feat: 截图功能验证。

截图需要 700 ms，转换成 webp 3 s。

src-tauri/.gitignore

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+# Generated by Cargo
+# will have compiled files and executables
+/target/
+

src-tauri/Cargo.toml

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+[package]
+name = "screen-bg-light-desktop"
+version = "0.0.0"
+description = "A Tauri App"
+authors = ["you"]
+license = ""
+repository = ""
+edition = "2021"
+rust-version = "1.57"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[build-dependencies]
+tauri-build = { version = "1.1", features = [] }
+
+[dependencies]
+serde_json = "1.0"
+serde = { version = "1.0", features = ["derive"] }
+tauri = { version = "1.1", features = ["api-all"] }
+scrap = "0.5"
+repng = "0.2.2"
+bmp = "0.5.0"
+webp = "0.2.2"
+base64 = "0.13.1"
+
+[features]
+# by default Tauri runs in production mode
+# when `tauri dev` runs it is executed with `cargo run --no-default-features` if `devPath` is an URL
+default = [ "custom-protocol" ]
+# this feature is used used for production builds where `devPath` points to the filesystem
+# DO NOT remove this
+custom-protocol = [ "tauri/custom-protocol" ]

src-tauri/build.rs

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+fn main() {
+  tauri_build::build()
+}

src-tauri/src/main.rs

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+#![cfg_attr(
+    all(not(debug_assertions), target_os = "windows"),
+    windows_subsystem = "windows"
+)]
+
+use bmp::{Image, Pixel};
+use scrap::{Capturer, Display};
+use std::io::ErrorKind::WouldBlock;
+use std::path::Path;
+use std::thread;
+use std::time::Duration;
+use std::{fs, time::Instant};
+
+// Learn more about Tauri commands at https://tauri.app/v1/guides/features/command
+#[tauri::command]
+fn greet(name: &str) -> String {
+    format!("Hello, {}! You've been greeted from Rust!", name)
+}
+
+#[tauri::command]
+fn take_snapshot() -> String {
+    let one_second = Duration::new(1, 0);
+    let one_frame = one_second / 60;
+
+    let display = Display::primary().expect("Couldn't find primary display.");
+    let mut capturer = Capturer::new(display).expect("Couldn't begin capture.");
+    let (w, h) = (capturer.width(), capturer.height());
+
+    loop {
+        // Wait until there's a frame.
+
+        let start = Instant::now();
+        let buffer = match capturer.frame() {
+            Ok(buffer) => buffer,
+            Err(error) => {
+                if error.kind() == WouldBlock {
+                    // Keep spinning.
+                    thread::sleep(one_frame);
+                    continue;
+                } else {
+                    panic!("Error: {}", error);
+                }
+            }
+        };
+
+        println!("Captured! Saving...");
+
+        // Flip the ARGB image into a BGRA image.
+
+        let mut bitflipped = Vec::with_capacity(w * h * 3);
+        let stride = buffer.len() / h;
+
+        let mut img = Image::new(w as u32, h as u32);
+
+        for y in 0..h {
+            for x in 0..w {
+                let i = stride * y + 4 * x;
+                bitflipped.extend_from_slice(&[buffer[i + 2], buffer[i + 1], buffer[i]]);
+                // img.set_pixel(
+                //     x as u32,
+                //     y as u32,
+                //     Pixel::new(buffer[i + 2], buffer[i + 1], buffer[i]),
+                // );
+            }
+        }
+
+        let webp_memory =
+            webp::Encoder::from_rgb(bitflipped.as_slice(), w as u32, h as u32).encode(100.0);
+        let encode_text = base64::encode(&*webp_memory);
+        // let output_path = Path::new("assets").join("lake").with_extension("webp");
+        // std::fs::write(&output_path, &*webp_memory).unwrap();
+        println!("运行耗时: {:?}", start.elapsed());
+        return encode_text;
+    }
+}
+
+fn main() {
+    tauri::Builder::default()
+        .invoke_handler(tauri::generate_handler![greet, take_snapshot])
+        .run(tauri::generate_context!())
+        .expect("error while running tauri application");
+}

src-tauri/tauri.conf.json

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+{
+  "build": {
+    "beforeDevCommand": "pnpm dev",
+    "beforeBuildCommand": "pnpm build",
+    "devPath": "http://localhost:1420",
+    "distDir": "../dist"
+  },
+  "package": {
+    "productName": "screen-bg-light-desktop",
+    "version": "0.0.0"
+  },
+  "tauri": {
+    "allowlist": {
+      "all": true
+    },
+    "bundle": {
+      "active": true,
+      "category": "DeveloperTool",
+      "copyright": "",
+      "deb": {
+        "depends": []
+      },
+      "externalBin": [],
+      "icon": [
+        "icons/32x32.png",
+        "icons/128x128.png",
+        "icons/128x128@2x.png",
+        "icons/icon.icns",
+        "icons/icon.ico"
+      ],
+      "identifier": "com.tauri.dev",
+      "longDescription": "",
+      "macOS": {
+        "entitlements": null,
+        "exceptionDomain": "",
+        "frameworks": [],
+        "providerShortName": null,
+        "signingIdentity": null
+      },
+      "resources": [],
+      "shortDescription": "",
+      "targets": "all",
+      "windows": {
+        "certificateThumbprint": null,
+        "digestAlgorithm": "sha256",
+        "timestampUrl": ""
+      }
+    },
+    "security": {
+      "csp": null
+    },
+    "updater": {
+      "active": false
+    },
+    "windows": [
+      {
+        "fullscreen": false,
+        "height": 600,
+        "resizable": true,
+        "title": "screen-bg-light-desktop",
+        "width": 800
+      }
+    ]
+  }
+}