Re: CGShading

FROM : John C. Randolph
DATE : Tue Oct 12 23:07:14 2004

On Oct 12, 2004, at 1:41 PM, R. Scott Thompson wrote:



>>> Just a note, I don't think that CGShading will let you create the 
>>> same kind of gradient in the sample (at least not easily).
>>>

>>
>> It can, you just need to use more than one gradient and composite one 
>> over the other.
>>

>
> That's why I said "(at least not easily)" :-)  You might try using 
> four radial shadings, one centered at each of the four corners and set 
> them up to fade to 0 by the time you get to the opposite corner.  That 
> would get something close, but not the same, as the barycentric 
> shading.
>
> You can't really use axial shadings because an axial shading can only 
> vary in one direction (i.e. you could get it to fade in the x 
> direction, but for the barycentric effect, you also want it to fade in 
> y and you can't do both with CGShading).


Sure you can.  You just draw it along a 45-degree vector.  See David 
Hill's example at: 
http://developer.apple.com/samplecode/Cocoa_CG_shading_demo/
Cocoa_CG_shading_demo.html

CGShading wouldn't be very useful if it could only be drawn along the X 
or Y axis.

-jcr






John C. Randolph <<email_removed>> (408) 974-8819
Sr. Cocoa Software Engineer,
Apple Worldwide Developer Relations
http://developer.apple.com/cocoa/index.html