397 lines
13 KiB
JavaScript
397 lines
13 KiB
JavaScript
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,
|
||
isSelected: false
|
||
};
|
||
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 generateDraw(element) {
|
||
if (element.type === "selection") {
|
||
element.draw = (rc, context) => {
|
||
const fillStyle = context.fillStyle;
|
||
context.fillStyle = "rgba(0, 0, 255, 0.10)";
|
||
context.fillRect(element.x, element.y, element.width, element.height);
|
||
context.fillStyle = fillStyle;
|
||
};
|
||
} else if (element.type === "rectangle") {
|
||
const shape = generator.rectangle(0, 0, element.width, element.height);
|
||
element.draw = (rc, context) => {
|
||
context.translate(element.x, element.y);
|
||
rc.draw(shape);
|
||
context.translate(-element.x, -element.y);
|
||
};
|
||
} else if (element.type === "ellipse") {
|
||
const shape = generator.ellipse(
|
||
element.width / 2,
|
||
element.height / 2,
|
||
element.width,
|
||
element.height
|
||
);
|
||
element.draw = (rc, context) => {
|
||
context.translate(element.x, element.y);
|
||
rc.draw(shape);
|
||
context.translate(-element.x, -element.y);
|
||
};
|
||
} else if (element.type === "arrow") {
|
||
const x1 = 0;
|
||
const y1 = 0;
|
||
const x2 = element.width;
|
||
const y2 = 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(x3, y3, x2, y2),
|
||
// -----
|
||
generator.line(x1, y1, x2, y2),
|
||
// /
|
||
generator.line(x4, y4, x2, y2)
|
||
];
|
||
|
||
element.draw = (rc, context) => {
|
||
context.translate(element.x, element.y);
|
||
shapes.forEach(shape => rc.draw(shape));
|
||
context.translate(-element.x, -element.y);
|
||
};
|
||
return;
|
||
} else if (element.type === "text") {
|
||
element.draw = (rc, context) => {
|
||
const font = context.font;
|
||
context.font = element.font;
|
||
context.fillText(
|
||
element.text,
|
||
element.x,
|
||
element.y + element.measure.actualBoundingBoxAscent
|
||
);
|
||
context.font = font;
|
||
};
|
||
} else {
|
||
throw new Error("Unimplemented type " + element.type);
|
||
}
|
||
}
|
||
|
||
// If the element is created from right to left, the width is going to be negative
|
||
// This set of functions retrieves the absolute position of the 4 points.
|
||
// We can't just always normalize it since we need to remember the fact that an arrow
|
||
// is pointing left or right.
|
||
function getElementAbsoluteX1(element) {
|
||
return element.width >= 0 ? element.x : element.x + element.width;
|
||
}
|
||
function getElementAbsoluteX2(element) {
|
||
return element.width >= 0 ? element.x + element.width : element.x;
|
||
}
|
||
function getElementAbsoluteY1(element) {
|
||
return element.height >= 0 ? element.y : element.y + element.height;
|
||
}
|
||
function getElementAbsoluteY2(element) {
|
||
return element.height >= 0 ? element.y + element.height : element.y;
|
||
}
|
||
|
||
function setSelection(selection) {
|
||
const selectionX1 = getElementAbsoluteX1(selection);
|
||
const selectionX2 = getElementAbsoluteX2(selection);
|
||
const selectionY1 = getElementAbsoluteY1(selection);
|
||
const selectionY2 = getElementAbsoluteY2(selection);
|
||
elements.forEach(element => {
|
||
const elementX1 = getElementAbsoluteX1(element);
|
||
const elementX2 = getElementAbsoluteX2(element);
|
||
const elementY1 = getElementAbsoluteY1(element);
|
||
const elementY2 = getElementAbsoluteY2(element);
|
||
element.isSelected =
|
||
element.type !== "selection" &&
|
||
selectionX1 <= elementX1 &&
|
||
selectionY1 <= elementY1 &&
|
||
selectionX2 >= elementX2 &&
|
||
selectionY2 >= elementY2;
|
||
});
|
||
}
|
||
|
||
function clearSelection() {
|
||
elements.forEach(element => {
|
||
element.isSelected = false;
|
||
});
|
||
}
|
||
|
||
class App extends React.Component {
|
||
componentDidMount() {
|
||
this.onKeyDown = event => {
|
||
if (event.key === "Backspace") {
|
||
for (var i = elements.length - 1; i >= 0; --i) {
|
||
if (elements[i].isSelected) {
|
||
elements.splice(i, 1);
|
||
}
|
||
}
|
||
drawScene();
|
||
event.preventDefault();
|
||
} else if (
|
||
event.key === "ArrowLeft" ||
|
||
event.key === "ArrowRight" ||
|
||
event.key === "ArrowUp" ||
|
||
event.key === "ArrowDown"
