Hi,
I'm trying to write a little class which gets as input an image file (gif, jpg or png) and outputs a resized version of it. My aim is to output allways an image having the same format like the input one. I saw that ImageIO.write accepts as parameter the String formatName.
The question is how can somebody get the formatName for the input-image?
Thanks,
IMIA
As input we have all kind of images uploaded by visitors over a web interface. It could be everything.
> As input we have all kind of images uploaded by
> visitors over a web interface. It could be everything.
Too vague. I'll try again. Give my the signature of the method you are trying to write.
I'd like to have a method like this:
public static String resizeImg(String imgPath, Integer newWidth, Integer newHeight)
It gets as parameter the absolutePath to an image and the new width&height; it should resize the image and return me the absolute path to the resized image.
What I want is that in the case the imgPath points to a gif image the resized image should be a gif as well. If it's a jpg the resized img should be a jpg as well. The only one pb I have is to find out inside the resizeImg what format the imgPath image has, the rest would be clear.
Thanks for your help.
Would you be happy with the file's suffix, for example:
C:/temp/feist.png
has suffix "png". Or are you concerned that jpeg file might be given suffix gif?
In that case you have to examine the first few bytes to determine the file format.
Yes, the file suffix can be manipulated, I would avoid using it.
It's nothing in Java which'd help in this case?
> It's nothing in Java which'd help in this case?
Help get the suffix of a string or help sniff the format of an input stream?
I think nobody has a problem with String operations. The interesting problem is how to detect if an input stream it's a gif or a jpeg or a png?
Found a nice example how to solve the problem using the javax.imageio package.
The ideea behind is:
S1) Getting an ImageInputStream for our image file:
ImageInputStream iis = ImageIO.createImageInputStream(o);
S2) Getting all image-readers which are able to read the format:
Iterator iter = ImageIO.getImageReaders(iis);
S3) Get the first reader and call its getFormatName()
The full example is available here:
http://www.exampledepot.com/egs/javax.imageio/DiscType.html
Seems to work fine for me.
Thanks for all your help!
