feat(editor): 图片可拖拽手柄缩放（docs/31 补）

上一笔只有弹窗输数值，用户追问为何不能拖边缘。NodeView 改包装结构 span.img-wrap > img + 右下角手柄：图片选中时手柄出现，拖动实时预览（只改 CSS），松手提交 width 属性（px，夹取 20..段落宽）。两个坑：手柄的 mouse 事件须吞掉防 PM 按点击位置捣乱；setNodeMarkup 提交后 PM 会回读 DOM 选区把 NodeSelection 塌成文本光标，提交事务须同带 setSelection 保住选区（updateImageAtElement 同修）。无头 Chrome 真实拖拽实测：240→+80=320→−30=290，选区全程不丢； vitest 148+2、构建通过。
2026-11-15 09:48:54 +08:00
parent 5f4a80fa01
commit 0c09d94501
4 changed files with 76 additions and 3 deletions
--- a/src/editor/editor.ts
+++ b/src/editor/editor.ts
@@ -13,6 +13,7 @@ import { indent } from '@milkdown/kit/plugin/indent'
 import { math } from '@milkdown/plugin-math'
 import { upload, uploadConfig, type UploadOptions } from '@milkdown/kit/plugin/upload'
 import { createSyntaxRevealPlugin, createCodeBlockTabPlugin, createTableTabPlugin, createFocusDimPlugin, createPlainTextPastePlugin, createImageDisplayPlugin, createImageEnterPlugin, createEmptyPlaceholderPlugin, selectionInTable } from './plugins'
+import { NodeSelection } from '@milkdown/kit/prose/state'
 import { createListItemViewPlugin, createCodeBlockViewPlugin } from './nodeViews'
 import { extendImageSchema } from './imageSchema'

@@ -296,6 +297,10 @@ export function updateImageAtElement(editor: Editor, el: HTMLElement, patch: Ima
          if (patch.linkHref) tr.addMark(pos, pos + 1, linkType.create({ href: patch.linkHref }))
        }
      }
+      // 同 plugins 的拖拽提交：换节点属性后保住节点选区，别被回读塌掉
+      if (view.state.selection instanceof NodeSelection && view.state.selection.from === pos) {
+        tr.setSelection(NodeSelection.create(tr.doc, pos))
+      }
      if (tr.docChanged) view.dispatch(tr)
      return true
    })
--- a/src/editor/plugins.ts
+++ b/src/editor/plugins.ts
@@ -463,10 +463,20 @@ export function createImageDisplayPlugin(resolve: (src: string) => Promise<strin
  return $prose(() => new Plugin({
    props: {
      nodeViews: {
-        image: (node) => {
+        image: (node, view, getPos) => {
+          // 包装结构：span.img-wrap（PM 的节点视图 dom）> img + 拖拽手柄。
+          // 手柄在图片被选中时显示（.ProseMirror-selectednode 落在包装上），
+          // 拖动时实时改 img 的 CSS 宽度预览，松手才把宽度提交进节点属性。
+          const wrap = document.createElement('span')
+          wrap.className = 'img-wrap'
          const img = document.createElement('img')
          img.alt = (node.attrs.alt as string) ?? ''
+          img.draggable = false
          if (node.attrs.title) img.title = node.attrs.title as string
+          const handle = document.createElement('span')
+          handle.className = 'img-resize-handle'
+          wrap.append(img, handle)
+          let currentNode = node
          const applyWidth = (w: unknown) => {
            const css = widthToCss(typeof w === 'string' ? w : null)
            if (css) img.style.width = css
@@ -486,12 +496,53 @@ export function createImageDisplayPlugin(resolve: (src: string) => Promise<strin
              .catch(() => undefined)
          }
          apply((node.attrs.src as string) ?? '')
+
+          // PM 用的是 mouse 事件：手柄上的 mousedown/mouseup/click 必须吞掉，
+          // 否则松手时 PM 会按点击位置重设选区，手柄随即消失、没法连续拖。
+          for (const type of ['mousedown', 'mouseup', 'click', 'dblclick'] as const) {
+            handle.addEventListener(type, (e) => { e.preventDefault(); e.stopPropagation() })
+          }
+          let drag: { startX: number; startW: number; lastW: number } | null = null
