fix for zero width scrollbars (#3887)

* fix for zero width scrollbars * changelog * snapshot fix * simplify * change wait * early out, test fix * no early out * increase wait * auto pilot * increase wait * skip windoze * disable test * restore test * flush events * another flush * maybe fix race condition * uderline fix * simplify * remove flush events
Textualize · Dec 17, 2023 · 32b916f · 32b916f
1 parent 1ce6473
commit 32b916f
Show file tree

Hide file tree

Showing 6 changed files with 207 additions and 9 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ### Fixed
 
 - Disabled radio buttons could be selected with the keyboard https://github.com/Textualize/textual/issues/3839
+- Fixed zero width scrollbars causing content to disappear https://github.com/Textualize/textual/issues/3886
 
 ### Changed
 

diff --git a/src/textual/widget.py b/src/textual/widget.py
@@ -1392,8 +1392,7 @@ def scrollbars_enabled(self) -> tuple[bool, bool]:
         if not self.is_scrollable:
             return False, False
 
-        enabled = self.show_vertical_scrollbar, self.show_horizontal_scrollbar
-        return enabled
+        return (self.show_vertical_scrollbar, self.show_horizontal_scrollbar)
 
     @property
     def scrollbars_space(self) -> tuple[int, int]:
@@ -2756,6 +2755,13 @@ def _get_scrollable_region(self, region: Region) -> Region:
         scrollbar_size_horizontal = styles.scrollbar_size_horizontal
         scrollbar_size_vertical = styles.scrollbar_size_vertical
 
+        show_vertical_scrollbar: bool = (
+            show_vertical_scrollbar and scrollbar_size_vertical
+        )
+        show_horizontal_scrollbar: bool = (
+            show_horizontal_scrollbar and scrollbar_size_horizontal
+        )
+
         if styles.scrollbar_gutter == "stable":
             # Let's _always_ reserve some space, whether the scrollbar is actually displayed or not:
             show_vertical_scrollbar = True
@@ -2786,6 +2792,13 @@ def _arrange_scrollbars(self, region: Region) -> Iterable[tuple[Widget, Region]]
         scrollbar_size_horizontal = self.scrollbar_size_horizontal
         scrollbar_size_vertical = self.scrollbar_size_vertical
 
+        show_vertical_scrollbar: bool = (
+            show_vertical_scrollbar and scrollbar_size_vertical
+        )
+        show_horizontal_scrollbar: bool = (
+            show_horizontal_scrollbar and scrollbar_size_horizontal
+        )
+
         if show_horizontal_scrollbar and show_vertical_scrollbar:
             (
                 window_region,

diff --git a/src/textual/widgets/_tabs.py b/src/textual/widgets/_tabs.py
@@ -593,8 +593,17 @@ def _highlight_active(self, animate: bool = True) -> None:
 
                 def animate_underline() -> None:
                     """Animate the underline."""
-                    underline.animate("highlight_start", start, duration=0.3)
-                    underline.animate("highlight_end", end, duration=0.3)
+                    try:
+                        active_tab = self.query_one(f"#tabs-list > Tab.-active")
+                    except NoMatches:
+                        pass
+                    else:
+                        tab_region = active_tab.virtual_region.shrink(
+                            active_tab.styles.gutter
+                        )
+                        start, end = tab_region.column_span
+                        underline.animate("highlight_start", start, duration=0.3)
+                        underline.animate("highlight_end", end, duration=0.3)
 
                 self.set_timer(0.02, lambda: self.call_after_refresh(animate_underline))
             else:

diff --git a/tests/snapshot_tests/__snapshots__/test_snapshots.ambr b/tests/snapshot_tests/__snapshots__/test_snapshots.ambr
@@ -38206,3 +38206,158 @@
 
