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fix(docs): allow zooming out from initial auto-fit scale in mermaid modal #138

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Merged
JusterZhu merged 2 commits into from
Jun 21, 2026
Merged

fix(docs): allow zooming out from initial auto-fit scale in mermaid modal #138

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cea16d9
fix(docs): allow zooming out from initial auto-fit scale in mermaid m…
JusterZhu Jun 21, 2026
3c45636
fix(docs): add wheel scroll zoom to mermaid modal
JusterZhu Jun 21, 2026
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21 changes: 19 additions & 2 deletions website/src/theme/Mermaid/index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -41,13 +41,29 @@ function MermaidRenderResult({ renderResult }) {

const instance = panzoom(svgEl, {
maxScale: 10,
minScale: 0.1,
minScale: 0.05,
step: 0.15,
contain: 'outside',
contain: false,
pinchAndPan: true,
});
instanceRef.current = instance;

// Wheel zoom: forward wheel events from modal body to panzoom
const handleWheel = (e) => {
e.preventDefault();
const delta = e.deltaY > 0 ? -0.3 : 0.3;
// Calculate zoom around cursor position
const rect = svgEl.getBoundingClientRect();
const x = e.clientX - rect.left;
const y = e.clientY - rect.top;
instance.zoomWithWheel(e, {
step: 0.3,
minScale: 0.05,
maxScale: 10,
});
};
modalEl.addEventListener('wheel', handleWheel, { passive: false });

// Auto-fit: scale the SVG to fill the modal while keeping aspect ratio
const fitToScreen = () => {
const parent = modalRef.current;
Expand Down Expand Up @@ -105,6 +121,7 @@ function MermaidRenderResult({ renderResult }) {

return () => {
clearTimeout(fitTimer);
modalEl.removeEventListener('wheel', handleWheel);
window.removeEventListener('resize', fitToScreen);
window.removeEventListener('keydown', handleKeyDown);
if (instanceRef.current) {
Expand Down
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