feat(timeout): Add --timeout-elapsed for seamless dialog chaining

[mg-dev25]

PR: Add --timeout-elapsed for Seamless Dialog Chaining

Summary

This PR introduces a --timeout-elapsed option that allows yad dialogs to continue a shared timeout from a specified elapsed point. When chaining multiple dialogs in a script, this enables the progress bar to visually continue rather than restart at 100%.

Problem

When chaining yad dialogs with timeouts, each dialog restarts its progress bar from the beginning. For scripts that need a single timeout budget across multiple dialogs, this creates a jarring user experience where the progress appears to "reset" at each transition.

Solution

Add --timeout-elapsed=SECONDS to specify how much time has already passed. The progress bar and remaining time label initialize at the correct position.

Example:

#!/bin/bash
TIMEOUT=30

# Dialog 1 - starts at 100%
yad --text="Step 1" --timeout=$TIMEOUT --timeout-indicator=bottom
ELAPSED=$((TIMEOUT - remaining))  # Track elapsed time

# Dialog 2 - continues from where Dialog 1 left off
yad --text="Step 2" --timeout=$TIMEOUT --timeout-elapsed=$ELAPSED --timeout-indicator=bottom

Changes

File	Change
src/yad.h	Add timeout_elapsed field to YadData struct
src/option.c	Register --timeout-elapsed option, initialize to 0
src/main.c	Update timeout_cb and create_dialog to use elapsed value

Implementation Details

Timer callback (timeout_cb):

• Uses a static initialized flag to set the starting count once
• Initializes count to timeout_elapsed + 1 instead of hardcoded 1

Progress bar initialization (create_dialog):

• Calculates initial fraction as (timeout - elapsed) / timeout
• Sets the progress bar and text label to show remaining time correctly

Safety checks:

• Only applies elapsed offset when 0 < elapsed < timeout
• Prevents negative values or division by zero

Testing

Visual tests confirm correct behavior:

Test	Settings	Result
Normal	--timeout=10	Bar starts at 100%
50% elapsed	--timeout=10 --timeout-elapsed=5	Bar starts at 50%
80% elapsed	--timeout=10 --timeout-elapsed=8	Bar starts at 20%

Backward Compatibility

Fully backward compatible. Without --timeout-elapsed, behavior is identical to before (count starts at 1, progress starts at 100%).

Related

• Addresses use case for progress bar continuation in multi-dialog scripts
• Complements existing --timeout and --timeout-indicator options

[mg-dev25]

Closing in favor of upstream PR: v1cont#320