58 lines
1.3 KiB
TypeScript
58 lines
1.3 KiB
TypeScript
import { Directive } from "vue";
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const mountings = new Map<
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Element,
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{
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resize: ResizeObserver;
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intersection?: IntersectionObserver;
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fn: (w: number, h: number) => void;
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}
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>();
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function calc(src: Element) {
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const info = mountings.get(src);
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const height = src.clientHeight;
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const width = src.clientWidth;
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if (!info) return;
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// アクティベート前などでsrcが描画されていない場合
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if (!height) {
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// IntersectionObserverで表示検出する
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if (!info.intersection) {
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info.intersection = new IntersectionObserver((entries) => {
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if (entries.some((entry) => entry.isIntersecting)) calc(src);
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});
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}
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info.intersection.observe(src);
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return;
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}
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if (info.intersection) {
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info.intersection.disconnect();
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info.intersection = undefined;
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}
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info.fn(width, height);
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}
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export default {
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mounted(src, binding, vn) {
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const resize = new ResizeObserver((entries, observer) => {
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calc(src);
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});
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resize.observe(src);
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mountings.set(src, { resize, fn: binding.value });
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calc(src);
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},
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unmounted(src, binding, vn) {
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binding.value(0, 0);
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const info = mountings.get(src);
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if (!info) return;
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info.resize.disconnect();
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if (info.intersection) info.intersection.disconnect();
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mountings.delete(src);
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},
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} as Directive<Element, (w: number, h: number) => void>;
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