I am using ggplot and posted this question at that helplist. It was
suggested that I try a more general R-help list for a possible solution to
this problem.
Within ggplot, I am using geom_area with red and blue and expect where they
overlap should be purple. But instead, it's dark red.
Playing
On 02/03/2010 08:43 PM, bluecuttlefish wrote:
I am using ggplot and posted this question at that helplist. It was
suggested that I try a more general R-help list for a possible solution to
this problem.
Within ggplot, I am using geom_area with red and blue and expect where they
overlap should
Hi,
Adding two semi-transparent colours results in non-intuitive colour
mixing (a mystery for me anyway). Is it additive (light), substractive
(paint), or something else? Consider the following example, depending
on the order of the two layers the overlap region is either purple
or dark red. I
baptiste auguie baptiste.auguie at googlemail.com writes:
Adding two semi-transparent colours results in non-intuitive colour
mixing (a mystery for me anyway). Is it additive (light), substractive
(paint), or something else? Consider the following example, depending
on the order of the two
On 03/02/2010 8:50 AM, Ken Knoblauch wrote:
baptiste auguie baptiste.auguie at googlemail.com writes:
Adding two semi-transparent colours results in non-intuitive colour
mixing (a mystery for me anyway). Is it additive (light), substractive
(paint), or something else? Consider the following
That makes perfect sense, thank you, except that I'm not sure where
the white comes from when I set the background to transparent?
png(testingOrder.png, bg = transparent)
plot.new()
par(bg=transparent)
rect(0.3, 0.5, 1, 1, col=rgb(1, 0, 0, alpha=0.5))
rect(0, 0.5, 0.7, 1, col=rgb(0, 0, 1,
On 03/02/2010 9:38 AM, baptiste auguie wrote:
That makes perfect sense, thank you, except that I'm not sure where
the white comes from when I set the background to transparent?
You'd have to check the png device documentation or source code to find
out what it does when you mix half red
On Wed, 3 Feb 2010, baptiste auguie wrote:
That makes perfect sense, thank you, except that I'm not sure where
the white comes from when I set the background to transparent?
png(testingOrder.png, bg = transparent)
plot.new()
par(bg=transparent)
rect(0.3, 0.5, 1, 1, col=rgb(1, 0, 0, alpha=0.5))
On MacOSX I can tell Preview or Photoshop not to use a white
background yet the mixing still shows a difference (with either pdf or
png for that matter). So I guess it's something to do with mixing
colours with the transparent channel as you say. I'll try to find the
reason in the source code
Thanks for this complementary information. My head itches slightly
when reading about these virtual layers with unidirectional absorption
and reflection properties but I guess that's imputable to my personal
background as a physicist.
I still have a few questions,
- is this behavior documented?
On Wed, 3 Feb 2010, baptiste auguie wrote:
Thanks for this complementary information. My head itches slightly
when reading about these virtual layers with unidirectional absorption
and reflection properties but I guess that's imputable to my personal
background as a physicist.
It's not
11 matches
Mail list logo
