I've been trying to add an image overlay to mapbox-gl-js on a project that uses Ionic 5 + Vue.js, similar to what Leaflet does, but i cannot get it to work.
The only way that I can get it to work is by following this tutorial, but the image does not fit properly into the polygon. I've also tried this, and I can see when Capacitor requests the image, but it does not load. It works fine on Chrome, but on mobile it does not.
This is the code that I have now:
const { map } = this;
if (map.getLayer(layerId)) {
map.removeLayer(layerId);
}
if (map.getSource(sourceId)) {
map.removeSource(sourceId);
}
map.addSource(sourceId, { ...source, url: Capacitor.convertFileSrc(source.url) });
map.addLayer(layer);
whereas the source and layer objects are like this:
const sourceId = `${talhao.id}-image`;
const layerId = `${talhao.id}-image-${image.id}`;
const bbox = getBoundingBox(talhao);
const source = {
type: "image",
url: image.imagemPng,
coordinates: [
bbox.getNorthWest().toArray(),
bbox.getNorthEast().toArray(),
bbox.getSouthEast().toArray(),
bbox.getSouthWest().toArray()
]
};
const layer = {
id: layerId,
source: sourceId,
type: "raster",
paint: {
"raster-opacity": 0.85
}
};
Any help would be appreciated!
edit: It is worth noticing that I do not think that the image is the problem here, because I use the same image in another part of the screen that I'm working and it loads fine.
Turns out the mapbox-gl-js library had a bug in version 1.x that prevented the image from showing on mobile.
Upgraded to version 2.0.1 and it worked.
Related
Is there any caching policy of images in GitHub?
I am facing trouble while rendering an image from an API. The image works fine when I open it in the browser.
However, Github renders some older version of that image.
How can I workaround this issue or is there any fix?
Considering this netlify/netlify-cms PR, maybe adding the ts=$(date) as parameter of a GitHub API v3 call would be enough of a "cache busting" for your need.
From the code:
const cacheBuster = new Date().getTime();
const params = [`ts=${cacheBuster}`];
if (options.params) {
for (const key in options.params) {
params.push(`${ key }=${ encodeURIComponent(options.params[key]) }`);
}
}
if (params.length) {
path += `?${ params.join("&") }`;
}
return this.api_root + path;
This adds a &ts=xxx timestamp parameter to the api.github.com call.
I am using vue 2.6.10 and I have the following dependencies vue-mapbox 0.4.1 and mapbox-gl 1.3.2
The map works, but I cannot get all the points of the map, create bounds and make the map zoom there.
What I am doing now, based on this and this
In my template
<MglMap
ref="map"
#load="mapLoaded()">
and then in my javascript
import Mapbox from "mapbox-gl";
components: { Mapbox}
methods :{
mapLoaded(){
let coords = [];
//coords is array , contains arrays like [-118.578, 51.524]
let bounds = coords.reduce((bounds, coord)=> {
return bounds.extend(coord);
}, this.mapbox.LngLatBounds(coords[0], coords[0])
);
this.$refs['map'].map.fitBounds(bounds, { padding: 20 });
}
},
created(){
this.mapbox = Mapbox;
}
This should work, but I keep getting
TypeError: this.setSouthWest is not a function
so I guess there is a problem in this.mapbox.LngLatBounds(coords[0], coords[0]) , maybe the this.mapbox. or the LngLatBounds does not work.
If I console log the coords[0], prints an array [10.467778, 37.600833]
What am I missing? Thanks
I have got the same error. Turns out I have missed "new" keyword.