   '''
 # ---
+# name: test_zero_scrollbar_size
+  '''
+  <svg class="rich-terminal" viewBox="0 0 994 635.5999999999999" xmlns="http://www.w3.org/2000/svg">
+      <!-- Generated with Rich https://www.textualize.io -->
+      <style>
+
+      @font-face {
+          font-family: "Fira Code";
+          src: local("FiraCode-Regular"),
+                  url("https://cdnjs.cloudflare.com/ajax/libs/firacode/6.2.0/woff2/FiraCode-Regular.woff2") format("woff2"),
+                  url("https://cdnjs.cloudflare.com/ajax/libs/firacode/6.2.0/woff/FiraCode-Regular.woff") format("woff");
+          font-style: normal;
+          font-weight: 400;
+      }
+      @font-face {
+          font-family: "Fira Code";
+          src: local("FiraCode-Bold"),
+                  url("https://cdnjs.cloudflare.com/ajax/libs/firacode/6.2.0/woff2/FiraCode-Bold.woff2") format("woff2"),
+                  url("https://cdnjs.cloudflare.com/ajax/libs/firacode/6.2.0/woff/FiraCode-Bold.woff") format("woff");
+          font-style: bold;
+          font-weight: 700;
+      }
+
+      .terminal-2277926227-matrix {
+          font-family: Fira Code, monospace;
+          font-size: 20px;
+          line-height: 24.4px;
+          font-variant-east-asian: full-width;
+      }
+
+      .terminal-2277926227-title {
+          font-size: 18px;
+          font-weight: bold;
+          font-family: arial;
+      }
+
+      .terminal-2277926227-r1 { fill: #e1e1e1 }
+  .terminal-2277926227-r2 { fill: #c5c8c6 }
+      </style>
+
+      <defs>
+      <clipPath id="terminal-2277926227-clip-terminal">
+        <rect x="0" y="0" width="975.0" height="584.5999999999999" />
+      </clipPath>
+      <clipPath id="terminal-2277926227-line-0">
+      <rect x="0" y="1.5" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-1">
+      <rect x="0" y="25.9" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-2">
+      <rect x="0" y="50.3" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-3">
+      <rect x="0" y="74.7" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-4">
+      <rect x="0" y="99.1" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-5">
+      <rect x="0" y="123.5" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-6">
+      <rect x="0" y="147.9" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-7">
+      <rect x="0" y="172.3" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-8">
+      <rect x="0" y="196.7" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-9">
+      <rect x="0" y="221.1" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-10">
+      <rect x="0" y="245.5" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-11">
+      <rect x="0" y="269.9" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-12">
+      <rect x="0" y="294.3" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-13">
+      <rect x="0" y="318.7" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-14">
+      <rect x="0" y="343.1" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-15">
+      <rect x="0" y="367.5" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-16">
+      <rect x="0" y="391.9" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-17">
+      <rect x="0" y="416.3" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-18">
+      <rect x="0" y="440.7" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-19">
+      <rect x="0" y="465.1" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-20">
+      <rect x="0" y="489.5" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-21">
+      <rect x="0" y="513.9" width="976" height="24.65"/>
+              </clipPath>
+  <clipPath id="terminal-2277926227-line-22">
+      <rect x="0" y="538.3" width="976" height="24.65"/>
+              </clipPath>
+      </defs>
+
+      <rect fill="#292929" stroke="rgba(255,255,255,0.35)" stroke-width="1" x="1" y="1" width="992" height="633.6" rx="8"/><text class="terminal-2277926227-title" fill="#c5c8c6" text-anchor="middle" x="496" y="27">TestApp</text>
+              <g transform="translate(26,22)">
+              <circle cx="0" cy="0" r="7" fill="#ff5f57"/>
+              <circle cx="22" cy="0" r="7" fill="#febc2e"/>
+              <circle cx="44" cy="0" r="7" fill="#28c840"/>
+              </g>
+
+      <g transform="translate(9, 41)" clip-path="url(#terminal-2277926227-clip-terminal)">
+      <rect fill="#1e1e1e" x="0" y="1.5" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="1.5" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="25.9" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="25.9" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="50.3" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="50.3" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="74.7" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="74.7" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="99.1" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="99.1" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="123.5" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="123.5" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="147.9" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="147.9" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="172.3" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="172.3" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="196.7" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="196.7" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="221.1" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="221.1" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="245.5" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="245.5" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="269.9" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="269.9" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="294.3" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="294.3" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="318.7" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="318.7" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="343.1" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="343.1" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="367.5" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="367.5" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="391.9" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="391.9" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="416.3" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="416.3" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="440.7" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="440.7" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="465.1" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="465.1" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="489.5" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="489.5" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="513.9" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="513.9" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="538.3" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="538.3" width="817.4" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="0" y="562.7" width="158.6" height="24.65" shape-rendering="crispEdges"/><rect fill="#1e1e1e" x="158.6" y="562.7" width="817.4" height="24.65" shape-rendering="crispEdges"/>
