Summary

Adds a new --fps option to make typing animations smoother. Perfect for demos and presentations where you want fluid, professional-looking recordings.

The Problem

The default 4 fps capture rate can make fast typing appear choppy. Multiple keystrokes within a 250ms window get compressed into a single frame, making the animation feel "jumpy".

The Solution

You can now increase the capture framerate up to 15 fps for smoother animations:

# Smooth typing (10 fps, 100ms intervals)
t-rec --fps 10

# Very smooth (15 fps, 66ms intervals)
t-rec --fps 15

# Or use the new preset profile
t-rec --profile smooth

Usage Examples

Config File Support

You can save your preferred framerate in the config file:

[default]
fps = 10

[profiles.smooth]
fps = 10
idle-pause = "2s"

Trade-offs

Higher framerates produce larger files (roughly proportional to fps increase). The idle frame detection still works, so file sizes are optimized during pauses.

Test plan

• cargo build succeeds
• cargo test passes
• cargo clippy passes
• Manual test: t-rec --fps 4 (default behavior)
• Manual test: t-rec --fps 10 (visibly smoother)
• Manual test: t-rec --fps 15 (very smooth)
• Manual test: t-rec --fps 3 errors (below minimum)
• Manual test: t-rec --fps 16 errors (above maximum)
• Manual test: Config file with fps = 10 works

Completes #28