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[wxWidgets.git] / 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_pixel = the_colour->m_pixel;
77 m_isInit = TRUE;
78 }
79 else
80 {
81 m_red = 0;
82 m_green = 0;
83 m_blue = 0;
84 m_isInit = FALSE;
85 }
86 }
87
88 wxColour::~wxColour ()
89 {
90 }
91
92 wxColour& wxColour::operator = (const wxString& col)
93 {
94 wxColour *the_colour = wxTheColourDatabase->FindColour (col);
95 if (the_colour)
96 {
97 m_red = the_colour->Red ();
98 m_green = the_colour->Green ();
99 m_blue = the_colour->Blue ();
100 m_pixel = the_colour->m_pixel;
101 m_isInit = TRUE;
102 }
103 else
104 {
105 m_red = 0;
106 m_green = 0;
107 m_blue = 0;
108 m_isInit = FALSE;
109 }
110
111 return (*this);
112 }
113
114 void wxColour::Set (unsigned char r, unsigned char g, unsigned char b)
115 {
116 m_red = r;
117 m_green = g;
118 m_blue = b;
119 m_isInit = TRUE;
120 m_pixel = -1;
121 }
122
123 // Allocate a colour, or nearest colour, using the given display.
124 // If realloc is TRUE, ignore the existing pixel, otherwise just return
125 // the existing one.
126 // Returns the old or allocated pixel.
127
128 // TODO: can this handle mono displays? If not, we should have an extra
129 // flag to specify whether this should be black or white by default.
130
131 int wxColour::AllocColour(WXDisplay* display, bool realloc)
132 {
133 if ((m_pixel != -1) && !realloc)
134 return m_pixel;
135
136 XColor color;
137 color.red = (unsigned short) Red ();
138 color.red |= color.red << 8;
139 color.green = (unsigned short) Green ();
140 color.green |= color.green << 8;
141 color.blue = (unsigned short) Blue ();
142 color.blue |= color.blue << 8;
143
144 color.flags = DoRed | DoGreen | DoBlue;
145
146 WXColormap cmap = wxTheApp->GetMainColormap(display);
147
148 if (!XAllocColor ((Display*) display, (Colormap) cmap, &color))
149 {
150 m_pixel = wxGetBestMatchingPixel((Display*) display, &color,(Colormap) cmap);
151 return m_pixel;
152 }
153 else
154 {
155 m_pixel = (int) color.pixel;
156 return m_pixel;
157 }
158 }
159
160 /*-------------------------------------------
161 Markus Emmenegger <mege@iqe.ethz.ch>
162 Find the pixel value with an assigned color closest to the desired color
163 Used if color cell allocation fails
164 As the returned pixel value may be in use by another application,
165 the color might change anytime.
166 But in many cases, that is still better than always using black.
167 --
168 Chris Breeze <chris@hel.co.uk>
169 Improvements:
170 1) More efficient calculation of RGB distance of colour cell from
171 the desired colour. There is no need to take the sqrt of 'dist', and
172 since we are only interested in the top 8-bits of R, G and B we
173 can perform integer arithmetic.
174 2) Attempt to allocate a read-only colour when a close match is found.
175 A read-only colour will not change.
176 3) Fall back to the closest match if no read-only colours are available.
177
178 Possible further improvements:
179 1) Scan the lookup table and sort the colour cells in order of
180 increasing
181 distance from the desired colour. Then attempt to allocate a
182 read-only
183 colour starting from the nearest match.
184 2) Linear RGB distance is not a particularly good method of colour
185 matching
186 (though it is quick). Converting the colour to HLS and then comparing
187 may give better matching.
188 -------------------------------------------*/
189
190 int wxGetBestMatchingPixel(Display *display, XColor *desiredColor, Colormap cmap)
191 {
192 if (cmap == (Colormap) NULL)
193 cmap = (Colormap) wxTheApp->GetMainColormap(display);
194
195 int numPixVals = XDisplayCells(display, DefaultScreen (display));
196 int mindist = 256 * 256 * 3;
197 int bestpixel = (int) BlackPixel (display, DefaultScreen (display));
198 int red = desiredColor->red >> 8;
199 int green = desiredColor->green >> 8;
200 int blue = desiredColor->blue >> 8;
201 const int threshold = 2 * 2 * 3; // allow an error of up to 2 in R,G & B
202
203 for (int pixelcount = 0; pixelcount < numPixVals; pixelcount++)
204 {
205 XColor matching_color;
206 matching_color.pixel = pixelcount;
207 XQueryColor(display,cmap,&matching_color);
208
209 int delta_red = red - (matching_color.red >> 8);
210 int delta_green = green - (matching_color.green >> 8);
211 int delta_blue = blue - (matching_color.blue >> 8);
212
213 int dist = delta_red * delta_red +
214 delta_green * delta_green +
215 delta_blue * delta_blue;
216
217 if (dist <= threshold)
218 {
219 // try to allocate a read-only colour...
220 if (XAllocColor (display, cmap, &matching_color))
221 {
222 return matching_color.pixel;
223 }
224 }
225 if (dist < mindist)
226 {
227 bestpixel = pixelcount;
228 mindist = dist;
229 }
230 }
231 return bestpixel;
232 }