Move cover loading and culling to guifunctions module

lector/guifunctions.py

@@ -16,7 +16,8 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from PyQt5 import QtGui
+from PyQt5 import QtCore, QtGui
+from lector import database
 from lector.resources import resources
 
 
@@ -30,3 +31,98 @@ class QImageFactory:
 
         this_qicon = QtGui.QIcon(icon_path)
         return this_qicon
+
+
+class CoverLoadingAndCulling:
+    def __init__(self, main_window):
+        self.main_window = main_window
+        self.lib_ref = self.main_window.lib_ref
+        self.listView = self.main_window.listView
+
+    def cull_covers(self, event=None):
+        blank_pixmap = QtGui.QPixmap()
+        blank_pixmap.load(':/images/blank.png')  # Keep this. Removing it causes the
+                                                 # listView to go blank on a resize
+
+        all_indexes = set()
+        for i in range(self.lib_ref.item_proxy_model.rowCount()):
+            all_indexes.add(self.lib_ref.item_proxy_model.index(i, 0))
+
+        y_range = list(range(0, self.listView.viewport().height(), 100))
+        y_range.extend((-20, self.listView.viewport().height() + 20))
+        x_range = range(0, self.listView.viewport().width(), 80)
+
+        visible_indexes = set()
+        for i in y_range:
+            for j in x_range:
+                this_index = self.listView.indexAt(QtCore.QPoint(j, i))
+                visible_indexes.add(this_index)
+
+        invisible_indexes = all_indexes - visible_indexes
+        for i in invisible_indexes:
+            model_index = self.lib_ref.item_proxy_model.mapToSource(i)
+            this_item = self.lib_ref.view_model.item(model_index.row())
+
+            if this_item:
+                this_item.setIcon(QtGui.QIcon(blank_pixmap))
+                this_item.setData(False, QtCore.Qt.UserRole + 8)
+
+        hash_index_dict = {}
+        hash_list = []
+        for i in visible_indexes:
+            model_index = self.lib_ref.item_proxy_model.mapToSource(i)
+
+            book_hash = self.lib_ref.view_model.data(
+                model_index, QtCore.Qt.UserRole + 6)
+            cover_displayed = self.lib_ref.view_model.data(
+                model_index, QtCore.Qt.UserRole + 8)
+
+            if book_hash and not cover_displayed:
+                hash_list.append(book_hash)
+                hash_index_dict[book_hash] = model_index
+
+        all_covers = database.DatabaseFunctions(
+            self.main_window.database_path).fetch_covers_only(hash_list)
+
+        for i in all_covers:
+            book_hash = i[0]
+            cover = i[1]
+            model_index = hash_index_dict[book_hash]
+
+            book_item = self.lib_ref.view_model.item(model_index.row())
+            self.cover_loader(book_item, cover)
+
+    def load_all_covers(self):
+        all_covers_db = database.DatabaseFunctions(
+            self.main_window.database_path).fetch_data(
+                ('Hash', 'CoverImage',),
+                'books',
+                {'Hash': ''},
+                'LIKE')
+
+        if not all_covers_db:
+            return
+
+        all_covers = {
+            i[0]: i[1] for i in all_covers_db}
+
+        for i in range(self.lib_ref.view_model.rowCount()):
+            this_item = self.lib_ref.view_model.item(i, 0)
+
+            is_cover_already_displayed = this_item.data(QtCore.Qt.UserRole + 8)
+            if is_cover_already_displayed:
+                continue
+
+            book_hash = this_item.data(QtCore.Qt.UserRole + 6)
+            cover = all_covers[book_hash]
+            self.cover_loader(this_item, cover)
+
+    def cover_loader(self, item, cover):
+        img_pixmap = QtGui.QPixmap()
+        if cover:
+            img_pixmap.loadFromData(cover)
+        else:
+            img_pixmap.load(':/images/NotFound.png')
+        img_pixmap = img_pixmap.scaled(420, 600, QtCore.Qt.IgnoreAspectRatio)
+        item.setIcon(QtGui.QIcon(img_pixmap))
+        item.setData(True, QtCore.Qt.UserRole + 8)