Convert the code in src/core/image.js to use ES6 classes

src/core/image.js

@@ -20,7 +20,6 @@ import { DecodeStream } from "./stream.js";
 import { JpegStream } from "./jpeg_stream.js";
 import { JpxImage } from "./jpx.js";
 
-var PDFImage = (function PDFImageClosure() {
 /**
  * Decode and clamp a value. The formula is different from the spec because we
  * don't decode to float range [0,1], we decode it in the [0,max] range.
@@ -79,8 +78,8 @@ var PDFImage = (function PDFImageClosure() {
   return dest;
 }
 
-  // eslint-disable-next-line no-shadow
-  function PDFImage({
+class PDFImage {
+  constructor({
     xref,
     res,
     image,
@@ -247,11 +246,12 @@ var PDFImage = (function PDFImageClosure() {
       }
     }
   }
+
   /**
    * Handles processing of image data and returns the Promise that is resolved
    * with a PDFImage when the image is ready to be used.
    */
-  PDFImage.buildImage = async function ({
+  static async buildImage({
     xref,
     res,
     image,
@@ -286,9 +286,9 @@ var PDFImage = (function PDFImageClosure() {
       pdfFunctionFactory,
       localColorSpaceCache,
     });
-  };
+  }
 
-  PDFImage.createMask = function ({
+  static createMask({
     imgArray,
     width,
     height,
@@ -340,24 +340,23 @@ var PDFImage = (function PDFImageClosure() {
     }
 
     return { data, width, height };
-  };
+  }
 
-  PDFImage.prototype = {
   get drawWidth() {
     return Math.max(
       this.width,
       (this.smask && this.smask.width) || 0,
       (this.mask && this.mask.width) || 0
     );
-    },
+  }
 
   get drawHeight() {
     return Math.max(
       this.height,
       (this.smask && this.smask.height) || 0,
       (this.mask && this.mask.height) || 0
     );
-    },
+  }
 
   decodeBuffer(buffer) {
     var bpc = this.bpc;
@@ -387,7 +386,7 @@ var PDFImage = (function PDFImageClosure() {
         index++;
       }
     }
-    },
+  }
 
   getComponents(buffer) {
     var bpc = this.bpc;
@@ -477,7 +476,7 @@ var PDFImage = (function PDFImageClosure() {
       }
     }
     return output;
-    },
+  }
 
   fillOpacity(rgbaBuf, width, height, actualHeight, image) {
     if (
@@ -499,14 +498,7 @@ var PDFImage = (function PDFImageClosure() {
       alphaBuf = new Uint8ClampedArray(sw * sh);
       smask.fillGrayBuffer(alphaBuf);
       if (sw !== width || sh !== height) {
-          alphaBuf = resizeImageMask(
-            alphaBuf,
-            smask.bpc,
-            sw,
-            sh,
-            width,
-            height
-          );
+        alphaBuf = resizeImageMask(alphaBuf, smask.bpc, sw, sh, width, height);
       }
     } else if (mask) {
       if (mask instanceof PDFImage) {
@@ -522,14 +514,7 @@ var PDFImage = (function PDFImageClosure() {
         }
 
         if (sw !== width || sh !== height) {
-            alphaBuf = resizeImageMask(
-              alphaBuf,
-              mask.bpc,
-              sw,
-              sh,
-              width,
-              height
-            );
+          alphaBuf = resizeImageMask(alphaBuf, mask.bpc, sw, sh, width, height);
         }
       } else if (Array.isArray(mask)) {
         // Color key mask: if any of the components are outside the range
@@ -564,7 +549,7 @@ var PDFImage = (function PDFImageClosure() {
         rgbaBuf[j] = 255;
       }
     }
-    },
+  }
 
   undoPreblend(buffer, width, height) {
     if (
@@ -600,7 +585,7 @@ var PDFImage = (function PDFImageClosure() {
       buffer[i + 1] = (buffer[i + 1] - matteG) * k + matteG;
       buffer[i + 2] = (buffer[i + 2] - matteB) * k + matteB;
     }
-    },
+  }
 
   createImageData(forceRGBA = false) {
     var drawWidth = this.drawWidth;
@@ -747,7 +732,7 @@ var PDFImage = (function PDFImageClosure() {
     }
 
     return imgData;
-    },
+  }
 
   fillGrayBuffer(buffer) {
     if (
@@ -803,17 +788,15 @@ var PDFImage = (function PDFImageClosure() {
     for (i = 0; i < length; ++i) {
       buffer[i] = scale * comps[i];
     }
-    },
+  }
 
   getImageBytes(length, drawWidth, drawHeight, forceRGB = false) {
     this.image.reset();
     this.image.drawWidth = drawWidth || this.width;
     this.image.drawHeight = drawHeight || this.height;
     this.image.forceRGB = !!forceRGB;
     return this.image.getBytes(length, /* forceClamped = */ true);
-    },
-  };
-  return PDFImage;
-})();
+  }
+}
 
 export { PDFImage };