feat(#36): Add framerate cli option

sassman · sassman · commit a4cc8d64bb29 · 2022-02-15T10:26:25.000+01:00
- add a framerate cli argument `-f | --framerate`
- limit the possible framerates to 4 and 8 for now
- introduce new wrapper types for better readability
- adjust the docs
diff --git a/Cargo.toml b/Cargo.toml
@@ -52,7 +52,7 @@ e2e_tests = []
 section = "x11"
 depends = "imagemagick"
 extended-description = """## Features
-- Screenshotting your terminal with 4 frames per second (every 250ms)
+- Screenshotting your terminal with 4/8 frames per second
 - Generates high quality small sized animated gif images
 - **Build-In idle frames detection and optimization** (for super fluid
 presentations)
diff --git a/README.md b/README.md
@@ -18,11 +18,11 @@ Blazingly fast terminal recorder that generates animated gif images for the web
 ![demo](./docs/demo.gif)
 
 ## Features
-- Screenshotting your terminal with 4 frames per second (every 250ms)
-- Generates high quality small sized animated gif images or mp4 videos
+- Screenshotting your terminal with 4/8 frames per second
+- Generates high-quality small-sized animated gif images or mp4 videos
 - **Build-In idle frames detection and optimization** (for super fluid presentations)
 - Applies (can be disabled) border decor effects like drop shadow
-- Runs on MacOS and Linux
+- Runs on macOS and Linux
 - Uses native efficient APIs
 - Runs without any cloud service and entirely offline
 - No issues with terminal sizes larger than 80x24
@@ -123,7 +123,7 @@ t-rec /bin/sh
 ### Full Options
 
 ```sh
-t-rec 0.7.0
+t-rec 0.7.1
 Sven Assmann <sven.assmann.it@gmail.com>
 Blazingly fast terminal recorder that generates animated gif images for the web written in rust.
 
@@ -135,28 +135,56 @@ ARGS:
                                     pass it here. For example '/bin/sh'
 
 OPTIONS:
-    -b, --bg <bg>                     Background color when decors are used [default: transparent]
-                                      [possible values: white, black, transparent]
-    -d, --decor <decor>               Decorates the animation with certain, mostly border effects
-                                      [default: none] [possible values: shadow, none]
-    -e, --end-pause <s | ms | m>      to specify the pause time at the end of the animation, that
-                                      time the gif will show the last frame
-    -h, --help                        Print help information
-    -l, --ls-win                      If you want to see a list of windows available for recording
-                                      by their id, you can set env var 'WINDOWID' or `--win-id` to
-                                      record this specific window only
-    -m, --video                       Generates additionally to the gif a mp4 video of the recording
-    -M, --video-only                  Generates only a mp4 video and not gif
-    -n, --natural                     If you want a very natural typing experience and disable the
-                                      idle detection and sampling optimization
-    -q, --quiet                       Quiet mode, suppresses the banner: 'Press Ctrl+D to end
-                                      recording'
-    -s, --start-pause <s | ms | m>    to specify the pause time at the start of the animation, that
-                                      time the gif will show the first frame
-    -v, --verbose                     Enable verbose insights for the curious
-    -V, --version                     Print version information
-    -w, --win-id <win-id>             Window Id (see --ls-win) that should be captured, instead of
-                                      the current terminal
+    -b, --bg <bg>
+            Background color when decors are used [default: transparent] [possible values: white,
+            black, transparent]
+
+    -d, --decor <decor>
+            Decorates the animation with certain, mostly border effects [default: none] [possible
+            values: shadow, none]
+
+    -e, --end-pause <s | ms | m>
+            Specify the pause time at the end of the animation, that time the gif will show the last
+            frame
+
+    -f, --framerate <frames per second>
+            Increase the screen capturing rate (framerate) [default: 4] [possible values: 4, 8]
+
+    -h, --help
+            Print help information
+
+    -l, --ls-win
+            If you want to see a list of windows available for recording by their id, you can set
+            env var 'WINDOWID' or `--win-id` to record this specific window only
+
+    -m, --video
+            Generates additionally to the gif a mp4 video of the recording
+
+    -M, --video-only
+            Generates only a mp4 video and not gif
+
+    -n, --natural
+            If you want a very natural typing experience and disable the idle detection and sampling
+            optimization
+
+    -o, --output <file>
+            Specify the output file (without extension) [default: t-rec]
+
+    -q, --quiet
+            Quiet mode, suppresses the banner: 'Press Ctrl+D to end recording'
+
+    -s, --start-pause <s | ms | m>
+            Specify the pause time at the start of the animation, that time the gif will show the
+            first frame
+
+    -v, --verbose
+            Enable verbose insights for the curious
+
+    -V, --version
+            Print version information
+
+    -w, --win-id <win-id>
+            Window Id (see --ls-win) that should be captured, instead of the current terminal
 ```
 
