1 
2To WebAssembly (WASM) xekinise os enas tropos gia na ekteleite C++ ston browser. To 2026, trexei pantoy  -  browsers, servers, edge diktya, ensomates syskeves  -  kai trofoditei merikes apo tis pio apaitiikies efarmoges sto web. I mixani renderarismatos tis Figma, to Adobe Photoshop sto web, i epexergasia video toy Google Meet kai i platforma edge computing toy Cloudflare  -  ola trexoyn se WebAssembly.
3 
4To Chrome Platform Status deixnei oti to WASM vriskete sto peripoy 5,5% olon ton fortoseon selidas sto Chrome stis arxes toy 2026, apo 4,5% ton proigoymeno xrono. Me to WASM 3.0 na ginete protypo W3C kai to WASI na orimzei pros tin ekdosi 1.0, to oikosystima exei ftasei se simio kampes.
5 
6Aftos o odigos kalyptei ola osa prepei na gnorixeis gia na arxiseis na chtizeis me WebAssembly.
7 
8## Ti einai to WebAssembly?
9 
10To WebAssembly einai ena binario format odigion sxediasmenoo os stoxos syllogis. Grafeis kodika se glossa ypssiiloy epipedoy (Rust, C, C++, Go, Kotlin), ton metafraxeis se `.wasm` kai ton ekteleis se opoidipote perivvalon poy exei WASM runtime  -  browsers, Node.js, Cloudflare Workers, Wasmtime i Wasmer.
11 
12```mermaid
13graph LR
14    Rust[Rust / C / C++] --> Compiler[Compiler]
15    Compiler --> WASM[.wasm Binary]
16    WASM --> Browser[Browser V8/SpiderMonkey]
17    WASM --> Server[Server Wasmtime]
18    WASM --> Edge[Edge Cloudflare Workers]
19    WASM --> Embedded[Embedded WAMR]
20```
21 
22### Pos leitoyrgei
23 
24To WASM einai mia **virtual machine vasiismeni se stoiva**. Oi synartiseis topothethyn kai afairoun times apo mia stoiva telesion. To runtime toy filoxenoynte (V8 sto Chrome, SpiderMonkey sto Firefox) kanei JIT-compilation to WASM bytecode se gennimeno kodika mixanis, gi afto i apodosi einai konta sto native.
25 
26Vasika xaraktiristika:
27 
28- **Ektelesei se sandbox**: ta WASM modules mporoun na exoun prosvasi mono sta resources poy o filoxenonteas parexei riita. Den yparxei prosvasi se filesystem, diktyo i leitourgiko systima ektos an epitrapei. Afto einai thimelioddoos diaforetiko apo ton native kodika.
29- **Grammmiki mnimi**: enas monos synexis `ArrayBuffer` poy mirazetai metaxy WASM kai filoxenoynte. Syntheta dedomena (strings, structs) metaferontai me egrafi sti mnimi kai koinopoiisi deikti.
30- **Periorismeni typoi**: to WASM ypostirixei native mono tessera types: `i32`, `i64`, `f32`, `f64`. Ola ta alla (strings, arrays, objects) apaytoun kodikopiiisi mesa apo ti grammiki mnimi i to Component Model.
31- **Fornitotita**: to idio `.wasm` binary trexei se opoiadipote platforma me WASM runtime, xoris epanametafrasi.
32 
33### WASM vs JavaScript
34 
35To WASM den antikathistaa tin JavaScript. Ti symplirorei.
36 
37| Ptixii | JavaScript | WebAssembly |
38|--------|-----------|-------------|
39| **Analysi** | Analysi + metafrasi se xrono ektelesis | Prometafrasmeno binary, mono apokodikopiiisi |
40| **Taxytita ektelesis** | JIT-veltiomeni, metavliti | Konta se native, syntomi |
41| **Ekkiniisi** | Grigori gia mikra scripts | Grigori apokodikopiiisi, provlepii |
42| **Prosvasi DOM** | Amesi | Emesi (mesa apo JS glue) |
43| **Kalytero gia** | UI, DOM manipulation, diaxirisi events | CPU-inteniis ypologismous |
44| **Garbage collection** | Ensoomatoomeno | WasmGC (neo) i xeirokiinto |
45 
46Xrisimopiiise JavaScript gia UI kai DOM ergasia. Xrisimopiiise WASM gia varous ypologismous: epexergasia eikonon, kodikopiiisi video, fysikes proomoioseis, kryptografia, analysi dedomenon.
