Improve toolbar position calculation (#15983)

* 🎨 Improve toolbar position calculation

* 🎨 Improve toolbar position calculation

* 🎨 Improve toolbar position calculation

app/src/assets/scss/protyle/_toolbar.scss

@@ -6,7 +6,10 @@
     box-shadow: var(--b3-point-shadow);
     border-radius: var(--b3-border-radius);
     display: flex;
-    transition: top .15s cubic-bezier(0, 0, .2, 1) 0ms;
+
+    &__transition {
+      transition: top .15s cubic-bezier(0, 0, .2, 1) 0ms;
+    }
 
     &__item {
       color: var(--b3-theme-on-surface);

app/src/protyle/toolbar/index.ts

@@ -164,12 +164,17 @@ export class Toolbar {
             this.element.classList.add("fn__none");
             return;
         }
-        const rangePosition = getSelectionPosition(nodeElement, range);
+        this.element.classList.remove("fn__none", "protyle-toolbar__transition");
-        this.element.classList.remove("fn__none");
+        
         this.toolbarHeight = this.element.clientHeight;
-        const y = rangePosition.top - this.toolbarHeight - 4;
+        const rangePosition = getSelectionPosition(nodeElement, range, this.element.clientWidth);
+        const y = rangePosition.isToolbarAtBottom ?
+            Math.min(rangePosition.top + 4, protyle.element.getBoundingClientRect().bottom - this.toolbarHeight) :
+            Math.max(rangePosition.top - this.toolbarHeight - 4, protyle.element.getBoundingClientRect().top + 30);
         this.element.setAttribute("data-inity", y + Constants.ZWSP + protyle.contentElement.scrollTop.toString());
-        setPosition(this.element, rangePosition.left - 52, Math.max(y, protyle.element.getBoundingClientRect().top + 30));
+        setPosition(this.element, rangePosition.left, y);
+
+        this.element.classList.add("protyle-toolbar__transition");
         this.element.querySelectorAll(".protyle-toolbar__item--current").forEach(item => {
             item.classList.remove("protyle-toolbar__item--current");
         });

app/src/protyle/util/selection.ts

@@ -194,7 +194,7 @@ export const getEditorRange = (element: Element): Range => {
     return range;
 };
 
-export const getSelectionPosition = (nodeElement: Element, range?: Range) => {
+export const getSelectionPosition = (nodeElement: Element, range?: Range, toolbarWidth?: number) => {
     if (!range) {
         range = getEditorRange(nodeElement);
     }
@@ -261,9 +261,24 @@ export const getSelectionPosition = (nodeElement: Element, range?: Range) => {
     } else {
         const rects = range.getClientRects(); // 由于长度过长折行，光标在行首时有多个 rects https://github.com/siyuan-note/siyuan/issues/6156
         if (range.toString()) {
-            return {    // 选中多行不应遮挡第一行 https://github.com/siyuan-note/siyuan/issues/7541
+            const selection = window.getSelection();
-                left: rects[rects.length - 1].left,
+            // 判断选择方向
-                top: rects[0].top
+            const isBackward = selection && "direction" in selection ?
+                (selection as { direction: "forward" | "backward" | "none" }).direction === "backward"
+                : range.startContainer === selection?.focusNode && range.startOffset === selection?.focusOffset;
+            let isToolbarAtBottom = false;
+            if (!isBackward) {
+                // 检查是否有多个垂直位置不同的矩形
+                isToolbarAtBottom = rects.length > 1 && Array.from(rects).some((rect: DOMRect) => rect.top !== rects[0].top);
+            }
+
+            return {
+                // 向左选择：使用第一个矩形的左边界；向右选择：使用最后一个矩形的右边界
+                // 减去工具栏宽度的1/4：将工具栏中不太常用的按钮往右偏一点
+                left: (isBackward ? rects[0].left : rects[rects.length - 1].right) - (toolbarWidth || 0) / 4,
+                // 如果向右选择时有多个垂直位置不同的矩形：使用最后一个矩形的下边界；否则使用第一个矩形的上边界
+                top: isToolbarAtBottom ? rects[rects.length - 1].bottom : rects[0].top,
+                isToolbarAtBottom: isToolbarAtBottom,
             };
         } else {
             return {    // 代码块首 https://github.com/siyuan-note/siyuan/issues/13113