display the content of the annotation being hovered in a tooltip. (#396)

* display the content of the annotation being hovered in a tooltip.

* fix a spell error.

app/pdf-viewer/buffer.py

@@ -24,6 +24,7 @@ from PyQt5.QtCore import Qt, QRect, QEvent
 from PyQt5.QtGui import QColor, QPixmap, QImage, QFont, QCursor
 from PyQt5.QtGui import QPainter
 from PyQt5.QtWidgets import QWidget
+from PyQt5.QtWidgets import QToolTip
 from core.buffer import Buffer
 from core.utils import touch, interactive
 import fitz
@@ -296,6 +297,8 @@ class PdfViewerWidget(QWidget):
 
         self.remember_offset = None
 
+        self.last_hover_annot_id = None
+
         # To avoid 'PDF only' method errors
         self.inpdf = True
         if os.path.splitext(self.url)[-1] != ".pdf":
@@ -1065,6 +1068,14 @@ class PdfViewerWidget(QWidget):
             self.page_cache_pixmap_dict.clear()
             self.update()
 
+        if current_annot and current_annot.info["content"]:
+            if current_annot.info["id"] != self.last_hover_annot_id or not QToolTip.isVisible():
+                QToolTip.showText(QCursor.pos(), current_annot.info["content"], None, QRect(), 10 * 1000)
+            self.last_hover_annot_id = current_annot.info["id"]
+        else:
+            if QToolTip.isVisible():
+                QToolTip.hideText()
+
         return page, current_annot
 
     def save_annot(self):
@@ -1088,7 +1099,7 @@ class PdfViewerWidget(QWidget):
             annot.setInfo(content=annot_text)
             annot.update()
         self.save_annot()
-        self.edited_annot = (None, None)
+        self.edited_page_annot = (None, None)
 
     def jump_to_page(self, page_num):
         self.update_vertical_offset(min(max(self.scale * (int(page_num) - 1) * self.page_height, 0), self.max_scroll_offset()))