src/motif/colour.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        colour.cpp
   3 // Purpose:     wxColour class
   4 // Author:      Julian Smart
   5 // Modified by:
   6 // Created:     17/09/98
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Julian Smart
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 //// TODO: make wxColour a ref-counted object,
  13 //// so pixel values get shared.
  14
  15 #ifdef __GNUG__
  16 #pragma implementation "colour.h"
  17 #endif
  18
  19 #include "wx/gdicmn.h"
  20 #include "wx/colour.h"
  21 #include "wx/app.h"
  22
  23 #include <Xm/Xm.h>
  24
  25 #include "wx/motif/private.h"
  26
  27 #if !USE_SHARED_LIBRARY
  28 IMPLEMENT_DYNAMIC_CLASS(wxColour, wxObject)
  29 #endif
  30
  31 // Colour
  32
  33 wxColour::wxColour ()
  34 {
  35     m_isInit = FALSE;
  36     m_red = m_blue = m_green = 0;
  37     m_pixel = -1;
  38 }
  39
  40 wxColour::wxColour (unsigned char r, unsigned char g, unsigned char b)
  41 {
  42     m_red = r;
  43     m_green = g;
  44     m_blue = b;
  45     m_isInit = TRUE;
  46     m_pixel = -1;
  47 }
  48
  49 wxColour::wxColour (const wxColour& col)
  50 {
  51     m_red = col.m_red;
  52     m_green = col.m_green;
  53     m_blue = col.m_blue;
  54     m_isInit = col.m_isInit;
  55     m_pixel = col.m_pixel;
  56 }
  57
  58 wxColour& wxColour::operator =(const wxColour& col)
  59 {
  60   m_red = col.m_red;
  61   m_green = col.m_green;
  62   m_blue = col.m_blue;
  63   m_isInit = col.m_isInit;
  64   m_pixel = col.m_pixel;
  65   return *this;
  66 }
  67
  68 wxColour::wxColour (const wxString& col)
  69 {
  70     wxColour *the_colour = wxTheColourDatabase->FindColour (col);
  71     if (the_colour)
  72     {
  73         m_red = the_colour->Red ();
  74         m_green = the_colour->Green ();
  75         m_blue = the_colour->Blue ();
  76         m_isInit = TRUE;
  77     }
  78     else
  79     {
  80         m_red = 0;
  81         m_green = 0;
  82         m_blue = 0;
  83         m_isInit = FALSE;
  84     }
  85 /* TODO
  86     m_pixel = PALETTERGB (m_red, m_green, m_blue);
  87 */
  88 }
  89
  90 wxColour::~wxColour ()
  91 {
  92 }
  93
  94 wxColour& wxColour::operator = (const wxString& col)
  95 {
  96     wxColour *the_colour = wxTheColourDatabase->FindColour (col);
  97     if (the_colour)
  98     {
  99         m_red = the_colour->Red ();
 100         m_green = the_colour->Green ();
 101         m_blue = the_colour->Blue ();
 102         m_isInit = TRUE;
 103     }
 104     else
 105     {
 106         m_red = 0;
 107         m_green = 0;
 108         m_blue = 0;
 109         m_isInit = FALSE;
 110     }
 111 /* TODO
 112     m_pixel = PALETTERGB (m_red, m_green, m_blue);
 113 */
 114     return (*this);
 115 }
 116
 117 void wxColour::Set (unsigned char r, unsigned char g, unsigned char b)
 118 {
 119     m_red = r;
 120     m_green = g;
 121     m_blue = b;
 122     m_isInit = TRUE;
 123 /* TODO
 124     m_pixel = PALETTERGB (m_red, m_green, m_blue);
 125 */
 126 }
 127
 128 // Allocate a colour, or nearest colour, using the given display.
 129 // If realloc is TRUE, ignore the existing pixel, otherwise just return
 130 // the existing one.
 131 // Returns FALSE if an exact match was not found, TRUE otherwise.
 132
 133 // TODO: can this handle mono displays? If not, we should have an extra
 134 // flag to specify whether this should be black or white by default.
