Specifying the file format for SaveSelectedImagesToBytes()

Jason · **Joined:** Fri Jul 22, 2011 7:13 am **Posts:** 14

This documentation (http://www.dynamsoft.com/help/TWAIN/Web ... oBytes.htm) states that the method "Saves the selected images in buffer to a byte array in the specified file format."

However, the manner in which to specify the file format is not clear. Can you please explain it?

I intend to specify multipage Tiff or PDF from the selection of files.

Thanks,

Jason

Catherine · **Joined:** Tue Mar 08, 2005 12:23 am **Posts:** 1075

Hi Jason,

You can use the GetSelectedImagesSize method to specify the file format. For instance, if you want to save the selected images in buffer to a byte array in TIFF format, you can use the following code:

Code:

Twain.SelectedImagesCount = 2;
Twain.SelectedImageIndex(0) = 4；// Set the 5th image as the first selected image.
Twain.SelectedImageIndex(1) = 3；// Set the 4th image as the second selected image.

var size = Twain.GetSelectedImagesSize(2); //Calculate the size of selected images in TIFF format
     
var ary = new Array(size);
for (var i =0; i<size; i++)
    ary[i] = 0;

Twain.SaveSelectedImagesToBytes(size, ary);

Jason · **Joined:** Fri Jul 22, 2011 7:13 am **Posts:** 14

Thanks. So the GetSelectedImagesSize() has a side-effect of updating the image output mode internally?

If so, I suggest that this be added to the documentation.

Catherine · **Joined:** Tue Mar 08, 2005 12:23 am **Posts:** 1075

Hi Jason,

You are right. And thanks for your suggestion. I'll forward your info to our team and improve the help documentation.

Jason · **Joined:** Fri Jul 22, 2011 7:13 am **Posts:** 14

Ok, can you further list other methods (especially Get* methods) which have similar side-effects? It is unclear to me if/how the various methods are intended to work together.

For example, from the other post, GetImageSize() provides the byte length (?? unit of measure assumed, but not documented - and if it is integral bytes, then why is the return type double?) of a resized version of the image. But with what other methods is GetImageSize() intended to be used?

That's just an example - I'm interested in all others.

Catherine · **Joined:** Tue Mar 08, 2005 12:23 am **Posts:** 1075

Hi Jason,

Currently, it is necessary to call GetSelectedImagesSize (also the only Get* method) in order to use SaveSelectedImagesToBytes. You cannot use GetImageSize or GetImageSizeWithSpecifiedType together with SaveSelectedImagesToBytes.

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Specifying the file format for SaveSelectedImagesToBytes()

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