使用 WinJS 将映像保存到磁盘

Save image to disk with WinJS

本文关键字：磁盘 保存 映像 WinJS 使用      更新时间：2023-09-26

我将画布转换为图像，现在我想将图像保存到磁盘。我的问题是：我可以保存或下载映像到用户磁盘吗？我正在使用WinJS - JavaScript

当然。正如Kraig在 social.msdn.com 上发布的几乎相同的问题：在Windows 8中将画布另存为图像


var Imaging = Windows.Graphics.Imaging;
var picker = new Windows.Storage.Pickers.FileSavePicker();
picker.suggestedStartLocation = Windows.Storage.Pickers.PickerLocationId.picturesLibrary;
picker.fileTypeChoices.insert("PNG file", [".png"]);
var imgData, fileStream = null;
picker.pickSaveFileAsync().then(function (file) {            
    if (file) {
        return file.openAsync(Windows.Storage.FileAccessMode.readWrite);                
    } else {
        return WinJS.Promise.wrapError("No file selected");
    }
}).then(function (stream) {
    fileStream = stream;
    var canvas = document.getElementById("canvas1");            
    var ctx = canvas.getContext("2d");
    imgData = ctx.getImageData(0, 0, canvas.width, canvas.height);
    return Imaging.BitmapEncoder.createAsync(Imaging.BitmapEncoder.pngEncoderId, stream);
}).then(function (encoder) {
    //Set the pixel data--assume "encoding" object has options from elsewhere
    encoder.setPixelData(encoding.pixelFormat, encoding.alphaMode,
        encoding.width, encoding.height, encoding.dpiX, encoding.dpiY,
        new Uint8Array(imgData.data));
    //Go do the encoding
    return encoder.flushAsync();
}).done(function () {
    //Make sure to do this at the end
    fileStream.close();  
}, function () {
    //Empty error handler (do nothing if the user canceled the picker
});
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