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Resizing and Pasting into new image
Posted: 2010-02-21T08:22:24-07:00
by steveq
Hey All,
I think this is a simple question!
I am writing software for Digital Cinema Packages (DCPs) and it is pretty much complete.
I was using the CxImage class for my image manipulation, but given that ImageMagick supports dpx files, I was thinking of switching over to it.
I also need to do a colour transformation for RGB to XYZ (gamma 2.6), however I have written my own class to do this.
I have successfully loaded an image and resized it:
Code: Select all
Image img;
try
{
img.read( "Dancing.jpg" );
img.sample( Geometry(1998,1080));
}
etc...
I would now like create a black image and paste the resized image into the centre of it (The image is portrait so it will have black borders).
I also need to save this 8 bit image as a 16 bit TIF file. I'm also not sure how to do this?
Could someone please give me some guidance on how to do this?
Many thanks,
Steve Q.
Re: Resizing and Pasting into new image
Posted: 2010-02-21T08:27:51-07:00
by magick
Use resize() rather than sample() to get superior results.
Use depth(8) to set your image to 8-bits.
To save to TIFF, use write() with a filename with a TIFF extention (.e.g. image.tif).
Use composite() with an OverCompositeOp operator to composite an image over a background image.
Re: Resizing and Pasting into new image
Posted: 2010-02-21T08:36:06-07:00
by steveq
Hey magick,
That is the fastest reply I have ever had from ANY forum ever! Thanks so much.
I have tried this:
Code: Select all
img.read( "Dancing.jpg" );
img.resize( Geometry(1998,1080));
img.depth(16);
img.write( "Dancing_resized_16bpp.tif" );
However I get an unhandled exception?
I want to create a 16bit image from the resized 8 bit image and save it as a 16bit TIF.
Also how do I create a new black image at a given resolution? (for the composite call)?
Thanks heaps,
Steve Q.
Re: Resizing and Pasting into new image
Posted: 2010-02-21T08:56:49-07:00
by magick
You need to catch exceptions and print them so you know what ImageMagick is complaining about. Its possible your instance of ImageMagick does not include TIFF support. Type
and make sure TIFF is listed with a mode of rw-. If not, you'll need to rebuild / reinstall ImageMagick with TIFF support.
To get a black image to composite on, create an image and set its size with Geometry() and use backgroundColor() to set its color. Download the source and take a look at ImageMagick-6.5.9-9/Magick++/demo and ImageMagick-6.5.9-9/Magick++/test for example Magick++ demos.
Re: Resizing and Pasting into new image
Posted: 2010-02-21T09:03:53-07:00
by steveq
Hey magick,
Thanks again for your help.
Strange, however this works:
Code: Select all
Image img;
Image img2( "1998x1080", "black" );
try
{
img.read( "Dancing.jpg" );
img.resize( Geometry(1998,1080));
img2.depth(16);
img2.composite( img, 100, 0, OverCompositeOp );
img2.write( "Dancing_resized_16bpp.tif" );
AfxMessageBox( _T("Image loaded") );
}
catch ( Error& my_error )
{
CString error;
error = my_error.what();
AfxMessageBox( error );
}
catch ( ... )
{
AfxMessageBox( _T("Unhandled Error") );
}
I don't know why my previous example crashed without falling into my catch?
Thanks for the info on creating a new image. I'll probably modify my code and use what you have suggested.
Thanks again for your help.
Steve Q.