Prettier plotting, improve gaps calculation

camelot/parsers/hybrid.py

@@ -22,25 +22,8 @@ from matplotlib import patches as patches
 MAX_COL_SPREAD_IN_HEADER = 3
 
 
-def plot_annotated_bbox(plot, bbox, text, rect_color):
-    plot.add_patch(
-        patches.Rectangle(
-            (bbox[0], bbox[1]),
-            bbox[2] - bbox[0], bbox[3] - bbox[1],
-            color="purple", linewidth=3,
-            fill=False
-        )
-    )
-    plot.text(
-        bbox[0], bbox[1],
-        text,
-        fontsize=12, color="black", verticalalignment="top",
-        bbox=dict(facecolor="purple", alpha=0.5)
-    )
-
-
 def todo_move_me_expand_area_for_header(area, textlines, col_anchors,
-                                        average_row_height):
+                                        max_v_gap):
     """The core algorithm is based on fairly strict alignment of text.
     It works ok for the table body, but might fail on tables' headers
     since they tend to be in a different font, alignment (e.g. vertical),
@@ -78,13 +61,13 @@ def todo_move_me_expand_area_for_header(area, textlines, col_anchors,
         all_above = []
         for te in textlines:
             # higher than the table, directly within its bounds
-            if te.y0 > top and te.x0 > left and te.x1 < right:
+            if te.y0 > top and te.x0 >= left and te.x1 <= right:
                 all_above.append(te)
                 if closest_above is None or closest_above.y0 > te.y0:
                     closest_above = te
 
         if closest_above and \
-                closest_above.y0 < top + average_row_height:
+                closest_above.y0 < top + max_v_gap:
             # b/ We have a candidate cell that is within the correct
             # vertical band, and directly above the table. Starting from
             # this anchor, we list all the textlines within the same row.
@@ -475,37 +458,42 @@ class TextEdges2(object):
             self._textlines_alignments = {}
             self._compute_alignment_counts()
 
-    def _build_bbox_candidate(self, debug_info=None):
-        """ Seed the process with the textline with the highest alignment
-        score, then expand the bbox with textlines within threshold.
+    def _most_connected_textline(self):
+        """ Retrieve the textline that is most connected across vertical and
+        horizontal axis.
+
+        """
+        # Find the textline with the highest alignment score
+        return max(
+            self._textlines_alignments.keys(),
+            key=lambda textline:
+                self._textlines_alignments[textline].alignment_score(),
+            default=None
+        )
+
+    def _compute_plausible_gaps(self):
+        """ Evaluate plausible gaps between cells horizontally and vertically
+        based on the textlines aligned with the most connected textline.
+
+        Returns
+        -------
+        gaps_hv : tuple
+            (horizontal_gap, horizontal_gap) in pdf coordinate space.
 
-        Parameters
-        ----------
-        debug_info : array
-            Optional parameter array, in which to store extra information
-            to help later visualization of the table creation.
         """
         if self.max_rows <= 1 or self.max_cols <= 1:
             return None
-        tls_search_space = list(self._textlines_alignments.keys())
 
-        def get_best_textline(textlines):
-            # Find the textline with the highest alignment score
-            return max(
-                textlines,
-                key=lambda textline:
-                    self._textlines_alignments[textline].alignment_score(),
-                default=None
-            )
+        # Determine the textline that has the most combined
+        # alignments across horizontal and vertical axis.
+        # It will serve as a reference axis along which to collect the average
+        # spacing between rows/cols.
+        most_aligned_tl = self._most_connected_textline()
+        most_aligned_coords = TextEdges2.get_textline_coords(
+            most_aligned_tl)
 
-        # First, determine the textline that has the most combined alignments
-        # across horizontal and vertical axis.
-        # It will serve both as a starting point for the table boundary search,
-        # and as a way to estimate the average spacing between rows/cols.
-        most_aligned_tl = get_best_textline(tls_search_space)
-        most_aligned_coords = TextEdges2.get_textline_coords(most_aligned_tl)
-
-        # Retrieve the list of textlines it's aligned with, across both axis
+        # Retrieve the list of textlines it's aligned with, across both
+        # axis
         best_alignment = self._textlines_alignments[most_aligned_tl]
         ref_h_edge_name = best_alignment.max_h_edge_name()
         ref_v_edge_name = best_alignment.max_v_edge_name()
@@ -544,9 +532,30 @@ class TextEdges2(object):
             return None
         percentile = 75
         gaps_hv = (
-            np.percentile(h_gaps, percentile),
-            np.percentile(v_gaps, percentile)
+            2.0 * np.percentile(h_gaps, percentile),
+            2.0 * np.percentile(v_gaps, percentile)
         )
+        return gaps_hv
+
+    def _build_bbox_candidate(self, gaps_hv, debug_info=None):
+        """ Seed the process with the textline with the highest alignment
+        score, then expand the bbox with textlines within threshold.
+
+        Parameters
+        ----------
+        gaps_hv : tuple
+             The maximum distance allowed to consider surrounding lines/columns
+             as part of the same table.
+        debug_info : array (optional)
+            Optional parameter array, in which to store extra information
+            to help later visualization of the table creation.
+        """
+        # First, determine the textline that has the most combined
+        # alignments across horizontal and vertical axis.
+        # It will serve both as a starting point for the table boundary
+        # search, and as a way to estimate the average spacing between
+        # rows/cols.
+        most_aligned_tl = self._most_connected_textline()
 
