Shrink ignores what cannot be seen; blank lines at a block's end go

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tests/test_end_to_end.py

@@ -14,6 +14,7 @@ the second participant sees it at the end.
 
 import base64
 import json
+import math
 import os
 import pathlib
 import re
@@ -1587,6 +1588,84 @@ class EndToEndTest(unittest.TestCase):
         firefox.run("document.getElementById('manual_close').click();")
         self.assertFalse(firefox.run("return document.getElementById('manual_dialog').open;"))
 
+    def test_shrink_ignores_the_invisible(self):
+        """Andy, 2026-10-14: what cannot be seen does not count for Shrink:
+        strokes and free text in the paper's white, and the blank lines at
+        the end of a text block, which go when its typing ends (a box
+        grown by them shrinks back) and, for one's own, at Shrink."""
+        firefox = self.firefox
+        firefox.go(self.address("Late"))
+        self.enter_name("Shrinker", "start_session")
+        state = self.wait_until(lambda s: s["page"]["number"] == 1, "the page")
+        scale = firefox.run("return window.kokkoja.renderer.cssPixelsPerUnit;")
+        origin = state["origin"]
+        px = lambda x: (x - origin[0]) * scale
+        py = lambda y: (y - origin[1]) * scale
+        swatch = lambda i: firefox.run(f"document.querySelectorAll('#colors .swatch')[{i}].click();")
+
+        # A black stroke, then a white stroke and white free text far to the
+        # right and below, where they would widen the shrunk page if counted.
+        firefox.drag("#page", px(500), py(500), px(900), py(520))
+        self.wait_until(lambda s: len(s["layers"]["Shrinker"]) == 1 and s["layers"]["Shrinker"][0]["done"], "the black stroke")
+        swatch(4)
+        firefox.drag("#page", px(2000), py(1500), px(2500), py(1600))
+        self.wait_until(lambda s: len(s["layers"]["Shrinker"]) == 2 and s["layers"]["Shrinker"][1]["done"], "the white stroke")
+        self.assertEqual(self.state()["layers"]["Shrinker"][1]["id"] and firefox.run(
+            "return [...window.kokkoja.session.ownLayer.strokes.values()][1].color;"), "#ffffff")
+        firefox.run("document.querySelector('[data-tool=text]').click();")
+        firefox.run(TEXT_GESTURE, px(2000) / state["page"]["width"] / scale, py(600) / state["page"]["height"] / scale,
+                    px(2000) / state["page"]["width"] / scale, py(600) / state["page"]["height"] / scale)
+        firefox.type_into(".text_field", "unsichtbar")
+        # A small text rectangle, in black, grown by blank lines typed after
+        # the word: finishing removes them and the box shrinks back to its
+        # one line.  Dragging it open finishes the white text first; the
+        # colour is chosen after, since a change restyles the block typed in.
+        fx = lambda x: px(x) / (state["page"]["width"] * scale)
+        fy = lambda y: py(y) / (state["page"]["height"] * scale)
+        firefox.run(TEXT_GESTURE, fx(500), fy(800), fx(1100), fy(830))
+        swatch(0)
+        firefox.type_into(".text_field", "Antwort\n\n\n\n")
+        grown = self.wait_until(lambda s: len(s["texts"]["Shrinker"]) == 2 and s["texts"]["Shrinker"][1]["text"] == "Antwort\n\n\n\n",
+                                "the box typed in")
+        box = grown["texts"]["Shrinker"][1]
+        self.assertGreater(box["height"], 300, "grown by the blank lines: five lines of about 70 units")
+        self.assertEqual(box["height"], math.ceil(box["boxHeight"]))
+        firefox.run("document.querySelector('[data-tool=pen]').click();")
+        trimmed = self.wait_until(lambda s: s["texts"]["Shrinker"][1]["text"] == "Antwort", "the blank lines gone")
+        box = trimmed["texts"]["Shrinker"][1]
+        self.assertEqual(box["height"], math.ceil(box["boxHeight"]))
+        self.assertLess(box["height"], 80, "back to one line")
+        self.assertEqual(trimmed["texts"]["Shrinker"][0]["text"], "unsichtbar")
+        self.assertEqual(firefox.run("return [...window.kokkoja.session.ownLayer.texts.values()][0].color;"), "#ffffff")
+
+        # Shrink: the sheet holds the black stroke and the box with the
+        # margin, and nothing of the white marks.
+        before = self.state()["page"]
+        firefox.run("document.getElementById('zoom_shrink').click();")
+        shrunk = self.wait_until(lambda s: s["page"]["width"] < before["width"], "the shrunk page")
+        sheet = firefox.run("const p = window.kokkoja.session.page; return [p.baseLeft, p.baseTop, p.baseWidth, p.baseHeight];")
+        self.assertAlmostEqual(sheet[0], 500 - 14 - 50, delta=4)       # the stroke's reach, then the margin
+        self.assertAlmostEqual(sheet[1], 500 - 14 - 50, delta=4)
+        self.assertAlmostEqual(sheet[0] + sheet[2], 1100 + 50, delta=4)  # the box's right edge
+        self.assertAlmostEqual(sheet[1] + sheet[3], 800 + box["height"] + 50, delta=4)
+
+        # A box of one's own that still has blank lines at its end, as one
+        # from a page made before the trimming would, is trimmed by Shrink
+        # itself, as one gesture to undo.  Finishing typing trims now, so
+        # such a block is made by script here, the way a loaded page is.
+        firefox.run("""
+            const s = window.kokkoja.session;
+            const b = [...s.ownLayer.texts.values()][1];
+            b.text += '\\n\\n\\n';
+            b.lines = [...b.lines, '', '', ''];
+            s.setText(b);
+        """)
+        self.wait_until(lambda s: s["texts"]["Shrinker"][1]["text"] == "Antwort\n\n\n", "the blank lines on the block")
+        firefox.run("document.getElementById('zoom_shrink').click();")
+        self.wait_until(lambda s: s["texts"]["Shrinker"][1]["text"] == "Antwort", "trimmed by Shrink")
+        firefox.run("document.getElementById('undo').click();")
+        self.wait_until(lambda s: s["texts"]["Shrinker"][1]["text"] == "Antwort\n\n\n", "the trim undone")
+
     def test_text_being_typed_stays_on_the_page_left(self):
         """Andy, 2026-10-06: a guest was typing when the host pressed New,
         and the text reappeared on the new page."""