feat: avif removes the alphaQuality option and uses internal calculat…

…ions

__test__/draw.spec.ts

@@ -916,7 +916,7 @@ test('toDataURL', async (t) => {
   t.deepEqual(pngBuffer, await canvas.encode('png'))
 })
 
-test('toDataURL with quality', async (t) => {
+test('JPEG toDataURL with quality', async (t) => {
   const { ctx, canvas } = t.context
   drawTranslate(ctx)
 
@@ -928,6 +928,18 @@ test('toDataURL with quality', async (t) => {
   t.deepEqual(pngBuffer, await canvas.encode('jpeg', 20))
 })
 
+test('WebP toDataURL with quality', async (t) => {
+  const { ctx, canvas } = t.context
+  drawTranslate(ctx)
+
+  const output = canvas.toDataURL('image/webp', 100)
+  const prefix = 'data:image/webp;base64,'
+  t.true(output.startsWith(prefix))
+  const imageBase64 = output.substr(prefix.length)
+  const pngBuffer = Buffer.from(imageBase64, 'base64')
+  t.deepEqual(pngBuffer, await canvas.encode('webp', 100))
+})
+
 test('toDataURLAsync', async (t) => {
   const { ctx, canvas } = t.context
   drawTranslate(ctx)

example/anime-girl.js

@@ -30,7 +30,10 @@ async function main() {
   await fs.writeFile(join(__dirname, 'anime-girl.png'), pngData)
   const t1 = performance.now()
 
-  const avifData = await canvas.encode('avif')
+  const avifData = await canvas.encode('avif', {
+    quality: 79,
+    speed: 5,
+  })
   await fs.writeFile(join(__dirname, 'anime-girl.avif'), avifData)
 
   const t2 = performance.now()

index.d.ts

@@ -298,7 +298,6 @@ export interface SvgCanvas {
 
 export interface AvifConfig {
   quality?: number
-  alphaQuality?: number
   speed?: number
   threads?: number
 }

index.js

@@ -221,16 +221,28 @@ function createCanvas(width, height, flag) {
     toDataURLAsync: canvasToDataURLAsync,
   } = Object.getPrototypeOf(canvasElement)
 
+  // See also: https://github.com/kornelski/cavif-rs#usage
+  const avifDefaultQuality = 80
+  const avifConfig = {
+    // Quality from 1 (worst) to 100 (best), the default value is 80. The numbers have different meaning than JPEG's quality scale. Beware when comparing codecs. There is no lossless compression support.
+    quality: avifDefaultQuality,
+
+    // Calculate alphaQuality, this is consistent with cavif.
+    // https://github.com/kornelski/cavif-rs/blob/37847b95bb81d4cf90e36b7fab2c7fbbcf95abe2/src/main.rs#L97
+    alphaQuality: Math.min((avifDefaultQuality + 100) / 2, avifDefaultQuality + avifDefaultQuality / 4 + 2),
+    threads: 0,
+
+    // Encoding speed between 1 (best, but slowest) and 10 (fastest, but a blurry mess), the default value is 4. Speeds 1 and 2 are unbelievably slow, but make files ~3-5% smaller. Speeds 7 and above degrade compression significantly, and are not recommended.
+    speed: 4,
+  }
+
   canvasElement.encode = function encode(type, qualityOrConfig) {
     if (type === 'avif') {
       return canvasEncode.call(
         this,
         type,
         JSON.stringify({
-          quality: 80,
-          alphaQuality: 92,
-          threads: 0,
-          speed: 4,
+          ...avifConfig,
           ...(qualityOrConfig || {}),
         }),
       )
@@ -244,10 +256,7 @@ function createCanvas(width, height, flag) {
         this,
         type,
         JSON.stringify({
-          quality: 80,
-          alphaQuality: 92,
-          threads: 0,
-          speed: 4,
+          ...avifConfig,
           ...(qualityOrConfig || {}),
         }),
       )
@@ -261,10 +270,7 @@ function createCanvas(width, height, flag) {
         this,
         type,
         JSON.stringify({
-          quality: 80,
-          alphaQuality: 92,
-          threads: 0,
-          speed: 4,
+          ...avifConfig,
           ...(qualityOrConfig || {}),
         }),
       )
@@ -278,10 +284,7 @@ function createCanvas(width, height, flag) {
         this,
         type,
         JSON.stringify({
-          quality: 80,
-          alphaQuality: 92,
-          threads: 0,
-          speed: 4,
+          ...avifConfig,
           ...(qualityOrConfig || {}),
         }),
       )
@@ -295,10 +298,7 @@ function createCanvas(width, height, flag) {
         this,
         type,
         JSON.stringify({
-          quality: 80,
-          alphaQuality: 92,
-          threads: 0,
-          speed: 4,
+          ...avifConfig,
           ...(qualityOrConfig || {}),
         }),
       )

