feat: imp move cursor up down by position

2026-04-28 16:15:21 +00:00 · 2021-06-09 02:21:57 +08:00
parent fe3fa70fc9
commit 237857aafe
4 changed files with 141 additions and 33 deletions
--- a/src/main/frontend/util/cursor.cljs
+++ b/src/main/frontend/util/cursor.cljs
@@ -0,0 +1,116 @@
+(ns frontend.util.cursor
+  (:require ["/frontend/caret_pos" :as caret-pos]
+            [cljs-bean.core :as bean]
+            [clojure.string :as string]
+            [frontend.util :as util]
+            [goog.dom :as gdom]
+            [goog.object :as gobj]))
+
+(defn- closer [a b c]
+  (let [a-left (or (:left a) 0)
+        b-left (:left b)
+        c-left (or (:left c) js/Number.MAX_SAFE_INTEGER)]
+    (if (< (- b-left a-left) (- c-left b-left))
+      a
+      c)))
+
+(defn mock-char-pos [e]
+  {:left (.-offsetLeft e)
+   :top  (.-offsetTop e)
+   :pos  (-> (.-id e)
+             (string/split "_")
+             second
+             int)})
+
+(defn get-caret-pos
+  [input]
+  (when input
+    (try
+      (let [pos ((gobj/get caret-pos "position") input)]
+        (bean/->clj pos))
+      (catch js/Error e
+        (js/console.error e)))))
+
+(defn move-cursor-to [input n]
+  (.setSelectionRange input n n))
+
+(defn move-cursor-up [input]
+  (let [elms  (-> (gdom/getElement "mock-text")
+                  gdom/getChildren
+                  array-seq)
+        cusor (-> input
+                  (util/get-caret-pos)
+                  (select-keys [:left :top :pos]))
+        chars (->> elms
+                   (map mock-char-pos)
+                   (group-by :top))
+        tops  (sort (keys chars))
+        tops-p (partition-by #(== (:top cusor) %) tops)
+        prev-t (-> tops-p first last)
+        lefts
+        (->> (get chars prev-t)
+             (partition-by (fn [char-pos]
+                             (<= (:left char-pos) (:left cusor)))))
+        left-a (-> lefts first last)
+        left-c (-> lefts last first)
+        closer
+        (if (> 2 (count lefts))
+          left-a
+          (closer left-a cusor left-c))]
+    (move-cursor-to input (:pos closer))))
+
+(defn move-cursor-down [input]
+  (let [elms  (-> (gdom/getElement "mock-text")
+                  gdom/getChildren
+                  array-seq)
+        cusor (-> input
+                  (util/get-caret-pos)
+                  (select-keys [:left :top :pos]))
+        chars (->> elms
+                   (map mock-char-pos)
+                   (group-by :top))
+        tops  (sort (keys chars))
+        tops-p (partition-by #(== (:top cusor) %) tops)
+        next-t (-> tops-p last first)
+        lefts
+        (->> (get chars next-t)
+             (partition-by (fn [char-pos]
+                             (<= (:left char-pos) (:left cusor)))))
+        left-a (-> lefts first last)
+        left-c (-> lefts last first)
+        closer
+        (if (< (count lefts) 2)
+          left-a
+          (closer left-a cusor left-c))]
+    (move-cursor-to input (:pos closer))))
+
+(comment
+  ;; previous implementation of up/down
+  (defn move-cursor-up
+    "Move cursor up. If EOL, always move cursor to previous EOL."
+    [input]
+    (let [val (gobj/get input "value")
+          pos (.-selectionStart input)
+          prev-idx (string/last-index-of val \newline pos)
+          pprev-idx (or (string/last-index-of val \newline (dec prev-idx)) -1)
+          cal-idx (+ pprev-idx pos (- prev-idx))]
+      (if (or (== pos (count val))
+              (> (- pos prev-idx) (- prev-idx pprev-idx)))
+        (move-cursor-to input prev-idx)
+        (move-cursor-to input cal-idx))))
+
+  (defn move-cursor-down
+    "Move cursor down by calculating current cursor line pos.
+  If EOL, always move cursor to next EOL."
+    [input]
+    (let [val (gobj/get input "value")
+          pos (.-selectionStart input)
+          prev-idx (or (string/last-index-of val \newline pos) -1)
+          next-idx (or (string/index-of val \newline (inc pos))
+                       (count val))
+          nnext-idx (or (string/index-of val \newline (inc next-idx))
+                        (count val))
+          cal-idx (+ next-idx pos (- prev-idx))]
+      (if (> (- pos prev-idx) (- nnext-idx next-idx))
+        (move-cursor-to input nnext-idx)
+        (move-cursor-to input cal-idx)))))