clip-annotator/src/river_annotation_tool/mask_canvas.py

import cv2
import numpy as np
from matplotlib.backends.backend_qtagg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure
from matplotlib.patches import Circle
from PySide6.QtCore import Qt
from PySide6.QtWidgets import QPushButton, QSlider


class MaskCanvas:
    """Matplotlib canvas with brush/polygon mask drawing, undo/redo, and erase."""

    _BRUSH_DEFAULT = 5
    _ALPHA_DEFAULT = 40
    _BRIGHTNESS_DEFAULT = 0
    _CONTRAST_DEFAULT = 0
    _GAMMA_DEFAULT = 100
    _CLOSE_THRESHOLD = 15  # image-pixel distance to first vertex that closes a polygon

    def __init__(self, frames, dh: int, dw: int):
        self.dh = dh
        self.dw = dw

        self.mask = np.zeros((dh, dw), dtype=np.uint8)
        self.history: list[np.ndarray] = []
        self.redo_stack: list[np.ndarray] = []
        self.erase_mode = False
        self.drawing = False
        self.mask_visible = True
        self._current_frame = frames[0]

        self.tool_mode = "brush"
        self._shapes: list[list[tuple]] = []
        self._current_poly: list[tuple] = []
        self._poly_artists: list = []
        self._mouse_pos: tuple | None = None

        self._build_figure(frames)
        self._build_controls()
        self._connect_events()

    def _build_figure(self, frames):
        self.fig = Figure(figsize=(self.dw / 80, self.dh / 80))
        self.canvas = FigureCanvas(self.fig)
        self.ax = self.fig.add_subplot(111)
        self.ax.axis("off")
        self.img_artist = self.ax.imshow(frames[0])
        self.mask_artist = self.ax.imshow(np.zeros((self.dh, self.dw, 4)))
        self.title_text = self.ax.set_title("", fontsize=10, pad=4)
        self.brush_circle = Circle(
            (0, 0), radius=5, fill=False, color="white", linewidth=1.5, visible=False
        )
        self.ax.add_patch(self.brush_circle)

    def _build_controls(self):
        self.btn_erase = QPushButton("Eraser")
        self.btn_mask = QPushButton("Hide Mask")

        self.btn_brush = QPushButton("Brush")
        self.btn_brush.setStyleSheet("background-color: #4488ff; color: white;")
        self.btn_polygon = QPushButton("Polygon")
        self.btn_fill = QPushButton("Fill")
        self.btn_fill.setEnabled(False)
        self.btn_del_shape = QPushButton("Del Shape")
        self.btn_del_shape.setEnabled(False)
        self.btn_cancel_poly = QPushButton("Cancel Current Poly")

        self.brush_slider = QSlider(Qt.Horizontal)
        self.brush_slider.setRange(2, 50)
        self.brush_slider.setValue(self._BRUSH_DEFAULT)
        self.brush_reset = QPushButton("↺")
        self.brush_reset.setFixedWidth(28)

        self.alpha_slider = QSlider(Qt.Horizontal)
        self.alpha_slider.setRange(0, 100)
        self.alpha_slider.setValue(self._ALPHA_DEFAULT)
        self.alpha_reset = QPushButton("↺")
        self.alpha_reset.setFixedWidth(28)

        self.brightness_slider = QSlider(Qt.Vertical)
        self.brightness_slider.setRange(-100, 100)
        self.brightness_slider.setValue(self._BRIGHTNESS_DEFAULT)
        self.brightness_reset = QPushButton("↺")
        self.brightness_reset.setFixedWidth(28)

        self.contrast_slider = QSlider(Qt.Vertical)
        self.contrast_slider.setRange(-100, 100)
        self.contrast_slider.setValue(self._CONTRAST_DEFAULT)
        self.contrast_reset = QPushButton("↺")
        self.contrast_reset.setFixedWidth(28)

        self.gamma_slider = QSlider(Qt.Vertical)
        self.gamma_slider.setRange(10, 300)
        self.gamma_slider.setValue(self._GAMMA_DEFAULT)
        self.gamma_reset = QPushButton("↺")
        self.gamma_reset.setFixedWidth(28)

