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openchamber/packages/ui/src/components/chat/markdown/mermaidViewer.ts
T

585 lines
19 KiB
TypeScript

type MermaidViewBox = {
x: number;
y: number;
width: number;
height: number;
};
type MermaidViewport = {
width: number;
height: number;
};
type MermaidPoint = {
x: number;
y: number;
};
type MermaidViewerController = {
zoomIn: () => void;
zoomOut: () => void;
fit: () => void;
cleanup: () => void;
};
type InternalMermaidViewerController = MermaidViewerController & {
viewport: HTMLElement;
fitToViewport: (viewport: MermaidViewport) => void;
};
type MermaidViewerRegistryState = {
container: HTMLElement;
controllers: Map<HTMLElement, InternalMermaidViewerController>;
signatures: Map<HTMLElement, string>;
disposed: boolean;
};
type MermaidSvgBoundsSource = {
viewBox?: string | null;
width?: string | number | null;
height?: string | number | null;
};
type MermaidViewerSignatureSource = MermaidSvgBoundsSource & {
renderMode?: string | null;
svgMarkup?: string | null;
};
const isPositiveFinite = (value: number): boolean => Number.isFinite(value) && value > 0;
const parseSvgNumber = (value: string | number | null | undefined): number | null => {
if (value === null || value === undefined) return null;
const match = String(value).trim().match(/^([+-]?(?:(?:\d+\.?\d*)|(?:\.\d+))(?:[eE][+-]?\d+)?)(?:px)?$/);
if (!match) {
return null;
}
const parsed = Number(match[1]);
return isPositiveFinite(parsed) ? parsed : null;
};
const clamp = (value: number, min: number, max: number): number => Math.min(max, Math.max(min, value));
const VIEW_BOX_PRECISION = 6;
const ZOOM_STEP = 1.25;
const WHEEL_ZOOM_BASE = 1.0015;
const MIN_SCALE = 0.5;
const MAX_SCALE = 12;
const DRAG_CLICK_SUPPRESSION_THRESHOLD_PX = 3;
const DRAG_CLICK_SUPPRESSION_CLEAR_MS = 400;
export const MERMAID_BLOCK_SELECTOR = '[data-markdown="mermaid-block"]';
export const shouldRefreshMermaidViewers = (container: Pick<HTMLElement, 'querySelector'>): boolean => (
container.querySelector(MERMAID_BLOCK_SELECTOR) !== null
);
export const formatMermaidViewBox = (box: MermaidViewBox): string => (
[box.x, box.y, box.width, box.height]
.map((value) => {
const rounded = Number(value.toFixed(VIEW_BOX_PRECISION));
return Object.is(rounded, -0) ? '0' : String(rounded);
})
.join(' ')
);
export const getMermaidSvgContentBox = (source: MermaidSvgBoundsSource): MermaidViewBox | null => {
const viewBoxParts = source.viewBox
?.trim()
.split(/[\s,]+/)
.map((part) => Number.parseFloat(part));
if (viewBoxParts?.length === 4) {
const [x, y, width, height] = viewBoxParts;
if (
Number.isFinite(x)
&& Number.isFinite(y)
&& isPositiveFinite(width)
&& isPositiveFinite(height)
) {
return { x, y, width, height };
}
}
const width = parseSvgNumber(source.width);
const height = parseSvgNumber(source.height);
if (width === null || height === null) {
return null;
}
return { x: 0, y: 0, width, height };
};
const hashMermaidSignaturePart = (value: string): string => {
let hash = 2166136261;
for (let i = 0; i < value.length; i += 1) {
hash ^= value.charCodeAt(i);
hash = Math.imul(hash, 16777619);
}
return (hash >>> 0).toString(36);
};
export const getMermaidViewerSignature = (source: MermaidViewerSignatureSource): string => {
const renderMode = source.renderMode || 'unknown';
const svgMarkup = source.svgMarkup ?? '';
if (!svgMarkup) {
const bounds = [source.viewBox ?? '', source.width ?? '', source.height ?? ''];
return bounds.some((part) => part !== '') ? `${renderMode}:bounds:${bounds.join(':')}` : `${renderMode}:no-svg`;
