image-comparator - npm Package Compare versions

Comparing version 1.1.0 to 1.2.0

index.js

@@ -7,15 +7,25 @@ const {
   extractBitmapAndChannelCount,
+  MIMES,
 } = require("./lib");
 
 module.exports = {
-  compare: async (buffer1, buffer2) =>
-    areBuffersEqual(
+  compare: async (buffer1, buffer2) => {
+    const isInterformatComparison =
+      buffer1[0] === MIMES.WEBP && buffer1[0] !== buffer2[0];
+
+    if (isInterformatComparison) {
+      throw new Error("Interformat webp comparison not supported");
+    }
+
+    return areBuffersEqual(
       ...(await Promise.all([compareImpl(buffer1), compareImpl(buffer2)])),
-      BYTE_COMPARERS[buffer1.at(0)],
-      BYTE_COMPARERS[buffer2.at(0)]
-    ),
+      BYTE_COMPARERS[buffer1[0]],
+      BYTE_COMPARERS[buffer2[0]],
+      buffer1[0]
+    );
+  },
 };
 
 const compareImpl = async (buffer) => {
-  const { width, height } = getDimensions[buffer.at(0)](buffer);
+  const { width, height } = getDimensions[buffer[0]](buffer);
 
@@ -22,0 +32,0 @@ const { channels, data: bitmap } = await extractBitmapAndChannelCount(buffer);

lib/checkers.js

@@ -1,2 +0,2 @@
-const { HIT_THRESHOLD } = require("./enums");
+const { HIT_THRESHOLD, MIMES } = require("./enums");
 
@@ -8,3 +8,4 @@ // https://stackoverflow.com/a/21554107
   comparerOfBuffer1,
-  comparerOfBuffer2
+  comparerOfBuffer2,
+  mime
 ) => {
@@ -14,2 +15,18 @@ const view1 = new Int8Array(buffer1);
 
+  if (mime === MIMES.WEBP) {
+    const total = 16;
+    let hits = 0;
+
+    for (let i = 0; i < total; i++) {
+      if (
+        comparerOfBuffer1(view1[i], view2[i]) ||
+        comparerOfBuffer2(view1[i], view2[i])
+      ) {
+        hits++;
+      }
+    }
+
+    return hits / total >= 0.7;
+  }
+
   if (buffer1.byteLength != buffer2.byteLength) {
@@ -16,0 +33,0 @@ let hits = 0;

lib/enums.js

 const MIMES = {
   PNG: 0x89,
   JPG: 0xff,
+  WEBP: 0x52,
 };
@@ -9,2 +10,3 @@
   [MIMES.JPG]: (byte1, byte2) => Math.abs(byte1 - byte2) < 30,
+  [MIMES.WEBP]: (byte1, byte2) => Math.abs(byte1 - byte2) < 30,
 };
@@ -11,0 +13,0 @@

lib/getters.js

@@ -17,3 +17,9 @@ const {
 const { toUTF8String, toHexString } = require("./formatters");
-const { readUInt32BE, readUInt, readUInt16BE } = require("./readers");
+const {
+  readUInt32BE,
+  readUInt,
+  readUInt16BE,
+  readInt16LE,
+  readUInt24LE,
+} = require("./readers");
 
@@ -103,2 +109,27 @@ function isEXIF(input) {
 
+function calculateExtended(input) {
+  return {
+    height: 1 + readUInt24LE(input, 7),
+    width: 1 + readUInt24LE(input, 4),
+  };
+}
+
+function calculateLossless(input) {
+  return {
+    height:
+      1 +
+      (((input[4] & 0xf) << 10) | (input[3] << 2) | ((input[2] & 0xc0) >> 6)),
+    width: 1 + (((input[2] & 0x3f) << 8) | input[1]),
+  };
+}
+
+function calculateLossy(input) {
+  // `& 0x3fff` returns the last 14 bits
+  // TO-DO: include webp scaling in the calculations
+  return {
+    height: readInt16LE(input, 8) & 0x3fff,
+    width: readInt16LE(input, 6) & 0x3fff,
+  };
+}
+
 const getDimensions = {
@@ -158,2 +189,33 @@ // https://github.com/image-size/image-size/blob/08389eb1d6804485a3ae5964dfe827df885b0c54/lib/types/png.ts#L25
   },
+  // https://github.com/image-size/image-size/blob/08389eb1d6804485a3ae5964dfe827df885b0c54/lib/types/webp.ts#L38
+  [MIMES.WEBP]: (input) => {
+    const chunkHeader = toUTF8String(input, 12, 16);
+    input = input.slice(20, 30);
+
+    // Extended webp stream signature
+    if (chunkHeader === "VP8X") {
+      const extendedHeader = input[0];
+      const validStart = (extendedHeader & 0xc0) === 0;
+      const validEnd = (extendedHeader & 0x01) === 0;
+      if (validStart && validEnd) {
+        return calculateExtended(input);
+      } else {
+        // TODO: breaking change
+        throw new TypeError("Invalid WebP");
+      }
+    }
+
+    // Lossless webp stream signature
+    if (chunkHeader === "VP8 " && input[0] !== 0x2f) {
+      return calculateLossy(input);
+    }
+
+    // Lossy webp stream signature
+    const signature = toHexString(input, 3, 6);
+    if (chunkHeader === "VP8L" && signature !== "9d012a") {
+      return calculateLossless(input);
+    }
+
+    throw new TypeError("Invalid WebP");
+  },
 };
@@ -160,0 +222,0 @@

