[英]Openlayers 2 + HERE tiles caching
我需要在Windows機器上創建一個離線地圖演示,唯一的選擇是使用切片緩存,我使用的是Openlayers 2,當我初始化OSM層時,一切都按預期工作:
map = new OpenLayers.Map({
layers: [
new OpenLayers.Layer.OSM("OpenStreetMap (CORS)", null, {
eventListeners: {
tileloaded: updateStatus,
loadend: detect
}})
]
}
調用“ detect”方法並檢查是否可以為圖塊調用getCanvasContext()函數,並且一切正常! 當我使用XYZ圖層將OSM替換為HERE映射時,它停止工作:
var urlTpl = 'https://1.{base}.maps.cit.api.here.com' + '/{type}/2.1/maptile/newest/{scheme}/${z}/${x}/${y}/256/png' + '?app_id=?????&app_code=??????';
var hereLayer = {
base: 'base',
type: 'maptile',
scheme: 'normal.day',
app_id: platform['app_id'],
app_code: platform['app_code']
};
map = new OpenLayers.Map({
layers: [
new OpenLayers.Layer.XYZ("HERE", [createUrl(urlTpl, hereLayer)], {
eventListeners: {
tileloaded: updateStatus,
loadend: detect
}
})
]
}
在此示例中,確實調用了detect方法,但是這次函數getCanvasContext()拋出異常:
碼:18
消息:無法在“ HTMLCanvasElement”上執行“ toDataURL”:可能無法導出污染的畫布。
名稱:SecurityError
我能做什么?
從https://gis.stackexchange.com/questions/71715/enabling-cors-in-openlayers中的答案中:您將需要在layers
選項中包含tileOptions
設置以啟用CORS:
map = new OpenLayers.Map({
layers: [
new OpenLayers.Layer.XYZ("HERE", [createUrl(urlTpl, hereLayer)], {
tileOptions: {crossOriginKeyword: 'anonymous'},
eventListeners: {
tileloaded: updateStatus,
loadend: detect
}
})
]
}
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