}
return [
renderMode,
hashMermaidSignaturePart(svgMarkup),
].join(':');
};
export const fitMermaidViewBox = (contentBox: MermaidViewBox, viewport: MermaidViewport): MermaidViewBox => {
if (!isPositiveFinite(viewport.width) || !isPositiveFinite(viewport.height)) {
return contentBox;
}
const contentAspect = contentBox.width / contentBox.height;
const viewportAspect = viewport.width / viewport.height;
if (contentAspect > viewportAspect) {
const height = contentBox.width / viewportAspect;
return {
x: contentBox.x,
y: contentBox.y - (height - contentBox.height) / 2,
width: contentBox.width,
height,
};
}
const width = contentBox.height * viewportAspect;
return {
x: contentBox.x - (width - contentBox.width) / 2,
y: contentBox.y,
width,
height: contentBox.height,
};
};
export const panMermaidViewBox = ({
currentBox,
viewport,
delta,
}: {
currentBox: MermaidViewBox;
viewport: MermaidViewport;
delta: MermaidPoint;
}): MermaidViewBox => {
if (
!isPositiveFinite(viewport.width)
|| !isPositiveFinite(viewport.height)
|| !isPositiveFinite(currentBox.width)
|| !isPositiveFinite(currentBox.height)
) {
return currentBox;
}
return {
x: currentBox.x - (delta.x / viewport.width) * currentBox.width,
y: currentBox.y - (delta.y / viewport.height) * currentBox.height,
width: currentBox.width,
height: currentBox.height,
};
};
export const hasMermaidPointerDragMoved = (start: MermaidPoint, current: MermaidPoint): boolean => {
const deltaX = current.x - start.x;
const deltaY = current.y - start.y;
return (deltaX * deltaX) + (deltaY * deltaY) > (DRAG_CLICK_SUPPRESSION_THRESHOLD_PX * DRAG_CLICK_SUPPRESSION_THRESHOLD_PX);
};
export const zoomMermaidViewBoxAtPoint = ({
currentBox,
contentBox,
viewport,
pointer,
zoomFactor,
minScale,
maxScale,
}: {
currentBox: MermaidViewBox;
contentBox: MermaidViewBox;
viewport: MermaidViewport;
pointer: MermaidPoint;
zoomFactor: number;
minScale: number;
maxScale: number;
}): MermaidViewBox => {
if (
!isPositiveFinite(viewport.width)
|| !isPositiveFinite(viewport.height)
|| !isPositiveFinite(zoomFactor)
|| !isPositiveFinite(currentBox.width)
|| !isPositiveFinite(currentBox.height)
|| !isPositiveFinite(contentBox.width)
|| !isPositiveFinite(contentBox.height)
|| !isPositiveFinite(minScale)
|| !isPositiveFinite(maxScale)
) {
return currentBox;
}
const min = Math.min(minScale, maxScale);
const max = Math.max(minScale, maxScale);
const fittedBox = fitMermaidViewBox(contentBox, viewport);
const currentScale = fittedBox.width / currentBox.width;
const nextScale = clamp(currentScale * zoomFactor, min, max);
const nextWidth = fittedBox.width / nextScale;
const nextHeight = nextWidth / (currentBox.width / currentBox.height);
const pointerRatioX = clamp(pointer.x / viewport.width, 0, 1);
const pointerRatioY = clamp(pointer.y / viewport.height, 0, 1);
const svgPointX = currentBox.x + pointerRatioX * currentBox.width;
const svgPointY = currentBox.y + pointerRatioY * currentBox.height;
return {
x: svgPointX - pointerRatioX * nextWidth,
y: svgPointY - pointerRatioY * nextHeight,
width: nextWidth,
height: nextHeight,
};
};
const controllerByBlock = new WeakMap<HTMLElement, MermaidViewerController>();
const controllerByViewport = new WeakMap<HTMLElement, InternalMermaidViewerController>();
const activeControllers = new Set<InternalMermaidViewerController>();
const pendingRegistries = new Set<MermaidViewerRegistryState>();
// Controllers are non-essential for the static SVG. Initialize all renderers
// from one post-presentation batch so geometry reads precede every SVG write.
