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-rw-r--r--modern/src/map/mapUtil.js52
1 files changed, 52 insertions, 0 deletions
diff --git a/modern/src/map/mapUtil.js b/modern/src/map/mapUtil.js
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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;
+ }
+}