fix: step4 采样点过密 — 提高自适应下限 + 默认关闭自适应模式

问题: min_interval=10 导致每个水面产生数千个密集采样点 (8242点)

修复:
  1. sampling.py: min_interval 默认值 10→50 (提高 5×)
     两个入口函数同步修改 (chunked + full)
  2. step4_sampling_panel.py: 自适应采样复选框默认 False
     用户设置的固定间隔 (interval=100px) 真正生效

src/gui/panels/step12_viz_panel.py

@@ -978,12 +978,18 @@ class ImageViewerWidget(QWidget):
         layout.addLayout(toolbar)
 
         self.scroll_area = QScrollArea()
-        self.scroll_area.setWidgetResizable(True)
+        # setWidgetResizable(False): QLabel 保持自身 pixmap 固有尺寸，
+        # 放大时自然超出视口触发滚动条，而非被 QScrollArea 强制压缩
+        self.scroll_area.setWidgetResizable(False)
+        self.scroll_area.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Expanding)
+        self.scroll_area.setHorizontalScrollBarPolicy(Qt.ScrollBarAsNeeded)
+        self.scroll_area.setVerticalScrollBarPolicy(Qt.ScrollBarAsNeeded)
         self.scroll_area.setStyleSheet("background-color: white;")
 
         self.image_label = QLabel()
         self.image_label.setAlignment(Qt.AlignCenter)
-        self.image_label.setStyleSheet("background-color:  white;")
+        self.image_label.setSizePolicy(QSizePolicy.Ignored, QSizePolicy.Ignored)
+        self.image_label.setStyleSheet("background-color: white;")
 
         self.scroll_area.setWidget(self.image_label)
 

src/gui/panels/step4_sampling_panel.py

@@ -130,7 +130,7 @@ class Step4SamplingPanel(QWidget):
         params_layout.addRow("内存处理块大小:", w3)
 
         self.use_adaptive_sampling = QCheckBox("启用自适应边缘采样")
-        self.use_adaptive_sampling.setChecked(True)
+        self.use_adaptive_sampling.setChecked(False)
         params_layout.addRow("智能模式:", self.use_adaptive_sampling)
 
         params_group.setLayout(params_layout)

src/utils/sampling.py

@@ -86,7 +86,7 @@ def get_wavelengths_from_bil_header(bil_file):
 
 def get_spectral_sampling_points_chunked(bil_file, water_mask_shp, severe_glint=None, output_csvpath=None,
                                          interval=100, sample_radius=1, chunk_size=1000,
-                                         use_adaptive_sampling=True, min_interval=10, max_interval=200):
+                                         use_adaptive_sampling=True, min_interval=50, max_interval=200):
     """
     基于bil文件、shp格式water_mask和severe_glint生成采样点并提取光谱数据（分块处理版本）
 
@@ -423,7 +423,7 @@ def get_spectral_sampling_points_chunked(bil_file, water_mask_shp, severe_glint=
 
 def get_spectral_sampling_points(bil_file, water_mask_shp, severe_glint=None, output_csvpath=None,
                                  interval=100, sample_radius=1,
-                                 use_adaptive_sampling=True, min_interval=10, max_interval=200):
+                                 use_adaptive_sampling=True, min_interval=50, max_interval=200):
     """
     基于bil文件、shp格式water_mask和severe_glint生成采样点并提取光谱数据