 135
 136 bool wxColour::AllocColour(WXDisplay* display, bool realloc)
 137 {
 138     if ((m_pixel != -1) && !realloc)
 139        return TRUE;
 140
 141     XColor color;
 142     color.red = (unsigned short) Red ();
 143     color.red |= color.red << 8;
 144     color.green = (unsigned short) Green ();
 145     color.green |= color.green << 8;
 146     color.blue = (unsigned short) Blue ();
 147     color.blue |= color.blue << 8;
 148
 149     color.flags = DoRed | DoGreen | DoBlue;
 150
 151     WXColormap cmap = wxTheApp->GetMainColormap(display);
 152
 153     if (!XAllocColor ((Display*) display, (Colormap) cmap, &color))
 154     {
 155        m_pixel = wxGetBestMatchingPixel((Display*) display, &color,(Colormap) cmap);
 156        return FALSE;
 157     }
 158     else
 159     {
 160        m_pixel = (int) color.pixel;
 161        return TRUE;
 162     }
 163 }
 164
 165 /*-------------------------------------------
 166 Markus Emmenegger <mege@iqe.ethz.ch>
 167 Find the pixel value with an assigned color closest to the desired color
 168 Used if color cell allocation fails
 169 As the returned pixel value may be in use by another application,
 170 the color might change anytime.
 171 But in many cases, that is still better than always using black.
 172 --
 173 Chris Breeze <chris@hel.co.uk>
 174 Improvements:
 175 1) More efficient calculation of RGB distance of colour cell from
 176    the desired colour. There is no need to take the sqrt of 'dist', and
 177    since we are only interested in the top 8-bits of R, G and B we
 178    can perform integer arithmetic.
 179 2) Attempt to allocate a read-only colour when a close match is found.
 180    A read-only colour will not change.
 181 3) Fall back to the closest match if no read-only colours are available.
 182
 183 Possible further improvements:
 184 1) Scan the lookup table and sort the colour cells in order of
 185 increasing
 186    distance from the desired colour. Then attempt to allocate a
 187 read-only
 188    colour starting from the nearest match.
 189 2) Linear RGB distance is not a particularly good method of colour
 190 matching
 191    (though it is quick). Converting the colour to HLS and then comparing
 192    may give better matching.
 193 -------------------------------------------*/
 194
 195 int wxGetBestMatchingPixel(Display *display, XColor *desiredColor, Colormap cmap)
 196 {
 197     if (cmap == (Colormap) NULL)
 198       cmap = (Colormap) wxTheApp->GetMainColormap(display);
 199
 200     int numPixVals = XDisplayCells(display, DefaultScreen (display));
 201     int mindist = 256 * 256 * 3;
 202     int bestpixel = (int) BlackPixel (display, DefaultScreen (display));
 203     int red = desiredColor->red >> 8;
 204     int green = desiredColor->green >> 8;
 205     int blue = desiredColor->blue >> 8;
 206     const int threshold = 2 * 2 * 3;    // allow an error of up to 2 in R,G & B
 207
 208     for (int pixelcount = 0; pixelcount < numPixVals; pixelcount++)
 209     {
 210         XColor matching_color;
 211         matching_color.pixel = pixelcount;
 212         XQueryColor(display,cmap,&matching_color);
 213
 214         int delta_red = red - (matching_color.red >> 8);
 215         int delta_green = green - (matching_color.green >> 8);
 216         int delta_blue = blue - (matching_color.blue >> 8);
 217
 218         int dist = delta_red * delta_red +
 219                    delta_green * delta_green +
 220                    delta_blue * delta_blue;
 221
 222         if (dist <= threshold)
 223         {
 224             // try to allocate a read-only colour...
 225             if (XAllocColor (display, cmap, &matching_color))
 226             {
 227                 return matching_color.pixel;
 228             }
 229         }
 230         if (dist < mindist)
 231         {
 232             bestpixel = pixelcount;
 233             mindist = dist;
 234         }
 235     }
 236     return bestpixel;
 237 }