Javascript 将多个梯形合并为一个形状
我正在做一个项目,用户可以通过添加多个梯形来绘制形状。现在看起来是这样的: 但我喜欢的是删除/隐藏形状内的线条,使其成为单个形状: 这些形状是用3个点{bsup;binf;h;}创建的,它们表示顶线的长度、底线的长度和形状的高度Javascript 将多个梯形合并为一个形状,javascript,reactjs,canvas,html5-canvas,Javascript,Reactjs,Canvas,Html5 Canvas,我正在做一个项目,用户可以通过添加多个梯形来绘制形状。现在看起来是这样的: 但我喜欢的是删除/隐藏形状内的线条,使其成为单个形状: 这些形状是用3个点{bsup;binf;h;}创建的,它们表示顶线的长度、底线的长度和形状的高度 export const drawPolygonComplex = (ctx, values, inputValues, distanceUnits, displayCote = true) => { const hCumul = calcHeigh
export const drawPolygonComplex = (ctx, values, inputValues,
distanceUnits, displayCote = true) => {
const hCumul = calcHeight(values);
const middleX = ctx.canvas.width / 2;
const middleY = ctx.canvas.height / 2;
const startY = middleY - hCumul / 2;
let nbPiece = 0;
let currentY = startY;
if (inputValues.length) {
let cotes = [];
for (let key in values) {
//#region attribution des valeurs pour placer les cotes
let intKey = parseInt(key);
let upperLongestValue = values[intKey].b_sup;
let lowerLongestValue = values[intKey].b_inf;
if (values.length > 1) {
if (intKey == 0) {
if (values[intKey + 1].b_sup) {
lowerLongestValue =
values[intKey].b_inf > values[intKey + 1].b_sup
? values[intKey].b_inf
: values[intKey + 1].b_sup;
}
} else if (intKey == values.length - 1) {
upperLongestValue =
values[intKey].b_sup > values[intKey - 1].b_inf
? values[intKey].b_sup
: values[intKey - 1].b_inf;
} else {
lowerLongestValue =
values[intKey].b_inf > values[intKey + 1].b_sup
? values[intKey].b_inf
: values[intKey + 1].b_sup;
upperLongestValue =
values[intKey].b_sup > values[intKey - 1].b_inf
? values[intKey].b_sup
: values[intKey - 1].b_inf;
}
}
let coteUpLeft = { x: middleX - upperLongestValue / 2, y: currentY };
let coteUpRight = { x: middleX + upperLongestValue / 2, y: currentY };
let coteDownLeft = { x: middleX - lowerLongestValue / 2, y: currentY + values[key].h };
let coteDownRight = { x: middleX + lowerLongestValue / 2, y: currentY + values[key].h };
//#endregion
//Définir les coins
let upLeft = { x: middleX - values[key].b_sup / 2, y: currentY };
let upRight = { x: middleX + values[key].b_sup / 2, y: currentY };
let downLeft = { x: middleX - values[key].b_inf / 2, y: currentY + values[key].h };
let downRight = { x: middleX + values[key].b_inf / 2, y: currentY + values[key].h };
//Dessiner la shape
ctx.lineWidth = 2;
ctx.strokeStyle = 'black';
ctx.fillStyle = ctx.createPattern(HatchPattern(), 'repeat');
ctx.beginPath();
ctx.moveTo(upLeft.x, upLeft.y);
ctx.lineTo(upRight.x, upRight.y);
ctx.lineTo(downRight.x, downRight.y);
ctx.lineTo(downLeft.x, downLeft.y);
ctx.lineTo(upLeft.x, upLeft.y);
ctx.closePath();
ctx.fill();
ctx.stroke();
if (displayCote) {
//Placer les cotes
if (nbPiece % 2 == 0) {
cotes[intKey + 1] = drawRightCote(
ctx,
coteUpRight.x,
coteDownRight.x,
coteUpRight.y,
coteDownRight.y,
distanceUnits,
inputValues[key].h,
1
);
} else {
cotes[intKey + 1] = drawLeftCote(
ctx,
coteUpLeft.x,
coteDownLeft.x,
coteUpLeft.y,
coteDownLeft.y,
distanceUnits,
inputValues[key].h,
1
);
}
}
//Calcul des variables
currentY += values[key].h;
nbPiece++;
if (displayCote) {
//Cote du haut et du bas
if (intKey == 0) {
cotes[0] = drawUpperCote(
ctx,
coteUpLeft.x,
coteUpRight.x,
startY,
distanceUnits,
inputValues[key].b_sup,
1
);
}
if (intKey == values.length - 1) {
cotes[values.length + 1] = drawLowerCote(
ctx,
coteDownLeft.x,
coteDownRight.x,
currentY,
distanceUnits,
inputValues[key].b_inf,
1
);
//Cote hauteur
drawLeftCote(
ctx,
middleX - values[0].b_sup / 2,
coteDownLeft.x,
startY,
currentY,
distanceUnits,
calcHeight(inputValues),
2
);
}
}
}
return cotes;
}
}; 您可以找到一种方法来跟踪连接点,然后清除它们。首先,您需要确定形状连接在一起的位置
const draw梯形=(ctx、x、y、宽度、高度、缩进=0)=>{
ctx.beginPath();
ctx.移动到(x+缩进,y);
ctx.lineTo(x-缩进+宽度,y);
ctx.lineTo(x+宽度,y+高度);
ctx.lineTo(x,y+高度);
ctx.closePath();
ctx.stroke();
}
const ctx=document.querySelector('#drawing').getContext('2d');
赋值(ctx.canvas,{宽度:300,高度:300});
常数
x=20,y=20,
高度=160,宽度=60,
厚度=6;
ctx.线宽=厚度;
ctx.strokeStyle='绿色';
牵引梯形(ctx,x,y,宽度,20,-10);
ctx.冲程(x,y+20,宽度,高度-40);
牵引梯形(ctx,x-10,y+高度-20,宽度+20,20,10);
常数thickHalf=厚度/2;
ctx.fillStyle='红色';
ctx.fillRect(x+thickHalf,y-thickHalf+20,宽度-厚度,厚度);
ctx.fillRect(x+thickHalf,y-thickHalf+height-20,width-thickHalf,thickness)代码>
您必须在另一个画布上绘制所有形状(带有轮廓)。然后擦除形状相交的线条。最后,从画布上抓取绘图数据,并将其写入主画布。如何找到线条的相交处?