Added undershoot grid cells to hex grid

src/components/Grid.js

@@ -2,7 +2,12 @@ import React from "react";
 import { Line, Group, RegularPolygon } from "react-konva";
 
 import { getStrokeWidth } from "../helpers/drawing";
-import { getCellSize, getCellLocation, shouldClampCell } from "../helpers/grid";
+import {
+  getCellSize,
+  getCellLocation,
+  gridClipFunction,
+  shouldClipCell,
+} from "../helpers/grid";
 
 function Grid({ grid, strokeWidth, width, height, stroke }) {
   if (!grid?.size.x || !grid?.size.y) {
@@ -62,30 +67,16 @@ function Grid({ grid, strokeWidth, width, height, stroke }) {
       );
     }
   } else if (grid.type === "hexVertical" || grid.type === "hexHorizontal") {
-    for (let x = 0; x < grid.size.x; x++) {
-      for (let y = 0; y < grid.size.y; y++) {
+    // Start at -1 to overshoot the bounds of the grid to ensure all lines are drawn
+    for (let x = -1; x < grid.size.x; x++) {
+      for (let y = -1; y < grid.size.y; y++) {
         const cellLocation = getCellLocation(grid, x, y, cellSize);
-
-        // If our hex shape will go past the bounds of the grid
-        const overshot = shouldClampCell(grid, x, y);
         shapes.push(
           <Group
             key={`grid_${x}_${y}`}
-            // Clip the hex if it will overshoot
             clipFunc={
-              overshot &&
-              ((context) => {
-                context.rect(
-                  -cellSize.radius,
-                  -cellSize.radius,
-                  grid.type === "hexVertical"
-                    ? cellSize.radius
-                    : cellSize.radius * 2,
-                  grid.type === "hexVertical"
-                    ? cellSize.radius * 2
-                    : cellSize.radius
-                );
-              })
+              shouldClipCell(grid, x, y) &&
+              ((context) => gridClipFunction(context, grid, x, y, cellSize))
             }
             x={cellLocation.x}
             y={cellLocation.y}

src/helpers/grid.js

@@ -93,7 +93,10 @@ export function getCellLocation(grid, x, y, cellSize) {
  * @param {number} y Y-axis location of the cell
  * @returns {boolean}
  */
-export function shouldClampCell(grid, x, y) {
+export function shouldClipCell(grid, x, y) {
+  if (x < 0 || y < 0) {
+    return true;
+  }
   switch (grid.type) {
     case "square":
       return false;
@@ -106,6 +109,32 @@ export function shouldClampCell(grid, x, y) {
   }
 }
 
+/**
+ * Canvas clip function for culling hex cells that overshoot/undershoot the grid
+ * @param {CanvasRenderingContext2D} context
+ * @param {Grid} grid
+ * @param {number} x
+ * @param {number} y
+ * @param {CellSize} cellSize
+ */
+export function gridClipFunction(context, grid, x, y, cellSize) {
+  // Clip the undershooting cells unless they are needed to fill out a specific grid type
+  if ((x < 0 && grid.type !== "hexVertical") || (x < 0 && y % 2 === 0)) {
+    return;
+  }
+  if ((y < 0 && grid.type !== "hexHorizontal") || (y < 0 && x % 2 === 0)) {
+    return;
+  }
+  context.rect(
+    x < 0 ? 0 : -cellSize.radius,
+    y < 0 ? 0 : -cellSize.radius,
+    x > 0 && grid.type === "hexVertical"
+      ? cellSize.radius
+      : cellSize.radius * 2,
+    y > 0 && grid.type === "hexVertical" ? cellSize.radius * 2 : cellSize.radius
+  );
+}
+
 /**
  * Get the height of a grid based off of its width
  * @param {Grid} grid