47 
48## WASM 3.0: Ti neo yparxei
49 
50To WebAssembly 3.0 egine protypo W3C ton Septemvrio 2025, typopoiontas ennea xaraktiristika poy itan ypo anaptyksi gia xronia.
51 
52| Xaraktiristiko | Ti epetrepei |
53|---------|----------------|
54| **WasmGC** | Gennimeni syllogi skoypidion sto WASM. Diaxeiriziomenes glosses (Java, Kotlin, Dart) mporoyn na metafraztoun se WASM xoris na sylperilvanoun to diko tous GC runtime. Ypostirrixetai se Chrome 119+, Firefox 120+, Safari 18.2+. |
55| **Exception Handling** | Gennimeno `try`/`catch` sto WASM. Prooigoymenos, ta exceptions apaytousan akriva roundtrips sti JavaScript. |
56| **Tail Calls** | Epetrepei apotelesmmatiki anadromi xoris stack overflow. Krisimo gia functional glosses. |
57| **Relaxed SIMD** | 128-bit vektoriikes odigies gia parallili epexergasia dedomenon. Epetrepei hardware-specific veltiostiopoiiseis. |
58| **Memory64** | Xeperna to orio grammikis mniimis 4GB. Apaiiteto gia epexergasia dedomenon megalis kliimakas. |
59| **Multi-memory** | Pollaples anexartiites perioxes mniimis se ena module. |
60 
61To pio simaantiko einai to **WasmGC**. Prin apo afto, i metafrasi Java i Kotlin se WASM siimaine apostoli enos olokliiroy garbage collector os meros toy binary, poy foyskone ta megethi arxeion. Tora o idios GC toy browser diaxeirizetai ti diaxeirisi mniimis gia ta WASM modules, opos akriviis kanei gia ti JavaScript.
62 
63## WASI: WebAssembly pera apo ton browser
64 
65To WASM ston browser einai dynato, alla to **WASI (WebAssembly System Interface)** einai afto poy kanei to WASM enan pagkosmio runtime. To WASI parexei typopoiimenes diepafes gia poroys systimatos  -  arxeia, diktyo, roloia, tyxaioys arithmous  -  epitrepontas sta WASM modules na trexoun exo apo ton browser.
66 
67```mermaid
68graph TD
69    subgraph "Browser"
70        B[WASM Module] --> Web[Web APIs\nDOM, Fetch, Canvas]
71    end
72 
73    subgraph "Server / Edge / Embedded"
74        S[WASM Module] --> WASI[WASI Interfaces]
75        WASI --> FS[wasi:filesystem]
76        WASI --> Net[wasi:sockets]
77        WASI --> HTTP[wasi:http]
78        WASI --> Clock[wasi:clocks]
79        WASI --> Rand[wasi:random]
80    end
81```
82 
83To WASI Preview 2 (i trexousa statheri ekdosi) orixei tis akloythes diepafes:
84 
85- `wasi:filesystem`  -  leitoyrgies arxeion meso capability handles (oxi paradosiakous file descriptors)
86- `wasi:sockets`  -  TCP/UDP diktyo
87- `wasi:http`  -  diaxirisi HTTP request/response
88- `wasi:clocks`  -  roloi toixoy, monotonico roloi
89- `wasi:random`  -  kryptografiki tyxaiotita
90- `wasi:cli`  -  orismmata grammis entoloon, perivallontiikes metavlites, stdio
91 
92I vasiki arxi einai i **asfaleia vasismeni se dynamotites**: ena WASM module den mporei na exei prosvasi sto filesystem ektos an o filoxenonteas parexei riita ena handle se sygkekrimeno fakelo. Afto kanei to WASI thymelioddoos asfalessteroo apo tin ektelesei gennimennon ektelessimon arxeion.
