| Re: Does object graphics have true-color? [message #50342] |
Thu, 28 September 2006 10:49  |
Rick Towler
Messages: 821
Registered: August 1998
|
Senior Member |
|
|
Object graphics on a
yy wrote:
> In direct graphics, I can use the following to define my own colors:
> cc=0.99*tanh((findgen(ncolors)/30-4.)/2.)/2+0.5
> plots,[0,u],[0,v],[0,w], /t3d, $
> color=256.^2*B(cc(c)*255.)+256.*G(cc(c)*255.)+R(cc(c)*255.)
ummm. o.k.
> Can I do the same thing in object graphics?
> Does SetRGB in IDLgrPalette work in the
> same way? Thank you!
Unless you specify otherwise, object graphics uses an RGB color model so
you can define your colors however you wish. You'll probably find it
easier to simply define your colors as an RGB triplet instead of as an
index into a palette.
myPlot = OBJ_NEW('IDLgrPlot', FINDGEN(360), $
SIN(FINDGEN(360)*!DTOR)*!RADEG, COLOR=[255,100,50]
myModel = OBJ_NEW('IDLgrModel')
myModel -> Add, myPlot
XOBJVIEW, myModel, /BLOCK
OBJ_DESTROY, myModel
-Rick
|
|
|
|
| Re: Does object graphics have true-color? [message #50458 is a reply to message #50342] |
Fri, 29 September 2006 13:44  |
yy
Messages: 14
Registered: September 2006
|
Junior Member |
|
|
Rick Towler wrote:
> Object graphics on a
>
> yy wrote:
>> In direct graphics, I can use the following to define my own colors:
>> cc=0.99*tanh((findgen(ncolors)/30-4.)/2.)/2+0.5
>> plots,[0,u],[0,v],[0,w], /t3d, $
>> color=256.^2*B(cc(c)*255.)+256.*G(cc(c)*255.)+R(cc(c)*255.)
>
> ummm. o.k.
>
>> Can I do the same thing in object graphics?
>> Does SetRGB in IDLgrPalette work in the
>> same way? Thank you!
>
> Unless you specify otherwise, object graphics uses an RGB color model so
> you can define your colors however you wish. You'll probably find it
> easier to simply define your colors as an RGB triplet instead of as an
> index into a palette.
>
> myPlot = OBJ_NEW('IDLgrPlot', FINDGEN(360), $
> SIN(FINDGEN(360)*!DTOR)*!RADEG, COLOR=[255,100,50]
> myModel = OBJ_NEW('IDLgrModel')
> myModel -> Add, myPlot
> XOBJVIEW, myModel, /BLOCK
> OBJ_DESTROY, myModel
>
>
> -Rick
I tried to use color to visualize the phase and intensity of a field by
the following definition:
; Define RGB value of the palette
red = phase*Intensity
green = (255-phase)*Intensity
blue = fltarr(128,128)
oPalette = OBJ_NEW('IDLgrPalette', red, green, blue)
; Use the palette to draw the picture
oImage = OBJ_NEW('IDLgrImage', BYTSCL(phase*intensity), $
PALETTE = oPalette)
The purpose of such a definition is: the intensity affects the
brightness of the image, and the phase affects the hue of the
image.
However, I think there is something wrong when I use this palette to
draw my picture. My problem is I don't know how to address the
color map I defined meaningfully. In this case, the data becomes
the multiplication of the phase and intensity, which I don't think
will use the palette correctly. But I don't know how to make this
correct.
Jingyi
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