         # Calculate the 75th percentile of the horizontal/vertical
         # gaps between textlines.  Use this as a reference for a threshold
@@ -555,7 +564,7 @@ class TextEdges2(object):
         # gaps_hv = self._calculate_gaps_thresholds(75)
         # if (gaps_hv[0] is None or gaps_hv[1] is None):
         #    return None
-        max_h_gap, max_v_gap = gaps_hv[0] * 3, gaps_hv[1] * 3
+        max_h_gap, max_v_gap = gaps_hv[0], gaps_hv[1]
 
         if debug_info is not None:
             # Store debug info
@@ -571,6 +580,11 @@ class TextEdges2(object):
         MINIMUM_TEXTLINES_IN_TABLE = 6
         bbox = (most_aligned_tl.x0, most_aligned_tl.y0,
                 most_aligned_tl.x1, most_aligned_tl.y1)
+
+        # For the body of the table, we only consider cells with alignments
+        # on both axis.
+        tls_search_space = list(self._textlines_alignments.keys())
+        # tls_search_space = []
         tls_search_space.remove(most_aligned_tl)
         tls_in_bbox = [most_aligned_tl]
         last_bbox = None
@@ -639,57 +653,6 @@ class TextEdges2(object):
                 color="black"
             )
 
-    def plotFRHTableSearch(self, plot, debug_info):
-        if debug_info is None:
-            return
-        # Display a bbox per region
-        for region_str in debug_info["table_regions"] or []:
-            plot_annotated_bbox(
-                plot, bbox_from_str(region_str),
-                "region: ({region_str})".format(region_str=region_str),
-                "purple"
-            )
-        # Display a bbox per area
-        for area_str in debug_info["table_areas"] or []:
-            plot_annotated_bbox(
-                plot, bbox_from_str(area_str),
-                "area: ({area_str})".format(area_str=area_str), "pink"
-            )
-        for box_id, bbox_search in enumerate(debug_info["bboxes_searches"]):
-            max_h_gap = bbox_search["max_h_gap"]
-            max_v_gap = bbox_search["max_v_gap"]
-            iterations = bbox_search["iterations"]
-            for iteration, bbox in enumerate(iterations):
-                final = iteration == len(iterations) - 1
-                plot.add_patch(
-                    patches.Rectangle(
-                        (bbox[0], bbox[1]),
-                        bbox[2] - bbox[0], bbox[3] - bbox[1],
-                        color="red",
-                        linewidth=5 if final else 2,
-                        fill=False
-                    )
-                )
-                plot.text(
-                    bbox[0],
-                    bbox[1],
-                    f"box #{box_id+1} / iter #{iteration}",
-                    fontsize=12,
-                    color="black",
-                    verticalalignment="top",
-                    bbox=dict(facecolor="orange", alpha=0.5)
-                )
-
-                plot.add_patch(
-                    patches.Rectangle(
-                        (bbox[0]-max_h_gap, bbox[1]-max_v_gap),
-                        bbox[2] - bbox[0] + 2 * max_h_gap,
-                        bbox[3] - bbox[1] + 2 * max_v_gap,
-                        color="orange",
-                        fill=False
-                    )
-                )
-
 
 class Hybrid(BaseParser):
     """Hybrid method of parsing looks for spaces between text
@@ -738,7 +701,7 @@ class Hybrid(BaseParser):
         flag_size=False,
         split_text=False,
         strip_text="",
-        edge_tol=50,
+        edge_tol=None,
         row_tol=2,
         column_tol=0,
         debug=False,
@@ -754,6 +717,8 @@ class Hybrid(BaseParser):
             debug=debug
         )
         self.columns = columns
+        self.textedges = None
+
         self._validate_columns()
         self.edge_tol = edge_tol
         self.row_tol = row_tol
@@ -973,7 +938,11 @@ class Hybrid(BaseParser):
             self.table_bbox = table_bbox
             return
 
