From a96a77a237a62f0881a2b106b040f29c840fff58 Mon Sep 17 00:00:00 2001
From: Hufe921 <huangyunfeihufe@hotmail.com>
Date: Thu, 3 Aug 2023 21:44:03 +0800
Subject: [PATCH] fix: cursor navigation across pages #229

---
 src/editor/core/event/handlers/keydown.ts | 149 ++++++++++++----------
 1 file changed, 82 insertions(+), 67 deletions(-)

diff --git a/src/editor/core/event/handlers/keydown.ts b/src/editor/core/event/handlers/keydown.ts
index b6460aa..c2f2ca7 100644
--- a/src/editor/core/event/handlers/keydown.ts
+++ b/src/editor/core/event/handlers/keydown.ts
@@ -205,86 +205,101 @@ export function keydown(evt: KeyboardEvent, host: CanvasEvent) {
       }
     }
     const {
-      rowNo,
       index,
-      pageNo,
-      coordinate: { leftTop, rightTop }
+      rowNo,
+      rowIndex,
+      coordinate: {
+        leftTop: [curLeftX],
+        rightTop: [curRightX]
+      }
     } = anchorPosition
-    if ((isUp && rowNo !== 0) || (!isUp && rowNo !== draw.getRowCount())) {
-      // 下一个光标点所在行位置集合
-      const probablePosition = isUp
-        ? positionList
-            .slice(0, index)
-            .filter(p => p.rowNo === rowNo - 1 && pageNo === p.pageNo)
-        : positionList
-            .slice(index, positionList.length - 1)
-            .filter(p => p.rowNo === rowNo + 1 && pageNo === p.pageNo)
-      // 查找与当前位置元素点交叉最多的位置
-      let maxIndex = 0
-      let maxDistance = 0
-      for (let p = 0; p < probablePosition.length; p++) {
-        const position = probablePosition[p]
-        // 当前光标在前
+    // 向上时在首行、向下时再最尾则忽略
+    if (
+      (isUp && rowIndex === 0) ||
+      (!isUp && rowIndex === draw.getRowCount() - 1)
+    ) {
+      return
+    }
+    // 查找下一行信息
+    const probablePosition: IElementPosition[] = []
+    if (isUp) {
+      let p = index - 1
+      while (p > 0) {
+        const position = positionList[p]
+        p--
+        if (position.rowNo === rowNo) continue
         if (
-          position.coordinate.leftTop[0] >= leftTop[0] &&
-          position.coordinate.leftTop[0] <= rightTop[0]
+          probablePosition[0] &&
+          probablePosition[0].rowNo !== position.rowNo
         ) {
-          const curDistance = rightTop[0] - position.coordinate.leftTop[0]
-          if (curDistance > maxDistance) {
-            maxIndex = position.index
-            maxDistance = curDistance
-            break
-          }
+          break
         }
-        // 当前光标在后
-        else if (
-          position.coordinate.leftTop[0] <= leftTop[0] &&
-          position.coordinate.rightTop[0] >= leftTop[0]
+        probablePosition.unshift(position)
+      }
+    } else {
+      let p = index + 1
+      while (p < positionList.length) {
+        const position = positionList[p]
+        p++
+        if (position.rowNo === rowNo) continue
+        if (
+          probablePosition[0] &&
+          probablePosition[0].rowNo !== position.rowNo
         ) {
-          const curDistance = position.coordinate.rightTop[0] - leftTop[0]
-          if (curDistance > maxDistance) {
-            maxIndex = position.index
-            maxDistance = curDistance
-            break
-          }
+          break
         }
-        // 匹配不到
-        if (p === probablePosition.length - 1 && maxIndex === 0) {
-          maxIndex = position.index
+        probablePosition.push(position)
+      }
+    }
+    // 查找下一行位置：第一个存在交叉宽度的元素位置
+    let nextIndex = 0
+    for (let p = 0; p < probablePosition.length; p++) {
+      const nextPosition = probablePosition[p]
+      const {
+        coordinate: {
+          leftTop: [nextLeftX],
+          rightTop: [nextRightX]
         }
+      } = nextPosition
+      if (p === probablePosition.length - 1) {
+        nextIndex = nextPosition.index
       }
-      const curIndex = maxIndex
-      // shift则缩放选区
-      let anchorStartIndex = curIndex
-      let anchorEndIndex = curIndex
-      if (evt.shiftKey) {
-        if (startIndex !== endIndex) {
-          if (startIndex === cursorPosition.index) {
-            anchorStartIndex = startIndex
-          } else {
-            anchorEndIndex = endIndex
-          }
+      if (curRightX <= nextLeftX || curLeftX >= nextRightX) continue
+      nextIndex = nextPosition.index
+      break
+    }
+    if (!nextIndex) return
+    const curIndex = nextIndex
+    // shift则缩放选区
+    let anchorStartIndex = curIndex
+    let anchorEndIndex = curIndex
+    if (evt.shiftKey) {
+      if (startIndex !== endIndex) {
+        if (startIndex === cursorPosition.index) {
+          anchorStartIndex = startIndex
         } else {
-          if (isUp) {
-            anchorEndIndex = endIndex
-          } else {
-            anchorStartIndex = startIndex
-          }
+          anchorEndIndex = endIndex
+        }
+      } else {
+        if (isUp) {
+          anchorEndIndex = endIndex
+        } else {
+          anchorStartIndex = startIndex
         }
       }
-      if (anchorStartIndex > anchorEndIndex) {
-        // prettier-ignore
-        [anchorStartIndex, anchorEndIndex] = [anchorEndIndex, anchorStartIndex]
-      }
-      rangeManager.setRange(anchorStartIndex, anchorEndIndex)
-      const isCollapsed = anchorStartIndex === anchorEndIndex
-      draw.render({
-        curIndex: isCollapsed ? anchorStartIndex : undefined,
-        isSetCursor: isCollapsed,
-        isSubmitHistory: false,
-        isCompute: false
-      })
     }
+    if (anchorStartIndex > anchorEndIndex) {
+      // prettier-ignore
+      [anchorStartIndex, anchorEndIndex] = [anchorEndIndex, anchorStartIndex]
+    }
+    rangeManager.setRange(anchorStartIndex, anchorEndIndex)
+    const isCollapsed = anchorStartIndex === anchorEndIndex
+    draw.render({
+      curIndex: isCollapsed ? anchorStartIndex : undefined,
+      isSetCursor: isCollapsed,
+      isSubmitHistory: false,
+      isCompute: false
+    })
   } else if (isMod(evt) && evt.key === KeyMap.Z) {
     if (isReadonly) return
     historyManager.undo()