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Refactor point-to-line distance calculation in VideoEditor

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This commit refines the distance calculation method in the VideoEditor class by introducing a new function, _point_to_line_distance_and_foot, which computes the distance from a point to an infinite line and returns the foot of the perpendicular. The snapping logic has been updated to utilize this new method, enhancing the accuracy of line snapping between tracking points. Additionally, debug statements have been added to assist in tracking the snapping process and verifying point conversions.
This commit is contained in:
PhatPhuckDave
2025-09-17 15:36:05 +02:00
parent 68a1cc3e7d
commit c3e0088a60
1 changed files with 66 additions and 35 deletions
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101
croppa/main.py
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@@ -1132,26 +1132,31 @@ class VideoEditor:
next_frame = min(next_frames) next_frame = min(next_frames)
return next_frame, self.tracking_points[next_frame] return next_frame, self.tracking_points[next_frame]
def _point_to_line_distance(self, px, py, x1, y1, x2, y2): def _point_to_line_distance_and_foot(self, px, py, x1, y1, x2, y2):
"""Calculate distance from point (px, py) to line segment (x1, y1) to (x2, y2)""" """Calculate distance from point (px, py) to infinite line (x1, y1) to (x2, y2) and return foot of perpendicular"""
# Vector from line start to end # Convert line to general form: Ax + By + C = 0
line_dx = x2 - x1 # (y2 - y1)(x - x1) - (x2 - x1)(y - y1) = 0
line_dy = y2 - y1 A = y2 - y1
line_length_sq = line_dx * line_dx + line_dy * line_dy B = -(x2 - x1) # Note the negative sign
C = -(A * x1 + B * y1)
if line_length_sq == 0: # Calculate distance: d = |Ax + By + C| / sqrt(A^2 + B^2)
denominator = (A * A + B * B) ** 0.5
if denominator == 0:
# Line is actually a point # Line is actually a point
return ((px - x1) ** 2 + (py - y1) ** 2) ** 0.5 distance = ((px - x1) ** 2 + (py - y1) ** 2) ** 0.5
return distance, (x1, y1)
# Parameter t for closest point on line (0 = start, 1 = end) distance = abs(A * px + B * py + C) / denominator
t = max(0, min(1, ((px - x1) * line_dx + (py - y1) * line_dy) / line_length_sq))
# Closest point on line segment # Calculate foot of perpendicular: (xf, yf)
closest_x = x1 + t * line_dx # xf = xu - A(Axu + Byu + C)/(A^2 + B^2)
closest_y = y1 + t * line_dy # yf = yu - B(Axu + Byu + C)/(A^2 + B^2)
numerator = A * px + B * py + C
xf = px - A * numerator / (A * A + B * B)
yf = py - B * numerator / (A * A + B * B)
# Distance to closest point return distance, (xf, yf)
return ((px - closest_x) ** 2 + (py - closest_y) ** 2) ** 0.5
def advance_frame(self) -> bool: def advance_frame(self) -> bool:
"""Advance to next frame - handles playback speed and marker looping""" """Advance to next frame - handles playback speed and marker looping"""
@@ -2183,7 +2188,7 @@ class VideoEditor:
best_snap_point = None best_snap_point = None
# Check all tracking points from all frames for point snapping # Check all tracking points from all frames for point snapping
for _, points in self.tracking_points.items(): for frame_num, points in self.tracking_points.items():
for (px, py) in points: for (px, py) in points:
sxp, syp = self._map_rotated_to_screen(px, py) sxp, syp = self._map_rotated_to_screen(px, py)
distance = ((sxp - x) ** 2 + (syp - y) ** 2) ** 0.5 distance = ((sxp - x) ** 2 + (syp - y) ** 2) ** 0.5
@@ -2191,50 +2196,76 @@ class VideoEditor:
best_snap_distance = distance best_snap_distance = distance
best_snap_point = (int(px), int(py)) best_snap_point = (int(px), int(py))
# Check for line snapping between consecutive tracking points # Check for line snapping between previous and next tracking points (the actual cyan arrows)
tracking_frames = sorted(self.tracking_points.keys()) prev_result = self._get_previous_tracking_point()
for i in range(len(tracking_frames) - 1): next_result = self._get_next_tracking_point()
frame1 = tracking_frames[i]
frame2 = tracking_frames[i + 1] print(f"DEBUG: Line snapping - prev_result: {prev_result}, next_result: {next_result}")
points1 = self.tracking_points[frame1]
points2 = self.tracking_points[frame2] if prev_result and next_result:
prev_frame, prev_pts = prev_result
next_frame, next_pts = next_result
# Check each corresponding pair of points print(f"DEBUG: Checking line between prev frame {prev_frame} and next frame {next_frame}")
for j in range(min(len(points1), len(points2))):
px1, py1 = points1[j] # Check each corresponding pair of points between previous and next
px2, py2 = points2[j] for j in range(min(len(prev_pts), len(next_pts))):
px1, py1 = prev_pts[j]
px2, py2 = next_pts[j]
# Convert to screen coordinates # Convert to screen coordinates
sx1, sy1 = self._map_rotated_to_screen(px1, py1) sx1, sy1 = self._map_rotated_to_screen(px1, py1)
sx2, sy2 = self._map_rotated_to_screen(px2, py2) sx2, sy2 = self._map_rotated_to_screen(px2, py2)
# Calculate distance to line segment # Calculate distance to infinite line and foot of perpendicular
line_distance = self._point_to_line_distance(x, y, sx1, sy1, sx2, sy2) line_distance, (foot_x, foot_y) = self._point_to_line_distance_and_foot(x, y, sx1, sy1, sx2, sy2)
print(f"DEBUG: Line {j}: ({sx1},{sy1}) to ({sx2},{sy2}), distance to click ({x},{y}) = {line_distance:.2f}, foot = ({foot_x:.1f}, {foot_y:.1f})")
if line_distance <= threshold and line_distance < best_snap_distance: if line_distance <= threshold and line_distance < best_snap_distance:
# Find the closest point on the line segment print(f"DEBUG: Line snap found! Distance {line_distance:.2f} <= threshold {threshold}")
# Clamp the foot to the line segment
# Calculate parameter t for the foot point
line_dx = sx2 - sx1 line_dx = sx2 - sx1
line_dy = sy2 - sy1 line_dy = sy2 - sy1
line_length_sq = line_dx * line_dx + line_dy * line_dy line_length_sq = line_dx * line_dx + line_dy * line_dy
if line_length_sq > 0: if line_length_sq > 0:
t = max(0, min(1, ((x - sx1) * line_dx + (y - sy1) * line_dy) / line_length_sq)) t = ((foot_x - sx1) * line_dx + (foot_y - sy1) * line_dy) / line_length_sq
closest_sx = sx1 + t * line_dx t = max(0, min(1, t)) # Clamp to [0, 1]
closest_sy = sy1 + t * line_dy
# Convert back to rotated coordinates # Calculate clamped foot point
closest_rx, closest_ry = self._map_screen_to_rotated(int(closest_sx), int(closest_sy)) clamped_foot_x = sx1 + t * line_dx
clamped_foot_y = sy1 + t * line_dy
print(f"DEBUG: Clamped foot from ({foot_x:.1f}, {foot_y:.1f}) to ({clamped_foot_x:.1f}, {clamped_foot_y:.1f})")
# Convert clamped foot back to rotated coordinates
closest_rx, closest_ry = self._map_screen_to_rotated(int(clamped_foot_x), int(clamped_foot_y))
best_snap_distance = line_distance best_snap_distance = line_distance
best_snap_point = (int(closest_rx), int(closest_ry)) best_snap_point = (int(closest_rx), int(closest_ry))
print(f"DEBUG: Best line snap point: ({closest_rx}, {closest_ry})")
else:
print(f"DEBUG: No prev/next points found for line snapping")
# Apply the best snap if found # Apply the best snap if found
if best_snap_point: if best_snap_point:
print(f"DEBUG: Final best_snap_point: {best_snap_point} (distance: {best_snap_distance:.2f})")
self.tracking_points.setdefault(self.current_frame, []).append(best_snap_point) self.tracking_points.setdefault(self.current_frame, []).append(best_snap_point)
snapped = True snapped = True
else:
print(f"DEBUG: No snap found, adding new point at: ({rx}, {ry})")
# If no snapping, add new point at clicked location # If no snapping, add new point at clicked location
if not snapped: if not snapped:
print(f"DEBUG: No snap found, adding new point at: ({rx}, {ry})")
print(f"DEBUG: Click was at screen coords: ({x}, {y})")
print(f"DEBUG: Converted to rotated coords: ({rx}, {ry})")
# Verify the conversion
verify_sx, verify_sy = self._map_rotated_to_screen(rx, ry)
print(f"DEBUG: Verification - rotated ({rx}, {ry}) -> screen ({verify_sx}, {verify_sy})")
self.tracking_points.setdefault(self.current_frame, []).append((int(rx), int(ry))) self.tracking_points.setdefault(self.current_frame, []).append((int(rx), int(ry)))
# self.show_feedback_message("Tracking point added") # self.show_feedback_message("Tracking point added")