Files
odysseus/static/js/editor/precision-guides.js
T

254 lines
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JavaScript

/** Rulers, grid, and document-space guides. These are viewport overlays only. */
import { state } from './state.js';
export const RULER_SIZE = 18;
export function chooseRulerStep(zoom, minimumPixels = 48) {
const safeZoom = Math.max(0.0001, Number(zoom) || 1);
const target = minimumPixels / safeZoom;
const magnitude = 10 ** Math.floor(Math.log10(Math.max(1, target)));
for (const factor of [1, 2, 5, 10]) {
const step = magnitude * factor;
if (step >= target) return step;
}
return magnitude * 10;
}
export function pointerToDocument(clientX, clientY, canvasRect, width, height) {
const scaleX = canvasRect.width / Math.max(1, width);
const scaleY = canvasRect.height / Math.max(1, height);
return {
x: (clientX - canvasRect.left) / Math.max(scaleX, 0.0001),
y: (clientY - canvasRect.top) / Math.max(scaleY, 0.0001),
};
}
function normalizedGuides() {
if (!state.guides || typeof state.guides !== 'object') state.guides = { vertical: [], horizontal: [] };
state.guides.vertical = Array.isArray(state.guides.vertical) ? state.guides.vertical : [];
state.guides.horizontal = Array.isArray(state.guides.horizontal) ? state.guides.horizontal : [];
return state.guides;
}
export function createPrecisionGuides({ canvasArea, composite, saveState, schedulePersist }) {
const corner = document.createElement('div');
corner.className = 'ge-ruler-corner';
const horizontal = document.createElement('canvas');
horizontal.className = 'ge-ruler ge-ruler-horizontal';
horizontal.title = 'Drag down to add a horizontal guide';
const vertical = document.createElement('canvas');
vertical.className = 'ge-ruler ge-ruler-vertical';
vertical.title = 'Drag right to add a vertical guide';
canvasArea.append(corner, horizontal, vertical);
let drag = null;
let frame = null;
function themeColors() {
const styles = getComputedStyle(state.container || canvasArea);
return {
background: styles.getPropertyValue('--panel').trim() || '#111',
foreground: styles.getPropertyValue('--fg').trim() || '#ddd',
border: styles.getPropertyValue('--border').trim() || '#333',
};
}
function prepareRuler(canvas) {
const rect = canvas.getBoundingClientRect();
const ratio = Math.max(1, window.devicePixelRatio || 1);
const width = Math.max(1, Math.round(rect.width * ratio));
const height = Math.max(1, Math.round(rect.height * ratio));
if (canvas.width !== width) canvas.width = width;
if (canvas.height !== height) canvas.height = height;
const ctx = canvas.getContext('2d');
ctx.setTransform(ratio, 0, 0, ratio, 0, 0);
return { ctx, rect };
}
function drawRuler(canvas, orientation) {
if (!state.rulersVisible || !state.mainCanvas) return;
const { ctx, rect } = prepareRuler(canvas);
const areaRect = canvasArea.getBoundingClientRect();
const imageRect = state.mainCanvas.getBoundingClientRect();
const colors = themeColors();
ctx.clearRect(0, 0, rect.width, rect.height);
ctx.fillStyle = colors.background;
ctx.fillRect(0, 0, rect.width, rect.height);
ctx.strokeStyle = colors.border;
ctx.beginPath();
if (orientation === 'horizontal') {
ctx.moveTo(0, rect.height - 0.5); ctx.lineTo(rect.width, rect.height - 0.5);
} else {
ctx.moveTo(rect.width - 0.5, 0); ctx.lineTo(rect.width - 0.5, rect.height);
}
ctx.stroke();
const scale = orientation === 'horizontal'
? imageRect.width / Math.max(1, state.imgWidth)
: imageRect.height / Math.max(1, state.imgHeight);
const origin = orientation === 'horizontal'
? imageRect.left - areaRect.left - RULER_SIZE
: imageRect.top - areaRect.top - RULER_SIZE;
const limit = orientation === 'horizontal' ? state.imgWidth : state.imgHeight;
const major = chooseRulerStep(scale);
const minor = major / 5;
ctx.strokeStyle = colors.foreground;
ctx.fillStyle = colors.foreground;
ctx.globalAlpha = 0.62;
ctx.lineWidth = 1;
ctx.font = '8px ui-monospace, monospace';
ctx.textBaseline = 'top';
for (let value = 0; value <= limit + 0.001; value += minor) {
const pixel = origin + value * scale;
const rulerLimit = orientation === 'horizontal' ? rect.width : rect.height;
if (pixel < -2 || pixel > rulerLimit + 2) continue;
const isMajor = Math.round(value / minor) % 5 === 0;
if (orientation === 'horizontal') {
ctx.beginPath();
ctx.moveTo(Math.round(pixel) + 0.5, rect.height);
ctx.lineTo(Math.round(pixel) + 0.5, rect.height - (isMajor ? 9 : 4));
ctx.stroke();
if (isMajor) ctx.fillText(String(Math.round(value)), pixel + 2, 1);
} else {
ctx.beginPath();
ctx.moveTo(rect.width, Math.round(pixel) + 0.5);
