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const createImage = url =>
new Promise((resolve, reject) => {
const image = new Image();
image.addEventListener('load', () => resolve(image));
image.addEventListener('error', error => reject(error));
image.setAttribute('crossOrigin', 'anonymous') ;// needed to avoid cross-origin issues on CodeSandbox
image.src = url
});
export async function getCroppedImg(imageSrc, pixelCrop) {
const image = await createImage(imageSrc);
const canvas = document.createElement('canvas');
const ctx = canvas.getContext('2d');
const maxSize = Math.max(image.width, image.height);
const safeArea = 2 * ((maxSize / 2) * Math.sqrt(2));
// set each dimensions to double largest dimension to allow for a safe area for the
// image to rotate in without being clipped by canvas context
canvas.width = safeArea;
canvas.height = safeArea;
// translate canvas context to a central location on image to allow rotating around the center.
ctx.translate(safeArea / 2, safeArea / 2);
ctx.translate(-safeArea / 2, -safeArea / 2);
// draw rotated image and store data.
ctx.drawImage(
image,
safeArea / 2 - image.width * 0.5,
safeArea / 2 - image.height * 0.5
);
const data = ctx.getImageData(0, 0, safeArea, safeArea);
// set canvas width to final desired crop size - this will clear existing context
canvas.width = pixelCrop.width;
canvas.height = pixelCrop.height;
// paste generated rotate image with correct offsets for x,y crop values.
ctx.putImageData(
data,
Math.round(0 - safeArea / 2 + image.width * 0.5 - pixelCrop.x),
Math.round(0 - safeArea / 2 + image.height * 0.5 - pixelCrop.y)
);
// As Base64 string
// return canvas.toDataURL('image/jpeg');
// As a blob
return new Promise(resolve => {
canvas.toBlob(file => resolve(file))
})
}
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