improved library screen, fixed issues with image rendering and navigation

tests/test_backward_nav_minimal.py

@@ -0,0 +1,85 @@
+"""
+Minimal reproduction test for backward navigation bug.
+
+BUG: Backward navigation cannot reach block_index=0 from block_index=1.
+
+This is a pyWebLayout issue, not a dreader-application issue.
+"""
+
+import unittest
+import tempfile
+import shutil
+from pathlib import Path
+
+from dreader.application import EbookReader
+
+
+class TestBackwardNavigationBug(unittest.TestCase):
+    """Minimal reproduction of backward navigation bug"""
+
+    def setUp(self):
+        """Set up test environment"""
+        self.temp_dir = tempfile.mkdtemp()
+        self.epub_path = "tests/data/test.epub"
+
+        if not Path(self.epub_path).exists():
+            self.skipTest(f"Test EPUB not found at {self.epub_path}")
+
+    def tearDown(self):
+        """Clean up test environment"""
+        shutil.rmtree(self.temp_dir, ignore_errors=True)
+
+    def test_minimal_backward_navigation_bug(self):
+        """
+        MINIMAL REPRODUCTION:
+
+        1. Start at block_index=0
+        2. Go forward once (to block_index=1)
+        3. Go backward once
+        4. BUG: Lands at block_index=1 instead of block_index=0
+
+        This proves backward navigation cannot reach the first block.
+        """
+        reader = EbookReader(
+            page_size=(800, 1000),
+            bookmarks_dir=self.temp_dir,
+            buffer_size=0
+        )
+
+        reader.load_epub(self.epub_path)
+
+        # Starting position
+        pos_start = reader.manager.current_position.copy()
+        print(f"\n1. Starting at block_index={pos_start.block_index}")
+        self.assertEqual(pos_start.block_index, 0, "Should start at block 0")
+
+        # Go forward
+        reader.next_page()
+        pos_forward = reader.manager.current_position.copy()
+        print(f"2. After next_page(): block_index={pos_forward.block_index}")
+        self.assertEqual(pos_forward.block_index, 1, "Should be at block 1")
+
+        # Go backward
+        reader.previous_page()
+        pos_final = reader.manager.current_position.copy()
+        print(f"3. After previous_page(): block_index={pos_final.block_index}")
+
+        # THE BUG: This assertion will fail
+        print(f"\nEXPECTED: block_index=0")
+        print(f"ACTUAL:   block_index={pos_final.block_index}")
+
+        if pos_final.block_index != 0:
+            print("\n❌ BUG CONFIRMED: Cannot navigate backward to block_index=0")
+            print("   This is a pyWebLayout bug in the previous_page() method.")
+
+        self.assertEqual(
+            pos_final.block_index,
+            0,
+            "BUG: Backward navigation from block 1 should return to block 0"
+        )
+
+        reader.close()
+
+
+if __name__ == '__main__':
+    unittest.main()