lib/parsers.js

 const Resize = require("./Resize");
+const { MIMES } = require("./enums");
+const parseJpg = require("./jpgparse");
+const { WebPDecoder, WebPRiffParser } = require("./webpparse");
 const { parse: parsePng } = require("./pngparse");
-const parseJpg = require("./jpgparse");
 
 const parseMapper = {
-  [0x89]: (buffer) =>
+  [MIMES.PNG]: (buffer) =>
     new Promise((resolve, reject) => {
@@ -16,7 +18,24 @@ parsePng(buffer, (error, bitmap) => {
     }),
-  [0xff]: parseJpg,
+  [MIMES.JPG]: parseJpg,
+  [MIMES.WEBP]: async (buffer) => {
+    const {
+      frames: [{ src_off: srcOff, src_size: srcSize }],
+    } = WebPRiffParser(buffer, 0);
+
+    const decoder = new WebPDecoder();
+    const dimensions = { width: [], height: [] };
+    return {
+      data: decoder.WebPDecodeRGBA(
+        buffer,
+        srcOff,
+        srcSize,
+        dimensions.width,
+        dimensions.height
+      ),
+      channels: 4,
+    };
+  },
 };
 
-const extractBitmapAndChannelCount = (buffer) =>
-  parseMapper[buffer.at(0)](buffer);
+const extractBitmapAndChannelCount = (buffer) => parseMapper[buffer[0]](buffer);
 
@@ -23,0 +42,0 @@ module.exports = {

lib/readers.js

@@ -12,2 +12,7 @@ // github.com/image-size/image-size/blob/08389eb1d6804485a3ae5964dfe827df885b0c54/lib/types/utils.ts
 
+const readInt16LE = (input, offset = 0) => {
+  const val = input[offset] + input[offset + 1] * 2 ** 8;
+  return val | ((val & (2 ** 15)) * 0x1fffe);
+};
+
 const readUInt = (input, bits, offset, isBigEndian) => {
@@ -20,6 +25,11 @@ offset = offset || 0;
 
+const readUInt24LE = (input, offset = 0) =>
+  input[offset] + input[offset + 1] * 2 ** 8 + input[offset + 2] * 2 ** 16;
+
 module.exports = {
   readUInt,
+  readInt16LE,
+  readUInt24LE,
   readUInt32BE,
   readUInt16BE,
 };

package.json

 {
   "name": "image-comparator",
-  "version": "1.1.0",
+  "version": "1.2.0",
   "description": "Compares images by resizing without dependencies",
@@ -5,0 +5,0 @@ "main": "index.js",

test/index.js

@@ -62,2 +62,28 @@ const assert = require("node:assert");
 
+describe("webp", () => {
+  const commonJpgImagesPath = [...commonImagesPath, "webp"];
+
+  it("should return false for different webp images", async () => {
+    const expected = false;
+    const commonPathSegments = [...commonJpgImagesPath, "different"];
+    const image1 = readFileSync(join(...commonPathSegments, "image1.webp"));
+    const image2 = readFileSync(join(...commonPathSegments, "image2.webp"));
+
+    const actual = await compare(image1, image2);
+
+    assert.strictEqual(actual, expected);
+  });
+
+  it("should return true for same webp images", async () => {
+    const expected = true;
+    const commonPathSegments = [...commonJpgImagesPath, "same"];
+    const image1 = readFileSync(join(...commonPathSegments, "image1.webp"));
+    const image2 = readFileSync(join(...commonPathSegments, "image2.webp"));
+
+    const actual = await compare(image1, image2);
+
+    assert.strictEqual(actual, expected);
+  });
+});
+
 describe("mixins", () => {
@@ -94,2 +120,16 @@ const commonPngImagesPath = [...commonImagesPath, "png"];
   });
+
+  it("should throw on interformat webp comparison (not implemented)", async () => {
+    const expected = Error;
+    const jpgImage = readFileSync(
+      join(...commonImagesPath, "webp", "same", "image1.webp")
+    );
+    const pngImage = readFileSync(
+      join(...commonImagesPath, "mixins", "image.png")
+    );
+
+    const actual = () => compare(jpgImage, pngImage);
+
+    assert.rejects(actual, expected);
+  });
 });

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Improved metrics

Total package byte prevSize

177675

increased by81.9%

Number of package files

30

increased by25%

Lines of code

3026

increased by21.04%

Worsened metrics

Number of medium supply chain risk alerts

4

increased byInfinity%

No dependency changes