Initial commit

src/index.js

@@ -0,0 +1,187 @@
+import React from "react";
+import ReactDOM from "react-dom";
+import rough from "roughjs/dist/rough.umd.js";
+
+import "./styles.css";
+
+var elements = [];
+
+function newElement(type, x, y) {
+  const element = {
+    type: type,
+    x: x,
+    y: y,
+    width: 0,
+    height: 0
+  };
+  generateShape(element);
+  return element;
+}
+
+function rotate(x1, y1, x2, y2, angle) {
+  // 𝑎′𝑥=(𝑎𝑥−𝑐𝑥)cos𝜃−(𝑎𝑦−𝑐𝑦)sin𝜃+𝑐𝑥
+  // 𝑎′𝑦=(𝑎𝑥−𝑐𝑥)sin𝜃+(𝑎𝑦−𝑐𝑦)cos𝜃+𝑐𝑦.
+  // https://math.stackexchange.com/questions/2204520/how-do-i-rotate-a-line-segment-in-a-specific-point-on-the-line
+  return [
+    (x1 - x2) * Math.cos(angle) - (y1 - y2) * Math.sin(angle) + x2,
+    (x1 - x2) * Math.sin(angle) + (y1 - y2) * Math.cos(angle) + y2
+  ];
+}
+
+var generator = rough.generator();
+
+function generateShape(element) {
+  if (element.type === "selection") {
+    element.draw = (rc, context) => {
+      context.fillStyle = "rgba(0, 0, 255, 0.10)";
+      context.fillRect(element.x, element.y, element.width, element.height);
+    };
+  } else if (element.type === "rectangle") {
+    const shape = generator.rectangle(
+      element.x,
+      element.y,
+      element.width,
+      element.height
+    );
+    element.draw = (rc, context) => {
+      rc.draw(shape);
+    };
+  } else if (element.type === "ellipse") {
+    const shape = generator.ellipse(
+      element.x + element.width / 2,
+      element.y + element.height / 2,
+      element.width,
+      element.height
+    );
+    element.draw = (rc, context) => {
+      rc.draw(shape);
+    };
+  } else if (element.type === "arrow") {
+    const x1 = element.x;
+    const y1 = element.y;
+    const x2 = element.x + element.width;
+    const y2 = element.y + element.height;
+
+    const size = 30; // pixels
+    const distance = Math.sqrt(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2));
+    // Scale down the arrow until we hit a certain size so that it doesn't look weird
+    const minSize = Math.min(size, distance / 2);
+    const xs = x2 - ((x2 - x1) / distance) * minSize;
+    const ys = y2 - ((y2 - y1) / distance) * minSize;
+
+    const angle = 20; // degrees
+    const [x3, y3] = rotate(xs, ys, x2, y2, (-angle * Math.PI) / 180);
+    const [x4, y4] = rotate(xs, ys, x2, y2, (angle * Math.PI) / 180);
+
+    const shapes = [
+      generator.line(x1, y1, x2, y2),
+      generator.line(x3, y3, x2, y2),
+      generator.line(x4, y4, x2, y2)
+    ];
+
+    element.draw = (rc, context) => {
+      shapes.forEach(shape => rc.draw(shape));
+    };
+    return;
+  } else if (element.type === "text") {
+    if (element.text === undefined) {
+      element.text = prompt("What text do you want?");
+    }
+    element.draw = (rc, context) => {
+      context.font = "20px Virgil";
+      const measure = context.measureText(element.text);
+      const height =
+        measure.actualBoundingBoxAscent + measure.actualBoundingBoxDescent;
+      context.fillText(
+        element.text,
+        element.x - measure.width / 2,
+        element.y + measure.actualBoundingBoxAscent - height / 2
+      );
+    };
+  } else {
+    throw new Error("Unimplemented type " + element.type);
+  }
+}
+
+function App() {
+  const [draggingElement, setDraggingElement] = React.useState(null);
+  const [elementType, setElementType] = React.useState("selection");
+  const [selectedElements, setSelectedElements] = React.useState([]);
+  function ElementOption({ type, children }) {
+    return (
+      <label>
+        <input
+          type="radio"
+          checked={elementType === type}
+          onChange={() => setElementType(type)}
+        />
+        {children}
+      </label>
+    );
+  }
+  return (
+    <div>
+      <ElementOption type="rectangle">Rectangle</ElementOption>
+      <ElementOption type="ellipse">Ellipse</ElementOption>
+      <ElementOption type="arrow">Arrow</ElementOption>
+      <ElementOption type="text">Text</ElementOption>
+      <ElementOption type="selection">Selection</ElementOption>
+      <canvas
+        id="canvas"
+        width={window.innerWidth}
+        height={window.innerHeight}
+        onMouseDown={e => {
+          const element = newElement(
+            elementType,
+            e.clientX - e.target.offsetLeft,
+            e.clientY - e.target.offsetTop
+          );
+          elements.push(element);
+          setDraggingElement(element);
+          drawScene();
+        }}
+        onMouseUp={e => {
+          setDraggingElement(null);
+          drawScene();
+        }}
+        onMouseMove={e => {
+          if (!draggingElement) return;
+          let width = e.clientX - e.target.offsetLeft - draggingElement.x;
+          let height = e.clientY - e.target.offsetTop - draggingElement.y;
+          draggingElement.width = width;
+          // Make a perfect square or circle when shift is enabled
+          draggingElement.height = e.shiftKey ? width : height;
+          generateShape(draggingElement);
+          drawScene();
+        }}
+      />
+    </div>
+  );
+}
+const rootElement = document.getElementById("root");
+
+function drawScene() {
+  ReactDOM.render(<App />, rootElement);
+
+  const canvas = document.getElementById("canvas");
+  const rc = rough.canvas(canvas);
+  const context = canvas.getContext("2d");
+  context.clearRect(0, 0, canvas.width, canvas.height);
+
+  elements.forEach(element => {
+    element.draw(rc, context);
+    if (true || element.isSelected) {
+      const margin = 4;
+      context.setLineDash([8, 4]);
+      context.strokeRect(
+        element.x - margin,
+        element.y - margin,
+        element.width + margin * 2,
+        element.height + margin * 2
+      );
+      context.setLineDash([]);
+    }
+  });
+}
+
+drawScene();

src/styles.css

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+/* http://www.eaglefonts.com/fg-virgil-ttf-131249.htm */
+@font-face {
+  font-family: "Virgil";
+  src: url("https://uploads.codesandbox.io/uploads/user/ed077012-e728-4a42-8395-cbd299149d62/AflB-FG_Virgil.ttf");
+}