Re: NSImage - Converting image formats
Re: NSImage - Converting image formats
- Subject: Re: NSImage - Converting image formats
- From: Andrei Kolev <email@hidden>
- Date: Tue, 26 Jun 2001 18:48:09 +0300
The quotation below shows the right way to save a JPEG file. But I am afraid
that the compression factor is a float between 0 and 1 (1 -> best quality,
low compression, 0 -> low quality, max compression).
Andrei
On Monday, June 25, 2001, at 07:31 , Ivan Salina Fernandes wrote:
>
>
> I'm trying to convert PDF images into Jpeg images. I used
>
> TIFFRepresentation in a NSBitmapImageRep, but I can't change the
>
> compression. Can anybody help me to change this parameters?
>
>
I think you want to use NSBitmapImageRep's method
>
>
- (NSData
>
*)representationUsingType:(NSBitmapImageFileType)storageType
>
properties:(NSDictionary *)properties;
>
>
with NSJPEGFileType as the storageType.
>
>
If you want an actual jpeg file, then I don't think you
>
want to use - TIFFRepresentation.
>
>
eg,
>
>
//I haven't compiled or run this, so you may have to tweak it.
>
>
NSBitmapImageRep *imageRep;
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NSDictionary *propertyDict;
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NSNumber *compressionFactor;
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NSData *jpgData;
>
>
// The compression factor is a float between 1.0 and 255.0,
>
// with larger numbers providing greater compression and
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// more distortion. See the HTML docs for NSBitmapImageRep.
>
>
compressionFactor = [NSNumber numberWithFloat:10.0];
>
>
propertyDict = [NSDictionary dictionaryWithObject:compressionFactor
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forKey:NSImageCompressionFactor];
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>
jpgData = [imageRep representationUsingType:NSJPEGFileType
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properties:propertyDict];
>
>
[jpgData writeToFile:@"foo.jpg" atomically:NO];