arcTo畫邊框圓角
阿新 • • 發佈：2018-12-15
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <!-- <meta name="viewport" content="width=device-width, initial-scale=1.0"> --> <!-- <meta http-equiv="X-UA-Compatible" content="ie=edge"> --> <title>arcTo繪製圓角</title> <style> #canvas{ display: block; margin: 0 auto; border: 1px solid #666; } </style> </head> <body> <canvas id="canvas" width="600" height="400"></canvas> </body> <script> var myCanvas = document.getElementById("canvas"); var ctx = myCanvas.getContext("2d"); function toRad(d) { return d * Math.PI / 180; } function circleRect(x,y,width,height,r,color) { // 儲存之前的繪圖狀態 ctx.save(); ctx.beginPath(); // 繪製四條邊 ctx.moveTo(x + r, y); ctx.lineTo(x + width - r, y); ctx.moveTo(x + r, y + height); ctx.lineTo(x + width - r, y + height); ctx.moveTo(x, y + r); ctx.lineTo(x, y + height - r); ctx.moveTo(x + width, y + r); ctx.lineTo(x + width, y + height - r); ctx.moveTo(x + r, y); ctx.arcTo(x, y, x, y + r, r); ctx.moveTo(x + width - r, y); ctx.arcTo(x + width, y, x + width, y + r, r); ctx.moveTo(x, y + height - r); ctx.arcTo(x, y + height, x + r, y + height, r); ctx.moveTo(x + width - r, y + height); ctx.arcTo(x + width, y + height, x + width, y + height - r, r); // 傳入顏色，則使用傳入的顏色，否則預設是黑色 ctx.strokeStyle = color || '#000'; ctx.stroke(); // 恢復之前的繪圖狀態 ctx.restore(); } circleRect(100,100,200,200,50,"red") </script> </html>