ctx.lineTo(rect.width - (isMajor ? 9 : 4), Math.round(pixel) + 0.5);
ctx.stroke();
if (isMajor) {
ctx.save();
ctx.translate(1, pixel - 2);
ctx.rotate(-Math.PI / 2);
ctx.fillText(String(Math.round(value)), 0, 0);
ctx.restore();
}
}
}
ctx.globalAlpha = 1;
}
function redrawRulers() {
if (frame) cancelAnimationFrame(frame);
frame = requestAnimationFrame(() => {
frame = null;
canvasArea.classList.toggle('ge-rulers-visible', !!state.rulersVisible);
corner.hidden = !state.rulersVisible;
horizontal.hidden = !state.rulersVisible;
vertical.hidden = !state.rulersVisible;
if (state.rulersVisible) {
drawRuler(horizontal, 'horizontal');
drawRuler(vertical, 'vertical');
}
});
}
function drawDocumentOverlay(ctx) {
if (!ctx || !state.imgWidth || !state.imgHeight) return;
ctx.save();
if (state.gridVisible) {
const base = Math.max(2, Number(state.gridSize) || 16);
const multiplier = Math.max(1, Math.ceil(5 / Math.max(0.0001, base * state.zoom)));
const spacing = base * multiplier;
ctx.lineWidth = 1 / state.zoom;
for (let x = spacing; x < state.imgWidth; x += spacing) {
ctx.beginPath(); ctx.moveTo(x, 0); ctx.lineTo(x, state.imgHeight);
ctx.strokeStyle = Math.round(x / spacing) % 4 === 0
? 'rgba(110, 180, 220, 0.42)' : 'rgba(110, 180, 220, 0.22)';
ctx.stroke();
}
for (let y = spacing; y < state.imgHeight; y += spacing) {
ctx.beginPath(); ctx.moveTo(0, y); ctx.lineTo(state.imgWidth, y);
ctx.strokeStyle = Math.round(y / spacing) % 4 === 0
? 'rgba(110, 180, 220, 0.42)' : 'rgba(110, 180, 220, 0.22)';
ctx.stroke();
}
}
const guides = normalizedGuides();
ctx.strokeStyle = 'rgba(78, 190, 255, 0.92)';
ctx.lineWidth = 1 / state.zoom;
ctx.setLineDash([]);
for (const x of guides.vertical) {
ctx.beginPath(); ctx.moveTo(x, 0); ctx.lineTo(x, state.imgHeight); ctx.stroke();
}
for (const y of guides.horizontal) {
ctx.beginPath(); ctx.moveTo(0, y); ctx.lineTo(state.imgWidth, y); ctx.stroke();
}
if (drag?.moved && Number.isFinite(drag.position)) {
ctx.strokeStyle = 'rgba(120, 215, 255, 1)';
if (drag.orientation === 'vertical') {
ctx.beginPath(); ctx.moveTo(drag.position, 0); ctx.lineTo(drag.position, state.imgHeight); ctx.stroke();
} else {
ctx.beginPath(); ctx.moveTo(0, drag.position); ctx.lineTo(state.imgWidth, drag.position); ctx.stroke();
}
}
ctx.restore();
}
function updateDrag(event) {
if (!drag || !state.mainCanvas) return;
const point = pointerToDocument(
event.clientX, event.clientY,
state.mainCanvas.getBoundingClientRect(),
state.imgWidth, state.imgHeight,
);
const delta = Math.hypot(event.clientX - drag.startX, event.clientY - drag.startY);
drag.moved = drag.moved || delta > 3;
drag.position = drag.orientation === 'vertical'
? Math.max(0, Math.min(state.imgWidth, Math.round(point.x)))
: Math.max(0, Math.min(state.imgHeight, Math.round(point.y)));
if (drag.moved) composite();
}
function beginGuide(event, orientation) {
if (event.button != null && event.button !== 0) return;
event.preventDefault();
event.stopPropagation();
drag = { orientation, startX: event.clientX, startY: event.clientY, moved: false, position: 0 };
const move = next => updateDrag(next);
const cancel = () => finish(false);
const finish = (commit, next) => {
if (next) updateDrag(next);
if (commit && drag?.moved) {
const values = normalizedGuides()[drag.orientation];
if (!values.some(value => Math.abs(value - drag.position) < 0.5)) {
saveState?.('Add guide');
values.push(drag.position);
values.sort((a, b) => a - b);
schedulePersist?.();
}
}
drag = null;
window.removeEventListener('pointermove', move);
window.removeEventListener('pointerup', end);
window.removeEventListener('pointercancel', cancel);
composite();
redrawRulers();
};
const end = next => finish(true, next);
window.addEventListener('pointermove', move);
window.addEventListener('pointerup', end);
window.addEventListener('pointercancel', cancel);
}
horizontal.addEventListener('pointerdown', event => beginGuide(event, 'horizontal'));
vertical.addEventListener('pointerdown', event => beginGuide(event, 'vertical'));
canvasArea.addEventListener('scroll', redrawRulers, { passive: true });
const observer = window.ResizeObserver ? new ResizeObserver(redrawRulers) : null;
observer?.observe(canvasArea);
redrawRulers();
return {
drawDocumentOverlay,
redrawRulers,
syncVisibility() { redrawRulers(); composite(); },
clearGuides() {
const guides = normalizedGuides();
if (!guides.vertical.length && !guides.horizontal.length) return;
saveState?.('Clear guides');
state.guides = { vertical: [], horizontal: [] };
schedulePersist?.();
composite();
redrawRulers();
},
};
}