Paul, thanks for such an exhaustive answer!
Here are answers to your questions:
1. My case is the simple one -- I'm rendering all text layers at once.
2. Yes and no. As I said, I am implementing the cross-fade effect,
when one text fades out and another text fades in. The texts can be of
the same
With a second thought, I think it would do perfectly with simply
averaging ALL channels, R, G, B, and A, for this cross-fade effect.
So I am reformulating my questions as follows: How do I produce the
blending mode when the foreground and background colors are averaged
channel-wise, for all
This simplifies things a lot.
Just do an animated mix (crossfade) of the 2 text layers, including the
alpha channels, then simply composite the result over your background.
I'm not sure exactly which blend mode you'd use, but it will be a simple
alpha composite/blend/mix.
paulm
On 28/09/2009,
Thanks!
It seemed exactly what I need but I've found that it doesn't work as
expected. The interpolated semi-transparent parts of the rendered text
still appears brighter than it should.
Namely, consider drawing white text on black background, and then
drawing the same white text one more time
This is a multi-pass operation - you wont find a single
blend mode that will do this in any simple manner.
First question: Are you doing this all in one hit, or sequentially,
ie, rendering the first layer of text then adding subsequent
layers later?
Second question: is the text all the same
Hi,
I'd like to draw in a graphics context in such a compositing mode:
R = MAX(S, D)
i.e. out of two colors (source and destination), the maximum color
(channel-wise) was chosen. This is basically equivalent to ORing the
colors.
Is this possible? I don't see such NSCompositingOperation.
On 22 Sep, 2009, at 15:22, Oleg Krupnov wrote:
Hi,
I'd like to draw in a graphics context in such a compositing mode:
R = MAX(S, D)
i.e. out of two colors (source and destination), the maximum color
(channel-wise) was chosen. This is basically equivalent to ORing the
colors.
Is this
the MAX
compositing operation (this time I need MAX, but maybe I will also
need other, such as MIN, OR, AND, NOT, whatever). I have checked all
values of NSCompositingOperation, but haven't found what I need. They
all seem to be dealing with transparency mostly, not with color
values.
Any ideas
the MAX
compositing operation (this time I need MAX, but maybe I will also
need other, such as MIN, OR, AND, NOT, whatever). I have checked all
values of NSCompositingOperation, but haven't found what I need. They
all seem to be dealing with transparency mostly, not with color
values.
Any ideas
On Sep 22, 2009, at 6:22 AM, Oleg Krupnov wrote:
Hi,
I'd like to draw in a graphics context in such a compositing mode:
R = MAX(S, D)
i.e. out of two colors (source and destination), the maximum color
(channel-wise) was chosen. This is basically equivalent to ORing the
colors.
This is the
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