From 31d8cbb2c028f729f50a1e95b90b72bb2378d855 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20R=C3=B6ssler?= <rene@freshx.de>
Date: Fri, 17 Dec 2021 18:18:25 +0100
Subject: [PATCH] add virtual scroll demo

---
 egui_demo_lib/src/apps/demo/table_demo.rs | 51 ++++++++++++++++++-----
 1 file changed, 41 insertions(+), 10 deletions(-)

diff --git a/egui_demo_lib/src/apps/demo/table_demo.rs b/egui_demo_lib/src/apps/demo/table_demo.rs
index 6f24ac57..16165276 100644
--- a/egui_demo_lib/src/apps/demo/table_demo.rs
+++ b/egui_demo_lib/src/apps/demo/table_demo.rs
@@ -1,10 +1,12 @@
-use egui::RichText;
+use egui::{Label, RichText};
 use egui_dynamic_grid::{Padding, Size, TableBuilder};
 
 /// Shows off a table with dynamic layout
 #[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 #[derive(Default)]
-pub struct TableDemo {}
+pub struct TableDemo {
+    virtual_scrool: bool,
+}
 
 impl super::Demo for TableDemo {
     fn name(&self) -> &'static str {
@@ -15,7 +17,7 @@ impl super::Demo for TableDemo {
         egui::Window::new(self.name())
             .open(open)
             .resizable(true)
-            .default_width(300.0)
+            .default_width(400.0)
             .show(ctx, |ui| {
                 use super::View as _;
                 self.ui(ui);
@@ -25,12 +27,14 @@ impl super::Demo for TableDemo {
 
 impl super::View for TableDemo {
     fn ui(&mut self, ui: &mut egui::Ui) {
+        ui.checkbox(&mut self.virtual_scrool, "Virtual scroll demo");
+
         // TODO: Fix table as a padding smaller than 16 grows the window
         TableBuilder::new(ui, Padding::new(3.0, 16.0))
             .striped(true)
+            .column(Size::Absolute(120.0))
+            .column(Size::RemainderMinimum(180.0))
             .column(Size::Absolute(100.0))
-            .column(Size::RemainderMinimum(150.0))
-            .column(Size::Absolute(50.0))
             .header(20.0, |mut header| {
                 header.col(|ui| {
                     ui.label(RichText::new("Left").heading());
@@ -43,18 +47,45 @@ impl super::View for TableDemo {
                 });
             })
             .body(|mut body| {
-                for i in 0..100 {
-                    body.row(20.0, |mut row| {
+                if self.virtual_scrool {
+                    body.rows(20.0, 100_000, |index, mut row| {
                         row.col(|ui| {
-                            ui.label(format!("{}", i));
+                            ui.label(format!("{}", index));
                         });
                         row.col(|ui| {
-                            ui.label(format!("{}", i));
+                            ui.add(
+                                Label::new("virtual scroll, easily with thousands of rows!")
+                                    .wrap(false),
+                            );
                         });
                         row.col(|ui| {
-                            ui.label(format!("{}", i));
+                            ui.label(format!("{}", index));
                         });
                     });
+                } else {
+                    for i in 0..100 {
+                        let height = match i % 8 {
+                            0 => 25.0,
+                            4 => 30.0,
+                            _ => 20.0,
+                        };
+                        body.row(height, |mut row| {
+                            row.col(|ui| {
+                                ui.label(format!("{}", i));
+                            });
+                            row.col(|ui| {
+                                ui.add(
+                                    Label::new(
+                                        format!("Normal scroll, each row can have a different height. Height: {}", height),
+                                    )
+                                    .wrap(false),
+                                );
+                            });
+                            row.col(|ui| {
+                                ui.label(format!("{}", i));
+                            });
+                        });
+                    }
                 }
             });
     }