From 629316c8d0fa20885f5f2f0c4e488bd43e066d5a Mon Sep 17 00:00:00 2001
From: Mitchell McCaffrey <mitchemmc@gmail.com>
Date: Tue, 23 Feb 2021 14:11:12 +1100
Subject: [PATCH] Added zoom shortcut

---
 src/docs/howTo/shortcuts.md      |  2 ++
 src/docs/releaseNotes/v1.8.0.md  |  1 +
 src/hooks/useStageInteraction.js | 40 ++++++++++++++++++++++++++++++++
 3 files changed, 43 insertions(+)

diff --git a/src/docs/howTo/shortcuts.md b/src/docs/howTo/shortcuts.md
index 2c09145..1155cee 100644
--- a/src/docs/howTo/shortcuts.md
+++ b/src/docs/howTo/shortcuts.md
@@ -9,6 +9,8 @@
 | M                | Measure Tool |
 | Q                | Pointer Tool |
 | N                | Note Tool    |
+| +                | Zoom In      |
+| -                | Zoom Out     |
 
 ## Fog Tool
 
diff --git a/src/docs/releaseNotes/v1.8.0.md b/src/docs/releaseNotes/v1.8.0.md
index b0b278e..91ac30d 100644
--- a/src/docs/releaseNotes/v1.8.0.md
+++ b/src/docs/releaseNotes/v1.8.0.md
@@ -53,6 +53,7 @@ A GM can toggle this setting by clicking on a note once it is on the map and cli
 - Notes are now shown above drawings to prevent the case where you can't move your note because a drawing was on top of it.
 - Notes text is now left aligned and text scales down further to allow for more text to be shown per note.
 - Added an information dialog that is shown when joining a game that has timed out.
+- Added a new zoom shortcut with the + and - keys.
 - Updated how to page with general site settings.
 - Moved shortcuts on how to page into its own section with all shortcuts listed.
 - Fixed a bug that would cause you join a game multiple times when using the back function in a browser.
diff --git a/src/hooks/useStageInteraction.js b/src/hooks/useStageInteraction.js
index 353ca40..17714ee 100644
--- a/src/hooks/useStageInteraction.js
+++ b/src/hooks/useStageInteraction.js
@@ -2,6 +2,8 @@ import { useRef, useEffect } from "react";
 import { useGesture } from "react-use-gesture";
 import normalizeWheel from "normalize-wheel";
 
+import { useKeyboard } from "../contexts/KeyboardContext";
+
 const wheelZoomSpeed = -1;
 const touchZoomSpeed = 0.005;
 const minZoom = 0.1;
@@ -173,6 +175,44 @@ function useStageInteraction(
       },
     }
   );
+
+  function handleKeyDown(event) {
+    // TODO: Find better way to detect whether keyboard event should fire.
+    // This one fires on all open stages
+    if (preventInteraction) {
+      return;
+    }
+    const { key, ctrlKey, metaKey } = event;
+    if (
+      (key === "=" || key === "+" || key === "-" || key === "_") &&
+      !ctrlKey &&
+      !metaKey
+    ) {
+      const pixelY = key === "=" || key === "+" ? -100 : 100;
+      const newScale = Math.min(
+        Math.max(
+          stageScale +
+            (pixelY * wheelZoomSpeed * stageScale) / window.innerHeight,
+          minZoom
+        ),
+        maxZoom
+      );
+
+      // Center on pointer
+      const pointer = { x: window.innerWidth / 2, y: window.innerHeight / 2 };
+      const newTranslate = {
+        x: pointer.x - ((pointer.x - stage.x()) / stageScale) * newScale,
+        y: pointer.y - ((pointer.y - stage.y()) / stageScale) * newScale,
+      };
+
+      stage.position(newTranslate);
+      stageTranslateRef.current = newTranslate;
+
+      onStageScaleChange(newScale);
+    }
+  }
+
+  useKeyboard(handleKeyDown);
 }
 
 export default useStageInteraction;