Fixes disappearing canvas grid lines

frontend/src/features/canvas/IAICanvasGrid.tsx

@@ -1,88 +1,119 @@
 // Grid drawing adapted from https://longviewcoder.com/2021/12/08/konva-a-better-grid/
 
 import { useColorMode } from '@chakra-ui/react';
+import { createSelector } from '@reduxjs/toolkit';
+import { useAppSelector } from 'app/store';
 import _ from 'lodash';
+import {
+  ReactNode,
+  useCallback,
+  useEffect,
+  useLayoutEffect,
+  useState,
+} from 'react';
 import { Group, Line as KonvaLine } from 'react-konva';
+import { currentCanvasSelector } from './canvasSlice';
 import useUnscaleCanvasValue from './hooks/useUnscaleCanvasValue';
 import { stageRef } from './IAICanvas';
 
+const selector = createSelector(
+  [currentCanvasSelector],
+  (currentCanvas) => {
+    const { stageScale, stageCoordinates, stageDimensions } = currentCanvas;
+    return { stageScale, stageCoordinates, stageDimensions };
+  },
+  {
+    memoizeOptions: {
+      resultEqualityCheck: _.isEqual,
+    },
+  }
+);
+
 const IAICanvasGrid = () => {
   const { colorMode } = useColorMode();
-  const unscale = useUnscaleCanvasValue();
+  // const unscale = useUnscaleCanvasValue();
+  const { stageScale, stageCoordinates, stageDimensions } =
+    useAppSelector(selector);
+  const [gridLines, setGridLines] = useState<ReactNode[]>([]);
 
-  if (!stageRef.current) return null;
-  const gridLineColor =
-    colorMode === 'light' ? 'rgba(0,0,0,0.3)' : 'rgba(255,255,255,0.3)';
-
-  const stage = stageRef.current;
-  const width = stage.width();
-  const height = stage.height();
-  const x = stage.x();
-  const y = stage.y();
-
-  const stageRect = {
-    x1: 0,
-    y1: 0,
-    x2: width,
-    y2: height,
-    offset: {
-      x: unscale(x),
-      y: unscale(y),
+  const unscale = useCallback(
+    (value: number) => {
+      return value / stageScale;
     },
-  };
-
-  const gridOffset = {
-    x: Math.ceil(unscale(x) / 64) * 64,
-    y: Math.ceil(unscale(y) / 64) * 64,
-  };
-
-  const gridRect = {
-    x1: -gridOffset.x,
-    y1: -gridOffset.y,
-    x2: unscale(width) - gridOffset.x + 64,
-    y2: unscale(height) - gridOffset.y + 64,
-  };
-
-  const gridFullRect = {
-    x1: Math.min(stageRect.x1, gridRect.x1),
-    y1: Math.min(stageRect.y1, gridRect.y1),
-    x2: Math.max(stageRect.x2, gridRect.x2),
-    y2: Math.max(stageRect.y2, gridRect.y2),
-  };
-
-  const fullRect = gridFullRect;
-
-  const // find the x & y size of the grid
-    xSize = fullRect.x2 - fullRect.x1,
-    ySize = fullRect.y2 - fullRect.y1,
-    // compute the number of steps required on each axis.
-    xSteps = Math.round(xSize / 64) + 1,
-    ySteps = Math.round(ySize / 64) + 1;
-
-  return (
-    <Group>
-      {_.range(0, xSteps).map((i) => (
-        <KonvaLine
-          key={`x_${i}`}
-          x={fullRect.x1 + i * 64}
-          y={fullRect.y1}
-          points={[0, 0, 0, ySize]}
-          stroke={gridLineColor}
-          strokeWidth={1}
-        />
-      ))}
-      {_.range(0, ySteps).map((i) => (
-        <KonvaLine
-          key={`y_${i}`}
-          x={fullRect.x1}
-          y={fullRect.y1 + i * 64}
-          points={[0, 0, xSize, 0]}
-          stroke={gridLineColor}
-          strokeWidth={1}
-        />
-      ))}
-    </Group>
+    [stageScale]
   );
+
+  useLayoutEffect(() => {
+    const gridLineColor =
+      colorMode === 'light' ? 'rgba(136, 136, 136, 1)' : 'rgba(84, 84, 84, 1)';
+
+    const { width, height } = stageDimensions;
+    const { x, y } = stageCoordinates;
+
+    const stageRect = {
+      x1: 0,
+      y1: 0,
+      x2: width,
+      y2: height,
+      offset: {
+        x: unscale(x),
+        y: unscale(y),
+      },
+    };
+
+    const gridOffset = {
+      x: Math.ceil(unscale(x) / 64) * 64,
+      y: Math.ceil(unscale(y) / 64) * 64,
+    };
+
+    const gridRect = {
+      x1: -gridOffset.x,
+      y1: -gridOffset.y,
+      x2: unscale(width) - gridOffset.x + 64,
+      y2: unscale(height) - gridOffset.y + 64,
+    };
+
+    const gridFullRect = {
+      x1: Math.min(stageRect.x1, gridRect.x1),
+      y1: Math.min(stageRect.y1, gridRect.y1),
+      x2: Math.max(stageRect.x2, gridRect.x2),
+      y2: Math.max(stageRect.y2, gridRect.y2),
+    };
+
+    const fullRect = gridFullRect;
+
+    const // find the x & y size of the grid
+      xSize = fullRect.x2 - fullRect.x1,
+      ySize = fullRect.y2 - fullRect.y1,
+      // compute the number of steps required on each axis.
+      xSteps = Math.round(xSize / 64) + 1,
+      ySteps = Math.round(ySize / 64) + 1;
+
+    const xLines = _.range(0, xSteps).map((i) => (
+      <KonvaLine
+        key={`x_${i}`}
+        x={fullRect.x1 + i * 64}
+        y={fullRect.y1}
+        points={[0, 0, 0, ySize]}
+        stroke={gridLineColor}
+        strokeWidth={1}
+      />
+    ));
+    const yLines = _.range(0, ySteps).map((i) => (
+      <KonvaLine
+        key={`y_${i}`}
+        x={fullRect.x1}
+        y={fullRect.y1 + i * 64}
+        points={[0, 0, xSize, 0]}
+        stroke={gridLineColor}
+        strokeWidth={1}
+      />
+    ));
+
+    setGridLines(xLines.concat(yLines));
+  }, [stageScale, stageCoordinates, stageDimensions, colorMode, unscale]);
+
+  return <Group>{gridLines}</Group>;
 };
 
 export default IAICanvasGrid;