let sharedResizeObserver: ResizeObserver | null = null;
let pendingRegistryFlushFrame: number | null = null;
let pendingResizeFrame: number | null = null;
const getSvgViewport = (block: HTMLElement): HTMLElement | null => (
block.querySelector<HTMLElement>('[data-markdown="mermaid-viewport"]')
?? block.querySelector<HTMLElement>('[data-markdown="mermaid"]')
);
const getBlockViewerSignature = (block: HTMLElement): string => {
const svg = block.querySelector<SVGSVGElement>('[data-markdown="mermaid"] svg');
const svgHost = block.querySelector<HTMLElement>('[data-markdown="mermaid"]');
return getMermaidViewerSignature({
renderMode: block.getAttribute('data-mermaid-render'),
svgMarkup: svgHost?.getAttribute('data-md-original-svg') ?? svg?.outerHTML ?? null,
viewBox: svg?.getAttribute('viewBox'),
width: svg?.getAttribute('width'),
height: svg?.getAttribute('height'),
});
};
const getViewportSize = (viewport: HTMLElement): MermaidViewport => {
const rect = viewport.getBoundingClientRect();
return { width: rect.width, height: rect.height };
};
const getPointerInViewport = (event: Pick<PointerEvent | WheelEvent, 'clientX' | 'clientY'>, viewport: HTMLElement): MermaidPoint => {
const rect = viewport.getBoundingClientRect();
return {
x: event.clientX - rect.left,
y: event.clientY - rect.top,
};
};
const isPanExcludedTarget = (target: EventTarget | null): boolean => (
target instanceof Element && Boolean(target.closest('button, a, [role="button"]'))
);
const fitControllers = (controllers: readonly InternalMermaidViewerController[]): void => {
const viewportSizes = controllers.map((controller) => getViewportSize(controller.viewport));
controllers.forEach((controller, index) => {
const viewport = viewportSizes[index];
if (viewport) controller.fitToViewport(viewport);
});
};
const scheduleActiveControllerFit = (): void => {
if (pendingResizeFrame !== null || activeControllers.size === 0) return;
pendingResizeFrame = window.requestAnimationFrame(() => {
pendingResizeFrame = null;
fitControllers(Array.from(activeControllers));
});
};
const ensureSharedResizeObserver = (): ResizeObserver | null => {
if (sharedResizeObserver) return sharedResizeObserver;
const ResizeObserverConstructor = globalThis.ResizeObserver;
if (!ResizeObserverConstructor) return null;
sharedResizeObserver = new ResizeObserverConstructor((entries) => {
for (const entry of entries) {
if (!(entry.target instanceof HTMLElement)) continue;
controllerByViewport.get(entry.target)?.fitToViewport({
width: entry.contentRect.width,
height: entry.contentRect.height,
});
}
});
return sharedResizeObserver;
};
const registerController = (controller: InternalMermaidViewerController): void => {
if (activeControllers.has(controller)) return;
const wasEmpty = activeControllers.size === 0;
activeControllers.add(controller);
controllerByViewport.set(controller.viewport, controller);
ensureSharedResizeObserver()?.observe(controller.viewport);
if (wasEmpty) window.addEventListener('resize', scheduleActiveControllerFit);
};
const unregisterController = (controller: InternalMermaidViewerController): void => {
if (!activeControllers.delete(controller)) return;
sharedResizeObserver?.unobserve(controller.viewport);
controllerByViewport.delete(controller.viewport);
if (activeControllers.size > 0) return;
sharedResizeObserver?.disconnect();
sharedResizeObserver = null;
window.removeEventListener('resize', scheduleActiveControllerFit);
if (pendingResizeFrame !== null) {
window.cancelAnimationFrame(pendingResizeFrame);
pendingResizeFrame = null;
}
};
const createMermaidViewerController = (block: HTMLElement): InternalMermaidViewerController | null => {
