<script lang="ts" setup>
import { onMounted, ref } from 'vue';
import { useWindowSize } from '@vueuse/core';
import Konva from 'konva/lib';
import { Stage } from 'konva/lib/Stage';

const { width, height } = useWindowSize();
const stage = ref<Stage>();
const SCALE_BY = 1.1;

const zoomed = () => {
	stage.value?.on('wheel', ev => {
		if (!stage.value) return;

		// 原始缩放比例
		const scaleX = stage.value?.scaleX();
		const scaleY = stage.value?.scaleY();

		// 当前鼠标位置
		const pointer = stage.value?.getPointerPosition();

		// 鼠标在画布平移量
		const mousePointTo = {
			x: (pointer!.x - stage.value?.x()) / scaleX,
			y: (pointer!.y - stage.value?.y()) / scaleY,
		};

		// 判断鼠标是向上滚动还是向下滚动
		const direction = ev.evt.deltaY > 0 ? -1 : 1;

		// 设置新的缩放比例
		const x = direction > 0 ? scaleX * SCALE_BY : scaleX / SCALE_BY;
		const y = direction > 0 ? scaleY * SCALE_BY : scaleY / SCALE_BY;
		stage.value?.scale({ x, y });

		// 设置新的鼠标位置，缩放时保持不变
		const position = {
			x: pointer!.x - mousePointTo.x * x,
			y: pointer!.y - mousePointTo.y * y,
		};
		stage.value?.position(position);
	});
};

const initial = () => {
	stage.value = new Konva.Stage({ container: 'container', width: width.value, height: height.value });
	const layer = new Konva.Layer();
	stage.value.add(layer);

	const text1 = new Konva.Text({
		x: 50,
		y: 70,
		fontSize: 20,
		text: '不缩放',
		draggable: true,
	});
	layer.add(text1);

	const text2 = new Konva.Text({
		x: 50,
		y: 180,
		fontSize: 20,
		text: '缩放',
		draggable: true,
	});
	layer.add(text2);

	const tr1 = new Konva.Transformer({
		nodes: [text1],
		keepRatio: true,
		enabledAnchors: ['top-left', 'top-right', 'bottom-left', 'bottom-right'],
	});
	layer.add(tr1);

	const tr2 = new Konva.Transformer({
		nodes: [text2],
		keepRatio: false,
		enabledAnchors: ['top-left', 'top-right', 'bottom-left', 'bottom-right'],
	});

	layer.add(tr2);

	zoomed();
};

onMounted(() => {
	initial();
});
</script>

<template>
	<div id="container"></div>
</template>

<style lang="scss" scoped></style>