93 
94### I poreia pros to WASI 1.0
95 
96To WASI 0.3.0 (prosthiiki async/symplektikon primitiivon) anameenetai to 2026, me to WASI 1.0 na akoloythei. I kyria prosthiki einai to glossiika ensoomatoomeno async me zero-copy streaming I/O.
97 
98## To Component Model
99 
100Ta vasika WASM modules mporoyn na atallaaxoun mono arithmoys. To **Component Model** lyni afton ton periorismo prosthetondas ena plousio systima typon kai ena epipedo synthetotitas pano apo to WASM.
101 
102### WIT (WebAssembly Interface Types)
103 
104To WIT einai mia glossa orismoy diepafon poy epitrepei sta components na dilosoun ta imports kai exports tous me ploysious typous  -  strings, records, lists, variants, enums  -  oxi mono `i32` kai `f64`.
105 
106```wit
107// calculator.wit
108package myorg:calculator@1.0.0;
109 
110interface operations {
111    record calculation {
112        expression: string,
113        result: f64,
114        timestamp: u64,
115    }
116 
117    add: func(a: f64, b: f64) -> f64;
118    multiply: func(a: f64, b: f64) -> f64;
119    history: func() -> list<calculation>;
120}
121 
122world calculator {
123    export operations;
124}
125```
126 
127Ergaleia opos to `wit-bindgen` paragoun glossikes syndeseis apo arxeia WIT. Ena Rust component kai ena Python component mporoyn na antalaaxoun strings, records kai lists meso WIT contracts xoris kamia pleyra na gnorixei ti glossa ylpoiisis tis allis.
128 
129## Xtiismo toy protoy WASM module soy me Rust
130 
131I Rust exei ta pio orimma ergaleia WASM. As chtisoyame ena praktiko paradeigma: ena module epexergasias eikonon poy trexei ston browser.
132 
133### Ryhthmisi
134 
135```bash
136# Install the WASM target for Rust
137rustup target add wasm32-unknown-unknown
138 
139# Install wasm-pack (builds Rust to WASM + generates JS bindings)
140cargo install wasm-pack
141 
142# Create a new library project
143cargo new --lib image-processor
144cd image-processor
145```
146 
147### Ryhthmisi Cargo.toml
148 
149```toml
150[package]
151name = "image-processor"
152version = "0.1.0"
153edition = "2021"
154 
155[lib]
156crate-type = ["cdylib"]
157 
158[dependencies]
159wasm-bindgen = "0.2"
160```
161 
162### Grapse ton kodika Rust
163 
164```rust
165// src/lib.rs
166use wasm_bindgen::prelude::*;
167 
168/// Convert an image buffer to grayscale.
169/// Input: RGBA pixel data as a flat u8 array (4 bytes per pixel).
170/// Output: Modified in place for zero-copy performance.
171#[wasm_bindgen]
172pub fn grayscale(pixels: &mut [u8]) {
173    for chunk in pixels.chunks_exact_mut(4) {
174        let r = chunk[0] as f32;
175        let g = chunk[1] as f32;
176        let b = chunk[2] as f32;
177        // ITU-R BT.709 luminance coefficients
178        let gray = (0.2126 * r + 0.7152 * g + 0.0722 * b) as u8;
179        chunk[0] = gray;
180        chunk[1] = gray;
181        chunk[2] = gray;
182        // chunk[3] is alpha, leave unchanged
183    }
184}
185 
186/// Adjust brightness of an image.
187/// factor > 1.0 brightens, < 1.0 darkens.
188#[wasm_bindgen]
189pub fn adjust_brightness(pixels: &mut [u8], factor: f32) {
190    for chunk in pixels.chunks_exact_mut(4) {
191        chunk[0] = ((chunk[0] as f32 * factor).min(255.0)) as u8;
192        chunk[1] = ((chunk[1] as f32 * factor).min(255.0)) as u8;
193        chunk[2] = ((chunk[2] as f32 * factor).min(255.0)) as u8;
194    }
195}
196 
197/// Invert all colors in the image.
