QImage, get file format

[greenvirag]

Hi!

I have a problem, maybe with a trivial answer.
How can I get the file format of an QImage?

There is a format() function, but it is an enum, like QImage::Format_Invalid, QImage::Format_Mono, QImage::Format_MonoLSB, QImage::Format_Indexed8, QImage::Format_RGB32, QImage::Format_ARGB32, but I need this information in the following form: char* like PNG, JPG, JPEG, etc.

What is the easiest solution for this problem?

Thank you,
greenvirag

[jpn]

QImage can load and save images in various file formats listed by:

• QImageReader::supportedImageFormats()
• QImageWriter::supportedImageFormats()

but after QImage has the image data loaded to memory, it doesn't really care what was the file format. All it cares about is the image format defining how the image data is stored in memory.

[aamer4yu]

There is a format() function, but it is an enum, like QImage::Format_Invalid, QImage::Format_Mono, QImage::Format_MonoLSB, QImage::Format_Indexed8, QImage::Format_RGB32, QImage::Format_ARGB32, but I need this information in the following form: char* like PNG, JPG, JPEG, etc.

What is the easiest solution for this problem?

best thing would be store the format urself when u load the image

[greenvirag]

Ok, then I ask my question a little other way.

If I open a file, how can I get the file type/extension?

[jpn]

See QFileInfo.

[caduel]

Have a look at QFileInfo::completeSuffix().
(Of course, that function might be cheated if a file is named .png but isn't reallz a png... if you want/need to check that too, you might want to use the "file" utility.)

HTH

[aamer4yu]

If you want to go the harder way...
Files usually have a signature by which they are identified. These signatures are stored as first few bytes of the file.
You can read these bytes and determine which file they are.
For eg., jpg files have a signature of "FFD8FFE0"

Hope this helps