windows-ffi
v0.0.4
Published
NodeJS wrappers around Windows p-invoke/dll functions in user32, gdi32, etc. (based on node-ffi-napi)
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Windows FFI
NodeJS wrappers around Windows p-invoke/dll functions in user32, gdi32, etc. (based on node-ffi-napi)
Installation
- 1) Install
ffi-napi
in your project:npm i ffi-napi
- 1.1) You may need to install the windows-build-tools first for
ffi-napi
to be able to build:npm install --global --production windows-build-tools
- 1.1) You may need to install the windows-build-tools first for
- 2) Install:
npm i windows-ffi
- 2.1) If you're using
windows-ffi
in symlinked mode, supply the parent project's copy of thenode-ffi
libraries using the init code below:// Make sure the code below runs before windows-ffi is imported! (example approach: https://stackoverflow.com/a/42817956) import ffi from "ffi-napi"; import ref from "ref-napi"; import refStructDI from "ref-struct-di"; import {SupplyConfig} from "windows-ffi/Dist/@UserSupplied/PreImportConfig.js"; SupplyConfig({ffi, ref, refStructDI});
- 2.1) If you're using
Usage
While this library is meant to gradually expand to cover more of the Windows API, it will never be 100%, because it's a "develop as you need it" sort of endeavor.
Some of the most common and/or noteworthy functionalities are shown below.
Capture image-data from a region on-screen
import {VRect, CaptureScreenshot, GetForegroundWindowHandle} from "windows-ffi";
// First capture a screenshot of a section of the screen.
const screenshot = CaptureScreenshot({
windowHandle: GetForegroundWindowHandle(), // comment to screenshot all windows
rectToCapture: new VRect(0, 0, 800, 600),
});
// The image-data is now stored in the `screenshot.buffer` Buffer object.
// Access it directly (and cheaply) using the helper functions on `screenshot`.
for (let x = 0; x < 800; x++) {
console.log(`Pixel color at [${x}, 0] is:`, screenshot.GetPixel(x, 0).ToHex_RGB());
}
Performance:
- Full-screen (2560x1440), all windows (ie. "desktop" window): ~80ms
- Full-screen (2560x1440), single window: ~20ms
- Region (700x200), all windows (ie. "desktop" window): ~50ms
- Region (700x200), single window: ~4ms
Tasks
General:
- Create an accompanying library for Windows-specific functionalities that do not require the
ffi-napi
dependency. (I've had pains with ffi-related building during NodeJS updates, so things that can be done without that dependency is beneficial to bundle separately)