Add example

examples/hello-world.rs

@@ -0,0 +1,121 @@
+#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release
+
+use std::{
+    ops::{Deref, DerefMut},
+    sync::Arc,
+};
+
+use eframe::{
+    egui::{self, Slider},
+    egui_wgpu,
+    epaint::{
+        mutex::{Mutex, RwLock},
+        Rect, Vec2,
+    },
+    CreationContext,
+};
+use egui_glyphon::{
+    glyphon::{Attrs, Family, FontSystem, Metrics, Shaping},
+    BufferWithTextArea, GlyphonRenderer, GlyphonRendererCallback,
+};
+
+fn main() -> Result<(), eframe::Error> {
+    env_logger::init(); // Log to stderr (if you run with `RUST_LOG=debug`).
+    let options = eframe::NativeOptions {
+        viewport: egui::ViewportBuilder::default().with_inner_size([320.0, 240.0]),
+        ..Default::default()
+    };
+    eframe::run_native(
+        "My egui App",
+        options,
+        Box::new(|cc| Box::new(MyApp::new(cc))),
+    )
+}
+
+struct Buffer(egui_glyphon::glyphon::Buffer);
+
+impl AsRef<egui_glyphon::glyphon::Buffer> for Buffer {
+    fn as_ref(&self) -> &egui_glyphon::glyphon::Buffer {
+        &self.0
+    }
+}
+
+impl Deref for Buffer {
+    type Target = egui_glyphon::glyphon::Buffer;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl DerefMut for Buffer {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+struct MyApp {
+    font_system: Arc<Mutex<FontSystem>>,
+    size: f32,
+    buffer: Arc<RwLock<Buffer>>,
+}
+
+impl Default for MyApp {
+    fn default() -> Self {
+        let mut font_system = FontSystem::new();
+        let mut buffer = Buffer(egui_glyphon::glyphon::Buffer::new(
+            &mut font_system,
+            Metrics::new(30.0, 42.0),
+        ));
+
+        buffer.set_size(&mut font_system, 16.0, 9.0);
+        buffer.set_text(&mut font_system, "<== Hello world! ==> 👋\nThis is rendered with 🦅 glyphon 🦁\nThe text below should be partially clipped.\na b c d e f g h i j k l m n o p q r s t u v w x y z", Attrs::new().family(Family::SansSerif), Shaping::Advanced);
+        buffer.shape_until_scroll(&mut font_system);
+        Self {
+            font_system: Arc::new(Mutex::new(font_system)),
+            buffer: Arc::new(RwLock::new(buffer)),
+            size: 35.0,
+        }
+    }
+}
+
+impl MyApp {
+    fn new(cc: &CreationContext<'_>) -> Self {
+        let app = Self::default();
+
+        if let Some(ref wgpu) = cc.wgpu_render_state {
+            GlyphonRenderer::insert(wgpu, Arc::clone(&app.font_system));
+        }
+
+        app
+    }
+}
+
+impl eframe::App for MyApp {
+    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
+        let size = Vec2::new(16.0 * self.size, 9.0 * self.size);
+
+        {
+            let mut font_system = self.font_system.lock();
+            let mut buffer = self.buffer.write();
+            buffer.set_metrics(&mut font_system, Metrics::new(self.size, self.size));
+            buffer.set_size(&mut font_system, size.x, size.y);
+            buffer.shape_until_scroll(&mut font_system);
+        }
+
+        egui::CentralPanel::default().show(ctx, |ui| {
+            ui.add(Slider::new(&mut self.size, 0.1..=67.5));
+            let rect = Rect::from_min_size(ui.cursor().min, size);
+            let buffers: Vec<BufferWithTextArea<Buffer>> = vec![BufferWithTextArea::new(
+                Arc::clone(&self.buffer),
+                rect,
+                1.0,
+                egui_glyphon::glyphon::Color::rgb(255, 255, 255),
+                ui.ctx(),
+            )];
+            ui.painter().add(egui_wgpu::Callback::new_paint_callback(
+                ui.max_rect(),
+                GlyphonRendererCallback { buffers },
+            ));
+        });
+    }
+}