On 11/29/05 9:24 AM, Scott Thompson didst favor us with:
>
> On Nov 22, 2005, at 2:34 PM, Laurence Harris wrote:
>
>> On 11/22/05 3:24 PM, Alex Curylo didst favor us with:
>>
>>> on 11/22/05 12:01 PM, email@hidden at
>>> email@hidden wrote:
>>>
>>>> Is there a way to get the CGContext for the DB custom cell
>>>> drawing callback?
>>>> Or do I have to use QD APIs?
>>>
>>> CGContextRef cgContext = NULL;
>>> GrafPtr port = NULL;
>>> ::GetPort(&port);
>>> OSStatus status = ::QDBeginCGContext(port, &cgContext);
>>>
>>> ... draw ...
>>>
>>> ::QDEndCGContext(port, &cgContext);
>>
>> This will work, but I use the approach I suggested because it's more
>> efficient. If you get the context in the kEventControlDraw handler
>> and then
>> use it in the callback, you only have to get it once. If you use
>> the above
>> approach, you have to call all of that for every row and every custom
>> column, so if you had 20 rows and three custom columns, you'd end
>> up calling
>> the above code 60 times for a single redraw of the DataBrowser.
>
> Are you sure that it's more "efficient"? (have you profiled it).
>
> The system caches the CGContextRef between calls to
> QDBeginCGContext. Calling it repeatedly on the same port is a low-
> overhead operation.
No, I haven't profiled it, but I'm pretty sure that not calling this code at
all is more efficient than calling it repeatedly. Is that an evil
assumption?
Larry
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