fix(cv): resolve infinite page duplication bug caused by playback cursor

scripts/debug/dump_measure_numbers.py

@@ -0,0 +1,50 @@
+import cv2
+import numpy as np
+import os
+
+pdf_path = r"C:\Users\Certes\Desktop\guitar_score\output\shintakarajima_perfect.pdf"
+out_dir = r"C:\Users\Certes\Desktop\guitar_score\scripts\debug"
+
+img_path = os.path.join(out_dir, "verify_chunk_0.jpg") # from previous sessions
+if not os.path.exists(img_path):
+    print("verify_chunk_0.jpg not found. extracting a page from PDF...")
+    import fitz
+    doc = fitz.open(pdf_path)
+    page = doc.load_page(0)
+    pix = page.get_pixmap(dpi=150)
+    pix.save(os.path.join(out_dir, "pdf_test_page.png"))
+    img_path = os.path.join(out_dir, "pdf_test_page.png")
+
+img = cv2.imread(img_path)
+gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
+_, bin_inv = cv2.threshold(gray, 200, 255, cv2.THRESH_BINARY_INV)
+
+h, w = img.shape[:2]
+staff_y_top = int(h * 0.3)
+row_sums = np.sum(bin_inv[:, :min(w, 1000)], axis=1) / 255.0
+staff_rows = np.where(row_sums > min(w, 1000) * 0.4)[0]
+if len(staff_rows) >= 6: staff_y_top = staff_rows[0]
+
+# locate measure bars
+col_sums = np.sum(bin_inv[staff_y_top:staff_y_top+100, :], axis=0) / 255.0
+bar_xs = np.where(col_sums > 30)[0]
+bars = []
+if len(bar_xs) > 0:
+    curr = [bar_xs[0]]
+    for x in bar_xs[1:]:
+        if x - curr[-1] < 10: curr.append(x)
+        else:
+            bars.append(int(np.mean(curr)))
+            curr = [x]
+    bars.append(int(np.mean(curr)))
+
+# Crop first 5 measure numbers
+for i, x in enumerate(bars[:5]):
+    box_y1 = max(0, staff_y_top - 40)
+    box_y2 = staff_y_top
+    box_x1 = x
+    box_x2 = min(w, x + 60)
+    crop = img[box_y1:box_y2, box_x1:box_x2]
+    out_file = os.path.join(out_dir, f"measure_num_{i}.png")
+    cv2.imwrite(out_file, crop)
+    print(f"Saved measure number crop to {out_file}")