping files prevents sequence formation so each file is added as its own source. Modifier is read in QTTranslator, the Mu layer passes a "drop-no-sequence" tag into addSources, RvSession uses that tag so LoadState and the non-delayed path do not re-group.

Added RV_NO_SEQUENCE_PATTERN that can be set using export RV_NO_SEQUENCE_PATTERN="wanted_pattern". When set to a regex, matching file names are not grouped into sequences.

Describe the reason for the change.

The previous env substring (RV_NO_SEQUENCE_SUBSTRING) did not meet the client’s needs. They wanted a hotkey so they can have more control over sequence formation.

The client wanted something more powerful than the previous substring approach and suggested using RegEx instead.

Describe what you have tested and on which operating system.

The hotkey was tested on macOS by holding down the Option key and verifying that no sequence would form during a drag and drop of files.

Untitled.mov

The RegEx was tested on macOS by setting the environment variable by using export RV_NO_SEQUENCE_PATTERN="_[vV][0-9]+.jpg$"

Screen.Recording.2026-02-23.at.10.27.48.AM.mov

[bernie-laberge]

LGTM
Thank you @chenlj1 !

[Copilot]

Pull request overview

Adds user-controlled ways to prevent sequence formation when loading images—either interactively during drag-and-drop (Alt/Option) or globally via an environment-variable regex—so files can be loaded as individual sources instead of being contracted into sequences.

Changes:

• Add Alt/Option handling to drag-and-drop so dropped file lists bypass sequence contraction.
• Propagate a "drop-no-sequence" tag through the Mu layer into RvSession loading paths to avoid regrouping.
• Add RV_NO_SEQUENCE_PATTERN support in sequencesInFileList() to skip grouping for matching filenames.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/lib/base/TwkUtil/FrameUtils.cpp	Adds regex-based “do not sequence” filtering during sequence detection.
src/lib/app/mu_rvui/rvui.mu	Captures Alt modifier at drop time and forwards a tag to addSources.
src/lib/app/mu_rvui/rvtypes.mu	Extends UI State with ddNoSequence flag.
src/lib/app/RvCommon/QTTranslator.cpp	Uses Alt modifier to bypass sequence contraction and forwards modifiers into drag-drop events.
src/lib/app/RvApp/RvSession.cpp	Treats "drop-no-sequence" tag as a no-sequencing request in both delayed and immediate load paths.