Merge pull request #614 from zxing-js/bugfix/527-scan-fail

#527 Unable to scan PDF_417 codes
zxing-js · Aug 21, 2024 · fdeaca5 · fdeaca5
2 parents f1c51a5 + c103ed1
commit fdeaca5
Show file tree

Hide file tree

Showing 2 changed files with 64 additions and 64 deletions.
diff --git a/src/browser/BrowserCodeReader.ts b/src/browser/BrowserCodeReader.ts
@@ -934,14 +934,17 @@ export class BrowserCodeReader {
     mediaElement: HTMLVisualMediaElement
   ): BinaryBitmap {
     const ctx = this.getCaptureCanvasContext(mediaElement);
-    if(mediaElement instanceof HTMLVideoElement) {
+    // doing a scan with inverted colors on the second scan should only happen for video elements
+    let doAutoInvert = false;
+    if (mediaElement instanceof HTMLVideoElement) {
       this.drawFrameOnCanvas(<HTMLVideoElement>mediaElement);
+      doAutoInvert = true;
     } else {
       this.drawImageOnCanvas(<HTMLImageElement>mediaElement);
     }
     const canvas = this.getCaptureCanvas(mediaElement);
 
-    const luminanceSource = new HTMLCanvasElementLuminanceSource(canvas);
+    const luminanceSource = new HTMLCanvasElementLuminanceSource(canvas, doAutoInvert);
     const hybridBinarizer = new HybridBinarizer(luminanceSource);
 
     return new BinaryBitmap(hybridBinarizer);

diff --git a/src/browser/HTMLCanvasElementLuminanceSource.ts b/src/browser/HTMLCanvasElementLuminanceSource.ts
@@ -10,74 +10,71 @@ export class HTMLCanvasElementLuminanceSource extends LuminanceSource {
     private buffer: Uint8ClampedArray;
 
     private static DEGREE_TO_RADIANS = Math.PI / 180;
-	private static FRAME_INDEX = true;
+    private static FRAME_INDEX = true;
 
     private tempCanvasElement: HTMLCanvasElement = null;
 
-    public constructor(private canvas: HTMLCanvasElement) {
-        super(canvas.width, canvas.height);
-        this.buffer = HTMLCanvasElementLuminanceSource.makeBufferFromCanvasImageData(canvas);
+    public constructor(private canvas: HTMLCanvasElement, doAutoInvert: boolean = false) {
+      super(canvas.width, canvas.height);
+      this.buffer = HTMLCanvasElementLuminanceSource.makeBufferFromCanvasImageData(canvas, doAutoInvert);
     }
 
-    private static makeBufferFromCanvasImageData(canvas: HTMLCanvasElement): Uint8ClampedArray {
-        const imageData = canvas.getContext('2d').getImageData(0, 0, canvas.width, canvas.height);
-        return HTMLCanvasElementLuminanceSource.toGrayscaleBuffer(imageData.data, canvas.width, canvas.height);
+    private static makeBufferFromCanvasImageData(canvas: HTMLCanvasElement, doAutoInvert: boolean = false): Uint8ClampedArray {
+      const imageData = canvas.getContext('2d').getImageData(0, 0, canvas.width, canvas.height);
+      return HTMLCanvasElementLuminanceSource.toGrayscaleBuffer(imageData.data, canvas.width, canvas.height, doAutoInvert);
     }
 