198#[wasm_bindgen]
199pub fn invert(pixels: &mut [u8]) {
200    for chunk in pixels.chunks_exact_mut(4) {
201        chunk[0] = 255 - chunk[0];
202        chunk[1] = 255 - chunk[1];
203        chunk[2] = 255 - chunk[2];
204    }
205}
206 
207/// Calculate the average brightness of an image (0-255).
208#[wasm_bindgen]
209pub fn average_brightness(pixels: &[u8]) -> f32 {
210    let mut total: f64 = 0.0;
211    let pixel_count = pixels.len() / 4;
212    for chunk in pixels.chunks_exact(4) {
213        let luminance = 0.2126 * chunk[0] as f64
214            + 0.7152 * chunk[1] as f64
215            + 0.0722 * chunk[2] as f64;
216        total += luminance;
217    }
218    (total / pixel_count as f64) as f32
219}
220```
221 
222### Chtismo
223 
224```bash
225wasm-pack build --target web
226```
227 
228Afto dimiourgei enan katalogo `pkg/` me:
229- `image_processor_bg.wasm`  -  to metafrasmeno WASM binary
230- `image_processor.js`  -  JavaScript glue code me TypeScript definitions
231- `package.json`  -  etoimo gia dimosieysi sto npm
232 
233### Xrisi se JavaScript
234 
235```html
236<!DOCTYPE html>
237<html>
238<head><title>WASM Image Processor</title></head>
239<body>
240  <canvas id="canvas" width="800" height="600"></canvas>
241  <button onclick="applyGrayscale()">Grayscale</button>
242  <button onclick="applyBrightness()">Brighten</button>
243  <button onclick="applyInvert()">Invert</button>
244 
245  <script type="module">
246    import init, { grayscale, adjust_brightness, invert } from "./pkg/image_processor.js";
247 
248    let ctx;
249    let imageData;
250 
251    async function setup() {
252      await init();
253      const canvas = document.getElementById("canvas");
254      ctx = canvas.getContext("2d");
255 
256      // Load an image onto the canvas
257      const img = new Image();
258      img.onload = () => {
259        ctx.drawImage(img, 0, 0);
260        imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
261      };
262      img.src = "photo.jpg";
263    }
264 
265    window.applyGrayscale = () => {
266      grayscale(imageData.data);
267      ctx.putImageData(imageData, 0, 0);
268    };
269 
270    window.applyBrightness = () => {
271      adjust_brightness(imageData.data, 1.3);
272      ctx.putImageData(imageData, 0, 0);
273    };
274 
275    window.applyInvert = () => {
276      invert(imageData.data);
277      ctx.putImageData(imageData, 0, 0);
278    };
279 
280    setup();
281  </script>
282</body>
283</html>
284```
285 
286To vasiko symperasma: to `imageData.data` einai ena `Uint8ClampedArray` poy ypostirixetai apo ena `ArrayBuffer`. Otan perasetai sto WASM, moirazetai tin idia mnimi  -  xoris antigrafi. I synartisi Rust tropopoiei ta pixels epi topoy, kai i pleyra JavaScript vlepei tis allages amesa.
287 
288## Xamilitero epipedo: xeirokiiiti dimioyrgia WASM
289 
290An den theleis na xrisimopiiiseis to `wasm-bindgen`, mporeis na dimioyrgiiseis WASM modules apefthias:
291 
292```javascript
293const response = await fetch("calculator.wasm");
294const { instance } = await WebAssembly.instantiateStreaming(response, {
295  env: {
296    // Functions the WASM module can call
297    log_result: (value) => console.log("Result:", value),
298  },
299});
300 
301// Call exported functions
302const { add, multiply } = instance.exports;
303console.log(add(5, 3));       // 8
304console.log(multiply(4, 7));  // 28
305```
306 
307Afto einai xrisimo otan theleis elaxisto overhead kai den xreiaresai ploysio type interop.
