Update Screen Modes

update-screen-modes demonstrates how Terminal::updateScreen() behaves when you toggle overwrite mode, line buffering, safe margins, and the smart back buffer. It combines a small status dashboard with a sparse animation field so the redraw cost and visual behavior are easy to compare.

Use This Demo When You Need…

• A support example for diagnosing updateScreen() behavior and performance tradeoffs.

• A visual comparison of overwrite versus clear refresh strategies.

• A reference for line buffering, safe margins, and smart back-buffer updates.

Run the Demo

Start the demo from the build directory:

$ ./cmake-build-debug/demo-apps/update-screen-modes

Use O to toggle overwrite mode, L to toggle line buffering, B to toggle the back buffer, S to toggle safe margins, and Q to quit.

Captured Output (80x25)

╭──────────────────────────────────────────────────────────────────────────────╮
│                 Screen Update Demo | refresh mode: Overwrite                 │
│                                                                              │
│ ┌───────────────────────┐  ┌───────────────────────────────────────────────┐ │
│ │     Refresh Mode      │  │  Sparse animation field | frame 00007 | line  │ │
│ │                       │  │                                               │ │
│ │       Overwrite       │  │    .   .   .   .   .   .   .   .   .   .   .  │ │
│ │Last Update.......     │  │   .   .   .   .   .   .   .   .   .   .   .   │ │
│ │0.766 ms               │  │  .   .   .   .   .   .   .   .   .   .   .    │ │
│ │Average Update....     │  │ .   .   .   .   .   .   .   .   .   .   .   . │ │
│ │0.768 ms               │  │    .   .   .   .   .   .   .   .   .   .   .  │ │
│ │Overwrite Mode....[✓]  │  │   .   .   .   .   .   .   .   .   .   .   .   │ │
│ │Line Buffer.......[✓]  │  │ --------------------------------------------- │ │
│ │Back Buffer.......[✓]  │  │ .   .   .   .   .   .   .   .   .   .   .   . │ │
│ │Safe Margin.......[✕]  │  │    .   .   .   .   .   .   .   .   .   .   .  │ │
│ │                       │  │  *.   .   .   .   .   .   .   .   .   .   .   │ │
│ │                       │  │  . * * @ .   .   .   .   .   .   .   .   .    │ │
│ │                       │  │ .   .   .   .   .   .   .   .   .   .   .   . │ │
│ │                       │  │                                               │ │
│ │                       │  │                                               │ │
│ └───────────────────────┘  └───────────────────────────────────────────────┘ │
│                                                                              │
│ [O] overwrite [L] line buf [B] back buf [S] safe margin [Q] quit             │
│                                                                              │
╰──────────────────────────────────────────────────────────────────────────────╯

Features Demonstrated

• Terminal::RefreshMode::Overwrite versus Clear.

• Line buffering, safe margins, and smart back-buffer updates.

• Timing feedback for repeated updateScreen() calls.

• A sparse animation field that makes redraw strategy visible.

Related Demos

• Retro Plasma for a more visual animation built on the same update path.

• Key Input Demo for another input-driven full-screen loop.

• Frame Color Animations for a less diagnostic but still redraw-heavy full-screen demo.

Relevant Source Files

If you want to explore the implementation, start with demo/update-screen-modes/src/UpdateScreenModesApp.cpp and demo/update-screen-modes/src/UpdateScreenModesState.hpp.