Add ability to pan camera using keyboard

src/boomer.nim

@@ -489,6 +489,14 @@ proc main() =
         case key
         of XK_EQUAL: scrollUp()
         of XK_MINUS: scrollDown()
+        of XK_h, XK_Left:
+          camera.position.x = camera.position.x - config.camera_speed
+        of XK_j, XK_Down:
+          camera.position.y = camera.position.y + config.camera_speed
+        of XK_k, XK_Up:
+          camera.position.y = camera.position.y - config.camera_speed
+        of XK_l, XK_Right:
+          camera.position.x = camera.position.x + config.camera_speed
         of XK_0:
           camera.scale = 1.0
           camera.deltaScale = 0.0

src/config.nim

@@ -5,12 +5,14 @@ type Config* = object
   scroll_speed*: float
   drag_friction*: float
   scale_friction*: float
+  camera_speed*: float
 
 const defaultConfig* = Config(
   min_scale: 0.01,
   scroll_speed: 1.5,
   drag_friction: 6.0,
   scale_friction: 4.0,
+  camera_speed: 20.0,
 )
 
 proc loadConfig*(filePath: string): Config =
@@ -31,6 +33,8 @@ proc loadConfig*(filePath: string): Config =
       result.drag_friction = parseFloat(value)
     of "scale_friction":
       result.scale_friction = parseFloat(value)
+    of "camera_speed":
+      result.camera_speed = parseFloat(value)
     else:
       quit "Unknown config key `$#`" % [key]
 
@@ -41,3 +45,4 @@ proc generateDefaultConfig*(filePath: string) =
   f.write("scroll_speed = ", defaultConfig.scroll_speed, "\n")
   f.write("drag_friction = ", defaultConfig.drag_friction, "\n")
   f.write("scale_friction = ", defaultConfig.scale_friction, "\n")
+  f.write("camera_speed = ", defaultConfig.camera_speed, "\n")