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