如何在 canvas 元素內的另一個圖像上方居中圖像

Question

我正在嘗試在 canvas 元素中的另一個圖像上方添加圖像

我想要達到的目標：

這是我得到的：

圖片來源： https://imgur.com/gallery/jaSdhQ9

這是我的代碼：

 var shirt = new Image(); shirt.src = "https://i.imgur.com/3rTZGXP.png"; var draw = new Image(); draw.src = "https://i.imgur.com/2abnbj1.png"; //draw.src = "https://i.imgur.com/TSJRGjo.png"; window.onload = function() { var canvas = document.getElementById("canvas"); var ctx = canvas.getContext("2d"); ctx.fillStyle = "blue"; ctx.fillRect(0, 0, canvas.width, canvas.height); ctx.drawImage(draw,0,0 ); ctx.drawImage(shirt,0,0,canvas.width,canvas.height); }

 #canvas{ width: 352px; height: 448px; left: 0px; top: 0px; user-select: none; cursor: default; }

 <canvas id="canvas" width="352" height="448"></canvas>

Answer 1

你可以像 ctx.drawImage(draw,100,30,90,50);

 var shirt = new Image(); shirt.src = "https://i.imgur.com/3rTZGXP.png"; var draw = new Image(); draw.src = "https://i.imgur.com/2abnbj1.png"; //draw.src = "https://i.imgur.com/TSJRGjo.png"; window.onload = function() { var canvas = document.getElementById("canvas"); var ctx = canvas.getContext("2d"); ctx.fillStyle = "blue"; ctx.fillRect(0, 0, canvas.width, canvas.height); ctx.drawImage(draw,80,25,135,55 ); ctx.drawImage(shirt,0,0,canvas.width,canvas.height); }

 #canvas{ width: 352px; height: 448px; left: 0px; top: 0px; user-select: none; cursor: default; }

 <canvas id="canvas"></canvas>

Answer 2

我認為您正在尋找的是flex-box

#canvas{
  display:flex;
  justify-content: center;
  align-content: center;
}

在這里你可以閱讀更多關於flex-box

Answer 3

感謝@tokage-dizayn 和https://stackoverflow.com/a/19473880/7511165

我來到這個代碼

 var shirt = new Image(); shirt.src = "https://i.imgur.com/3rTZGXP.png"; var draw = new Image(); draw.src = "https://i.imgur.com/2abnbj1.png"; //draw.src = "https://i.imgur.com/TSJRGjo.png"; window.onload = function() { var canvas = document.getElementById("canvas"); var ctx = canvas.getContext("2d"); ctx.fillStyle = "blue"; ctx.fillRect(0, 0, canvas.width, canvas.height); console.log(draw.height,draw.width); var maxSize = 160; var ratio = Math.min(maxSize / draw.width, maxSize / draw.height); var width= draw.width*ratio, height= draw.height*ratio; console.log(ratio,width,height); ctx.drawImage(draw,95,90,width,height); ctx.drawImage(shirt,0,0,canvas.width,canvas.height); }

 #canvas{ width: 352px; height: 448px; left: 0px; top: 0px; user-select: none; cursor: default; }

 <canvas id="canvas" width="352" height="448"></canvas>