init

libs/browser-fingerprint/canvas.go

@@ -0,0 +1,65 @@
+package browserfingerprint
+
+import "fmt"
+
+func GetChangeCanvasJavaScript(rgba [4]int) string {
+	return fmt.Sprintf(`
+            const getImageData = CanvasRenderingContext2D.prototype.getImageData;
+
+            const noisify = (canvas, context) => {
+                if (context) {
+                    const shift = {
+                        r: %d,
+                        g: %d,
+                        b: %d,
+                        a: %d,
+                    };
+                    const width = canvas.width;
+                    const height = canvas.height;
+
+                    if (width && height) {
+                        const imageData = getImageData.apply(context, [0, 0, width, height]);
+
+                        for (let i = 0; i < height; i++) 
+                            for (let j = 0; j < width; j++) {
+                                const n = i * (width * 4) + j * 4;
+                                imageData.data[n + 0] = imageData.data[n + 0] + shift.r;
+                                imageData.data[n + 1] = imageData.data[n + 1] + shift.g;
+                                imageData.data[n + 2] = imageData.data[n + 2] + shift.b;
+                                imageData.data[n + 3] = imageData.data[n + 3] + shift.a;
+                            }
+                    
+
+                        context.putImageData(imageData, 0, 0);
+                    }
+                }
+            };
+
+            HTMLCanvasElement.prototype.toBlob = new Proxy(HTMLCanvasElement.prototype.toBlob, {
+                apply(target, self, args) {
+                    noisify(self, self.getContext('2d'));
+
+                    return Reflect.apply(target, self, args);
+                },
+            });
+
+            HTMLCanvasElement.prototype.toDataURL = new Proxy(HTMLCanvasElement.prototype.toDataURL, {
+                apply(target, self, args) {
+                    noisify(self, self.getContext('2d'));
+
+                    return Reflect.apply(target, self, args);
+                },
+            });
+
+            CanvasRenderingContext2D.prototype.getImageData = new Proxy(
+                CanvasRenderingContext2D.prototype.getImageData,
+                {
+                    apply(target, self, args) {
+                        noisify(self.canvas, self);
+
+                        return Reflect.apply(target, self, args);
+                    },
+                }
+            );
+`, rgba[0], rgba[1], rgba[2], rgba[3])
+}