Try to reduce false positives in ad detection

app/src/main/rust/src/img/qr_code.rs

@@ -1,13 +1,13 @@
 use crate::{jni_throwing, with_bitmap_content};
-use anyhow::Ok;
 use image::{ImageBuffer, Rgba};
 use jni::objects::JClass;
 use jni::sys::{jboolean, jobject};
 use jni::JNIEnv;
 use jni_fn::jni_fn;
 use rxing::common::HybridBinarizer;
-use rxing::qrcode::detector::Detector;
-use rxing::{BinaryBitmap, RGBLuminanceSource};
+use rxing::qrcode::detector::FinderPatternFinder;
+use rxing::{BinaryBitmap, DecodingHintDictionary, Point, RGBLuminanceSource};
+use std::f32::consts::FRAC_1_SQRT_2;
 use std::ptr::slice_from_raw_parts;
 
 fn detect_image_ad(image: ImageBuffer<Rgba<u8>, &[u8]>) -> bool {
@@ -16,7 +16,19 @@ fn detect_image_ad(image: ImageBuffer<Rgba<u8>, &[u8]>) -> bool {
     let pixels = unsafe { &*slice_from_raw_parts(buffer.as_ptr() as *const u32, buffer.len()) };
     let source = RGBLuminanceSource::new_with_width_height_pixels(width, height, pixels);
     let image = BinaryBitmap::new(HybridBinarizer::new(source));
-    Detector::new(image.get_black_matrix()).detect().is_ok()
+    match FinderPatternFinder::new(image.get_black_matrix()).find(&DecodingHintDictionary::new()) {
+        Ok(info) => {
+            // Check if the region is squarish
+            let top_left = Point::from(info.getTopLeft());
+            let top_right = Point::from(info.getTopRight());
+            let bottom_left = Point::from(info.getBottomLeft());
+            let length = top_right.distance(top_left);
+            let epsilon = length * 0.05;
+            (bottom_left.distance(top_left) - length).abs() < epsilon
+                && (bottom_left.distance(top_right) * FRAC_1_SQRT_2 - length).abs() < epsilon
+        }
+        Err(_) => false,
+    }
 }
 
 #[no_mangle]