feat(#28): higher framerate configurability

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "t-rec"
-version = "0.7.3"
+version = "0.7.3-alpha.1"
 authors = ["Sven Assmann <sven.assmann.it@gmail.com>"]
 edition = "2018"
 license = "GPL-3.0-only"
@@ -26,6 +26,8 @@ log = "0.4.16"
 env_logger = "0.9.0"
 simplerand = "1.3.0"
 humantime = "2.1.0"
+crossbeam-channel = "0.5"
+blockhash = "0.3"
 
 [dependencies.clap]
 version = "3.1.9"
@@ -52,7 +54,7 @@ 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)

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

src/capture/frame.rs

@@ -0,0 +1,55 @@
+use anyhow::Context;
+pub use blockhash::Image;
+use image::flat::View;
+use image::ColorType::Rgba8;
+use image::{save_buffer, FlatSamples, GenericImageView, Rgba};
+use tempfile::TempDir;
+
+use crate::capture::Timecode;
+use crate::utils::IMG_EXT;
+use crate::{ImageOnHeap, Result};
+
+pub struct Frame(FlatSamples<Vec<u8>>);
+
+impl Frame {
+    /// saves a frame as a IMG_EXT file
+    pub fn save(
+        &self,
+        tc: &Timecode,
+        tempdir: &TempDir,
+        file_name_for: fn(&Timecode, &str) -> String,
+    ) -> Result<()> {
+        let image = self.as_ref();
+        save_buffer(
+            tempdir.path().join(file_name_for(tc, IMG_EXT)),
+            &image.samples,
+            image.layout.width,
+            image.layout.height,
+            image.color_hint.unwrap_or(Rgba8),
+        )
+        .context("Cannot save frame")
+    }
+}
+
+impl Image for Frame {
+    fn dimensions(&self) -> (u32, u32) {
+        (self.0.layout.width, self.0.layout.height)
+    }
+
+    fn get_pixel(&self, x: u32, y: u32) -> [u8; 4] {
+        let image: View<_, Rgba<u8>> = self.0.as_view().unwrap();
+        image.get_pixel(x, y).0
+    }
+}
+
+impl AsRef<FlatSamples<Vec<u8>>> for Frame {
+    fn as_ref(&self) -> &FlatSamples<Vec<u8>> {
+        &self.0
+    }
+}
+
+impl From<ImageOnHeap> for Frame {
+    fn from(img: ImageOnHeap) -> Self {
+        Self(*img)
+    }
+}

src/capture/frame_comparator.rs

@@ -0,0 +1,45 @@
+use std::collections::LinkedList;
+
+use crate::capture::{FrameDropStrategy, FrameEssence};
+
+pub struct FrameComparator {
+    last_frames: LinkedList<FrameEssence>,
+    strategy: FrameDropStrategy,
+}
+
+impl FrameComparator {
+    pub fn new(strategy: FrameDropStrategy) -> Self {
+        Self {
+            last_frames: LinkedList::new(),
+            strategy,
+        }
+    }
+}
+
+impl FrameComparator {
+    pub fn should_drop_frame(&mut self, frame_essence: FrameEssence) -> bool {
+        match self.strategy {
+            FrameDropStrategy::DoNotDropAny => false,
+            FrameDropStrategy::DropIdenticalFrames => {
+                if let Some(FrameEssence { when, what }) = self.last_frames.pop_back() {
+                    if frame_essence.when > when && what == frame_essence.what {
+                        // so the last frame and this one is the same... so let's drop it..
+                        // but add the current frame
+                        self.last_frames.push_back(frame_essence);
+                        true
+                    } else {
+                        let previous_should_drop_frame = self.should_drop_frame(frame_essence);
+                        // restore the popped frame..
+                        self.last_frames.push_back(FrameEssence { when, what });
+
+                        previous_should_drop_frame
+                    }
+                } else {
+                    self.last_frames.push_back(frame_essence);
+
+                    false
+                }
+            }
+        }
+    }
+}

src/capture/frame_essence.rs

@@ -0,0 +1,24 @@
+use blockhash::{blockhash256, Blockhash256};
+
+use crate::capture::{Frame, Timecode};
+
+#[derive(Eq, PartialEq, Clone)]
+pub enum FrameDropStrategy {
+    DoNotDropAny,
+    DropIdenticalFrames,
+}
+
+#[derive(Eq, PartialOrd, PartialEq, Clone)]
+pub struct FrameEssence {
+    pub(crate) when: Timecode,
+    pub(crate) what: Blockhash256,
+}
+
+impl FrameEssence {
+    pub fn new(frame: &Frame, timecode: &Timecode) -> Self {
+        Self {
+            when: timecode.clone(),
+            what: blockhash256(frame),
+        }
+    }
+}