Merge pull request #20 from podusowski/fix-crashing-at-the-edges

Fix crashing at the edges

CHANGELOG.md

@@ -14,6 +14,10 @@ All notable changes to this project will be documented in this file.
 
  * Zooming using CTRL + mouse wheel or pinch gesture.
 
+### Fixed
+
+ * Fixed panic when dragging out of the map's boundaries.
+
 ## 0.5.0
 
 ### Breaking

src/map.rs

@@ -162,10 +162,13 @@ fn draw_tiles(
                 tile_id.east(),
                 tile_id.south(),
                 tile_id.west(),
-            ] {
+            ]
+            .iter()
+            .flatten()
+            {
                 draw_tiles(
                     painter,
-                    coordinates,
+                    *coordinates,
                     map_center_projected_position,
                     tiles,
                     ui,

src/mercator.rs

@@ -84,36 +84,36 @@ impl TileId {
         Pixels::new((self.x * TILE_SIZE) as f32, (self.y * TILE_SIZE) as f32)
     }
 
-    pub fn east(&self) -> TileId {
-        TileId {
+    pub fn east(&self) -> Option<TileId> {
+        Some(TileId {
             x: self.x + 1,
             y: self.y,
             zoom: self.zoom,
-        }
+        })
     }
 
-    pub fn west(&self) -> TileId {
-        TileId {
-            x: self.x - 1,
+    pub fn west(&self) -> Option<TileId> {
+        Some(TileId {
+            x: self.x.checked_sub(1)?,
             y: self.y,
             zoom: self.zoom,
-        }
+        })
     }
 
-    pub fn north(&self) -> TileId {
-        TileId {
+    pub fn north(&self) -> Option<TileId> {
+        Some(TileId {
             x: self.x,
-            y: self.y - 1,
+            y: self.y.checked_sub(1)?,
             zoom: self.zoom,
-        }
+        })
     }
 
-    pub fn south(&self) -> TileId {
-        TileId {
+    pub fn south(&self) -> Option<TileId> {
+        Some(TileId {
             x: self.x,
             y: self.y + 1,
             zoom: self.zoom,
-        }
+        })
     }
 }