Re: CGShading
Re: CGShading
- Subject: Re: CGShading
- From: Ricky Sharp <email@hidden>
- Date: Sun, 1 Aug 2004 09:13:00 -0500
On Jul 31, 2004, at 5:40 PM, Peter Laurens wrote:
I am attempting to draw a simple gradient shade, and I have been
slowly going through the Quartz documentation to try and learn how to
achieve this.
I was pleased to see a sample project that shows off some code how to
do this. Unfortunately it's a very complex set of code with all sorts
of bits scattered all over the place in strange different functions,
and so it's difficult for me to follow properly... impossible in fact.
I am having a hard time stripping out the core stuff I need for a
gradient to be drawn, and the extra fluff the developer has added
around it.
Does anyone have a real simple CGShading demo project for me to take a
look at?
I'd be incredibly grateful for any help at all,
I have yet no idea how the following would compare speed-wise (I do
plan to profile them over the next week as I too need a gradient
solution):
(1) For very simple linear gradients, what I used to do in Carbon was
to create a GWorld. Say I wanted a linear gradient going from top to
bottom for a 200 x 200 pixel area. The GWorld would be 1 pixel wide
and 200 pixels tall. Then, for all 200 pixels, I would directly draw
into the GWorld (Direct Pixel Access) the appropriate colored point.
Finally, I would use CopyBits with dither mode to draw the GWorld into
the 200 x 200 area. You'd get a nice dithered gradient at any
bit-depth. A similar solution should definitely existing if working
with NSImage
(2) Draw directly into an NSImage. Here's some sample code that
creates a pretty cool gradient by using a Category for NSImage:
<
http://developer.apple.com/samplecode/Transformed_Image/
Transformed_Image.html>
(3) Use CGShading.
(4) Believe it or not, it appears you can use QuickTime. I found this
in some older (1999) documentation:
<
http://developer.apple.com/documentation/QuickTime/REF/
refVectors.39.htm#pgfId=34866>
___________________________________________________________
Ricky A. Sharp
mailto:email@hidden
Instant Interactive(tm)
http://www.instantinteractive.com
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