-    private static toGrayscaleBuffer(imageBuffer: Uint8ClampedArray, width: number, height: number): Uint8ClampedArray {
-        const grayscaleBuffer = new Uint8ClampedArray(width * height);
-		HTMLCanvasElementLuminanceSource.FRAME_INDEX = !HTMLCanvasElementLuminanceSource.FRAME_INDEX;
-		if(HTMLCanvasElementLuminanceSource.FRAME_INDEX)
-		{
-			for (let i = 0, j = 0, length = imageBuffer.length; i < length; i += 4, j++) {
-				let gray;
-				const alpha = imageBuffer[i + 3];
-				// The color of fully-transparent pixels is irrelevant. They are often, technically, fully-transparent
-				// black (0 alpha, and then 0 RGB). They are often used, of course as the "white" area in a
-				// barcode image. Force any such pixel to be white:
-				if (alpha === 0) {
-					gray = 0xFF;
-				} else {
-					const pixelR = imageBuffer[i];
-					const pixelG = imageBuffer[i + 1];
-					const pixelB = imageBuffer[i + 2];
-					// .299R + 0.587G + 0.114B (YUV/YIQ for PAL and NTSC),
-					// (306*R) >> 10 is approximately equal to R*0.299, and so on.
-					// 0x200 >> 10 is 0.5, it implements rounding.
-					gray = (306 * pixelR +
-						601 * pixelG +
-						117 * pixelB +
-						0x200) >> 10;
-				}
-				grayscaleBuffer[j] = gray;
-			}
-		}
-		else
-		{
-			for (let i = 0, j = 0, length = imageBuffer.length; i < length; i += 4, j++) {
-				let gray;
-				const alpha = imageBuffer[i + 3];
-				// The color of fully-transparent pixels is irrelevant. They are often, technically, fully-transparent
-				// black (0 alpha, and then 0 RGB). They are often used, of course as the "white" area in a
-				// barcode image. Force any such pixel to be white:
-				if (alpha === 0) {
-					gray = 0xFF;
-				} else {
-					const pixelR = imageBuffer[i];
-					const pixelG = imageBuffer[i + 1];
-					const pixelB = imageBuffer[i + 2];
-					// .299R + 0.587G + 0.114B (YUV/YIQ for PAL and NTSC),
-					// (306*R) >> 10 is approximately equal to R*0.299, and so on.
-					// 0x200 >> 10 is 0.5, it implements rounding.
-					gray = (306 * pixelR +
-						601 * pixelG +
-						117 * pixelB +
-						0x200) >> 10;
-				}
-				grayscaleBuffer[j] = 0xFF - gray;
-			}
-		}
-        return grayscaleBuffer;
+    private static toGrayscaleBuffer(imageBuffer: Uint8ClampedArray, width: number, height: number, doAutoInvert: boolean = false): Uint8ClampedArray {
+      const grayscaleBuffer = new Uint8ClampedArray(width * height);
+      HTMLCanvasElementLuminanceSource.FRAME_INDEX = !HTMLCanvasElementLuminanceSource.FRAME_INDEX;
+      if (HTMLCanvasElementLuminanceSource.FRAME_INDEX || !doAutoInvert) {
+        for (let i = 0, j = 0, length = imageBuffer.length; i < length; i += 4, j++) {
+          let gray;
+          const alpha = imageBuffer[i + 3];
+          // The color of fully-transparent pixels is irrelevant. They are often, technically, fully-transparent
+          // black (0 alpha, and then 0 RGB). They are often used, of course as the "white" area in a
+          // barcode image. Force any such pixel to be white:
+          if (alpha === 0) {
+            gray = 0xFF;
+          } else {
+            const pixelR = imageBuffer[i];
+            const pixelG = imageBuffer[i + 1];
+            const pixelB = imageBuffer[i + 2];
+            // .299R + 0.587G + 0.114B (YUV/YIQ for PAL and NTSC),
+            // (306*R) >> 10 is approximately equal to R*0.299, and so on.
+            // 0x200 >> 10 is 0.5, it implements rounding.
+            gray = (306 * pixelR +
+              601 * pixelG +
+              117 * pixelB +
+              0x200) >> 10;
+          }
+          grayscaleBuffer[j] = gray;
+        }
+      } else {
+        for (let i = 0, j = 0, length = imageBuffer.length; i < length; i += 4, j++) {
+          let gray;
+          const alpha = imageBuffer[i + 3];
+          // The color of fully-transparent pixels is irrelevant. They are often, technically, fully-transparent
+          // black (0 alpha, and then 0 RGB). They are often used, of course as the "white" area in a
+          // barcode image. Force any such pixel to be white:
+          if (alpha === 0) {
+            gray = 0xFF;
+          } else {
+            const pixelR = imageBuffer[i];
+            const pixelG = imageBuffer[i + 1];
+            const pixelB = imageBuffer[i + 2];
+            // .299R + 0.587G + 0.114B (YUV/YIQ for PAL and NTSC),
+            // (306*R) >> 10 is approximately equal to R*0.299, and so on.
+            // 0x200 >> 10 is 0.5, it implements rounding.
+            gray = (306 * pixelR +
+              601 * pixelG +
+              117 * pixelB +
+              0x200) >> 10;
+          }
+          grayscaleBuffer[j] = 0xFF - gray;
+        }
+      }
+      return grayscaleBuffer;
     }
 
     public getRow(y: number /*int*/, row: Uint8ClampedArray): Uint8ClampedArray {
@@ -167,4 +164,4 @@ export class HTMLCanvasElementLuminanceSource extends LuminanceSource {
     public invert(): LuminanceSource {
         return new InvertedLuminanceSource(this);
     }
-}
+}