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export const loadImage = (url) => {
return new Promise(imageLoaded => {
const image = new Image();
image.onload = () => imageLoaded(image);
image.src = url;
});
};
export const loadIcon = async (key, background, url) => {
const image = await loadImage(url);
const pixelRatio = window.devicePixelRatio;
const canvas = document.createElement('canvas');
canvas.width = background.width * pixelRatio;
canvas.height = background.height * pixelRatio;
canvas.style.width = `${background.width}px`;
canvas.style.height = `${background.height}px`;
const context = canvas.getContext('2d');
context.drawImage(background, 0, 0, canvas.width, canvas.height);
const iconRatio = 0.5;
const imageWidth = canvas.width * iconRatio;
const imageHeight = canvas.height * iconRatio;
context.drawImage(image, (canvas.width - imageWidth) / 2, (canvas.height - imageHeight) / 2, imageWidth, imageHeight);
return context.getImageData(0, 0, canvas.width, canvas.height);
};
export const calculateBounds = features => {
if (features && features.length) {
const first = features[0].geometry.coordinates;
const bounds = [[...first], [...first]];
for (let feature of features) {
const longitude = feature.geometry.coordinates[0]
const latitude = feature.geometry.coordinates[1]
if (longitude < bounds[0][0]) {
bounds[0][0] = longitude;
} else if (longitude > bounds[1][0]) {
bounds[1][0] = longitude;
}
if (latitude < bounds[0][1]) {
bounds[0][1] = latitude;
} else if (latitude > bounds[1][1]) {
bounds[1][1] = latitude;
}
}
return bounds;
} else {
return null;
}
}
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