Make map draggable

The map can be dragged around, but since the grid is not yet infinitely
big, it feels quite weird to zoom and drag

1 files changed, 5 insertions, 0 deletions

diff --git a/src/transform.rs b/src/transform.rs
index ef94029..a91d7da 100644
--- a/src/transform.rs
+++ b/src/transform.rs
@@ -121,6 +121,11 @@ impl Transform {
         }
     }
 
+    /// Move the canvas by the vector in pixels.
+    pub fn move_by_px(&mut self, by: [f64; 2]) {
+        self.translation_px = math::add(self.translation_px, by);
+    }
+
     pub fn pixels_per_m(&self) -> f64 {
         self.pixels_per_m
     }