-        all_textlines = self.horizontal_text + self.vertical_text
+        # Take all the textlines that are not just spaces
+        all_textlines = [
+            t for t in self.horizontal_text + self.vertical_text
+            if len(t.get_text().strip()) > 0
+        ]
         textlines = self._apply_regions_filter(all_textlines)
 
         textlines_processed = {}
@@ -996,8 +965,15 @@ class Hybrid(BaseParser):
                 debug_info_edges_searches.append(
                     copy.deepcopy(self.textedges)
                 )
+            gaps_hv = self.textedges._compute_plausible_gaps()
+            if gaps_hv is None:
+                return None
+            if self.edge_tol is not None:
+                # edge_tol instructions override the calculated vertical gap
+                gaps_hv = (gaps_hv[0], self.edge_tol)
             bbox = self.textedges._build_bbox_candidate(
-                debug_info_bboxes_searches
+                gaps_hv,
+                debug_info=debug_info_bboxes_searches
             )
             if bbox is None:
                 break
@@ -1028,7 +1004,7 @@ class Hybrid(BaseParser):
                 bbox,
                 textlines,
                 cols_anchors,
-                average_tl_height
+                gaps_hv[1]  # average_tl_height
             )
 
             if self.debug_info is not None:

camelot/plotting.py

@@ -11,20 +11,50 @@ else:
 from .utils import bbox_from_str
 
 
-def draw_labeled_bbox(ax, bbox, text, rect_color):
+def draw_labeled_bbox(
+    ax, bbox, text,
+    color="black", linewidth=3,
+    linestyle="solid",
+    label_pos="top,left"
+):
     ax.add_patch(
         patches.Rectangle(
             (bbox[0], bbox[1]),
             bbox[2] - bbox[0], bbox[3] - bbox[1],
-            color="purple", linewidth=3,
+            color=color,
+            linewidth=linewidth, linestyle=linestyle,
             fill=False
         )
     )
+
+    vlabel, hlabel = label_pos.split(",")
+    if (vlabel == "top"):
+        y = max(bbox[1], bbox[3])
+    elif (vlabel == "bottom"):
+        y = min(bbox[1], bbox[3])
+    else:
+        y = 0.5 * (bbox[1] + bbox[3])
+
+    # We want to draw the label outside the box (above or below)
+    label_align_swap = {
+        "top": "bottom",
+        "bottom": "top",
+        "center": "center"
+    }
+    vlabel_out_of_box = label_align_swap[vlabel]
+    if (hlabel == "right"):
+        x = max(bbox[0], bbox[2])
+    elif (hlabel == "left"):
+        x = min(bbox[0], bbox[2])
+    else:
+        x = 0.5 * (bbox[0] + bbox[2])
     ax.text(
-        bbox[0], bbox[1],
+        x, y,
         text,
-        fontsize=12, color="black", verticalalignment="top",
-        bbox=dict(facecolor="purple", alpha=0.5)
+        fontsize=12, color="black",
+        verticalalignment=vlabel_out_of_box,
+        horizontalalignment=hlabel,
+        bbox=dict(facecolor=color, alpha=0.3)
     )
 
 
@@ -46,21 +76,6 @@ def draw_pdf(table, ax, to_pdf_scale=True):
     else:
         ax.imshow(img)
 
-    if table.debug_info:
-        # Display a bbox per region
-        for region_str in table.debug_info["table_regions"] or []:
-            draw_labeled_bbox(
-                ax, bbox_from_str(region_str),
-                "region: ({region_str})".format(region_str=region_str),
-                "purple"
-            )
-        # Display a bbox per area
-        for area_str in table.debug_info["table_areas"] or []:
-            draw_labeled_bbox(
-                ax, bbox_from_str(area_str),
-                "area: ({area_str})".format(area_str=area_str), "pink"
-            )
-
 
 def draw_parse_constraints(table, ax):
     """Draw any user provided constraints (area, region, columns, etc)
@@ -78,13 +93,20 @@ def draw_parse_constraints(table, ax):
             draw_labeled_bbox(
                 ax, bbox_from_str(region_str),
                 "region: ({region_str})".format(region_str=region_str),
-                "purple"
+                color="purple",
+                linestyle="dotted",
+                linewidth=1,
+                label_pos="bottom,right"
             )
         # Display a bbox per area
         for area_str in table.debug_info["table_areas"] or []:
             draw_labeled_bbox(
                 ax, bbox_from_str(area_str),
-                "area: ({area_str})".format(area_str=area_str), "pink"
+                "area: ({area_str})".format(area_str=area_str),
+                color="pink",
+                linestyle="dotted",
+                linewidth=1,
+                label_pos="bottom,right"
             )
 