 ### Disable idle detection & optimization
diff --git a/src/capture/capture.rs b/src/capture/capture.rs
@@ -1,4 +1,4 @@
-use anyhow::{Context, Result};
+use anyhow::Context;
 use image::save_buffer;
 use image::ColorType::Rgba8;
 use std::borrow::Borrow;
@@ -8,8 +8,15 @@ use std::sync::{Arc, Mutex};
 use std::time::{Duration, Instant};
 use tempfile::TempDir;
 
+use crate::capture::Framerate;
 use crate::utils::file_name_for;
-use crate::{ImageOnHeap, PlatformApi, WindowId};
+use crate::{ImageOnHeap, PlatformApi, Result, WindowId};
+
+#[derive(Eq, PartialEq)]
+pub enum FrameDropStrategy {
+    DoNotDropAny,
+    DropIdenticalFrames,
+}
 
 /// captures screenshots as file on disk
 /// collects also the timecodes when they have been captured
@@ -20,9 +27,10 @@ pub fn capture_thread(
     win_id: WindowId,
     time_codes: Arc<Mutex<Vec<u128>>>,
     tempdir: Arc<Mutex<TempDir>>,
-    force_natural: bool,
+    frame_drop_strategy: &FrameDropStrategy,
+    framerate: &Framerate,
 ) -> Result<()> {
-    let duration = Duration::from_millis(250);
+    let duration = Duration::from_secs(1) / *framerate.as_ref();
     let start = Instant::now();
     let mut idle_duration = Duration::from_millis(0);
     let mut last_frame: Option<ImageOnHeap> = None;
@@ -37,7 +45,7 @@ pub fn capture_thread(
         let effective_now = now.sub(idle_duration);
         let tc = effective_now.saturating_duration_since(start).as_millis();
         let image = api.capture_window_screenshot(win_id)?;
-        if !force_natural {
+        if frame_drop_strategy == &FrameDropStrategy::DropIdenticalFrames {
             if last_frame.is_some()
                 && image
                     .samples
diff --git a/src/capture/framerate.rs b/src/capture/framerate.rs
@@ -0,0 +1,29 @@
+use std::fmt::{Display, Formatter};
+
+#[derive(Clone)]
+pub struct Framerate(u32);
+
+impl Framerate {
+    pub fn new(f: u32) -> Self {
+        Self(f)
+    }
+}
+
+impl Display for Framerate {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        let framerate = self.0;
+        write!(f, "framerate {framerate} [fps]")
+    }
+}
+
+impl From<u32> for Framerate {
+    fn from(fr: u32) -> Self {
+        Self(fr)
+    }
+}
+
+impl AsRef<u32> for Framerate {
+    fn as_ref(&self) -> &u32 {
+        &self.0
+    }
+}
diff --git a/src/capture/mod.rs b/src/capture/mod.rs
@@ -0,0 +1,5 @@
+mod capture;
+mod framerate;
+
+pub use capture::*;
+pub use framerate::*;
diff --git a/src/cli.rs b/src/cli.rs
@@ -91,7 +91,7 @@ pub fn launch() -> ArgMatches {
                 .required(false)
                 .short('e')
                 .long("end-pause")
-                .help("to specify the pause time at the end of the animation, that time the gif will show the last frame"),
+                .help("Specify the pause time at the end of the animation, that time the gif will show the last frame"),
         )
         .arg(
             Arg::new("start-pause")
@@ -100,7 +100,7 @@ pub fn launch() -> ArgMatches {
                 .required(false)
                 .short('s')
                 .long("start-pause")
-                .help("to specify the pause time at the start of the animation, that time the gif will show the first frame"),
+                .help("Specify the pause time at the start of the animation, that time the gif will show the first frame"),
         )
         .arg(
             Arg::new("file")
@@ -109,7 +109,18 @@ pub fn launch() -> ArgMatches {
                 .short('o')
                 .long("output")
                 .default_value("t-rec")
-                .help("to specify the output file (without extension)"),
+                .help("Specify the output file (without extension)"),
+        )
+        .arg(
+            Arg::new("framerate")
+                .value_name("frames per second")
+                .takes_value(true)
+                .required(false)
+                .short('f')
+                .long("framerate")
+                .default_value("4")
+                .possible_values(&["4", "8"])
+                .help("Increase the screen capturing rate (framerate)"),
         )
         .arg(
             Arg::new("program")
diff --git a/src/main.rs b/src/main.rs
@@ -1,15 +1,15 @@
+mod capture;
 mod cli;
 mod common;
 mod decor_effect;
 mod generators;
 mod tips;
+mod utils;
 
