Add ability to zoom in/out with keyboard.

My mouse wheel broke.

README.md

@@ -34,22 +34,22 @@ For additional Developer Capabilities compile the application with the following
 $ nimble build -d:developer
 ```
 
-This will enable reloading the shaders with `Ctrl+R`. The shader files (`frag.glsl` and `vert.glsl`) should be located in the same folder as `boomer.nim` for this feature to work. If the shader files not found the program won't even start. 
+This will enable reloading the shaders with `Ctrl+R`. The shader files (`frag.glsl` and `vert.glsl`) should be located in the same folder as `boomer.nim` for this feature to work. If the shader files not found the program won't even start.
 
 **Keep in mind that the developer build is not suitable for day-to-day usage because it creates the external dependency on the shader files. Compiling the program without `-d:developer` "bakes" the shaders into the executable and eliminates the dependency.**
 
 ## Controls
 
-| Control                        | Description                                                   |
+| Control                                   | Description                                                   |
-|--------------------------------|---------------------------------------------------------------|
+|-------------------------------------------|---------------------------------------------------------------|
-| <kbd>0</kbd>                   | Reset the application state (position, scale, velocity, etc). |
+| <kbd>0</kbd>                              | Reset the application state (position, scale, velocity, etc). |
-| <kbd>q</kbd> or <kbd>ESC</kbd> | Quit the application.                                         |
+| <kbd>q</kbd> or <kbd>ESC</kbd>            | Quit the application.                                         |
-| <kbd>r</kbd>                   | Reload configuration.                                         |
+| <kbd>r</kbd>                              | Reload configuration.                                         |
-| <kbd>Ctrl</kbd> + <kbd>r</kbd> | Reload the shaders (only for Developer mode)                  |
+| <kbd>Ctrl</kbd> + <kbd>r</kbd>            | Reload the shaders (only for Developer mode)                  |
-| <kbd>f</kbd>                   | Toggle flashlight effect.                                     |
+| <kbd>f</kbd>                              | Toggle flashlight effect.                                     |
-| Drag with left mouse button    | Move the image around.                                        |
+| Drag with left mouse button               | Move the image around.                                        |
-| Scroll wheel                   | Zoom in/out.                                                  |
+| Scroll wheel or <kbd>=</kbd>/<kbd>-</kbd> | Zoom in/out.                                                  |
-| <kbd>Ctrl</kbd> + Scroll wheel | Change the radious of the flaslight.                          |
+| <kbd>Ctrl</kbd> + Scroll wheel            | Change the radious of the flaslight.                          |
 
 ## Configuration
 

src/boomer.nim

@@ -445,6 +445,21 @@ proc main() =
     var xev: TXEvent
     while XPending(display) > 0:
       discard XNextEvent(display, addr xev)
+
+      proc scrollUp() =
+        if (xev.xkey.state and ControlMask) > 0.uint32 and flashlight.isEnabled:
+          flashlight.deltaRadius += INITIAL_FL_DELTA_RADIUS
+        else:
+          camera.deltaScale += config.scrollSpeed
+          camera.scalePivot = mouse.curr
+
+      proc scrollDown() =
+        if (xev.xkey.state and ControlMask) > 0.uint32 and flashlight.isEnabled:
+          flashlight.deltaRadius -= INITIAL_FL_DELTA_RADIUS
+        else:
+          camera.deltaScale -= config.scrollSpeed
+          camera.scalePivot = mouse.curr
+
       case xev.theType
       of Expose:
         discard
@@ -470,6 +485,8 @@ proc main() =
       of KeyPress:
         var key = XLookupKeysym(cast[PXKeyEvent](xev.addr), 0)
         case key
+        of XK_EQUAL: scrollUp()
+        of XK_MINUS: scrollDown()
         of XK_0:
           camera.scale = 1.0
           camera.deltaScale = 0.0
@@ -507,21 +524,8 @@ proc main() =
           mouse.prev = mouse.curr
           mouse.drag = true
           camera.velocity = vec2(0.0, 0.0)
-
+        of Button4: scrollUp()
-        of Button4:             # Scroll up
+        of Button5: scrollDown()
-          if (xev.xkey.state and ControlMask) > 0.uint32 and flashlight.isEnabled:
-            flashlight.deltaRadius += INITIAL_FL_DELTA_RADIUS
-          else:
-            camera.deltaScale += config.scrollSpeed
-            camera.scalePivot = mouse.curr
-
-        of Button5:             # Scoll down
-          if (xev.xkey.state and ControlMask) > 0.uint32 and flashlight.isEnabled:
-            flashlight.deltaRadius -= INITIAL_FL_DELTA_RADIUS
-          else:
-            camera.deltaScale -= config.scrollSpeed
-            camera.scalePivot = mouse.curr
-
         else:
           discard