const viewport = getSvgViewport(block);
const svg = block.querySelector<SVGSVGElement>('[data-markdown="mermaid"] svg');
if (!viewport || !svg) {
return null;
}
const contentBox = getMermaidSvgContentBox({
viewBox: svg.getAttribute('viewBox'),
width: svg.getAttribute('width'),
height: svg.getAttribute('height'),
});
if (!contentBox) {
return null;
}
let currentBox = contentBox;
let activePointerId: number | null = null;
let dragStartPointer: MermaidPoint | null = null;
let lastPointer: MermaidPoint | null = null;
let clearClickSuppressionTimer: number | null = null;
const applyViewBox = (box: MermaidViewBox): void => {
currentBox = box;
svg.setAttribute('viewBox', formatMermaidViewBox(box));
svg.removeAttribute('width');
svg.removeAttribute('height');
};
const fitToViewport = (size: MermaidViewport): void => {
applyViewBox(fitMermaidViewBox(contentBox, size));
};
const fit = (): void => {
fitToViewport(getViewportSize(viewport));
};
const zoomAt = (pointer: MermaidPoint, zoomFactor: number): void => {
applyViewBox(zoomMermaidViewBoxAtPoint({
currentBox,
contentBox,
viewport: getViewportSize(viewport),
pointer,
zoomFactor,
minScale: MIN_SCALE,
maxScale: MAX_SCALE,
}));
};
const zoomIn = (): void => {
const size = getViewportSize(viewport);
zoomAt({ x: size.width / 2, y: size.height / 2 }, ZOOM_STEP);
};
const zoomOut = (): void => {
const size = getViewportSize(viewport);
zoomAt({ x: size.width / 2, y: size.height / 2 }, 1 / ZOOM_STEP);
};
const onWheel = (event: WheelEvent): void => {
if (!event.ctrlKey && !event.metaKey) {
return;
}
event.preventDefault();
event.stopPropagation();
zoomAt(getPointerInViewport(event, viewport), Math.pow(WHEEL_ZOOM_BASE, -event.deltaY));
};
const onPointerDown = (event: PointerEvent): void => {
if (event.button !== 0 || isPanExcludedTarget(event.target)) {
return;
}
activePointerId = event.pointerId;
dragStartPointer = { x: event.clientX, y: event.clientY };
lastPointer = dragStartPointer;
if (clearClickSuppressionTimer !== null) {
window.clearTimeout(clearClickSuppressionTimer);
clearClickSuppressionTimer = null;
}
block.removeAttribute('data-mermaid-suppress-click');
viewport.setPointerCapture?.(event.pointerId);
block.setAttribute('data-mermaid-panning', 'true');
event.preventDefault();
};
const onPointerMove = (event: PointerEvent): void => {
if (activePointerId !== event.pointerId || !lastPointer) {
return;
}
const nextPointer = { x: event.clientX, y: event.clientY };
applyViewBox(panMermaidViewBox({
currentBox,
viewport: getViewportSize(viewport),
delta: {
x: nextPointer.x - lastPointer.x,
y: nextPointer.y - lastPointer.y,
},
}));
lastPointer = nextPointer;
if (dragStartPointer && hasMermaidPointerDragMoved(dragStartPointer, nextPointer)) {
block.setAttribute('data-mermaid-suppress-click', 'true');
}
event.preventDefault();
};
const stopPan = (event: PointerEvent): void => {
if (activePointerId !== event.pointerId) {
return;
}
viewport.releasePointerCapture?.(event.pointerId);
activePointerId = null;
dragStartPointer = null;
lastPointer = null;
block.removeAttribute('data-mermaid-panning');
if (block.hasAttribute('data-mermaid-suppress-click')) {
clearClickSuppressionTimer = window.setTimeout(() => {
block.removeAttribute('data-mermaid-suppress-click');
clearClickSuppressionTimer = null;
}, DRAG_CLICK_SUPPRESSION_CLEAR_MS);
}
};
viewport.addEventListener('wheel', onWheel, { passive: false });
viewport.addEventListener('pointerdown', onPointerDown);
viewport.addEventListener('pointermove', onPointerMove);
viewport.addEventListener('pointerup', stopPan);
viewport.addEventListener('pointercancel', stopPan);
