Image plugin

[samdol]

@mrjj
Do I have to use plugin to show raw format image file?

[mrjj]

@samdol
Hi do you mean a raw image format like in cameras or just raw as in no header etc?
http://stackoverflow.com/questions/18637721/how-to-display-a-raw-image-file-in-a-qt-gui

[samdol]

This post is deleted!

[samdol]

@mrjj
I mean the image format like in cameras, such as CRW, NEF,...

[mrjj]

@samdol said in Image plugin:

CRW

Nope, never saw such plugin. For some camera vendors you have to use the SDK to read it.
http://amin-ahmadi.com/2016/06/09/how-to-handle-canon-eos-raw-images-in-qt-c/

Alternatively, you can use a lib
http://www.libraw.org/
and use to convert to format that you can
load or embed into Qt app so it can load native.

[samdol]

@mrjj
Thank you for the link.
Is the libraw OK to be used on commercial project?
Do I have to buy the license to use in commercial project?

[mchinand]

See the licensing options for libraw here. If you adhere to the terms of one of these licenses you can probably use it in a commercial project.

[samdol]

@mrjj

From the link, it seems we need to know
width, height ,QImage::Format about the raw image file before read it.
Could we know those information before read it?

[mrjj]

@samdol said in Image plugin:

Could we know those information before read it?

Not really. That is why raw means many things.
One can guess about it if knowing color format/depth and the filesize but
ultimately it could be anything.

For Cameras the raw format means uncompressed. Each vendor might save raw differently and hence
its not easy to "just" read raw files.

[samdol]

@mrjj
when tried the code in the link with some raw files (NiKON NEF, ..) I could only see unrecognizable dots on the screen. Is it because I did not put the right w, h and format?

[mrjj]

@samdol
Yes if you specify wrong parameters for the format it will look distorted.

[samdol]

@mrjj
I saw some image Viewer shows raw image file. I wonder how it could read raw image. Because in order to read it correctly, we need to know the w, h, format in advance and there is no way to know w,h, format.

[mrjj]

Well most of the viewers use a library and hence knows vendor raw format and can guess
at format otherwise. Many raw formats do have a header to give more info.
So for camera raw means uncompressed and non filtered and not so much raw block of image data as it
means in other contexts.