    def _connect_events(self):
        self.canvas.mpl_connect("button_press_event", self._on_press)
        self.canvas.mpl_connect("motion_notify_event", self._on_move)
        self.canvas.mpl_connect("button_release_event", self._on_release)
        self.canvas.mpl_connect("axes_leave_event", self._on_axes_leave)
        self.btn_erase.clicked.connect(self.toggle_erase)
        self.btn_mask.clicked.connect(self.toggle_mask)
        self.btn_brush.clicked.connect(lambda: self.set_tool_mode("brush"))
        self.btn_polygon.clicked.connect(lambda: self.set_tool_mode("polygon"))
        self.btn_fill.clicked.connect(lambda: self.set_tool_mode("fill"))
        self.btn_del_shape.clicked.connect(self.delete_last_shape)
        self.btn_cancel_poly.clicked.connect(self.cancel_polygon)
        self.alpha_slider.valueChanged.connect(self.redraw)
        self.brightness_slider.valueChanged.connect(self._refresh_frame)
        self.contrast_slider.valueChanged.connect(self._refresh_frame)
        self.gamma_slider.valueChanged.connect(self._refresh_frame)
        self.brush_reset.clicked.connect(
            lambda: self.brush_slider.setValue(self._BRUSH_DEFAULT)
        )
        self.alpha_reset.clicked.connect(
            lambda: self.alpha_slider.setValue(self._ALPHA_DEFAULT)
        )
        self.brightness_reset.clicked.connect(
            lambda: self.brightness_slider.setValue(self._BRIGHTNESS_DEFAULT)
        )
        self.contrast_reset.clicked.connect(
            lambda: self.contrast_slider.setValue(self._CONTRAST_DEFAULT)
        )
        self.gamma_reset.clicked.connect(
            lambda: self.gamma_slider.setValue(self._GAMMA_DEFAULT)
        )

    # ── clip transition ────────────────────────────────────────────
    def load_clip(self, frames, dh: int, dw: int, mask=None, title: str = ""):
        self.dh = dh
        self.dw = dw
        self.mask = mask if mask is not None else np.zeros((dh, dw), dtype=np.uint8)
        self.history = []
        self.redo_stack = []
        self._current_frame = frames[0]
        self._clear_poly_state()
        self.img_artist.set_data(self._apply_image_adjustments(frames[0]))
        self.set_title(title)
        self.redraw()

    def _clear_poly_state(self):
        self._shapes = []
        self._current_poly = []
        self._mouse_pos = None
        for a in self._poly_artists:
            a.remove()
        self._poly_artists = []
        self._update_poly_buttons()

    # ── frame / title ──────────────────────────────────────────────
    def set_frame(self, frame):
        self._current_frame = frame
        self.img_artist.set_data(self._apply_image_adjustments(frame))
        self.canvas.draw_idle()

    # ── image adjustments ──────────────────────────────────────────
    def _apply_image_adjustments(self, frame):
        img = frame.astype(np.float32)
        img += self.brightness_slider.value()
        c = self.contrast_slider.value() / 100.0
        img = (1.0 + c) * (img - 128.0) + 128.0
        np.clip(img, 0, 255, out=img)
        g = self.gamma_slider.value() / 100.0
        img = (img / 255.0) ** (1.0 / g) * 255.0
        return np.clip(img, 0, 255).astype(np.uint8)

    def _refresh_frame(self):
        if self._current_frame is not None:
            self.img_artist.set_data(self._apply_image_adjustments(self._current_frame))
            self.canvas.draw_idle()

    def set_title(self, text: str):
        self.title_text.set_text(text)

    # ── mask ops ───────────────────────────────────────────────────
    def reset(self, mask=None):
        self.mask = (
            mask if mask is not None else np.zeros((self.dh, self.dw), dtype=np.uint8)
        )
        self.history = []
        self.redo_stack = []
        self.redraw()

    def set_mask(self, mask):
        """Replace the mask and push the previous state onto the undo stack."""
        self.history.append(self.mask.copy())
        self.redo_stack.clear()
        self.mask = mask
        self.redraw()

    def redraw(self):
        if self.mask_visible:
            alpha = self.alpha_slider.value() / 100.0
            rgba = np.zeros((self.dh, self.dw, 4))
            rgba[..., 1] = self.mask * 0.7
            rgba[..., 3] = self.mask * alpha
        else:
            rgba = np.zeros((self.dh, self.dw, 4))
        self.mask_artist.set_data(rgba)
        self.canvas.draw_idle()

    def clear(self):
        self.mask[:] = 0
        self.redraw()