const controller: InternalMermaidViewerController = {
viewport,
zoomIn,
zoomOut,
fit,
fitToViewport,
cleanup: () => {
unregisterController(controller);
viewport.removeEventListener('wheel', onWheel);
viewport.removeEventListener('pointerdown', onPointerDown);
viewport.removeEventListener('pointermove', onPointerMove);
viewport.removeEventListener('pointerup', stopPan);
viewport.removeEventListener('pointercancel', stopPan);
if (clearClickSuppressionTimer !== null) {
window.clearTimeout(clearClickSuppressionTimer);
}
block.removeAttribute('data-mermaid-panning');
block.removeAttribute('data-mermaid-suppress-click');
controllerByBlock.delete(block);
},
};
return controller;
};
const removeStaleControllers = (state: MermaidViewerRegistryState): void => {
for (const [block, controller] of state.controllers) {
const signature = getBlockViewerSignature(block);
if (!state.container.contains(block) || signature !== state.signatures.get(block)) {
controller.cleanup();
state.controllers.delete(block);
state.signatures.delete(block);
}
}
};
const collectNewControllers = (state: MermaidViewerRegistryState): InternalMermaidViewerController[] => {
if (state.disposed) return [];
const newControllers: InternalMermaidViewerController[] = [];
for (const block of Array.from(state.container.querySelectorAll<HTMLElement>(MERMAID_BLOCK_SELECTOR))) {
if (state.controllers.has(block) || block.querySelector('[data-markdown="mermaid"] svg') === null) continue;
const controller = createMermaidViewerController(block);
if (!controller) continue;
state.controllers.set(block, controller);
state.signatures.set(block, getBlockViewerSignature(block));
controllerByBlock.set(block, controller);
newControllers.push(controller);
}
return newControllers;
};
const flushPendingRegistries = (): void => {
const registries = Array.from(pendingRegistries);
pendingRegistries.clear();
const newControllers: InternalMermaidViewerController[] = [];
for (const state of registries) {
if (state.disposed) continue;
removeStaleControllers(state);
newControllers.push(...collectNewControllers(state));
}
fitControllers(newControllers);
for (const controller of newControllers) registerController(controller);
};
const schedulePendingRegistryFlush = (): void => {
if (pendingRegistryFlushFrame !== null) return;
pendingRegistryFlushFrame = window.requestAnimationFrame(() => {
pendingRegistryFlushFrame = null;
pendingRegistryFlushFrame = window.requestAnimationFrame(() => {
pendingRegistryFlushFrame = null;
flushPendingRegistries();
});
});
};
const scheduleRegistryRefresh = (state: MermaidViewerRegistryState): void => {
if (state.disposed) return;
removeStaleControllers(state);
pendingRegistries.add(state);
schedulePendingRegistryFlush();
};
export const getMermaidViewerController = (block: Element | null): MermaidViewerController | null => {
if (!(block instanceof HTMLElement)) return null;
const existing = controllerByBlock.get(block);
if (existing) return existing;
for (const state of pendingRegistries) {
if (!state.container.contains(block)) continue;
flushPendingRegistries();
return controllerByBlock.get(block) ?? null;
}
return null;
};
export const createMermaidViewerRegistry = (container: HTMLElement) => {
const state: MermaidViewerRegistryState = {
container,
controllers: new Map(),
signatures: new Map(),
disposed: false,
};
const refresh = (): void => scheduleRegistryRefresh(state);
const cleanup = (): void => {
state.disposed = true;
pendingRegistries.delete(state);
for (const controller of state.controllers.values()) {
controller.cleanup();
}
state.controllers.clear();
state.signatures.clear();
};
refresh();
return { refresh, cleanup };
};