basic druid drawing canvas

Cargo.lock

@@ -67,6 +67,15 @@ version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 
+[[package]]
+name = "bitmaps"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "031043d04099746d8db04daf1fa424b2bc8bd69d92b25962dcde24da39ab64a2"
+dependencies = [
+ "typenum",
+]
+
 [[package]]
 name = "block"
 version = "0.1.6"
@@ -275,6 +284,7 @@ dependencies = [
  "fluent-langneg",
  "fluent-syntax",
  "fnv",
+ "im",
  "instant",
  "log",
  "simple_logger",
@@ -748,6 +758,20 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "im"
+version = "15.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "111c1983f3c5bb72732df25cddacee9b546d08325fb584b5ebd38148be7b0246"
+dependencies = [
+ "bitmaps",
+ "rand_core",
+ "rand_xoshiro",
+ "sized-chunks",
+ "typenum",
+ "version_check",
+]
+
 [[package]]
 name = "input"
 version = "0.5.0"
@@ -1113,6 +1137,21 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "rand_core"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "90bde5296fc891b0cef12a6d03ddccc162ce7b2aff54160af9338f8d40df6d19"
+
+[[package]]
+name = "rand_xoshiro"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a9fcdd2e881d02f1d9390ae47ad8e5696a9e4be7b547a1da2afbc61973217004"
+dependencies = [
+ "rand_core",
+]
+
 [[package]]
 name = "regex-automata"
 version = "0.1.9"
@@ -1224,6 +1263,16 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "sized-chunks"
+version = "0.6.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ec31ceca5644fa6d444cc77548b88b67f46db6f7c71683b0f9336e671830d2f"
+dependencies = [
+ "bitmaps",
+ "typenum",
+]
+
 [[package]]
 name = "slab"
 version = "0.4.2"
@@ -1310,6 +1359,7 @@ dependencies = [
  "gdk",
  "gio",
  "gtk",
+ "im",
  "input",
  "libc",
  "udev 0.2.0",
@@ -1441,6 +1491,12 @@ dependencies = [
  "fxhash",
 ]
 
+[[package]]
+name = "typenum"
+version = "1.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "373c8a200f9e67a0c95e62a4f52fbf80c23b4381c05a17845531982fa99e6b33"
+
 [[package]]
 name = "udev"
 version = "0.2.0"

Cargo.toml

@@ -12,7 +12,8 @@ udev = "0.2"
 libc = "0.2"
 errno = "0.2"
 csv = "1.1"
-druid = { git = "https://github.com/doppioandante/druid", branch = "stylus_events" }
+druid = { git = "https://github.com/doppioandante/druid", branch = "stylus_events", features = ["im"] }
+im = { version = "*" }
 
 [dependencies.gtk]
 version = "0.9.2"

src/main.rs

@@ -14,37 +14,67 @@
 
 //! An example of a custom drawing widget.
 
+use druid::im::{vector, Vector};
 use druid::kurbo::BezPath;
 use druid::piet::{FontFamily, ImageFormat, InterpolationMode};
 use druid::widget::prelude::*;
 use druid::{
-    Affine, AppLauncher, ArcStr, Color, FontDescriptor, LocalizedString, Point, Rect, TextLayout,
+    Affine, AppLauncher, ArcStr, Color, Data, Event, FontDescriptor, LocalizedString, Point, Rect, TextLayout,
     WindowDesc,
 };
 
-struct CustomWidget;
+#[derive(Clone, Data)]
+struct CanvasData {
+    drawn_paths: Vector<BezPath>,
+    is_drawing: bool,
+}
 
-impl Widget<String> for CustomWidget {
+struct CanvasWidget;
-    fn event(&mut self, _ctx: &mut EventCtx, event: &Event, _data: &mut String, _env: &Env) {
+
-        println!("{:?}", event);
+impl Widget<CanvasData> for CanvasWidget {
+    fn event(&mut self, _ctx: &mut EventCtx, event: &Event, data: &mut CanvasData, _env: &Env) {
+        match event {
+           Event::MouseDown(mouse_event) => {
+               if mouse_event.pointer_type == druid::PointerType::Stylus {
+                   data.is_drawing = true;
+                   let mut new_path = BezPath::new();
+                   new_path.move_to((mouse_event.pos.x, mouse_event.pos.y));
+                   data.drawn_paths.push_back(new_path);
+               }
+           },
+           Event::MouseMove(mouse_event) => {
+               if data.is_drawing && mouse_event.pointer_type == druid::PointerType::Stylus {
+                   data.drawn_paths.back_mut().unwrap().line_to((mouse_event.pos.x, mouse_event.pos.y));
+               }
+           },
+           Event::MouseUp(_) => {
+               if data.is_drawing {
+                   data.is_drawing = false;
+               }
+           },
+           _ => {}
+
+        }
     }
 
     fn lifecycle(
         &mut self,
         _ctx: &mut LifeCycleCtx,
         _event: &LifeCycle,
-        _data: &String,
+        _data: &CanvasData,
         _env: &Env,
     ) {
     }
 
