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.Dd May 21, 2005
.Dt AG_HSVPAL 3
.Os
.ds vT Agar API Reference
.ds oS Agar 1.0
.Sh NAME
.Nm AG_HSVPal
.Nd agar HSV color wheel widget
.Sh SYNOPSIS
.Bd -literal
#include <agar/core.h>
#include <agar/gui.h>
.Ed
.Sh DESCRIPTION
The
.Nm
widget is a HSV (Hue, Saturation, Value) color selector.
The user selects the hue using a circle, and the saturation/value using
a triangle.
.Pp
The widget can bind to floating-point hue, saturation, value and alpha
variables.
It can also bind to a pixel value (and matching
.Xr AG_PixelFormat 3 )
or an array of RGBA components in integer or floating-point format.
.Sh INHERITANCE HIERARCHY
.Xr AG_Object 3 ->
.Xr AG_Widget 3 ->
.Nm .
.Sh INITIALIZATION
.nr nS 1
.Ft "AG_HSVPal *"
.Fn AG_HSVPalNew "AG_Widget *parent" "Uint flags"
.Pp
.nr nS 0
The
.Fn AG_HSVPalNew
function allocates, initializes, and attaches a new
.Nm
widget.
There are currently no
.Fa flags
specific to this widget.
.Sh BINDINGS
The
.Nm
widget provides the following bindings:
.Pp
.Bl -tag -compact -width "AG_PixelFormat **pixel-format "
.It Va float *hue
Color hue (0..1).
.It Va float *saturation
Color saturation (0..1).
.It Va float *value
Color brightness (0..1).
.It Va float *alpha
Alpha component value (0..1).
.It Va AG_PixelFormat **pixel-format
Pointer to the
.Xr AG_PixelFormat 3
to use for generating the
.Va pixel
value.
.It Va Uint32 *pixel
Resulting pixel value.
The pixel's components are extracted immediately when this binding is made
(using the current
.Va pixel-format )
so make sure to always bind
.Va pixel-format
prior to
.Va pixel .
.It Va void *RGBv
A three-element array containing the RGB components.
Acceptable binding types include FLOAT and DOUBLE, INT and UINT8.
For floating point types, the values are scaled to 0.0-1.0.
For integral types, the values are scaled to 0-255.
.It Va void *RGBAv
Same as above, except that the array has 4 elements where the last element
is the alpha component.
.El
.Sh EVENTS
The
.Nm
widget reacts to the following events:
.Pp
.Bl -tag -compact -width 25n
.It window-mouse*
Edit the selected RGBA component.
.It bound
If a new
.Va pixel
binding is made, the pixel's components are extracted and the
.Va hue ,
.Va saturation ,
.Va value
and
.Va alpha
values are updated to reflect an approximation.
.El
.Pp
The
.Nm
widget generates the following events:
.Pp
.Bl -tag -compact -width 2n
.It Fn h-changed "void"
The hue has changed.
.It Fn sv-changed
The saturation or the value has changed.
.El
.Sh TROUBLETONS
The conversion between integer RGB and HSV triplets is not reversible without
loss of precision.
In cases where it is desirable to maintain the same hue throughout changes in
saturation, the color should be stored in HSV format.
.Sh SEE ALSO
.Xr AG_Intro 3 ,
.Xr AG_Widget 3 ,
.Xr AG_Window 3
.Bd -literal
EasyRGB - http://www.easyrgb.com/
The HSV color model - http://en.wikipedia.org/wiki/HSV_color_space
The RGB color model - http://en.wikipedia.org/wiki/RGB_color_model
.Ed
.Sh HISTORY
The
.Nm
widget first appeared in Agar 1.0.