|
||
) {
|
||
const step = event.shiftKey ? 5 : 1;
|
||
elements.forEach(element => {
|
||
if (element.isSelected) {
|
||
if (event.key === "ArrowLeft") element.x -= step;
|
||
else if (event.key === "ArrowRight") element.x += step;
|
||
else if (event.key === "ArrowUp") element.y -= step;
|
||
else if (event.key === "ArrowDown") element.y += step;
|
||
}
|
||
});
|
||
drawScene();
|
||
event.preventDefault();
|
||
}
|
||
};
|
||
document.addEventListener("keydown", this.onKeyDown, false);
|
||
}
|
||
|
||
componentWillUnmount() {
|
||
document.removeEventListener("keydown", this.onKeyDown, false);
|
||
}
|
||
|
||
constructor() {
|
||
super();
|
||
this.state = {
|
||
draggingElement: null,
|
||
elementType: "selection"
|
||
};
|
||
}
|
||
|
||
render() {
|
||
const ElementOption = ({ type, children }) => {
|
||
return (
|
||
<label>
|
||
<input
|
||
type="radio"
|
||
checked={this.state.elementType === type}
|
||
onChange={() => {
|
||
this.setState({ elementType: type });
|
||
clearSelection();
|
||
drawScene();
|
||
}}
|
||
/>
|
||
{children}
|
||
</label>
|
||
);
|
||
};
|
||
|
||
return (
|
||
<div>
|
||
{/* Can't use the <ElementOption> form because ElementOption is re-defined
|
||
on every render, which would blow up and re-create the entire DOM tree,
|
||
which in addition to being inneficient, messes up with browser text
|
||
selection */}
|
||
{ElementOption({ type: "rectangle", children: "Rectangle" })}
|
||
{ElementOption({ type: "ellipse", children: "Ellipse" })}
|
||
{ElementOption({ type: "arrow", children: "Arrow" })}
|
||
{ElementOption({ type: "text", children: "Text" })}
|
||
{ElementOption({ type: "selection", children: "Selection" })}
|
||
<canvas
|
||
id="canvas"
|
||
width={window.innerWidth}
|
||
height={window.innerHeight}
|
||
onMouseDown={e => {
|
||
const x = e.clientX - e.target.offsetLeft;
|
||
const y = e.clientY - e.target.offsetTop;
|
||
const element = newElement(this.state.elementType, x, y);
|
||
|
||
let isDraggingElements = false;
|
||
const cursorStyle = document.documentElement.style.cursor;
|
||
if (this.state.elementType === "selection") {
|
||
isDraggingElements = elements.some(el => {
|
||
if (el.isSelected) {
|
||
const minX = Math.min(el.x, el.x + el.width);
|
||
const maxX = Math.max(el.x, el.x + el.width);
|
||
const minY = Math.min(el.y, el.y + el.height);
|
||
const maxY = Math.max(el.y, el.y + el.height);
|
||
return minX <= x && x <= maxX && minY <= y && y <= maxY;
|
||
}
|
||
});
|
||
if (isDraggingElements) {
|
||
document.documentElement.style.cursor = "move";
|
||
}
|
||
}
|
||
|
||
if (this.state.elementType === "text") {
|
||
const text = prompt("What text do you want?");
|
||
if (text === null) {
|
||
return;
|
||
}
|
||
element.text = text;
|
||
element.font = "20px Virgil";
|
||
const font = context.font;
|
||
context.font = element.font;
|
||
element.measure = context.measureText(element.text);
|
||
context.font = font;
|
||
const height =
|
||
element.measure.actualBoundingBoxAscent +
|
||
element.measure.actualBoundingBoxDescent;
|
||
// Center the text
|
||
element.x -= element.measure.width / 2;
|
||
element.y -= element.measure.actualBoundingBoxAscent;
|
||
element.width = element.measure.width;
|
||
element.height = height;
|
||
}
|
||
|
||
generateDraw(element);
|
||
elements.push(element);
|
||
if (this.state.elementType === "text") {
|
||
this.setState({
|
||
draggingElement: null,
|
||
elementType: "selection"
|
||
});
|
||
element.isSelected = true;
|
||
} else {
|
||
this.setState({ draggingElement: element });
|
||
}
|
||
|
||
let lastX = x;
|
||
let lastY = y;
|
||
|
||
const onMouseMove = e => {
|
||
if (isDraggingElements) {
|
||
const selectedElements = elements.filter(el => el.isSelected);
|
||
if (selectedElements.length) {
|
||
const x = e.clientX - e.target.offsetLeft;
|
||
const y = e.clientY - e.target.offsetTop;
|
||
selectedElements.forEach(element => {
|
||
element.x += x - lastX;
|
||
element.y += y - lastY;
|
||
});
|
||
lastX = x;
|
||
lastY = y;
|
||
drawScene();
|
||
return;
|
||
}
|
||
}
|
||
|
||
// It is very important to read this.state within each move event,
|
||
// otherwise we would read a stale one!
