Question

按照上一个问题here，

我有一个桌面应用程序，使用 Electron 平台和Javascript，我正在使用以下方法将HTML5画布转换为JPEG：

function download(){ 
    var dt = canvas.toDataURL('image/jpeg');
    this.href=dt; 
}
document.getElementById('download').addEventListener('click', download, false);

然后，

     NSMutableDictionary *resultDic = [NSMutableDictionary new];
    for (int i = 0; i < arrayChildModel.count; i++)
    {


            ChildModel *model = [arrayChildModel objectAtIndex:i];
            NSString *keyOrder = [NSString stringWithFormat:@"Children_Gender[%d]",i];
            NSString *keyQuantity = [NSString stringWithFormat:@"Children_BirthDate[%d]",i];
            NSString *keyTobacco = [NSString stringWithFormat:@"Children_HasTobaccoUsage[%d]",i];

            //NSString *keyNotes = [NSString stringWithFormat:@"row[%d][description]",i];
            childDateOfBirthStr = model.ChildBirthDate ;
            childGenderStr = model.ChildGender ;
            childTobaccoStr = model.ChildTobaccoUsage;


            NSString *string1 = [NSString stringWithFormat:@"%@=%@&",keyOrder,childGenderStr];
            NSString *string2 = [NSString stringWithFormat:@"%@=%@",keyQuantity,childDateOfBirthStr];
            NSString *string3 = [NSString stringWithFormat:@"%@=%@",keyTobacco,childTobaccoStr];
            [stringParams appendString:string1];
            [stringParams appendString:string2];
            [stringParams appendString:string3];


            NSDictionary * ChildDict = [NSDictionary dictionaryWithObjectsAndKeys:childGenderStr,@"Child_Gender",childDateOfBirthStr,@"Child_DOB",childTobaccoStr,@"Child_tobbacoUse", nil];
            NSLog(@"Dictionary is %@",ChildDict);

            NSString *resultDicKey = [NSString stringWithFormat:@"%d",i+1];
            [resultDic setValue:ChildDict forKey:resultDicKey];

    }

    NSLog(@"Result dic %@",resultDic);

这会刷新我的整个申请。如何更改此行为，以便在单击下载属性时不刷新页面？

Answer 1

我可以想到这两个片段，一个使用blob，一个使用下载元素。外部图书馆：FileSave.js

// this one use FileSaver.js library
canvas.toBlob(function(blob) {
    saveAs(blob, "pretty image.png");
});

// or this way using download element.
// here you can encode your image-data and then send it.
var download = document.getElementById('download');
download.setAttribute('href', 'data:text/plain;charset=utf-8,' + encodeURIComponent(imageData));
download.setAttribute('download', 'file.jpg');

我刚刚发现这个，电子特定的解决方案： Saving files locally with electron

Answer 2

稍微编辑你的锚标记

clip(0,0.49999,0,100)
abline(lm(score ~ demvoteshare, data = subset(Lee, demvoteshare <= 0.5)), col="red")

clip(0.5,1,0,100)
abline(lm(score ~ demvoteshare, data = subset(Lee, demvoteshare > 0.5)), col="green")

然后是你的下载功能

lines(lowess(Lee$demvoteshare, Lee$score, f = 2/3, delta = 0.01*1), col="red")

这可能会有所帮助

电子问题与下载属性

2 个答案: