生成文档缩略图

Question

I am trying to display a grid of documents (saved in the documents directory) but I don't know how to generate the thumbnails for the documents. The documents can be anything that a QLPreviewController can display. PDF's and Images are fine to do but other things like .doc's I don't know about. Any guidance would help.

Answer 1

Since you have an UIView that can display any of this documents you could just take a shortcut:

-Create an instance of your preview controller with displayed document

-Do not add this view/controller to anything

-Create image from its layer

This might help:

+ (UIImage *)imageFromView:(UIView *)view {
    CALayer *layer = view.layer;
    UIGraphicsBeginImageContext([layer frame].size);
    [layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *outputImage = UIGraphicsGetImageFromCurrentImageContext();    
    UIGraphicsEndImageContext();    
    return outputImage;
}

Play around a bit with layers and initialization as I didn't test the code..

Answer 2

The better option of you can use a uiwebview in which you can just load the file giving the filepath. Then take the screen shot by using the code given above by Matic Oblak and you are done.