    def undo(self):
        if self.history:
            self.redo_stack.append(self.mask.copy())
            self.mask = self.history.pop()
            self.redraw()

    def undo10(self):
        for _ in range(10):
            if not self.history:
                break
            self.redo_stack.append(self.mask.copy())
            self.mask = self.history.pop()
        self.redraw()

    def redo(self):
        if self.redo_stack:
            self.history.append(self.mask.copy())
            self.mask = self.redo_stack.pop()
            self.redraw()

    def toggle_erase(self):
        self.erase_mode = not self.erase_mode
        if self.erase_mode:
            self.btn_erase.setText("Eraser ON")
            self.btn_erase.setStyleSheet("background-color: orange; color: black;")
        else:
            self.btn_erase.setText("Eraser")
            self.btn_erase.setStyleSheet("")

    def toggle_mask(self):
        self.mask_visible = not self.mask_visible
        if self.mask_visible:
            self.btn_mask.setText("Hide Mask")
            self.btn_mask.setStyleSheet("")
        else:
            self.btn_mask.setText("Show Mask")
            self.btn_mask.setStyleSheet("background-color: red; color: white;")
        self.redraw()

    def stamp(self, x, y):
        if x is None or y is None:
            return
        self.history.append(self.mask.copy())
        self.redo_stack.clear()
        r = self.brush_slider.value()
        ix, iy = int(x), int(y)
        y0, y1 = max(0, iy - r), min(self.dh, iy + r + 1)
        x0, x1 = max(0, ix - r), min(self.dw, ix + r + 1)
        Y, X = np.ogrid[y0:y1, x0:x1]
        circle = (X - ix) ** 2 + (Y - iy) ** 2 <= r**2
        self.mask[y0:y1, x0:x1][circle] = 0 if self.erase_mode else 1
        self.redraw()

    # ── tool mode ──────────────────────────────────────────────────
    def set_tool_mode(self, mode: str):
        self.tool_mode = mode
        active = "background-color: #4488ff; color: white;"
        self.btn_brush.setStyleSheet(active if mode == "brush" else "")
        self.btn_polygon.setStyleSheet(active if mode == "polygon" else "")
        self.btn_fill.setStyleSheet(active if mode == "fill" else "")
        if mode != "brush":
            self.brush_circle.set_visible(False)
            self.canvas.draw_idle()

    # ── polygon ops ────────────────────────────────────────────────
    def _near_first(self, x: float, y: float) -> bool:
        if not self._current_poly:
            return False
        fx, fy = self._current_poly[0]
        return (x - fx) ** 2 + (y - fy) ** 2 <= self._CLOSE_THRESHOLD**2

    def _update_poly_buttons(self):
        has = bool(self._shapes)
        self.btn_fill.setEnabled(has)
        self.btn_del_shape.setEnabled(has)

    def _draw_polygon_overlay(self, mouse_pos=None):
        for a in self._poly_artists:
            a.remove()
        self._poly_artists.clear()

        # Completed shapes — thick closed outline
        for shape in self._shapes:
            xs = [p[0] for p in shape] + [shape[0][0]]
            ys = [p[1] for p in shape] + [shape[0][1]]
            (line,) = self.ax.plot(xs, ys, color="cyan", linewidth=3, zorder=5)
            (dots,) = self.ax.plot(
                [p[0] for p in shape],
                [p[1] for p in shape],
                "o",
                color="cyan",
                markersize=4,
                zorder=6,
            )
            self._poly_artists.extend([line, dots])

        # In-progress polygon
        if self._current_poly:
            xs = [p[0] for p in self._current_poly]
            ys = [p[1] for p in self._current_poly]

            if len(self._current_poly) > 1:
                (edge,) = self.ax.plot(xs, ys, color="yellow", linewidth=1.5, zorder=5)
                self._poly_artists.append(edge)

            (verts,) = self.ax.plot(xs, ys, "o", color="yellow", markersize=5, zorder=6)
            # Red dot on first vertex as close-target indicator
            (first,) = self.ax.plot(
                [xs[0]], [ys[0]], "o", color="red", markersize=8, zorder=7
            )
            self._poly_artists.extend([verts, first])

            # Rubber-band line from last vertex to cursor
            if mouse_pos:
                mx, my = mouse_pos
                near = len(self._current_poly) >= 3 and self._near_first(mx, my)
                clr = "lime" if near else "yellow"
                (rband,) = self.ax.plot(
                    [xs[-1], mx], [ys[-1], my], "--", color=clr, linewidth=1, zorder=5
                )
                self._poly_artists.append(rband)

        self.canvas.draw_idle()

    def cancel_polygon(self):
        self._current_poly = []
        self._draw_polygon_overlay(mouse_pos=self._mouse_pos)

    def delete_last_shape(self):
        if self._shapes:
            self._shapes.pop()
            self._update_poly_buttons()
            self._draw_polygon_overlay(mouse_pos=self._mouse_pos)

    def _fill_shape_at(self, x: float, y: float):
        if not self._shapes:
            return

        polys = [
            np.array(
                [(int(round(px)), int(round(py))) for px, py in shape], dtype=np.int32
            )
            for shape in self._shapes
        ]

        # Find all shapes that contain the click point
        containing = []
        for i, poly in enumerate(polys):
            poly_f32 = poly.reshape(-1, 1, 2).astype(np.float32)
            if cv2.pointPolygonTest(poly_f32, (x, y), False) >= 0:
                containing.append((i, poly))

        if not containing:
            return  # click was outside all shapes

        # Pick the innermost (smallest area) shape that contains the click
        containing.sort(key=lambda t: cv2.contourArea(t[1]))
        target_idx, target_poly = containing[0]

        self.history.append(self.mask.copy())
        self.redo_stack.clear()

        temp = np.zeros((self.dh, self.dw), dtype=np.uint8)
        cv2.fillPoly(temp, [target_poly], 1)

        # Punch holes for any shapes completely inside the target
        target_f32 = target_poly.reshape(-1, 1, 2).astype(np.float32)
        for i, poly in enumerate(polys):
            if i == target_idx:
                continue
            cx = float(np.mean(poly[:, 0]))
            cy = float(np.mean(poly[:, 1]))
            if cv2.pointPolygonTest(target_f32, (cx, cy), False) > 0:
                cv2.fillPoly(temp, [poly], 0)

        self.mask |= temp
        self.redraw()

    # ── brush preview ──────────────────────────────────────────────
    def _update_brush_preview(self, e):
        if e.inaxes == self.ax and e.xdata is not None:
            self.brush_circle.center = (e.xdata, e.ydata)
            self.brush_circle.set_radius(self.brush_slider.value())
            self.brush_circle.set_visible(True)
        else:
            self.brush_circle.set_visible(False)
        self.canvas.draw_idle()

    def _on_axes_leave(self, _):
        self.brush_circle.set_visible(False)
        if self.tool_mode == "polygon":
            self._mouse_pos = None
            self._draw_polygon_overlay()
        else:
            self.canvas.draw_idle()

    # ── mouse events ───────────────────────────────────────────────
    def _on_press(self, e):
        if e.xdata is None:
            return
        if self.tool_mode == "brush":
            self.drawing = True
            self.stamp(e.xdata, e.ydata)
        elif self.tool_mode == "polygon":
            self._handle_polygon_click(e)
        elif self.tool_mode == "fill" and e.button == 1:
            self._fill_shape_at(e.xdata, e.ydata)

    def _handle_polygon_click(self, e):
        if e.button == 3:  # right-click: remove last vertex
            if self._current_poly:
                self._current_poly.pop()
                self._draw_polygon_overlay(mouse_pos=self._mouse_pos)
            return
        if e.button != 1:
            return
        x, y = e.xdata, e.ydata
        if len(self._current_poly) >= 3 and self._near_first(x, y):
            self._shapes.append(list(self._current_poly))
            self._current_poly = []
            self._update_poly_buttons()
            self._draw_polygon_overlay(mouse_pos=self._mouse_pos)
        else:
            self._current_poly.append((x, y))
            self._draw_polygon_overlay(mouse_pos=self._mouse_pos)

    def _on_move(self, e):
        if self.tool_mode == "brush":
            self._update_brush_preview(e)
            if self.drawing:
                self.stamp(e.xdata, e.ydata)
        elif self.tool_mode == "polygon":
            self.brush_circle.set_visible(False)
            if e.inaxes == self.ax and e.xdata is not None:
                self._mouse_pos = (e.xdata, e.ydata)
                self._draw_polygon_overlay(mouse_pos=self._mouse_pos)
            else:
                self._mouse_pos = None
                self._draw_polygon_overlay()

    def _on_release(self, _):
        self.drawing = False