You can try adding the "new" keyword for "this.mapbox.LngLatBounds"
The following code worked for me.
import mapboxgl from 'mapbox-gl';
Vue.prototype.$maps = mapboxgl
this.map = new this.$maps.Map({container: 'mapContainer', // container ID
style: 'mapbox://styles/mapbox/streets-v11', // style URL
zoom: 9 // starting zoom
});
const sourceMarker = new this.$maps.Marker().setLngLat(origin).addTo(this.map);
const destMarker = new this.$maps.Marker().setLngLat(destination).addTo(this.map);
const bounds = new this.$maps.LngLatBounds(origin, destination);
this.map.fitBounds(bounds);
Html2canvas screenshot is very different from the original picture. How to solve it
This is the address of my code https://github.com/cxm1308377432/html2canvas-screenshot
The above is the interface written with vue-grid-layout, you can modify the layout at will, and the below is the screenshot, but the two are very different
function download() {
var this1 = this;
setTimeout(function() {
html2canvas(this1.$refs.mine, { backgroundColor: null }).then(canvas =>
{
let dataURL = canvas.toDataURL("image/png");
this1.downImg = dataURL; console.log(dataURL);
});
}, 1000);
}
You better have a screenshot to show how different it is. But from my experience when I'm working with that library (html2canvas), the canvas can't render from difference origin. That's CORS problem. Unlucky, I haven't found any solution for this situation.
I read your source but can't found any image url so please update your answer with screenshot.
This one I've been banging my head against for a few weeks now.
Scenario:
Let user generate an image out of layers they select
Convert image to canvas
Share image from canvas on facebook wall using share_open_graph (along with the image, a short text and title will be shared)
I've already had a solution in place using publish_actions but that was recently removed from the API and is no longer available.
I am using js and html for all code handling.
The issue is that I can generate a png image from the canvas but that is saved as base64 and share_open_graph doesn't allow this type of image, it needs a straight forward url such as './example.png'. I have tried using several approaches and with canvas2image, converting and saving image using file-system but all of these fail.
Does anyone have similar scenario and possible solution from April/May 2018 using share_open_graph ?
My current code looks like this - it fails at the image conversion and save to a file (Uncaught (in promise) TypeError: r.existsSync is not a function at n (file-system.js:30)). But I am open to different solutions as this is clearly not working.
html2canvas(original, { width: 1200, height: 628
}).then(function(canvas)
{
fb_image(canvas);
});
var fb_image = function(canvas) {
canvas.setAttribute('id', 'canvas-to-share');
document.getElementById('img-to-share').append(canvas);
fbGenerate.style.display = 'none';
fbPost.style.display = 'block';
var canvas = document.getElementById('canvas-to-share');
var data = canvas.toDataURL('image/png');
var encodedPng = data.substring(data.indexOf(',') + 1, data.length);
var decodedPng = base64.decode(encodedPng);
const buffer = new Buffer(data.split(/,\s*/)[1], 'base64');
pngToJpeg({ quality: 90 })(buffer).then(output =>
fs.writeFile('./image-to-fb.jpeg', output));
var infoText_content = document.createTextNode('Your image is being
posted to facebook...');
infoText.appendChild(infoText_content);
// Posting png from imageToShare to facebook
fbPost.addEventListener('click', function(eve) {
FB.ui(
{
method: 'share_open_graph',
action_type: 'og.shares',
href: 'https:example.com',
action_properties: JSON.stringify({
object: {
'og:url': 'https://example.com',
'og:title': 'My shared image',
'og:description': 'Hey I am sharing on fb!',
'og:image': './image-to-fb.jpeg',
},
}),
},
function(response) {
console.log(response);
}
);
});
};
I'm trying to add a button to my interface that will download a screenshot taken of the web page.
It works for the side bar but my Cesium map appears plain white.
Can someone help me out with is?
Here is a code
var Capture = function() {
html2canvas(document.body, {
onrendered: function (canvas) {
var tempcanvas=document.createElement('canvas');
tempcanvas.width=1050;
tempcanvas.height=1050;
var context=tempcanvas.getContext('2d');
context.drawImage(canvas,5,5);
var link=document.createElement("a");
link.href=tempcanvas.toDataURL('image/jpg'); //function blocks CORS
link.download = 'screenshot.jpg';
link.click();
}
});
}
This was based on the question asked here
So the answer turned out to be by using scene.canvas.
I was directed to this solution by a similar question on the Cesium Forum.