-    fn update(&mut self, _ctx: &mut UpdateCtx, _old_data: &String, _data: &String, _env: &Env) {}
+    fn update(&mut self, ctx: &mut UpdateCtx, _old_data: &CanvasData, _data: &CanvasData, _env: &Env) {
+        ctx.request_paint();
+    }
 
     fn layout(
         &mut self,
         _layout_ctx: &mut LayoutCtx,
         bc: &BoxConstraints,
-        _data: &String,
+        _data: &CanvasData,
         _env: &Env,
     ) -> Size {
         // BoxConstraints are passed by the parent widget.
@@ -59,7 +89,7 @@ impl Widget<String> for CustomWidget {
     // The paint method gets called last, after an event flow.
     // It goes event -> update -> layout -> paint, and each method can influence the next.
     // Basically, anything that changes the appearance of a widget causes a paint.
-    fn paint(&mut self, ctx: &mut PaintCtx, data: &String, env: &Env) {
+    fn paint(&mut self, ctx: &mut PaintCtx, data: &CanvasData, _env: &Env) {
         // Let's draw a picture with Piet!
 
         // Clear the whole widget with the color of your choice
@@ -71,67 +101,23 @@ impl Widget<String> for CustomWidget {
         // Note: ctx also has a `clear` method, but that clears the whole context,
         // and we only want to clear this widget's area.
 
-        // Create an arbitrary bezier path
-        let mut path = BezPath::new();
-        path.move_to(Point::ORIGIN);
-        path.quad_to((80.0, 90.0), (size.width, size.height));
-        // Create a color
         let stroke_color = Color::rgb8(0, 128, 0);
-        // Stroke the path with thickness 1.0
+        for path in &data.drawn_paths {
-        ctx.stroke(path, &stroke_color, 1.0);
+            ctx.stroke(path, &stroke_color, 2.0);
-
+        }
-        // Rectangles: the path for practical people
-        let rect = Rect::from_origin_size((10., 10.), (100., 100.));
-        // Note the Color:rgba8 which includes an alpha channel (7F in this case)
-        let fill_color = Color::rgba8(0x00, 0x00, 0x00, 0x7F);
-        ctx.fill(rect, &fill_color);
-
-        // Text is easy; in real use TextLayout should be stored in the widget
-        // and reused.
-        let mut layout = TextLayout::<ArcStr>::from_text(data.to_owned());
-        layout.set_font(FontDescriptor::new(FontFamily::SERIF).with_size(24.0));
-        layout.set_text_color(fill_color);
-        layout.rebuild_if_needed(ctx.text(), env);
-
-        // Let's rotate our text slightly. First we save our current (default) context:
-        ctx.with_save(|ctx| {
-            // Now we can rotate the context (or set a clip path, for instance):
-            ctx.transform(Affine::rotate(0.1));
-            layout.draw(ctx, (80.0, 40.0));
-        });
-        // When we exit with_save, the original context's rotation is restored
-
-        // Let's burn some CPU to make a (partially transparent) image buffer
-        let image_data = make_image_data(256, 256);
-        let image = ctx
-            .make_image(256, 256, &image_data, ImageFormat::RgbaSeparate)
-            .unwrap();
-        // The image is automatically scaled to fit the rect you pass to draw_image
-        ctx.draw_image(&image, size.to_rect(), InterpolationMode::Bilinear);
     }
 }
 
 pub fn main() {
-    let window = WindowDesc::new(|| CustomWidget {}).title(
+    let window = WindowDesc::new(|| CanvasWidget {}).title(
         LocalizedString::new("custom-widget-demo-window-title").with_placeholder("Fancy Colors"),
     );
+    let canvas_data = CanvasData {
+        drawn_paths: vector![],
+        is_drawing: false,
+    };
     AppLauncher::with_window(window)
         .use_simple_logger()
-        .launch("Druid + Piet".to_string())
+        .launch(canvas_data)
         .expect("launch failed");
 }
-
-fn make_image_data(width: usize, height: usize) -> Vec<u8> {
-    let mut result = vec![0; width * height * 4];
-    for y in 0..height {
-        for x in 0..width {
-            let ix = (y * width + x) * 4;
-            result[ix] = x as u8;
-            result[ix + 1] = y as u8;
-            result[ix + 2] = !(x as u8);
-            result[ix + 3] = 127;
-        }
-    }
-    result
-}
-