From 91c7c9f9ada2cf24b9fa2f2da2a1f852f24d926f Mon Sep 17 00:00:00 2001
From: Mitchell McCaffrey <mitchemmc@gmail.com>
Date: Fri, 20 Mar 2020 21:46:52 +1100
Subject: [PATCH] Added pan and zoom to map

---
 src/components/Map.js   | 132 +++++++++++++++++++++++++++-------------
 src/components/Token.js |   9 ++-
 2 files changed, 99 insertions(+), 42 deletions(-)

diff --git a/src/components/Map.js b/src/components/Map.js
index a78376b..30add5f 100644
--- a/src/components/Map.js
+++ b/src/components/Map.js
@@ -1,5 +1,6 @@
-import React, { useRef } from "react";
+import React, { useRef, useEffect, useState } from "react";
 import { Box, Image } from "theme-ui";
+import interact from "interactjs";
 
 import Token from "../components/Token";
 import ProxyToken from "../components/ProxyToken";
@@ -7,6 +8,9 @@ import AddMapButton from "../components/AddMapButton";
 
 const mapTokenClassName = "map-token";
 const defaultTokenSize = 48;
+const zoomSpeed = -0.005;
+const minZoom = 0.1;
+const maxZoom = 5;
 
 function Map({
   mapSource,
@@ -26,6 +30,36 @@ function Map({
     }
   }
 
+  const [mapTranslate, setMapTranslate] = useState({ x: 0, y: 0 });
+  const [mapScale, setMapScale] = useState(1);
+
+  useEffect(() => {
+    interact(".map").draggable({
+      inertia: true,
+      listeners: {
+        move: event => {
+          setMapTranslate(previousMapTranslate => ({
+            x: previousMapTranslate.x + event.dx,
+            y: previousMapTranslate.y + event.dy
+          }));
+        }
+      }
+    });
+    interact(".map").on("doubletap", event => {
+      event.preventDefault();
+      setMapTranslate({ x: 0, y: 0 });
+      setMapScale(1);
+    });
+  }, []);
+
+  function handleZoom(event) {
+    event.preventDefault();
+    const deltaY = event.deltaY * zoomSpeed;
+    setMapScale(mapScale =>
+      Math.max(Math.min(mapScale + deltaY, maxZoom), minZoom)
+    );
+  }
+
   const mapRef = useRef(null);
   const rows = mapData && mapData.rows;
   const tokenSizePercent = (1 / rows) * 100;
@@ -42,58 +76,74 @@ function Map({
           backgroundColor: "rgba(0, 0, 0, 0.1)"
         }}
         bg="background"
+        onWheel={handleZoom}
       >
         <Box
           sx={{
             position: "relative",
-            overflow: "hidden",
             top: "50%",
             left: "50%",
             transform: "translate(-50%, -50%)"
           }}
         >
           <Box
-            sx={{
-              width: "100%",
-              height: 0,
-              paddingBottom: `${(1 / aspectRatio) * 100}%`
-            }}
-          />
-
-          <Box
-            sx={{ position: "absolute", top: 0, right: 0, bottom: 0, left: 0 }}
-          >
-            <Image ref={mapRef} id="map" src={mapSource} />
-          </Box>
-          <Box
-            sx={{
-              position: "absolute",
-              top: 0,
-              left: 0,
-              right: 0,
-              bottom: 0
+            style={{
+              transform: `translate(${mapTranslate.x}px, ${mapTranslate.y}px) scale(${mapScale})`
             }}
           >
-            {Object.values(tokens).map(token => (
-              <Box
-                key={token.id}
-                style={{
-                  left: `${token.x * 100}%`,
-                  top: `${token.y * 100}%`,
-                  width: `${tokenSizePercent}%`
-                }}
-                sx={{
-                  position: "absolute",
-                  display: "flex"
-                }}
-              >
-                <Token
-                  tokenId={token.id}
-                  image={token.image}
-                  className={mapTokenClassName}
-                />
-              </Box>
-            ))}
+            <Box
+              sx={{
+                width: "100%",
+                height: 0,
+                paddingBottom: `${(1 / aspectRatio) * 100}%`
+              }}
+            />
+            <Box
+              sx={{
+                position: "absolute",
+                top: 0,
+                right: 0,
+                bottom: 0,
+                left: 0
+              }}
+            >
+              <Image
+                ref={mapRef}
+                id="map"
+                sx={{ width: "100%" }}
+                src={mapSource}
+              />
+            </Box>
+            <Box
+              sx={{
+                position: "absolute",
+                top: 0,
+                left: 0,
+                right: 0,
+                bottom: 0
+              }}
+            >
+              {Object.values(tokens).map(token => (
+                <Box
+                  key={token.id}
+                  style={{
+                    left: `${token.x * 100}%`,
+                    top: `${token.y * 100}%`,
+                    width: `${tokenSizePercent}%`
+                  }}
+                  sx={{
+                    position: "absolute",
+                    display: "flex"
+                  }}
+                >
+                  <Token
+                    tokenId={token.id}
+                    image={token.image}
+                    className={mapTokenClassName}
+                  />
+                </Box>
+              ))}
+            </Box>
           </Box>
         </Box>
         <Box
diff --git a/src/components/Token.js b/src/components/Token.js
index 6b74f37..09f9708 100644
--- a/src/components/Token.js
+++ b/src/components/Token.js
@@ -4,7 +4,14 @@ import { Image } from "theme-ui";
 function Token({ image, className, tokenId }) {
   // Store the token id in the html element for the drag code to pick it up
   const idProp = tokenId ? { "data-token-id": tokenId } : {};
-  return <Image className={className} src={image} {...idProp} />;
+  return (
+    <Image
+      className={className}
+      sx={{ userSelect: "none" }}
+      src={image}
+      {...idProp}
+    />
+  );
 }
 
 export default Token;