Check for NULL before dereferencing

[wxWidgets.git] / src / motif / colour.cpp

diff --git a/src/motif/colour.cpp b/src/motif/colour.cpp
index a6b5b66879029e9aea802bdc28fb0065c19801cc..bd112d6a4ae17fefedbbb8d16f798dc970f0b960 100644 (file)
--- a/src/motif/colour.cpp
+++ b/src/motif/colour.cpp
@@ -9,26 +9,36 @@
 // Licence:    wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 
 // Licence:    wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 

+//// TODO: make wxColour a ref-counted object,
+//// so pixel values get shared.
+

 #ifdef __GNUG__
 #pragma implementation "colour.h"
 #endif
 
 #include "wx/gdicmn.h"
 #include "wx/colour.h"
 #ifdef __GNUG__
 #pragma implementation "colour.h"
 #endif
 
 #include "wx/gdicmn.h"
 #include "wx/colour.h"

+#include "wx/app.h"

 
 

-#if !USE_SHARED_LIBRARY
-IMPLEMENT_DYNAMIC_CLASS(wxColour, wxObject)
+#ifdef __VMS__
+#pragma message disable nosimpint
+#endif
+#include <Xm/Xm.h>
+#ifdef __VMS__
+#pragma message enable nosimpint

 #endif
 
 #endif
 

+#include "wx/motif/private.h"
+
+IMPLEMENT_DYNAMIC_CLASS(wxColour, wxObject)
+

 // Colour
 
 wxColour::wxColour ()
 {
     m_isInit = FALSE;
     m_red = m_blue = m_green = 0;
 // Colour
 
 wxColour::wxColour ()
 {
     m_isInit = FALSE;
     m_red = m_blue = m_green = 0;

-/* TODO
-    m_pixel = 0;
-*/
+    m_pixel = -1;

 }
 
 wxColour::wxColour (unsigned char r, unsigned char g, unsigned char b)
 }
 
 wxColour::wxColour (unsigned char r, unsigned char g, unsigned char b)


@@ -37,9 +47,7 @@ wxColour::wxColour (unsigned char r, unsigned char g, unsigned char b)
     m_green = g;
     m_blue = b;
     m_isInit = TRUE;
     m_green = g;
     m_blue = b;
     m_isInit = TRUE;

-/* TODO
-    m_pixel = PALETTERGB (m_red, m_green, m_blue);
-*/
+    m_pixel = -1;

 }
 
 wxColour::wxColour (const wxColour& col)
 }
 
 wxColour::wxColour (const wxColour& col)


@@ -48,24 +56,20 @@ wxColour::wxColour (const wxColour& col)
     m_green = col.m_green;
     m_blue = col.m_blue;
     m_isInit = col.m_isInit;
     m_green = col.m_green;
     m_blue = col.m_blue;
     m_isInit = col.m_isInit;

-/* TODO

     m_pixel = col.m_pixel;
     m_pixel = col.m_pixel;

-*/

 }
 
 wxColour& wxColour::operator =(const wxColour& col)
 {
 }
 
 wxColour& wxColour::operator =(const wxColour& col)
 {

-  m_red = col.m_red;
-  m_green = col.m_green;
-  m_blue = col.m_blue;
-  m_isInit = col.m_isInit;
-/* TODO
-  m_pixel = col.m_pixel;
-*/
-  return *this;
+    m_red = col.m_red;
+    m_green = col.m_green;
+    m_blue = col.m_blue;
+    m_isInit = col.m_isInit;
+    m_pixel = col.m_pixel;
+    return *this;

 }
 
 }
 

-wxColour::wxColour (const wxString& col)
+void wxColour::InitFromName(const wxString& col)

 {
     wxColour *the_colour = wxTheColourDatabase->FindColour (col);
     if (the_colour)
 {
     wxColour *the_colour = wxTheColourDatabase->FindColour (col);
     if (the_colour)


@@ -73,6 +77,7 @@ wxColour::wxColour (const wxString& col)
         m_red = the_colour->Red ();
         m_green = the_colour->Green ();
         m_blue = the_colour->Blue ();
         m_red = the_colour->Red ();
         m_green = the_colour->Green ();
         m_blue = the_colour->Blue ();

+        m_pixel = the_colour->m_pixel;

         m_isInit = TRUE;
     }
     else
         m_isInit = TRUE;
     }
     else


@@ -82,45 +87,128 @@ wxColour::wxColour (const wxString& col)
         m_blue = 0;
         m_isInit = FALSE;
     }
         m_blue = 0;
         m_isInit = FALSE;
     }

-/* TODO
-    m_pixel = PALETTERGB (m_red, m_green, m_blue);
-*/

 }
 
 wxColour::~wxColour ()
 {
 }
 
 }
 
 wxColour::~wxColour ()
 {
 }
 

-wxColour& wxColour::operator = (const wxString& col)
+void wxColour::Set (unsigned char r, unsigned char g, unsigned char b)

