wxWidgets/interface/wx/colour.h

/////////////////////////////////////////////////////////////////////////////
// Name:        colour.h
// Purpose:     interface of wxColour
// Author:      wxWidgets team
// RCS-ID:      $Id$
// Licence:     wxWindows license
/////////////////////////////////////////////////////////////////////////////

/**
    @class wxColour

    A colour is an object representing a combination of Red, Green, and Blue
    (RGB) intensity values, and is used to determine drawing colours. See the
    entry for wxColourDatabase for how a pointer to a predefined, named colour
    may be returned instead of creating a new colour.

    Valid RGB values are in the range 0 to 255.

    You can retrieve the current system colour settings with wxSystemSettings.

    @library{wxcore}
    @category{gdi}

    @stdobjects
    - ::wxNullColour - An empty, invalid colour.
    - ::wxBLACK
    - ::wxBLUE
    - ::wxCYAN
    - ::wxGREEN
    - ::wxLIGHT_GREY
    - ::wxRED
    - ::wxWHITE

    @see wxColourDatabase, wxPen, wxBrush, wxColourDialog, wxSystemSettings
*/
class wxColour : public wxObject
{
public:

    /**
        Default constructor.
    */
    wxColour();

    /**
        @param red
            The red value.
        @param green
            The green value.
        @param blue
            The blue value.
        @param alpha
            The alpha value. Alpha values range from 0 (wxALPHA_TRANSPARENT) to
            255 (wxALPHA_OPAQUE).
    */
    wxColour(unsigned char red, unsigned char green, unsigned char blue,
             unsigned char alpha = wxALPHA_OPAQUE);

    /**
        @param colourName
            The colour name.
    */
    wxColour(const wxString& colourName);

    /**
        Copy constructor.
    */
    wxColour(const wxColour& colour);

    /**
        Returns the alpha value, on platforms where alpha is not yet supported, this
        always returns wxALPHA_OPAQUE.
    */
    virtual unsigned char Alpha() const;

    /**
        Returns the blue intensity.
    */
    virtual unsigned char Blue() const;

    /**
        Converts this colour to a wxString using the given flags.

        The supported flags are wxC2S_NAME, to obtain the colour name (e.g.
        wxColour(255,0,0) == "red"), wxC2S_CSS_SYNTAX, to obtain the colour in
        the "rgb(r,g,b)" or "rgba(r,g,b,a)" syntax (e.g.
        wxColour(255,0,0,85) == "rgba(255,0,0,0.333)"), and wxC2S_HTML_SYNTAX,
        to obtain the colour as "#" followed by 6 hexadecimal digits (e.g.
        wxColour(255,0,0) == "#FF0000").

        This function never fails and always returns a non-empty string but
        asserts if the colour has alpha channel (i.e. is non opaque) but
        wxC2S_CSS_SYNTAX (which is the only one supporting alpha) is not
        specified in flags.

        @since 2.7.0
    */
    wxString GetAsString(long flags);

    /**
        Returns a pixel value which is platform-dependent. On Windows, a COLORREF is
        returned.
        On X, an allocated pixel value is returned.
        -1 is returned if the pixel is invalid (on X, unallocated).
    */
    long GetPixel() const;

    /**
        Returns the green intensity.
    */
    virtual unsigned char Green() const;

    /**
        Returns @true if the colour object is valid (the colour has been initialised
        with RGB values).
    */
    bool IsOk() const;

    /**
        Returns the red intensity.
    */
    virtual unsigned char Red() const;

    //@{
    /**
        Sets the RGB intensity values using the given values (first overload),
        extracting them from the packed long (second overload), using the given
        string (third overloard).

        When using third form, Set() accepts: colour names (those listed in
        wxTheColourDatabase()), the CSS-like @c "rgb(r,g,b)" or
        @c "rgba(r,g,b,a)" syntax (case insensitive) and the HTML-like syntax
        (i.e. @c "#" followed by 6 hexadecimal digits for red, green, blue
        components).

        Returns @true if the conversion was successful, @false otherwise.

        @since 2.7.0
    */
    void Set(unsigned char red, unsigned char green,
             unsigned char blue,
             unsigned char alpha = wxALPHA_OPAQUE);
    void Set(unsigned long RGB);
    bool Set(const wxString& str);
    //@}

    /**
        Tests the inequality of two colours by comparing individual red, green, blue
        colours and alpha values.
    */
    bool operator !=(const wxColour& colour);

    //@{
    /**
        Assignment operator, using a colour name to be found in the colour database.

        @see wxColourDatabase
    */
    wxColour operator =(const wxColour& colour);
    wxColour operator =(const wxString& colourName);
    //@}

    /**
        Tests the equality of two colours by comparing individual red, green, blue
        colours and alpha values.
    */
    bool operator ==(const wxColour& colour);
};


/** @name Predefined colors. */
//@{
wxColour wxNullColour;
wxColour* wxBLACK;
wxColour* wxBLUE;
wxColour* wxCYAN;
wxColour* wxGREEN;
wxColour* wxLIGHT_GREY;
wxColour* wxRED;
wxColour* wxWHITE;
//@}



// ============================================================================
// Global functions/macros
// ============================================================================

/** @ingroup group_funcmacro_misc */
//@{

/**
    Converts string to a wxColour best represented by the given string. Returns
    @true on success.

    @see wxToString(const wxColour&)

    @header{wx/colour.h}
*/
bool wxFromString(const wxString& string, wxColour* colour);

/**
    Converts the given wxColour into a string.

    @see wxFromString(const wxString&, wxColour*)

    @header{wx/colour.h}
*/
wxString wxToString(const wxColour& colour);

//@}