 
@@ -220,7 +242,9 @@ class PlotMethods(object):
                 ys.extend([t[1], t[3]])
                 ax.add_patch(
                     patches.Rectangle(
-                        (t[0], t[1]), t[2] - t[0], t[3] - t[1], color="blue"
+                        (t[0], t[1]), t[2] - t[0], t[3] - t[1],
+                        color="blue",
+                        alpha=0.5
                     )
                 )
 
@@ -329,3 +353,79 @@ class PlotMethods(object):
         for h in horizontal:
             ax.plot([h[0], h[2]], [h[1], h[3]])
         return fig
+
+    @staticmethod
+    def hybrid_table_search(table):
+        """Generates a plot illustrating the steps of the hybrid table search.
+
+        Parameters
+        ----------
+        table : camelot.core.Table
+
+        Returns
+        -------
+        fig : matplotlib.fig.Figure
+
+        """
+        fig = plt.figure()
+        ax = fig.add_subplot(111, aspect="equal")
+        draw_pdf(table, ax)
+        draw_parse_constraints(table, ax)
+
+        if table.debug_info is None:
+            return fig
+        debug_info = table.debug_info
+        for box_id, bbox_search in enumerate(debug_info["bboxes_searches"]):
+            max_h_gap = bbox_search["max_h_gap"]
+            max_v_gap = bbox_search["max_v_gap"]
+            iterations = bbox_search["iterations"]
+            for iteration, bbox in enumerate(iterations):
+                final = iteration == len(iterations) - 1
+
+                draw_labeled_bbox(
+                    ax, bbox,
+                    "box #{box_id} / iter #{iteration}".format(
+                        box_id=box_id,
+                        iteration=iteration
+                    ),
+                    color="red",
+                    linewidth=5 if final else 2,
+                    label_pos="bottom,left"
+                )
+
+                ax.add_patch(
+                    patches.Rectangle(
+                        (bbox[0]-max_h_gap, bbox[1]-max_v_gap),
+                        bbox[2] - bbox[0] + 2 * max_h_gap,
+                        bbox[3] - bbox[1] + 2 * max_v_gap,
+                        color="orange",
+                        fill=False
+                    )
+                )
+
+        for box_id, col_search in enumerate(debug_info["col_searches"]):
+            draw_labeled_bbox(
+                ax, col_search["expanded_bbox"],
+                "box body + header #{box_id}".format(
+                    box_id=box_id
+                ),
+                color="red",
+                linewidth=4,
+                label_pos="top,left"
+            )
+            draw_labeled_bbox(
+                ax, col_search["core_bbox"],
+                "box body #{box_id}".format(
+                    box_id=box_id
+                ),
+                color="orange",
+                linewidth=2,
+                label_pos="bottom,left"
+            )
+            # self.debug_info["col_searches"].append({
+            #     "core_bbox": bbox,
+            #     "cols_anchors": cols_anchors,
+            #     "expanded_bbox": expanded_bbox
+            # })
+
+        return fig

camelot/utils.py

@@ -1115,10 +1115,10 @@ def compare_tables(left, right):
         differences_str = " and ".join(differences)
         print(
             "Right has {differences_str} than left "
-            "{shape_right} vs {shape_left}".format(
+            "{shape_left} vs {shape_right}".format(
                 differences_str=differences_str,
+                shape_left=[left.shape[0], left.shape[1]],
                 shape_right=[right.shape[0], right.shape[1]],
-                shape_left=[left.shape[0], left.shape[1]]
             )
         )
 

tests/data.py

@@ -2442,6 +2442,10 @@ data_stream_edge_tol = [
     ["period.", ""],
 ]
 
+# The stream algorithm ends up including a footer, which hybrid correctly
+# skips.
+data_hybrid_edge_tol = data_stream_edge_tol[:-3]
+
 data_lattice = [
     [
         "Cycle \nName",

tests/test_common.py

@@ -7,6 +7,7 @@ from pandas.testing import assert_frame_equal
 
 import camelot
 from camelot.core import Table, TableList
+from camelot.utils import compare_tables
 from camelot.__version__ import generate_version
 
 from .data import *
@@ -193,7 +194,7 @@ def test_hybrid_table_regions():
     # The "stream" test looks for a region in ["320,460,573,335"], which
     # should exclude the header.
     tables = camelot.read_pdf(
-        filename, flavor="hybrid", table_regions=["320,505,573,330"]
+        filename, flavor="hybrid", table_regions=["320,335,573,505"]
     )
     assert_frame_equal(df, tables[0].df)
 
@@ -248,7 +249,7 @@ def test_hybrid_strip_text():
 
 
 def test_hybrid_edge_tol():
-    df = pd.DataFrame(data_stream_edge_tol)
+    df = pd.DataFrame(data_hybrid_edge_tol)
 
     filename = os.path.join(testdir, "edge_tol.pdf")
     tables = camelot.read_pdf(filename, flavor="hybrid", edge_tol=500)