|
||
const draggingElement = this.state.draggingElement;
|
||
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;
|
||
|
||
generateDraw(draggingElement);
|
||
|
||
if (this.state.elementType === "selection") {
|
||
setSelection(draggingElement);
|
||
}
|
||
drawScene();
|
||
};
|
||
|
||
const onMouseUp = e => {
|
||
window.removeEventListener("mousemove", onMouseMove);
|
||
window.removeEventListener("mouseup", onMouseUp);
|
||
document.documentElement.style.cursor = cursorStyle;
|
||
|
||
const draggingElement = this.state.draggingElement;
|
||
if (draggingElement === null) {
|
||
return;
|
||
}
|
||
if (this.state.elementType === "selection") {
|
||
if (isDraggingElements) {
|
||
isDraggingElements = false;
|
||
} else {
|
||
// Remove actual selection element
|
||
setSelection(draggingElement);
|
||
}
|
||
elements.pop();
|
||
} else {
|
||
draggingElement.isSelected = true;
|
||
}
|
||
this.setState({
|
||
draggingElement: null,
|
||
elementType: "selection"
|
||
});
|
||
drawScene();
|
||
};
|
||
|
||
window.addEventListener("mousemove", onMouseMove);
|
||
window.addEventListener("mouseup", onMouseUp);
|
||
|
||
drawScene();
|
||
}}
|
||
/>
|
||
</div>
|
||
);
|
||
}
|
||
}
|
||
|
||
const rootElement = document.getElementById("root");
|
||
ReactDOM.render(<App />, rootElement);
|
||
const canvas = document.getElementById("canvas");
|
||
const rc = rough.canvas(canvas);
|
||
const context = canvas.getContext("2d");
|
||
|
||
// Big hack to ensure that all the 1px lines are drawn at 1px instead of 2px
|
||
// https://stackoverflow.com/questions/13879322/drawing-a-1px-thick-line-in-canvas-creates-a-2px-thick-line/13879402#comment90766599_13879402
|
||
context.translate(0.5, 0.5);
|
||
|
||
function drawScene() {
|
||
ReactDOM.render(<App />, rootElement);
|
||
|
||
context.clearRect(-0.5, -0.5, canvas.width, canvas.height);
|
||
|
||
elements.forEach(element => {
|
||
element.draw(rc, context);
|
||
if (element.isSelected) {
|
||
const margin = 4;
|
||
|
||
const elementX1 = getElementAbsoluteX1(element);
|
||
const elementX2 = getElementAbsoluteX2(element);
|
||
const elementY1 = getElementAbsoluteY1(element);
|
||
const elementY2 = getElementAbsoluteY2(element);
|
||
const lineDash = context.getLineDash();
|
||
context.setLineDash([8, 4]);
|
||
context.strokeRect(
|
||
elementX1 - margin,
|
||
elementY1 - margin,
|
||
elementX2 - elementX1 + margin * 2,
|
||
elementY2 - elementY1 + margin * 2
|
||
);
|
||
context.setLineDash(lineDash);
|
||
}
|
||
});
|
||
}
|
||
|
||
drawScene();
|