308 
309## Apodosi: WASM vs JavaScript
310 
311Pragmatika benchmarks deixnoun simantiikes epiditaxynsis gia CPU-inteniis ergasies:
312 
313| Ergasia | JavaScript | WASM | Epiditaxynsii |
314|------|-----------|------|---------|
315| Epexergasia eikonas 4K | 180ms | 8ms (me SIMD) | 22x |
316| Allagi megethos eikonas (4K) | 250ms | 45ms | 5,5x |
317| Fysiki promoiosi (10K ontotites) | Aptosi frames | Omalo 60fps | ~10x |
318| Analysi JSON (megalo payload) | 12ms | 3ms | 4x |
319| Kryptografiko hashing | 45ms | 6ms | 7,5x |
320 
321To WASM trexei sto peripoy 95% tis taxytitas toy native kodika. Ta megalitera kerdi provainoun apo:
322- Provlepsimi apodosi (xoris JIT warmup, xoris GC pauses)
323- SIMD odigies gia parallili epexergasia dedomenon
324- Amesi prosvasi sti mnimi xoris paremvasi garbage collector
325 
326Opoy to WASM DEN einai grigoritero: DOM manipulation, mikres ypologismoi, I/O-bound ergasies. I JavaScript einai idi veltiomeni gi afta.
327 
328## Periptoseis xrisis stin paragogi
329 
330### Figma: Renderarisma vectors se pragmatiko xrono
331 
332I kyria mixani renderarismatos tis Figma einai C++ metafrasmeni se WASM. Kathe sxima, gradient kai efekt ypologizetai sto WASM kai ixnografeite se ena Canvas element. Afto epitrepei sti Figma na diaxeirizetai sintheta sxedia me xiliades layers sta 60fps ston browser  -  apodosi poy tha itan adynati se kathara JavaScript.
333 
334### Adobe Photoshop sto web
335 
336I Adobe metafere ta vasika filtra kai ergaleia toy Photoshop se WASM xrisimopoionteas Rust. Ta benchmarks tous deixnoun epexergasia eikonas 4K se 22ms me WASM SIMD enanti 180ms se JavaScript  -  mia 8x veltioosi poy kanei dynati tin pragmatikou xronou proepiskopisi filtron.
337 
338### Cloudflare Workers
339 
340To Cloudflare trexei WASM modules se V8 isolates se 330+ edge topothesies. Ta kria starts einai 1-5ms (se sygrisi me 100-500ms gia container-based serverless). Ton Fevrouario 2026, anaptixxan inference Llama-3-8b se olo to edge diktyo tous xrisimopoionteas WASM.
341 
342### Google Meet
343 
344To tholoma fontoy kai ta virtual backgrounds sto Google Meet xrisimopoioun WASM me SIMD gia epexergasia video se pragmatiko xrono. To WASM module epexergazetai kathe frame video arketa grigora gia na diatirei omalo video sta 30fps.
345 
346## Ypostirixi browser (2026)
347 
348| Xaraktiristiko | Chrome | Firefox | Safari | Edge |
349|---------|--------|---------|--------|------|
350| Core WASM | Plires | Plires | Plires | Plires |
351| Threads | Nai | Nai | Nai | Nai |
352| SIMD (128-bit) | Nai | Nai | Nai | Nai |
353| WasmGC | 119+ | 120+ | 18.2+ | Nai |
354| Exception Handling | Nai | Nai | Nai | Nai |
355| Memory64 | Nai | Nai | Merikos | Nai |
356 
357Oloi oi kyrioi browsers ypostirixoun pliros to WASM. Ta neotera xaraktiristika (WasmGC, Exception Handling) exoun ftasei se eyreia diathesimotita.
