docs: add transition example

docs/components/examples/transition/App.vue

@@ -0,0 +1,50 @@
+<script setup>
+import { ref } from 'vue'
+import { ConnectionMode, Position, VueFlow, useVueFlow } from '@braks/vue-flow'
+import TransitionEdge from './TransitionEdge.vue'
+
+const elements = ref([
+  {
+    id: '1',
+    type: 'input',
+    label: 'Dblclick me',
+    position: { x: 0, y: 0 },
+    sourcePosition: Position.Right,
+  },
+  {
+    id: '2',
+    type: 'output',
+    label: 'Dblclick me',
+    position: { x: 1000, y: 1000 },
+    targetPosition: Position.Left,
+  },
+
+  { id: 'e1-2', type: 'custom', source: '1', target: '2', animated: true, style: { stroke: '#fff' } },
+])
+const bgColor = ref('#1A192B')
+const connectionLineStyle = { stroke: '#fff' }
+const snapGrid = [16, 16]
+
+const { onPaneReady } = useVueFlow({
+  connectionMode: ConnectionMode.Loose,
+  connectionLineStyle,
+  snapToGrid: true,
+  snapGrid,
+  defaultZoom: 1.5,
+})
+
+onPaneReady((i) => {
+  i.fitView({
+    nodes: ['1'],
+  })
+  console.log('flow loaded:', i)
+})
+</script>
+
+<template>
+  <VueFlow v-model="elements" :style="{ backgroundColor: bgColor }">
+    <template #edge-custom="props">
+      <TransitionEdge v-bind="props" />
+    </template>
+  </VueFlow>
+</template>

docs/components/examples/transition/TransitionEdge.vue

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+<script setup>
+import { TransitionPresets, useDebounceFn, useTransition, watchDebounced } from '@vueuse/core'
+import { getBezierPath, useVueFlow } from '@braks/vue-flow'
+import { computed, ref } from 'vue'
+
+const props = defineProps({
+  id: {
+    type: String,
+    required: true,
+  },
+  source: {
+    type: String,
+    required: true,
+  },
+  target: {
+    type: String,
+    required: true,
+  },
+  sourceX: {
+    type: Number,
+    required: true,
+  },
+  sourceY: {
+    type: Number,
+    required: true,
+  },
+  targetX: {
+    type: Number,
+    required: true,
+  },
+  targetY: {
+    type: Number,
+    required: true,
+  },
+  sourcePosition: {
+    type: String,
+    required: true,
+  },
+  targetPosition: {
+    type: String,
+    required: true,
+  },
+  data: {
+    type: Object,
+    required: false,
+  },
+  markerEnd: {
+    type: String,
+    required: false,
+  },
+  style: {
+    type: Object,
+    required: false,
+  },
+})
+
+const curve = ref()
+
+const dot = ref()
+
+const transform = ref({ x: 0, y: 0 })
+
+const showDot = ref(false)
+
+const { onNodeDoubleClick, fitBounds, fitView } = useVueFlow()
+
+const edgePath = computed(() =>
+  getBezierPath({
+    sourceX: props.sourceX,
+    sourceY: props.sourceY,
+    sourcePosition: props.sourcePosition,
+    targetX: props.targetX,
+    targetY: props.targetY,
+    targetPosition: props.targetPosition,
+  }),
+)
+
+const debouncedFitBounds = useDebounceFn(fitBounds, 1, { maxWait: 1 })
+
+onNodeDoubleClick(({ node }) => {
+  const isSource = props.source === node.id
+  const isTarget = props.target === node.id
+
+  if (!showDot.value && (isSource || isTarget)) {
+    showDot.value = true
+    let totalLength = curve.value.getTotalLength()
+    const initialPos = ref(isSource ? 0 : totalLength)
+    let stopHandle
+
+    const output = useTransition(initialPos, {
+      duration: 4000,
+      transition: TransitionPresets.easeOutCubic,
+      onFinished: () => {
+        stopHandle?.()
+        showDot.value = false
+        fitView({
+          nodes: [isSource ? props.target : props.source],
+          duration: 500,
+        })
+      },
+    })
+
+    transform.value = curve.value.getPointAtLength(output.value)
+
+    debouncedFitBounds(
+      {
+        width: 100,
+        height: 200,
+        x: transform.value.x - 100,
+        y: transform.value.y - 100,
+      },
+      { duration: 500 },
+    )
+
+    setTimeout(() => {
+      initialPos.value = isSource ? totalLength : 0
+
+      stopHandle = watchDebounced(
+        output,
+        (next) => {
+          if (!showDot.value) return
+
+          const nextLength = curve.value.getTotalLength()
+
+          if (totalLength !== nextLength) {
+            totalLength = nextLength
+            initialPos.value = isSource ? totalLength : 0
+          }
+
+          transform.value = curve.value.getPointAtLength(next)
+
+          debouncedFitBounds({
+            width: 100,
+            height: 200,
+            x: transform.value.x - 100,
+            y: transform.value.y - 100,
+          })
+        },
+        { debounce: 1 },
+      )
+    }, 500)
+  }
+})
+</script>
+
+<script>
+export default {
+  inheritAttrs: false,
+}
+</script>
+
+<template>
+  <path :id="id" ref="curve" :style="style" class="vue-flow__edge-path" :d="edgePath" :marker-end="markerEnd" />
+  <Transition name="fade">
+    <circle
+      v-if="showDot"
+      ref="dot"
+      r="5"
+      cy="0"
+      cx="0"
+      :transform="`translate(${transform.x}, ${transform.y})`"
+      style="fill: #fdd023"
+    />
+  </Transition>
+</template>

docs/components/examples/transition/index.ts

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+export { default as TransitionApp } from './App.vue?raw'
+export { default as TransitionEdge } from './TransitionEdge.vue?raw'
+export { default as TransitionCSS } from './style.css'

docs/components/examples/transition/style.css

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+.fade-enter-active,
+.fade-leave-active {
+  transition: opacity 300ms ease;
+}
+
+.fade-enter-from,
+.fade-leave-to {
+  opacity: 0;
+}