Re: Image processing in Cocoa
Re: Image processing in Cocoa
- Subject: Re: Image processing in Cocoa
- From: "Christian Giordano" <email@hidden>
- Date: Thu, 25 Sep 2008 07:35:50 +0100
Hi Helder, I found this post that can be really helpful when I will
have to do my pixel operations:
http://www.rodgutierrez.com/blog/2008/07/how-to-create-a-rgba-cgimagere.html
I still have to find how to draw an CGImageRef in another one
regardless the current context, I'm still wondering if this is the
right approach.
I will look better in the documentation.
Thanks, chr
On Thu, Sep 25, 2008 at 5:06 AM, Helder da Rocha
<email@hidden> wrote:
> Since you can't use NSImage, you could try Core Image.
>
> You can do all that with CGImage in your restricted environment. You can use
> a bitmap or layer context and then later render it on whatever view you
> wish.
>
> There is a good Core Graphics Quartz tutorial at
> http://developer.apple.com/documentation/GraphicsImaging/Conceptual/drawingwithquartz2d/dq_intro/chapter_1_section_1.html
>
> Helder.
>
> --
> Helder da Rocha (email@hidden)
> Sao Paulo, Brazil
>
>
> Christian Giordano wrote:
>>
>> Thanks Mike, I can't use NSImage (guess why) but a subset. Btw, the
>> problem I have is that I have a view which contains an image. I would
>> like to draw in the image, not in the container view so I need to
>> provide to the draw method the image context. Is this a good approach
>> or all the drawing should happen in the view context? Should I extend
>> the image view and handle the routing internally?
>>
>> Thanks, chr
>>
>>
>> On Wed, Sep 24, 2008 at 11:08 AM, Mike Abdullah
>> <email@hidden> wrote:
>>
>>>
>>> On 24 Sep 2008, at 10:50, Christian Giordano wrote:
>>>
>>>
>>>>
>>>> Hi guys, is there some good tutorial around about how to manipulate
>>>> bitmaps in Cocoa?
>>>>
>>>> I would be interested on:
>>>>
>>>> - copy portion of image over another with a mask (this should be
>>>> pretty straight forward with quartz2d)
>>>>
>>>
>>> [[NSImage alloc] initWithSize:]
>>> [image lockFocus]
>>> [sourceImage drawAtPoint:point fromRect:imagePortionRect
>>> operation:operation
>>> fraction:1.0]
>>> [image unlockFocus]
>>>
>>>
>>>>
>>>> - apply threshold
>>>> - apply effects like blur
>>>>
>>>
>>> Core Image is your friend
>>>
>>>>
>>>> Not sure if some of this, like the blur, is recommended to do from an
>>>> higher level instead of doing it pixel by pixel. In case of the
>>>> latter, how to get the bytearray with all the pixels info?
>>>>
>>>> Thanks a lot, chr
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>>
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