Fix text color when selecting newline character (#7951)

* Closes https://github.com/emilk/egui/issues/7865

crates/egui/src/text_selection/visuals.rs

@@ -67,9 +67,7 @@ pub fn paint_text_selection(
             let first_vertex_index = row
                 .glyphs
                 .get(first_glyph_index)
-                .map_or(row.visuals.glyph_vertex_range.start, |g| {
-                    g.first_vertex as _
-                });
+                .map_or(row.visuals.glyph_vertex_range.end, |g| g.first_vertex as _);
             let last_vertex_index = row
                 .glyphs
                 .get(last_glyph_index)

crates/egui_demo_lib/tests/misc.rs

@@ -59,21 +59,27 @@ fn test_italics() {
 
 #[test]
 fn test_text_selection() {
-    let mut harness = Harness::builder().build_ui(|ui| {
-        let visuals = ui.visuals_mut();
-        visuals.selection.bg_fill = Color32::LIGHT_GREEN;
-        visuals.selection.stroke.color = Color32::DARK_BLUE;
+    let mut results = egui_kittest::SnapshotResults::new();
 
-        ui.label("Some varied ☺ text :)\nAnd it has a second line!");
-    });
-    harness.run();
-    harness.fit_contents();
+    for (test_idx, drag_start_x) in [0.2_f32, 0.9].into_iter().enumerate() {
+        let mut harness = Harness::builder().build_ui(|ui| {
+            let visuals = ui.visuals_mut();
+            visuals.selection.bg_fill = Color32::LIGHT_GREEN;
+            visuals.selection.stroke.color = Color32::RED;
 
-    // Drag to select text:
-    let label = harness.get_by_role(Role::Label);
-    harness.drag_at(label.rect().lerp_inside([0.2, 0.25]));
-    harness.drop_at(label.rect().lerp_inside([0.6, 0.75]));
-    harness.run();
+            ui.label("Some varied ☺ text :)\nAnd it has a second line!");
+        });
+        harness.run();
+        harness.fit_contents();
 
-    harness.snapshot("text_selection");
+        // Drag to select text:
+        let label = harness.get_by_role(Role::Label);
+        harness.drag_at(label.rect().lerp_inside([drag_start_x, 0.25]));
+        harness.drop_at(label.rect().lerp_inside([0.6, 0.75]));
+        harness.run();
+
+        harness.snapshot(format!("text_selection_{test_idx}"));
+
+        results.extend_harness(&mut harness);
+    }
 }

crates/egui_demo_lib/tests/snapshots/text_selection.png

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:0475c5ac04ab8f79b79d43cfdb985f05b61dbe90e81f898a6dc216c308a28841
-size 4707

crates/egui_demo_lib/tests/snapshots/text_selection_0.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:344d90928510855dc718a2e36e31a97f084f1163ab750d0217fb8620469b621a
+size 5276

crates/egui_demo_lib/tests/snapshots/text_selection_1.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:60449af267336663304e44e254d0984e037bebfa2d1efdf32234cab4374e8c79
+size 5301