Re: How to get image real number of bits per pixel
Re: How to get image real number of bits per pixel
- Subject: Re: How to get image real number of bits per pixel
- From: "Sebastien TOPIN" <email@hidden>
- Date: Thu, 27 Feb 2003 10:07:44 +0100
Thanks for your help,
Maybe I am doing something wrong, but when I try to check the colorSpaceName
on my NSBitmapImageRep, I get a "NSCalibratedRGBColorSpace" which is the
default value and does not tell me that this is a grayscale 8 bits picture.
Here is a part of my code:
//========================================
NSBitmapImageRep *myImageRep = [NSBitmapImageRep
imageRepWithContentsOfFile:@"myGrayscaleFile.bmp"];
NSString *myColorNameSpace = [myImageRep colorSpaceName];
int iBitsPerPixel = [myImageRep bitsPerPixel];
...
//========================================
and I get:
colorSpaceName = "NSCalibratedRGBColorSpace"
iBitsPerPixel = "24"
I start to wonder if I going to be able to do this simple thing with
Cocoa...?
Seb
----- Original Message -----
From: "Jeff Disher" <email@hidden>
To: "Sebastien TOPIN" <email@hidden>
Sent: Thursday, February 27, 2003 3:01 AM
Subject: Re: How to get image real number of bits per pixel
>
Get the colour space name of the NSBitmapImageRep to make sure that it
>
actually is a grayscale image. I know that I have been able to open
>
grayscale GIFs and correctly get the number of bits per pixel but they
>
do report as being in the white colour space.
>
>
This way you can at least find out what colour space it is loaded into.
>
>
Just an idea,
>
Jeff.
>
>
>
On Wednesday, February 26, 2003, at 10:04 AM, Sebastien TOPIN wrote:
>
>
> I am still not able to get the "real" number of bits per pixel from my
>
> bmp
>
> image.
>
> I tried to create an NSBitmapImageRep object from [NSBitmapImageRep
>
> WithContentOfFile:filename] and when I check the bitsPerPixel or
>
> samplePerPixel value I still have 24 or 32 for a 8 bits gray scale
>
> image.
>
> Do I have to use QuickTime component to get this kind of information
>
> or is
>
> there a way to do it with Cocoa?
>
>
>
> BTW, I am new to Cocoa (and even to Mac I was on Visual Studio last
>
> week!)
>
> and I do apologise in advance if I ask stupid questions...
>
> Seb
>
>
>
> ----- Original Message -----
>
> From: "Marco Binder" <email@hidden>
>
> To: "Sebastien TOPIN" <email@hidden>
>
> Cc: "Cocoa List" <email@hidden>
>
> Sent: Tuesday, February 25, 2003 6:25 PM
>
> Subject: Re: How to get image real number of bits per pixel
>
>
>
>
>
>> I guess you can ask the NSImageView for the path of the dropped file
>
>> (please see docs yourself- I m busy at the moment). With the path, you
>
>> can then instantiate a new NSBitmapImageRep. I know, this is waste of
>
>> memory (TWO bitmap reps of the same image), but I could not yet figure
>
>> out another way. You could of course subclass NSImageView and
>
>> intercept
>
>> the file-drop. Then set up a NSBitmapImageRep and add it to a newly
>
>> created NSImage. Supply then this image as an argument when calling
>
>> [myImageViewObject setImage:newlyCreatedImage].
>
>>
>
>> marco
>
>>
>
>>
>
>> Am Dienstag, 25.02.03 um 18:14 Uhr schrieb Sebastien TOPIN:
>
>>
>
>>> Thanks but how do you get the image data? Is it directly from the
>
>>> file?
>
>>> I was trying to use the drag'n drop functionality (drag an image from
>
>>> the
>
>>> Finder to your application image control) in order to open my image
>
>>> file. In
>
>>> this case I already get an instantiated NSBitmapImageRep from
>
>>> NSImageView
>
>>> and just extract its parameters. This is what gives me the 32 bits
>
>>> per
>
>>> pixel.
>
>>>
>
>>>
>
>>> ----- Original Message -----
>
>>> From: "Marco Binder" <email@hidden>
>
>>> To: "Sebastien TOPIN" <email@hidden>
>
>>> Cc: <email@hidden>
>
>>> Sent: Tuesday, February 25, 2003 5:57 PM
>
>>> Subject: Re: How to get image real number of bits per pixel
>
>>>
>
>>>
>
>>>> Directly instantiate an NSBitmapImageRep with the image-data and
>
>>>> call
>
>>>> the method. As to my experience, Cocoa will always use 8-bit RGBA to
>
>>>> display images in an NSImageView.
>
>>>>
>
>>>> marco
>
>>>>
>
>>>>
>
>>>> Am Dienstag, 25.02.03 um 17:21 Uhr schrieb Sebastien TOPIN:
>
>>>>
>
>>>>> Hi Folks,
>
>>>>>
>
>>>>> I am trying to get the real number of bits per pixel for a
>
>>>>> displayed
>
>>>>> image.
>
>>>>> A NSImageView object enables me to drag n' drop a bmp image from
>
>>>>> the
>
>>>>> Finder
>
>>>>> and display it in my app.
>
>>>>> Then I got an NSBitmapImageRep from the NSImageView and did that:
>
>>>>>
>
>>>>> int iBitsPerPix = [bittmapImageRep bitsPerPixel];
>
>>>>>
>
>>>>> The result is always 32 even for grayscale 8 bits per pixel images
>
>>>>> or
>
>>>>> 24 bits
>
>>>>> per pixel color images.
>
>>>>>
>
>>>>> How can I get the image real number of bits per pixel of those
>
>>>>> images?
>
>>>>>
>
>>>>> Thanks in advance,
>
>>>>> Seb
>
>>>>> _______________________________________________
>
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>
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>>>>>
>
>>>>>
>
>>>> --
>
>>>> |\ /| E-Mail: email@hidden WWW: www.marco-binder.de
>
>>>> | \/ | Telefon: 07531 / 94 19 94 Fax: 07531 / 94 19 92
>
>>>> | |ARCO Snail-Mail: Banater Str. 3 - 78467 Konstanz
>
>>>> BINDER _____________________________________________________
>
>>>>
>
>>>>
>
>>>
>
>>>
>
>>>
>
>> --
>
>> |\ /| E-Mail: email@hidden WWW: www.marco-binder.de
>
>> | \/ | Telefon: 07531 / 94 19 94 Fax: 07531 / 94 19 92
>
>> | |ARCO Snail-Mail: Banater Str. 3 - 78467 Konstanz
>
>> BINDER _____________________________________________________
>
> _______________________________________________
>
> cocoa-dev mailing list | email@hidden
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>
Jeff Disher
>
President and Lead Developer of Spectral Class
>
Spectral Class: Shedding Light on Innovation
>
http://www.spectralclass.com/
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