+          handle.addEventListener('pointerdown', (e) => {
+            e.preventDefault()
+            e.stopPropagation()
+            const w = img.getBoundingClientRect().width
+            drag = { startX: e.clientX, startW: w, lastW: w }
+            handle.setPointerCapture(e.pointerId)
+          })
+          handle.addEventListener('pointermove', (e) => {
+            if (!drag) return
+            const max = wrap.parentElement?.clientWidth || 10000
+            const w = Math.min(Math.max(20, drag.startW + (e.clientX - drag.startX)), Math.max(20, max))
+            drag.lastW = w
+            img.style.width = `${Math.round(w)}px`
+          })
+          const endDrag = () => {
+            if (!drag) return
+            const w = Math.round(drag.lastW)
+            drag = null
+            const pos = typeof getPos === 'function' ? getPos() : undefined
+            if (pos == null || String(w) === String(currentNode.attrs.width ?? '')) {
+              applyWidth(currentNode.attrs.width)
+              return
+            }
+            // setNodeMarkup 换掉节点实例后 PM 会按 DOM 选区回读、把节点选区
+            // 塌成文本光标（选区一丢手柄就消失，没法连续拖）——同一事务里把
+            // 节点选区明确设回去。
+            const tr = view.state.tr.setNodeMarkup(pos, undefined, { ...currentNode.attrs, width: String(w) })
+            tr.setSelection(NodeSelection.create(tr.doc, pos))
+            view.dispatch(tr)
+          }
+          handle.addEventListener('pointerup', endDrag)
+          handle.addEventListener('pointercancel', endDrag)
+
          return {
-            dom: img,
+            dom: wrap,
            update: (next) => {
              if (next.type.name !== 'image') return false
+              currentNode = next
              img.alt = (next.attrs.alt as string) ?? ''
-              applyWidth(next.attrs.width)
+              if (!drag) applyWidth(next.attrs.width)
              const src = (next.attrs.src as string) ?? ''
              if (src !== currentSrc) apply(src)
              return true
--- a/src/styles.css
+++ b/src/styles.css
@@ -185,6 +185,10 @@ kbd { background: var(--code-bg); border: 1px solid var(--border); border-radius
 .milkdown .ProseMirror th, .milkdown .ProseMirror td { border: 1px solid var(--border); padding: 6px 12px; }
 .milkdown .ProseMirror img { max-width: 100%; }
 .milkdown .ProseMirror img.ProseMirror-selectednode { outline: 2px solid var(--accent); outline-offset: 1px; border-radius: 2px; }
+.milkdown .ProseMirror .img-wrap { position: relative; display: inline-block; max-width: 100%; line-height: 0; }
+.milkdown .ProseMirror .img-wrap.ProseMirror-selectednode { outline: 2px solid var(--accent); outline-offset: 1px; border-radius: 2px; }
+.milkdown .ProseMirror .img-wrap .img-resize-handle { position: absolute; right: -6px; bottom: -6px; width: 12px; height: 12px; border-radius: 3px; background: var(--accent); border: 2px solid var(--bg-editor, #fff); box-shadow: 0 1px 4px rgba(0, 0, 0, 0.3); cursor: nwse-resize; opacity: 0; pointer-events: none; z-index: 3; }
+.milkdown .ProseMirror .img-wrap.ProseMirror-selectednode .img-resize-handle { opacity: 1; pointer-events: auto; }
 .milkdown .ProseMirror a { color: var(--accent); }
 .milkdown .ProseMirror hr { border: 0; border-top: 1px solid var(--border); }
 .milkdown .ProseMirror li.task-item { list-style: none; display: flex; align-items: flex-start; gap: 2px; margin-left: -1.1em; }