358 
359## Anafora ergaleion
360 
361| Ergaleio | Skopos | Egatastasi |
362|------|---------|---------|
363| **wasm-pack** | Chtismo Rust se WASM, dimioyrgia npm packages | `cargo install wasm-pack` |
364| **wasm-bindgen** | Rust/JS interop bindings (xrisimopoieitai apo wasm-pack) | Dependency sto Cargo.toml |
365| **wasm-opt** | Veltiostopiiisi megethous binary (50%+ meiosii) | Meros toy Binaryen: `brew install binaryen` |
366| **wit-bindgen** | Dimioyrgia bindings apo arxeia WIT | `cargo install wit-bindgen-cli` |
367| **Wasmtime** | Server-side WASM runtime (anafora ylpoiisis WASI) | `brew install wasmtime` |
368| **Wasmer** | Enallaktiko WASM runtime me ypostirixi WASI | `curl https://get.wasmer.io -sSfL \| sh` |
369| **wasm-feature-detect** | Anixneysi xaraktiristikon browser se xrono ektelesis | `npm install wasm-feature-detect` |
370 
371### Veltiostopiiisi megethous binary
372 
373Ta WASM binaries mporoyn na einai megala. Na pos ta mikroyneis:
374 
375```toml
376# Cargo.toml
377[profile.release]
378opt-level = "z"     # Optimize for size
379lto = true          # Link-time optimization
380codegen-units = 1   # Better optimization, slower compile
381strip = true        # Strip debug symbols
382```
383 
384```bash
385# Build in release mode
386wasm-pack build --release --target web
387 
388# Further optimize with wasm-opt
389wasm-opt -Oz pkg/image_processor_bg.wasm -o pkg/image_processor_bg.wasm
390```
391 
392Ena typiko Rust WASM module paei apo 500KB se kato apo 50KB me aftes tis veltiostopiiiseis.
393 
394## Xartis poreias gia xekinima
395 
396```mermaid
397flowchart TD
398    A[Week 1: Basics] --> B[Week 2: Real Project]
399    B --> C[Week 3: WASI and Server-side]
400    C --> D[Month 2+: Production]
401 
402    A --> A1[Install Rust + wasm-pack]
403    A --> A2[Build hello-world WASM module]
404    A --> A3[Call WASM functions from JavaScript]
405 
406    B --> B1[Build image processor or game physics]
407    B --> B2[Use wasm-bindgen for rich types]
408    B --> B3[Benchmark against pure JS]
409 
410    C --> C1[Run WASM with Wasmtime]
411    C --> C2[Explore WASI interfaces]
412    C --> C3[Try Component Model with WIT]
413 
414    D --> D1[Optimize binary size]
415    D --> D2[Use SIMD for parallelism]
416    D --> D3[Deploy to Cloudflare Workers or browser]
417```
418 
419## Symperasma
420 
421To WebAssembly den einai pia peiramatiko. Einai mia technologia paragogis poy xrisimopoieitai apo merikes apo tis pio apaitiitikes efarmoges sto web. Apodosi konta sti natiive, asfaleia sandboxed kai pagkosmia fornitotita  -  kanenas allos stoxos syllogis den soy dinei kai ta tria.
422 
423Den xreiazetai na xanagrapsis olis tin efarmogi soy se WASM. Arxise me mia moni CPU-intenii synartisi  -  ena filtro eikonas, enan analyti dedomenon, enan fysiko ypologismo  -  metafrase tin se WASM kai kalese tin apo JavaScript. Metrise ti diafora. Meta apofasise poy alloy mporei na voithisei to WASM.
424 
425Ta ergaleia einai orimma, i ypostirixi browser einai pagkosmia, kai to oikosystima megalononei. An grafeis Rust, eisai idi mia entoli makria apo ton browser.
426 
427> **Lista elegxoy gia xekinima:**
428>
429> - [x] Rust kai wasm-pack egatastimena
430> - [x] Proto WASM module xtismeno kai trexei ston browser
431> - [x] JavaScript interop leitourgei (klisi WASM apo JS)
432> - [x] Release build me veltiostopiiiseis megethous efarmosmenees
433> - [x] Apodosi axiologimeni enanti katharoy JavaScript isodinamoy
434> - [x] WASI exerevnimeno me Wasmtime gia server-side periptoseis xrisis
435