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import { useCallback, useEffect, useRef } from "react";
const primaryLineColor = "rgb(203,213,245)";
const subLineColor = "rgb(226,231,232)";
export default function GridLayer(props: {
width: number;
height: number;
leftPadding: number;
rightPadding: number;
topPadding: number;
bottomPadding: number;
columns: number;
rows: number;
colCellNum: number;
rowCellNum: number;
}) {
const xStartPx = props.leftPadding;
const xEndPx = props.width - props.rightPadding;
const xStepPx = (props.width - props.leftPadding - props.rightPadding) / props.columns;
const xUnitPx = xStepPx / props.colCellNum;
const yStartPx = props.topPadding;
const yEndPx = props.height - props.bottomPadding;
const yStepPx = (props.height - props.topPadding - props.bottomPadding) / props.rows;
const yUnitPx = yStepPx / props.rowCellNum;
const canvasRef = useRef<HTMLCanvasElement | null>(null);
const drawGrid = useCallback(
(ctx: CanvasRenderingContext2D) => {
ctx.beginPath();
ctx.strokeStyle = subLineColor;
for (let i = 1; i < props.columns * props.colCellNum; ++i) {
if (i % props.colCellNum === 0) continue;
ctx.moveTo(xStartPx + xUnitPx * i, yStartPx);
ctx.lineTo(xStartPx + xUnitPx * i, yEndPx);
}
for (let j = 1; j < props.rows * props.rowCellNum; ++j) {
if (j % props.rowCellNum === 0) continue;
ctx.moveTo(xStartPx, yStartPx + yUnitPx * j);
ctx.lineTo(xEndPx, yStartPx + yUnitPx * j);
}
ctx.stroke();
ctx.beginPath();
ctx.strokeStyle = primaryLineColor;
for (let i = 0; i <= props.columns; ++i) {
ctx.moveTo(xStartPx + xStepPx * i, yStartPx);
ctx.lineTo(xStartPx + xStepPx * i, yEndPx);
}
for (let j = 0; j <= props.rows; ++j) {
ctx.moveTo(xStartPx, yStartPx + yStepPx * j);
ctx.lineTo(xEndPx, yStartPx + yStepPx * j);
}
ctx.stroke();
},
[
props.colCellNum,
props.columns,
props.rowCellNum,
props.rows,
xEndPx,
xStartPx,
xStepPx,
xUnitPx,
yEndPx,
yStartPx,
yStepPx,
yUnitPx,
]
);
useEffect(() => {
// 获取canvas的2D绘图上下文
const canvas = canvasRef.current;
if (!canvas) return;
const context = canvas.getContext("2d");
if (!context) return;
// 使用context对象进行绘图
drawGrid(context);
}, [drawGrid]);
return (
<div>
<canvas ref={canvasRef} width={props.width} height={props.height}></canvas>
</div>
);
}