better grid colors

src/components/grid/grid.tsx

@@ -1,5 +1,13 @@
 import { useMouse, useWindowSize } from '@uidotdev/usehooks';
-import { FC, MouseEvent, useCallback, useMemo, useState } from 'react';
+import {
+    FC,
+    KeyboardEvent,
+    MouseEvent,
+    useCallback,
+    useEffect,
+    useMemo,
+    useState,
+} from 'react';
 
 import './grid.scss';
 
@@ -17,6 +25,14 @@ interface Range {
     y1: number;
 }
 
+interface Line {
+    x0: number;
+    y0: number;
+    x1: number;
+    y1: number;
+    stroke: string;
+}
+
 function pointsToRange(p0: Point, p1: Point): Range {
     return { x0: p0.x, y0: p0.y, x1: p1.x, y1: p1.y };
 }
@@ -48,31 +64,128 @@ function useMouseInRange(range: Range): Point {
     return { x: mouse.x + range.x0, y: mouse.y + range.y0 };
 }
 
+function useKeyPress(
+    callback: (event: KeyboardEvent) => void,
+    key: string,
+    ctrlKey: boolean = false
+) {
+    useEffect(() => {
+        const listener = (eventRaw: Event) => {
+            const event = eventRaw as any as KeyboardEvent;
+            if (event.key == key && event.ctrlKey == ctrlKey) {
+                callback(event);
+            }
+        };
+        window.addEventListener('keypress', listener);
+        return () => {
+            window.removeEventListener('keypress', listener);
+        };
+    }, [callback, key, ctrlKey]);
+}
+
+const THICK_COLOR = '#123456';
+const THIN_COLOR = '#0d1c2b';
+
 const Grid: FC = () => {
     const GAP = 20;
 
-    // const [offset, setOffset] = useState<Point>({ x: GAP / 2, y: GAP / 2 });
+    const [offset, setOffset] = useState<Point>({ x: GAP * 2, y: GAP * 2 });
-    const [offset, setOffset] = useState<Point>({ x: 10, y: 10 });
     const range = useRange(offset);
     const mousePoint = useMouseInRange(range);
 
     const gridLines = useMemo(() => {
-        const lines = [];
+        const lines_thin: Line[] = [];
+        const lines_thick: Line[] = [];
         const start = snapToGrid({ x: range.x0, y: range.y0 }, GAP);
         const end = snapToGrid({ x: range.x1, y: range.y1 }, GAP);
         for (let x = start.x; x <= end.x; x += GAP) {
-            lines.push({ ...range, x0: x, x1: x });
+            const thick = x % (GAP * 4) == 0;
+            const lines = thick ? lines_thick : lines_thin;
+            lines.push({
+                ...range,
+                x0: x,
+                x1: x,
+                stroke: thick ? THICK_COLOR : THIN_COLOR,
+            });
         }
         for (let y = start.y; y <= end.y; y += GAP) {
-            lines.push({ ...range, y0: y, y1: y });
+            const thick = y % (GAP * 4) == 0;
+            const lines = thick ? lines_thick : lines_thin;
+            lines.push({
+                ...range,
+                y0: y,
+                y1: y,
+                stroke: thick ? THICK_COLOR : THIN_COLOR,
+            });
         }
 
-        return lines;
+        return lines_thin.concat(lines_thick);
     }, [range, GAP]);
 
     const [userLines, setUserLines] = useState<Range[]>([]);
+    const [userRedoLines, setUserRedoLines] = useState<Range[]>([]);
     const [userStartPoint, setUserStartPoint] = useState<Point | null>(null);
 
+    // mouse clicks create lines
+    const onGridClick = useCallback(
+        (event: MouseEvent<SVGSVGElement>) => {
+            // right-click to unset the start point
+            if (event.button === 2) {
+                setUserStartPoint(null);
+                return;
+            }
+
+            const point = snapToGrid(mousePoint, GAP);
+
+            setUserRedoLines([]);
+
+            if (lodash.isEqual(userStartPoint, point)) return;
+            if (lodash.isNull(userStartPoint)) {
+                setUserStartPoint(point);
+                return;
+            }
+
+            const line = pointsToRange(userStartPoint, point);
+            setUserLines([...userLines, line]);
+
+            if (event.shiftKey == false) {
+                setUserStartPoint(null);
+            } else {
+                setUserStartPoint(point);
+            }
+        },
+        [userStartPoint, setUserStartPoint, setUserLines, GAP, mousePoint]
+    );
+
+    const onGridContextMenu = useCallback(
+        (event: MouseEvent<SVGSVGElement>) => {
+            event.preventDefault(); // disable default context menu
+        },
+        [setUserStartPoint]
+    );
+
+    // ctrl+z/ctrl+y for undo/redo
+    const onUndo = useCallback(() => {
+        console.log('onUndo', userLines);
+        const line = userLines.at(-1);
+        if (!line) return;
+
+        setUserLines(userLines.slice(0, -1));
+        setUserRedoLines([...userRedoLines, line]);
+    }, [userLines, setUserLines, userRedoLines, setUserRedoLines]);
+
+    const onRedo = useCallback(() => {
+        console.log('onRedo', userRedoLines);
+        const line = userRedoLines.at(-1);
+        if (!line) return;
+
+        setUserRedoLines(userRedoLines.slice(0, -1));
+        setUserLines([...userLines, line]);
+    }, [userLines, setUserLines, userRedoLines, setUserRedoLines]);
+
+    useKeyPress(onUndo, 'z', true);
+    useKeyPress(onRedo, 'y', true);
+
     const gridLineElements = useMemo(() => {
         return gridLines.map((line, idx) => (
             <line
@@ -82,8 +195,8 @@ const Grid: FC = () => {
                 y1={line.y0}
                 x2={line.x1}
                 y2={line.y1}
-                stroke="#123456"
+                stroke={line.stroke}
-                strokeWidth="2"
+                strokeWidth={2}
             />
         ));
     }, [gridLines]);
@@ -130,28 +243,6 @@ const Grid: FC = () => {
         ));
     }, [userLines]);
 
-    const onGridClick = useCallback(
-        (event: MouseEvent<SVGSVGElement>) => {
-            const point = snapToGrid(mousePoint, GAP);
-
-            if (lodash.isEqual(userStartPoint, point)) return;
-            if (lodash.isNull(userStartPoint)) {
-                setUserStartPoint(point);
-                return;
-            }
-
-            const line = pointsToRange(userStartPoint, point);
-            setUserLines([...userLines, line]);
-
-            if (event.shiftKey == false) {
-                setUserStartPoint(null);
-            } else {
-                setUserStartPoint(point);
-            }
-        },
-        [userStartPoint, setUserStartPoint, setUserLines, GAP, mousePoint]
-    );
-
     return (
         <svg
             className="grid"
@@ -159,20 +250,15 @@ const Grid: FC = () => {
             viewBox={`${range.x0} ${range.y0} ${range.x1 - range.x0} ${
                 range.y1 - range.y0
             }`}
-            onClick={onGridClick}
+            onMouseDown={onGridClick}
+            onContextMenu={onGridContextMenu}
+            // tabIndex={0}
+            // onKeyDown={onGridKeyDown}
         >
             {gridLineElements}
             {userLineElements}
             {userLineIndicatorElement}
             {userPointIndicatorElement}
-            <text
-                x={range.x0 + 20}
-                y={range.y0 + 60} // of baseline
-                fill="#ffffff"
-                fontSize="40px"
-            >
-                GRID
-            </text>
         </svg>
     );
 };