workbench: explorer icons read on a float's pane and every material

app/layout/ViewDrag.zig

@@ -2063,7 +2063,7 @@ fn drawTabFace(l: *Layout, d: ViewDrag, title: []const u8) void {
     // selected tab's — it is the tab in hand. The face drawn before the tab became glass is the
     // strip's own, so anything else here changed on the way back.
     const theme = dvui.themeGet();
-    const icon_color = theme.color(.control, .text);
+    const icon_color = core.widgets.treeGlyphColor(theme);
     const color = theme.color(.window, .text);
     if (asRows(d)) return drawRows(l, &d, icon_color, color);
     var row = dvui.box(@src(), .{ .dir = .horizontal }, .{ .gravity_x = 0.5, .gravity_y = 0.5 });

core/widgets.zig

@@ -319,6 +319,16 @@ pub fn treeRowGlyphSize() dvui.Size {
     return .{ .w = h, .h = h };
 }
 
+/// The colour a file's glyph rests in — a file tree's rows (lit toward their accent as the pointer
+/// nears), a document tab's, a row or tab carried in glass — so a file looks the same wherever it
+/// is shown: the theme's control text, as the tree's labels. Not the window's fill, the theme's
+/// darkest, which the tree's glyphs once rested in: that read only on the main window's own base,
+/// and on a pane's card (a popped-out float's, under any window material) it was the colour
+/// under them.
+pub fn treeGlyphColor(theme: dvui.Theme) dvui.Color {
+    return theme.color(.control, .text);
+}
+
 /// A tree row's expand caret, in its own glyph slot: down when `expanded`, right when not.
 ///
 /// The two arrows are different shapes (the down one wide, the right one tall) and the icon fits

plugins/workbench/src/Workspace.zig

@@ -329,7 +329,7 @@ fn drawTabs(self: *Workspace, region: sdk.Host.Region, tabs: []const *sdk.Surfac
 
         // Same fixed glyph slot as the file tree.
         const tab_doc_path = if (doc_opt) |doc| doc.owner.documentPath(doc) else loading.?.path;
-        const tab_icon_color = dvui.themeGet().color(.control, .text);
+        const tab_icon_color = core.widgets.treeGlyphColor(dvui.themeGet());
         {
             var icon_slot = core.widgets.treeRowGlyph(@src(), .{ .gravity_y = 0.5, .margin = .{ .x = 4, .w = 2 } });
             defer icon_slot.deinit();

plugins/workbench/src/files.zig

@@ -959,7 +959,7 @@ pub fn recurseFiles(root_directory: []const u8, root_label: []const u8, outer_tr
 
                 const t = 1.0 - (distance / max_distance);
 
-                color = dvui.themeGet().color(.window, .fill).lerp(color, t);
+                color = core.widgets.treeGlyphColor(dvui.themeGet()).lerp(color, t);
 
                 if (branch.floating()) {
                     if (dvui.dataGetSlice(null, inner_unique_id, "removed_path", []u8) == null)

tests/integration.zig

@@ -6991,6 +6991,39 @@ test "workbench: where a tab carried over a strip goes in is read as if its open
     try std.testing.expectEqual(@as(usize, 3), pane.insertIndexAt(500, 3));
 }
 
+fn glyphLuma(c: dvui.Color) f32 {
+    return 0.2126 * @as(f32, @floatFromInt(c.r)) + 0.7152 * @as(f32, @floatFromInt(c.g)) + 0.0722 * @as(f32, @floatFromInt(c.b));
+}
+
+test "workbench: a file tree's glyphs stand off the main window's base and a float's pane alike" {
+    // Fizzy Dark's colours, as `Editor` sets them up (no themes are loaded here).
+    var fizzy_dark = dvui.Theme.builtin.adwaita_dark;
+    fizzy_dark.window = .{ .fill = .{ .r = 28, .g = 29, .b = 36 }, .text = .{ .r = 206, .g = 163, .b = 127 } };
+    fizzy_dark.control = .{ .fill = .{ .r = 28, .g = 29, .b = 36 }, .text = .{ .r = 134, .g = 138, .b = 148 } };
+    fizzy_dark.fill = .{ .r = 42, .g = 44, .b = 54 };
+    // The report, measured in a popped-out float on Liquid Glass: its explorer's pane card, and the
+    // main window's sidebar beside it. The window's fill, which the glyphs rested in, was the
+    // sidebar's dark glyph and within a few steps of the float's card: invisible there.
+    const float_card: dvui.Color = .{ .r = 38, .g = 39, .b = 45 };
+    const main_base: dvui.Color = .{ .r = 65, .g = 67, .b = 74 };
+    try std.testing.expect(@abs(glyphLuma(fizzy_dark.color(.window, .fill)) - glyphLuma(float_card)) < 15);
+    const glyph = fizzy.core.widgets.treeGlyphColor(fizzy_dark);
+    try std.testing.expect(@abs(glyphLuma(glyph) - glyphLuma(float_card)) > 60);
+    try std.testing.expect(@abs(glyphLuma(glyph) - glyphLuma(main_base)) > 40);
+
+    // And in every theme fizzy ships with dvui's: off the window's fill and the content fill (a
+    // pane's card), whichever a tree is drawn on, in the main window or a float.
+    for (dvui.Theme.builtins) |theme| {
+        const g = fizzy.core.widgets.treeGlyphColor(theme);
+        for ([_]dvui.Color{ theme.color(.window, .fill), theme.color(.content, .fill) }) |base| {
+            std.testing.expect(@abs(glyphLuma(g) - glyphLuma(base)) > 40) catch |err| {
+                std.debug.print("{s}: glyph {f} on {f}\n", .{ theme.name, g, base });
+                return err;
+            };
+        }
+    }
+}
+
 // An app's home page in place of the workbench's: a surface keyworded `home`, shown in the `Home`
 // place the sole document pane declares while it is empty (`Workspace.drawHome`). The pane here is
 // declared as `Workspace.draw` declares it, through the plugin's `Host`, so the place is the one