 {
 {

-    wxColour *the_colour = wxTheColourDatabase->FindColour (col);
-    if (the_colour)
+    m_red = r;
+    m_green = g;
+    m_blue = b;
+    m_isInit = TRUE;
+    m_pixel = -1;
+}
+
+// Allocate a colour, or nearest colour, using the given display.
+// If realloc is TRUE, ignore the existing pixel, otherwise just return
+// the existing one.
+// Returns the old or allocated pixel.
+
+// TODO: can this handle mono displays? If not, we should have an extra
+// flag to specify whether this should be black or white by default.
+
+int wxColour::AllocColour(WXDisplay* display, bool realloc)
+{
+    if ((m_pixel != -1) && !realloc)
+        return m_pixel;
+    
+    XColor color;
+    color.red = (unsigned short) Red ();
+    color.red |= color.red << 8;
+    color.green = (unsigned short) Green ();
+    color.green |= color.green << 8;
+    color.blue = (unsigned short) Blue ();
+    color.blue |= color.blue << 8;
+    
+    color.flags = DoRed | DoGreen | DoBlue;
+    
+    WXColormap cmap = wxTheApp->GetMainColormap(display);
+    
+    if (!XAllocColor ((Display*) display, (Colormap) cmap, &color))

     {
     {

-        m_red = the_colour->Red ();
-        m_green = the_colour->Green ();
-        m_blue = the_colour->Blue ();
-        m_isInit = TRUE;
+        m_pixel = wxGetBestMatchingPixel((Display*) display, &color,(Colormap) cmap);
+        return m_pixel;

     }
     else
     {
     }
     else
     {

-        m_red = 0;
-        m_green = 0;
-        m_blue = 0;
-        m_isInit = FALSE;
+        m_pixel = (int) color.pixel;
+        return m_pixel;

     }
     }

-/* TODO
-    m_pixel = PALETTERGB (m_red, m_green, m_blue);
-*/
-    return (*this);

 }
 
 }
 

-void wxColour::Set (unsigned char r, unsigned char g, unsigned char b)
+/*-------------------------------------------
+Markus Emmenegger <mege@iqe.ethz.ch>
+Find the pixel value with an assigned color closest to the desired color
+Used if color cell allocation fails
+As the returned pixel value may be in use by another application,
+the color might change anytime.
+But in many cases, that is still better than always using black.
+--
+Chris Breeze <chris@hel.co.uk>
+Improvements:
+1) More efficient calculation of RGB distance of colour cell from
+the desired colour. There is no need to take the sqrt of 'dist', and
+since we are only interested in the top 8-bits of R, G and B we
+can perform integer arithmetic.
+2) Attempt to allocate a read-only colour when a close match is found.
+A read-only colour will not change.
+3) Fall back to the closest match if no read-only colours are available.
+
+  Possible further improvements:
+  1) Scan the lookup table and sort the colour cells in order of
+  increasing
+  distance from the desired colour. Then attempt to allocate a
+  read-only
+  colour starting from the nearest match.
+  2) Linear RGB distance is not a particularly good method of colour
+  matching
+  (though it is quick). Converting the colour to HLS and then comparing
+  may give better matching.
+-------------------------------------------*/
+
+int wxGetBestMatchingPixel(Display *display, XColor *desiredColor, Colormap cmap)

 {
 {

-    m_red = r;
-    m_green = g;
-    m_blue = b;
-    m_isInit = TRUE;
-/* TODO
-    m_pixel = PALETTERGB (m_red, m_green, m_blue);
-*/
+    if (cmap == (Colormap) NULL)
+        cmap = (Colormap) wxTheApp->GetMainColormap(display);
+    
+    int numPixVals = XDisplayCells(display, DefaultScreen (display));
+    int mindist = 256 * 256 * 3;
+    int bestpixel = (int) BlackPixel (display, DefaultScreen (display));
+    int red = desiredColor->red >> 8;
+    int green = desiredColor->green >> 8;
+    int blue = desiredColor->blue >> 8;
+    const int threshold = 2 * 2 * 3;    // allow an error of up to 2 in R,G & B
+    
+    for (int pixelcount = 0; pixelcount < numPixVals; pixelcount++)
+    {
+        XColor matching_color;
+        matching_color.pixel = pixelcount;
+        XQueryColor(display,cmap,&matching_color);
+        
+        int delta_red = red - (matching_color.red >> 8);
+        int delta_green = green - (matching_color.green >> 8);
+        int delta_blue = blue - (matching_color.blue >> 8);
+        
+        int dist = delta_red * delta_red +
+            delta_green * delta_green +
+            delta_blue * delta_blue;
+        
+        if (dist <= threshold)
+        {
+            // try to allocate a read-only colour...
+            if (XAllocColor (display, cmap, &matching_color))
+            {
+                return matching_color.pixel;
+            }
+        }
+        if (dist < mindist)
+        {
+            bestpixel = pixelcount;
+            mindist = dist;
+        }
+    }
+    return bestpixel;

 }
 }