From 1b6a7e0d00703e3da2e1620b5a2b2cba027161de Mon Sep 17 00:00:00 2001
From: Joris
Date: Tue, 28 Jan 2020 09:55:58 +0100
Subject: Implement game of life

---
 src/canvas.rs | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 src/canvas.rs

(limited to 'src/canvas.rs')

diff --git a/src/canvas.rs b/src/canvas.rs
new file mode 100644
index 0000000..38aef4d
--- /dev/null
+++ b/src/canvas.rs
@@ -0,0 +1,64 @@
+use wasm_bindgen::prelude::JsValue;
+use wasm_bindgen::JsCast;
+use web_sys::CanvasRenderingContext2d;
+
+pub struct Canvas {
+    context: CanvasRenderingContext2d,
+    width: u32,
+    height: u32,
+    scaled_width: u32,
+    scaled_height: u32,
+}
+
+impl Canvas {
+    pub fn new(attr_id: &str, width: u32, height: u32) -> Canvas {
+        let document = web_sys::window().unwrap().document().unwrap();
+        let canvas = document.get_element_by_id(attr_id).unwrap();
+        let canvas: web_sys::HtmlCanvasElement = canvas
+            .dyn_into::<web_sys::HtmlCanvasElement>()
+            .unwrap();
+
+        let context = canvas
+            .get_context("2d")
+            .unwrap()
+            .unwrap()
+            .dyn_into::<web_sys::CanvasRenderingContext2d>()
+            .unwrap();
+
+        let scaled_width = canvas.width() / width;
+        let scaled_height = canvas.height() / height;
+
+        Canvas {
+            context,
+            width,
+            height,
+            scaled_width,
+            scaled_height,
+        }
+    }
+
+    pub fn clear(&self) {
+        self.context.set_fill_style(&JsValue::from_str("white"));
+
+        self.context.fill_rect(
+            f64::from(0),
+            f64::from(0),
+            f64::from(self.width * self.scaled_width),
+            f64::from(self.height * self.scaled_height)
+        );
+    }
+
+    pub fn draw(&self, x: u32, y: u32, color: &str) {
+        assert!(x < self.width);
+        assert!(y < self.height);
+
+        self.context.set_fill_style(&JsValue::from_str(color));
+
+        self.context.fill_rect(
+            f64::from(x * self.scaled_width),
+            f64::from(y * self.scaled_height),
+            f64::from(self.scaled_width),
+            f64::from(self.scaled_height)
+        );
+    }
+}
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