+      <g class="terminal-2277926227-matrix">
+      <text class="terminal-2277926227-r1" x="0" y="20" textLength="158.6" clip-path="url(#terminal-2277926227-line-0)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="20" textLength="12.2" clip-path="url(#terminal-2277926227-line-0)">
+  </text><text class="terminal-2277926227-r1" x="0" y="44.4" textLength="158.6" clip-path="url(#terminal-2277926227-line-1)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="44.4" textLength="12.2" clip-path="url(#terminal-2277926227-line-1)">
+  </text><text class="terminal-2277926227-r1" x="0" y="68.8" textLength="158.6" clip-path="url(#terminal-2277926227-line-2)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="68.8" textLength="12.2" clip-path="url(#terminal-2277926227-line-2)">
+  </text><text class="terminal-2277926227-r1" x="0" y="93.2" textLength="158.6" clip-path="url(#terminal-2277926227-line-3)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="93.2" textLength="12.2" clip-path="url(#terminal-2277926227-line-3)">
+  </text><text class="terminal-2277926227-r1" x="0" y="117.6" textLength="158.6" clip-path="url(#terminal-2277926227-line-4)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="117.6" textLength="12.2" clip-path="url(#terminal-2277926227-line-4)">
+  </text><text class="terminal-2277926227-r1" x="0" y="142" textLength="158.6" clip-path="url(#terminal-2277926227-line-5)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="142" textLength="12.2" clip-path="url(#terminal-2277926227-line-5)">
+  </text><text class="terminal-2277926227-r1" x="0" y="166.4" textLength="158.6" clip-path="url(#terminal-2277926227-line-6)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="166.4" textLength="12.2" clip-path="url(#terminal-2277926227-line-6)">
+  </text><text class="terminal-2277926227-r1" x="0" y="190.8" textLength="158.6" clip-path="url(#terminal-2277926227-line-7)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="190.8" textLength="12.2" clip-path="url(#terminal-2277926227-line-7)">
+  </text><text class="terminal-2277926227-r1" x="0" y="215.2" textLength="158.6" clip-path="url(#terminal-2277926227-line-8)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="215.2" textLength="12.2" clip-path="url(#terminal-2277926227-line-8)">
+  </text><text class="terminal-2277926227-r1" x="0" y="239.6" textLength="158.6" clip-path="url(#terminal-2277926227-line-9)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="239.6" textLength="12.2" clip-path="url(#terminal-2277926227-line-9)">
+  </text><text class="terminal-2277926227-r1" x="0" y="264" textLength="158.6" clip-path="url(#terminal-2277926227-line-10)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="264" textLength="12.2" clip-path="url(#terminal-2277926227-line-10)">
+  </text><text class="terminal-2277926227-r1" x="0" y="288.4" textLength="158.6" clip-path="url(#terminal-2277926227-line-11)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="288.4" textLength="12.2" clip-path="url(#terminal-2277926227-line-11)">
+  </text><text class="terminal-2277926227-r1" x="0" y="312.8" textLength="158.6" clip-path="url(#terminal-2277926227-line-12)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="312.8" textLength="12.2" clip-path="url(#terminal-2277926227-line-12)">
+  </text><text class="terminal-2277926227-r1" x="0" y="337.2" textLength="158.6" clip-path="url(#terminal-2277926227-line-13)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="337.2" textLength="12.2" clip-path="url(#terminal-2277926227-line-13)">
+  </text><text class="terminal-2277926227-r1" x="0" y="361.6" textLength="158.6" clip-path="url(#terminal-2277926227-line-14)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="361.6" textLength="12.2" clip-path="url(#terminal-2277926227-line-14)">
+  </text><text class="terminal-2277926227-r1" x="0" y="386" textLength="158.6" clip-path="url(#terminal-2277926227-line-15)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="386" textLength="12.2" clip-path="url(#terminal-2277926227-line-15)">
+  </text><text class="terminal-2277926227-r1" x="0" y="410.4" textLength="158.6" clip-path="url(#terminal-2277926227-line-16)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="410.4" textLength="12.2" clip-path="url(#terminal-2277926227-line-16)">
+  </text><text class="terminal-2277926227-r1" x="0" y="434.8" textLength="158.6" clip-path="url(#terminal-2277926227-line-17)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="434.8" textLength="12.2" clip-path="url(#terminal-2277926227-line-17)">
+  </text><text class="terminal-2277926227-r1" x="0" y="459.2" textLength="158.6" clip-path="url(#terminal-2277926227-line-18)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="459.2" textLength="12.2" clip-path="url(#terminal-2277926227-line-18)">
+  </text><text class="terminal-2277926227-r1" x="0" y="483.6" textLength="158.6" clip-path="url(#terminal-2277926227-line-19)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="483.6" textLength="12.2" clip-path="url(#terminal-2277926227-line-19)">
+  </text><text class="terminal-2277926227-r1" x="0" y="508" textLength="158.6" clip-path="url(#terminal-2277926227-line-20)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="508" textLength="12.2" clip-path="url(#terminal-2277926227-line-20)">
+  </text><text class="terminal-2277926227-r1" x="0" y="532.4" textLength="158.6" clip-path="url(#terminal-2277926227-line-21)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="532.4" textLength="12.2" clip-path="url(#terminal-2277926227-line-21)">
+  </text><text class="terminal-2277926227-r1" x="0" y="556.8" textLength="158.6" clip-path="url(#terminal-2277926227-line-22)">Hello,&#160;world!</text><text class="terminal-2277926227-r2" x="976" y="556.8" textLength="12.2" clip-path="url(#terminal-2277926227-line-22)">
+  </text><text class="terminal-2277926227-r1" x="0" y="581.2" textLength="158.6" clip-path="url(#terminal-2277926227-line-23)">Hello,&#160;world!</text>
+      </g>
+      </g>
+  </svg>
+
+  '''
+# ---
diff --git a/tests/snapshot_tests/snapshot_apps/zero_scrollbar_size.py b/tests/snapshot_tests/snapshot_apps/zero_scrollbar_size.py
@@ -0,0 +1,17 @@
+from textual.app import App, ComposeResult
+from textual.widgets import Static
+
+
+class TestApp(App):
+    DEFAULT_CSS = """
+    Screen {
+        scrollbar-size: 0 0;
+    }
+    """
+
+    def compose(self) -> ComposeResult:
+        yield Static("Hello, world!\n" * 100)
+
+
+if __name__ == "__main__":
+    TestApp().run()