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Mattias Malm  
#1 Posted : Monday, June 12, 2006 9:46:49 PM(UTC)
Mattias Malm

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Joined: 5/4/2006(UTC)
Posts: 17

Since JPEG images don't support alpha channel, and simply saving an image with alpha as JPEG results in a blend to black, I would like to use DiscardAlpha() to blend the image to white before saving it as JPEG.

The blending works great, but every time i use DiscardAlpha() the ColorProfile property is set to NULL and the JPEG file doesn't have the assigned profile embedded. Is there a reason for this, is it a bug or am I doing something wrong?

Sample code (c#):

Code:
// Open image
Bitmap gmImage = new Bitmap(Server.MapPath("RgbFileWithAlpha.psd"));

// Turn color management on
gmImage.ColorManagement.ColorManagementEnabled = true;

// Set transformation intent
gmImage.ColorManagement.TransformationIntent = Aurigma.GraphicsMill.Transforms.ColorTransformationIntent.Perceptual;

// Set default ICC profile if it's not embedded
if (gmImage.ColorProfile == null && gmImage.IsRgb)
	gmImage.ColorProfile = new ColorProfile(Server.MapPath("ColorProfiles/sRGB IEC61966-21.icm"));

// Set destination ICC profile and convert
gmImage.ColorManagement.RgbColorProfile = new ColorProfile(Server.MapPath("Adobe RGB (1998).icm"));
gmImage.ColorManagement.ConvertToContinuous(ColorSpace.Rgb, gmImage.HasAlpha, false);

// Save file in correct format
if (gmImage.HasAlpha)
	gmImage.Channels.DiscardAlpha(Aurigma.GraphicsMill.Color.FromRgb(255, 255, 255));
gmImage.Save(Server.MapPath("NewFile.jpg"), new JpegEncoderOptions(90, false));

// Clean up
gmImage.Dispose();

Edited by user Wednesday, December 19, 2007 4:18:43 PM(UTC)  | Reason: Not specified

Dmitry  
#2 Posted : Tuesday, June 13, 2006 6:57:38 PM(UTC)
Dmitry

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Hello,

We confirm the problem - thanks for report. This problem will be resolved in the next version of Graphics Mill for .NET. At this moment you can use the following workaround:

Code:
Aurigma.GraphicsMill.ColorProfile profile = bmp.ColorProfile;
bmp.Channels.DiscardAlpha();
bmp.ColorProfile = profile;

Edited by user Wednesday, December 19, 2007 4:18:56 PM(UTC)  | Reason: Not specified

Sincerely yours,

Dmitry Sevostyanov

UserPostedImage Follow Aurigma on Twitter!

Mattias Malm  
#3 Posted : Tuesday, June 13, 2006 9:56:55 PM(UTC)
Mattias Malm

Rank: Member

Groups: Guest
Joined: 5/4/2006(UTC)
Posts: 17

Thanks for the confirmation. I've already tried solving the problem the way you suggested, but it seems that DiscardAlpha() releases all profile resources, including the . I get this error message:

Unable to open color profile 'C:\WINDOWS\TEMP\ICM13B0.tmp'.

I assign the original profile to the image from disk after using DiscardAlpha(), so the resulting file is correct now.

Dmitry  
#4 Posted : Wednesday, June 14, 2006 7:28:39 PM(UTC)
Dmitry

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Sorry, here is correct workaround:

Code:
Aurigma.GraphicsMill.ColorProfile profile = bmp.ColorProfile != null ? new Aurigma.GraphicsMill.ColorProfile(bmp.ColorProfile.FileName) : null;
bmp.Channels.DiscardAlpha();
bmp.ColorProfile = profile;

Edited by user Wednesday, December 19, 2007 4:19:11 PM(UTC)  | Reason: Not specified

Sincerely yours,

Dmitry Sevostyanov

UserPostedImage Follow Aurigma on Twitter!

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