-mod capture;
 #[cfg(target_os = "linux")]
 mod linux;
 #[cfg(target_os = "macos")]
 mod macos;
-mod utils;
 #[cfg(target_os = "windows")]
 mod win;
 
@@ -27,7 +27,7 @@ use crate::decor_effect::{apply_big_sur_corner_effect, apply_shadow_effect};
 use crate::generators::{check_for_gif, check_for_mp4, generate_gif, generate_mp4};
 use crate::tips::show_tip;
 
-use crate::capture::capture_thread;
+use crate::capture::{capture_thread, FrameDropStrategy, Framerate};
 use crate::utils::{sub_shell_thread, target_file, DEFAULT_EXT, MOVIE_EXT};
 use anyhow::{bail, Context};
 use clap::ArgMatches;
@@ -64,7 +64,8 @@ fn main() -> Result<()> {
     if args.is_present("list-windows") {
         return ls_win();
     }
-
+    let quiet = args.is_present("quiet");
+    let verbose = args.is_present("verbose");
     let program: String = {
         if args.is_present("program") {
             args.value_of("program").unwrap().to_owned()
@@ -77,13 +78,22 @@ fn main() -> Result<()> {
     let mut api = setup()?;
     api.calibrate(win_id)?;
 
-    let force_natural = args.is_present("natural-mode");
+    let frame_drop_strategy = args
+        .is_present("natural-mode")
+        .then(|| FrameDropStrategy::DoNotDropAny)
+        .unwrap_or_else(|| FrameDropStrategy::DropIdenticalFrames);
     let should_generate_gif = !args.is_present("video-only");
     let should_generate_video = args.is_present("video") || args.is_present("video-only");
     let (start_delay, end_delay) = (
         parse_delay(args.value_of("start-pause"), "start-pause")?,
         parse_delay(args.value_of("end-pause"), "end-pause")?,
     );
+    let framerate = args
+        .value_of("framerate")
+        .unwrap()
+        .parse::<u32>()
+        .map(|f| Framerate::new(f))
+        .context("Invalid value for framerate")?;
 
     if should_generate_gif {
         check_for_gif()?;
@@ -101,26 +111,35 @@ fn main() -> Result<()> {
     let photograph = {
         let tempdir = tempdir.clone();
         let time_codes = time_codes.clone();
-        let force_natural = force_natural;
+        let framerate = framerate.clone();
         thread::spawn(move || -> Result<()> {
-            capture_thread(&rx, api, win_id, time_codes, tempdir, force_natural)
+            capture_thread(
+                &rx,
+                api,
+                win_id,
+                time_codes,
+                tempdir,
+                &frame_drop_strategy,
+                &framerate,
+            )
         })
     };
     let interact = thread::spawn(move || -> Result<()> { sub_shell_thread(&program).map(|_| ()) });
 
     clear_screen();
-    if args.is_present("verbose") {
+    if verbose {
         println!(
             "Frame cache dir: {:?}",
             tempdir.lock().expect("Cannot lock tempdir resource").path()
         );
+        let fr = format!(" @ {}", &framerate);
         if let Some(window) = window_name {
-            println!("Recording window: {:?}", window);
+            println!("Recording window: {window}{fr}");
         } else {
-            println!("Recording window id: {}", win_id);
+            println!("Recording window id: {win_id}{fr}");
         }
     }
-    if args.is_present("quiet") {
+    if quiet {
         println!();
     } else {
         println!("[t-rec]: Press Ctrl+D to end recording");
diff --git a/src/tips.rs b/src/tips.rs
@@ -6,6 +6,7 @@ const TIPS: &[&str] = &[
     "To add a pause at the beginning of the gif loop, use e.g. option `-s 500ms` option",
     "To prevent cutting out stall frames, checkout the `-n` option",
     "To remove the shadow around the gif, use the `-d none` option",
+    "To double the capturing framerate, use the option `-f 8`",
     "For a mp4 video, use the `-m` option",
     "To suppress the 'Ctrl+D' banner, use the `-q` option",
 ];
