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October 8, 2018 15:50
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(() => { | |
const stretch = true; | |
const drawLocalImage = imgData => { | |
var canvas = document.querySelector('.drawing-board-canvas') | |
var ctx = canvas.getContext('2d') | |
var image = new Image(); | |
var size = Math.min(canvas.width, canvas.height); | |
image.onload = function () { | |
ctx.clearRect(0, 0, canvas.width, canvas.height); | |
if (stretch) | |
ctx.drawImage(this, 0, 0, canvas.width, canvas.height); | |
else | |
ctx.drawImage(this, (canvas.width - size) / 2, (canvas.height - size) / 2, size, size); | |
} | |
image.src = imgData; | |
}; | |
const drawFromURL = () => { | |
var req = new XMLHttpRequest(); | |
req.onload = function () { | |
drawLocalImage(btoa(req.response)); | |
} | |
req.open("GET", "https://github.com/hmage.png"); | |
req.responseType = "arraybuffer"; | |
req.send(); | |
}; | |
const drawFromLocalFile = path => { | |
var reader = new FileReader(); | |
reader.addEventListener("load", function () { | |
drawLocalImage(this.result); | |
}, false); | |
reader.readAsDataURL(path); | |
}; | |
(() => { | |
var body = document.querySelector("body"); | |
var fileSelector = document.createElement("input"); | |
fileSelector.type = "file"; | |
var drawButton = document.createElement("input"); | |
drawButton.type = "button"; | |
drawButton.value = "描画する"; | |
drawButton.onclick = () => drawFromLocalFile(fileSelector.files[0]); | |
var box = document.createElement("div"); | |
box.appendChild(fileSelector); | |
box.appendChild(drawButton); | |
body.appendChild(box); | |
})(); | |
})(); |
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