src/ctx.rs

@@ -2135,8 +2135,6 @@ fn get_text_baseline(ctx: CallContext) -> Result<JsString> {
 #[derive(Debug, Clone, Copy, PartialEq, Deserialize)]
 pub struct AVIFConfig {
   pub quality: f32,
-  #[serde(rename = "alphaQuality")]
-  pub alpha_quality: f32,
   pub speed: u8,
   pub threads: u8,
 }
@@ -2208,7 +2206,8 @@ impl Task for ContextData {
             ),
             &ravif::Config {
               quality: config.quality,
-              alpha_quality: config.alpha_quality,
+              alpha_quality: ((config.quality + 100.) / 2.)
+                .min(config.quality + config.quality / 4. + 2.),
               speed: config.speed,
               premultiplied_alpha: false,
               threads: 0,

src/lib.rs

@@ -236,7 +236,8 @@ fn encode_sync(ctx: CallContext) -> Result<JsBuffer> {
         ),
         &ravif::Config {
           quality: config.quality,
-          alpha_quality: config.alpha_quality,
+          alpha_quality: ((config.quality + 100.) / 2.)
+            .min(config.quality + config.quality / 4. + 2.),
           speed: config.speed,
           premultiplied_alpha: false,
           threads: 0,
@@ -280,10 +281,13 @@ fn encode_sync(ctx: CallContext) -> Result<JsBuffer> {
 fn to_buffer(ctx: CallContext) -> Result<JsBuffer> {
   let mime_js = ctx.get::<JsString>(0)?.into_utf8()?;
   let mime = mime_js.as_str()?;
-  let quality = if ctx.length < 2 {
-    DEFAULT_JPEG_QUALITY
-  } else {
+  let quality = if mime != MIME_AVIF {
     ctx.get::<JsNumber>(1)?.get_uint32()? as u8
+  } else if mime == MIME_WEBP {
+    DEFAULT_WEBP_QUALITY
+  } else {
+    // https://developer.mozilla.org/en-US/docs/Web/API/HTMLCanvasElement/toDataURL
+    DEFAULT_JPEG_QUALITY
   };
 
   let context_data = get_data_ref(&ctx, mime, quality)?;
@@ -332,11 +336,13 @@ fn data(ctx: CallContext) -> Result<JsBuffer> {
 fn to_data_url(ctx: CallContext) -> Result<JsString> {
   let mime_js = ctx.get::<JsString>(0)?.into_utf8()?;
   let mime = mime_js.as_str()?;
-  let quality = if ctx.length < 2 {
+  let quality = if mime != MIME_AVIF {
+    ctx.get::<JsNumber>(1)?.get_uint32()? as u8
+  } else if mime == MIME_WEBP {
+    DEFAULT_WEBP_QUALITY
+  } else {
     // https://developer.mozilla.org/en-US/docs/Web/API/HTMLCanvasElement/toDataURL
     DEFAULT_JPEG_QUALITY
-  } else {
-    ctx.get::<JsNumber>(1)?.get_uint32()? as u8
   };
   let data_ref = get_data_ref(&ctx, mime, quality)?;
   let mut output = format!("data:{};base64,", &mime);
@@ -355,11 +361,13 @@ fn to_data_url(ctx: CallContext) -> Result<JsString> {
 fn to_data_url_async(ctx: CallContext) -> Result<JsObject> {
   let mime_js = ctx.get::<JsString>(0)?.into_utf8()?;
   let mime = mime_js.as_str()?;
-  let quality = if ctx.length < 2 {
+  let quality = if mime != MIME_AVIF {
+    ctx.get::<JsNumber>(1)?.get_uint32()? as u8
+  } else if mime == MIME_WEBP {
+    DEFAULT_WEBP_QUALITY
+  } else {
     // https://developer.mozilla.org/en-US/docs/Web/API/HTMLCanvasElement/toDataURL
     DEFAULT_JPEG_QUALITY
-  } else {
-    ctx.get::<JsNumber>(1)?.get_uint32()? as u8
   };
   let data_ref = get_data_ref(&ctx, mime, quality)?;
   let async_task = AsyncDataUrl {
@@ -414,7 +422,8 @@ fn get_data_ref(ctx: &CallContext, mime: &str, quality: u8) -> Result<ContextOut
         ),
         &ravif::Config {
           quality: config.quality,
-          alpha_quality: config.alpha_quality,
+          alpha_quality: ((config.quality + 100.) / 2.)
+            .min(config.quality + config.quality / 4. + 2.),
           speed: config.speed,
           premultiplied_alpha: false,
           threads: 0,