improve MediaInput focalpoint selector

pages/add/MediaInput.vue

@@ -4,13 +4,19 @@
       v-card
         v-card-title {{$t('common.media')}}
         v-card-text
-          v-row
-            v-col(:span='4' :cols='4')
+          v-row.mt-1
+            v-col#focalPointSelector(
+                @mousedown='handleStart' @touchstart='handleStart'
+                @mousemove='handleMove' @touchmove='handleMove'
+                @mouseup='handleStop' @touchend='handleStop'
+              )
+              div.focalPoint(:style="{ top, left }")
+              img(v-if='mediaPreview' :src='mediaPreview')
+
+            v-col.col-12.col-sm-4
               p {{$t('event.choose_focal_point')}}
-              v-img(v-if='mediaPreview'
-                :src='mediaPreview'
-                aspect-ratio='1.7778'
-                :position="position")
+              img.img.d-none.d-sm-block(v-if='mediaPreview'
+                :src='mediaPreview' :style="{ 'object-position': position }")
 
               v-textarea.mt-4(type='text'
                 label='Alternative text'
@@ -23,18 +29,13 @@
                 v-btn(text @click='openMediaDetails=false' color='warning') Cancel
                 v-btn(text color='primary' @click='save') Save
 
-            v-col(:span='8' :cols='8')
-              v-img.cursorPointer(
-                v-if='mediaPreview' :src='mediaPreview'
-                @click='selectFocal')
-
     h3.mb-3.font-weight-regular(v-if='mediaPreview') {{$t('common.media')}}
     v-card-actions(v-if='mediaPreview')
       v-spacer
       v-btn(text color='primary' @click='openMediaDetails = true') {{$t('common.edit')}}
       v-btn(text color='error' @click='remove') {{$t('common.remove')}}
     div(v-if='mediaPreview')
-      v-img.col-12.col-sm-2.ml-3(:src='mediaPreview' aspect-ratio='1.7778' :position='savedPosition')
+      img.img.col-12.ml-3(:src='mediaPreview' :style="{ 'object-position': savedPosition }")
       span.float-right {{event.media[0].name}}
     v-file-input(
       v-else
@@ -57,7 +58,8 @@ export default {
     return {
       openMediaDetails: false,
       name: this.value.name || '',
-      focalpoint: this.value.focalpoint || [0, 0]
+      focalpoint: this.value.focalpoint || [0, 0],
+      dragging: false
     }
   },
   computed: {
@@ -68,6 +70,12 @@ export default {
       const url = this.value.image ? URL.createObjectURL(this.value.image) : /^https?:\/\//.test(this.value.url) ? this.value.url : `/media/thumb/${this.value.url}`
       return url
     },
+    top () {
+      return ((this.focalpoint[1] + 1) * 50) + '%'
+    },
+    left () {
+      return ((this.focalpoint[0] + 1) * 50) + '%'
+    },
     savedPosition () {
       const focalpoint = this.value.focalpoint || [0, 0]
       return `${(focalpoint[0] + 1) * 50}% ${(focalpoint[1] + 1) * 50}%`
@@ -90,22 +98,39 @@ export default {
     selectMedia (v) {
       this.$emit('input', { image: v, name: v.name, focalpoint: [0, 0] })      
     },
-    selectFocal (ev) {
-      const boundingClientRect = ev.target.getBoundingClientRect()
+    handleStart (ev) {
+      ev.preventDefault()
+      this.dragging = true
+      this.handleMove(ev, true)
+      return false
+    },
+    handleStop (ev) {
+      this.dragging = false
+    },
+    handleMove (ev, manual = false) {
+      if (!this.dragging && !manual) return
+      ev.stopPropagation()
+      const boundingClientRect = document.getElementById('focalPointSelector').getBoundingClientRect()
+
+      const clientX = ev.changedTouches ? ev.changedTouches[0].clientX : ev.clientX
+      const clientY = ev.changedTouches ? ev.changedTouches[0].clientY : ev.clientY
 
       // get relative coordinate
-      let x = Math.ceil(ev.clientX - boundingClientRect.left)
-      let y = Math.ceil(ev.clientY - boundingClientRect.top)
+      let x = Math.ceil(clientX - boundingClientRect.left)
+      let y = Math.ceil(clientY - boundingClientRect.top)
 
       // snap to border
-      x = x < 20 ? 0 : x > boundingClientRect.width - 20 ? boundingClientRect.width : x
-      y = y < 20 ? 0 : y > boundingClientRect.height - 20 ? boundingClientRect.height : y
+      x = x < 30 ? 0 : x > boundingClientRect.width - 30 ? boundingClientRect.width : x
+      y = y < 30 ? 0 : y > boundingClientRect.height - 30 ? boundingClientRect.height : y
+
+      // this.relativeFocalpoint = [x + 'px', y + 'px']
 
       // map to real image coordinate
       const posY = -1 + (y / boundingClientRect.height) * 2
       const posX = -1 + (x / boundingClientRect.width) * 2
 
       this.focalpoint = [posX, posY]
+      return false
     }
   }
 }
@@ -115,4 +140,36 @@ export default {
   cursor: crosshair;
 }
 
+.img {
+  width: 100%;
+  object-fit: cover;
+  object-position: top;
+  aspect-ratio: 1.7778;
+}
+
+#focalPointSelector {
+  position: relative;
+  cursor: move;
+  overflow: hidden;
+  display: flex;
+  height: 100%;
+  justify-self: center;
+  align-items: center;
+}
+
+#focalPointSelector img {
+  width: 100%;
+}
+
+.focalPoint {
+  position: absolute;
+  width: 50px;
+  height: 50px;
+  top: 100px;
+  left: 100px;
+  transform: translate(-25px, -25px);
+  border-radius: 50%;
+  border: 1px solid #ff6d408e;
+  box-shadow: 0 0 0 9999em rgba(0, 0, 0, .65);
+}
 </style>