integrate an addidition and some status bar at bottom of the grid as explained "expandable Measurement Tool that shows delta in snapping points between grid’s start-end snapping points. so, the idea is to make this tool always active on canvas when you hover over snapping point, click on starting point, and from this position this tool expanding until you press end point on grid. not sure if this’s correct method to make a measurement guidance tool. need to invent some shortcut system here, without shortcuts you will be unable to make any properre scientific instrument. for example, if you want to measure distance in points between multiple points in overall grid matrix, you can temporarly press ctrl plus left mouse click and measure all you need until you unhold ctrl. also, when you are using this measurement method through ctrl shorcut, the actual line shouldn’t be drawn on grid, only measurement action. need to place that distance inbetween grid points value in total points to some user interface near grid adjustment values, because showing this on grid itself will block points. yeah. ". output only full code.: <html lang=“en”><head>
<meta charset='UTF-8'>
<title>schematoid</title>
<style>
canvas {
display: block;
margin: auto;
}
.grid-container {
display: flex;
justify-content: center;
margin-bottom: 20px;
}
.grid-input{
margin: 0 10px;
}
</style>
</head>
<body>
<div class='grid-container'>
<label for='gridSize'>Grid Size: </label>
<input type='number' id='gridSize' class='grid-input' value='50'>
<label for='gridSpacing'>Grid Spacing: </label>
<input type='number' id='gridSpacing' class='grid-input' value='25'>
</div>
<canvas id='canvas'></canvas>
<script>
const canvas = document.getElementById('canvas');
const ctx = canvas.getContext('2d');

canvas.width = window.innerWidth;
canvas.height = window.innerHeight;

let grid = [];
let gridSize = 120;
let gridSpacing = 10;

function updateGrid() {
grid = [];
for (let x = -gridSize; x <= gridSize; x += gridSpacing) {
for (let y = -gridSize; y <= gridSize; y += gridSpacing) {
grid.push({ x, y });
}
}
}

function updateCanvasSize() {
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
}

function updateUI() {
const gridSizeInput = document.getElementById('gridSize');
const gridSpacingInput = document.getElementById('gridSpacing');

gridSizeInput.value = gridSize;
gridSpacingInput.value = gridSpacing;
}

function drawLine(line) {
ctx.beginPath();
for (let i = 0; i < line.length - 1; i++) {
const projectedStart = project(line[i]);
const projectedEnd = project(line[i + 1]);

ctx.moveTo(projectedStart.x, projectedStart.y);
ctx.lineTo(projectedEnd.x, projectedEnd.y);
}

ctx.strokeStyle = 'rgba(25,200,25,0.2)';
ctx.lineWidth = 2;
ctx.stroke();
}

function calculateGridCenter(grid) {
let totalX = 0;
let totalY = 0;
const pointsCount = grid.length;

for (const point of grid) {
totalX += point.x;
totalY += point.y;
}

return {
x: totalX / pointsCount,
y: totalY / pointsCount
};
}

const clickedPoints = [];
let lastClickedPoint = null;
let activeLine = null;
const lines = [];

function project(point) {
const { x, y } = point;

const scale = 1;
const newX = x * scale + canvas.width / 2;
const newY = y * scale + canvas.height / 2;

return { x: newX, y: newY, scale };
}

function findClosestPoint(point) {
const threshold = 20;
let minDist = Infinity;
let minIndex = -1;

for (let i = 0; i < grid.length; i++) {
const projected = project(grid[i]);
const dx = point.x - projected.x;
const dy = point.y - projected.y;
const dist = Math.sqrt(dx * dx + dy * dy);

if (dist < minDist && dist <= threshold) {
minDist = dist;
minIndex = i;
}
}

return minIndex !== -1 ? grid[minIndex] : null;
}

let mouseDown = false;
let dragStart = null;

canvas.addEventListener('mousedown', (e) => {
dragStart = { x: e.clientX, y: e.clientY };
});

canvas.addEventListener('mousemove', (e) => {
if (dragStart) {
const deltaX = e.clientX - dragStart.x;
const deltaY = e.clientY - dragStart.y;
dragStart = { x: e.clientX, y: e.clientY };
}
});

canvas.addEventListener('mouseup', (e) => {
mouseDown = false;
dragStart = null;
if (activeLine !== null) {
const canvasRect = canvas.getBoundingClientRect();
const mouseX = e.clientX - canvasRect.left;
const mouseY = e.clientY - canvasRect.top;
const endPoint = findClosestPoint({ x: mouseX, y: mouseY });

if (endPoint !== activeLine[activeLine.length - 1]) {
activeLine.push(endPoint);
lines.push(activeLine);
}
activeLine = null;
}

if (lastClickedPoint !== null) {
const canvasRect = canvas.getBoundingClientRect();
const mouseX = e.clientX - canvasRect.left;
const mouseY = e.clientY - canvasRect.top;
const clickedPoint = findClosestPoint({ x: mouseX, y: mouseY });

if (clickedPoint !== null) {
if (lastClickedPoint === clickedPoint) {
lastClickedPoint = null;
} else {
lines.push([lastClickedPoint, clickedPoint]);
clickedPoints.push(clickedPoint);
lastClickedPoint = null;
}
}
} else {
const canvasRect = canvas.getBoundingClientRect();
const mouseX = e.clientX - canvasRect.left;
const mouseY = e.clientY - canvasRect.top;
const clickedPoint = findClosestPoint({ x: mouseX, y: mouseY });

if (clickedPoint !== null) {
lastClickedPoint = clickedPoint;
clickedPoints.push(clickedPoint);
}
}
});

function draw() {
ctx.fillStyle = 'rgba(1,2,1,0.8)';
ctx.fillRect(0, 0, canvas.width, canvas.height);

for (const point of grid) {
const projected = project(point);

ctx.beginPath();
if (projected.scale > 0) {
ctx.arc(projected.x, projected.y, 2 * projected.scale, 0, Math.PI * 2);
ctx.closePath();
const gradient = ctx.createRadialGradient(projected.x, projected.y, 0, projected.x, projected.y, 2 * projected.scale);
gradient.addColorStop(0, 'rgba(255,155,255,0.5)');
gradient.addColorStop(0.5, 'rgba(55,255,25,0.8)');
gradient.addColorStop(1, 'rgba(55,25,255,0.2)');
ctx.fillStyle = gradient;
ctx.fill();
}
}

// Drawing clicked points in green
ctx.fillStyle = 'rgba(255,200,50,0.5)';
for (const clickedPoint of clickedPoints) {
const projected = project(clickedPoint);

ctx.beginPath();
if (projected.scale > 0) {
ctx.arc(projected.x, projected.y, 4 * projected.scale, 0, Math.PI * 2);
ctx.closePath();
ctx.fill();
}
}

for (const line of lines) {
drawLine(line);
}

if (activeLine !== null) {
drawLine(activeLine);
}

requestAnimationFrame(draw);
}

window.addEventListener('resize', () => {
updateCanvasSize();
updateUI();
});

const gridSizeInput = document.getElementById('gridSize');
gridSizeInput.addEventListener('change', (e) => {
gridSize = parseInt(e.target.value);
updateGrid();
});

const gridSpacingInput = document.getElementById('gridSpacing');
gridSpacingInput.addEventListener('change', (e) => {
gridSpacing = parseInt(e.target.value);
updateGrid();
});

updateUI();
updateGrid();
draw();
</script>
</body>
</html>