add rendercolor class, with a cache of gcs for the colors

1 files changed, 83 insertions, 0 deletions

diff --git a/otk/rendercolor.cc b/otk/rendercolor.cc
new file mode 100644
index 00000000..99dd3341
--- /dev/null
+++ b/otk/rendercolor.cc
@@ -0,0 +1,83 @@
+// -*- mode: C++; indent-tabs-mode: nil; c-basic-offset: 2; -*-
+
+#ifdef    HAVE_CONFIG_H
+#  include "../config.h"
+#endif // HAVE_CONFIG_H
+
+#include "rendercolor.hh"
+#include "display.hh"
+#include "screeninfo.hh"
+
+namespace otk {
+
+std::map<unsigned long, RenderColor::CacheItem*> *RenderColor::_cache = 0;
+
+void RenderColor::initialize()
+{
+  _cache = new std::map<unsigned long, CacheItem*>[ScreenCount(**display)];
+}
+
+void RenderColor::destroy()
+{
+  delete [] _cache;
+}
+  
+RenderColor::RenderColor(int screen, unsigned char red,
+			 unsigned char green, unsigned char blue)
+  : _screen(screen),
+    _red(red),
+    _green(green),
+    _blue(blue),
+    _gc(0)
+{
+  unsigned long color = _blue | _green << 8 | _red << 16;
+  
+  // try get a gc from the cache
+  CacheItem *item = _cache[_screen][color];
+
+  if (item) {
+    _gc = item->gc;
+    ++item->count;
+  } else {
+    XGCValues gcv;
+
+    // allocate a color and GC from the server
+    const ScreenInfo *info = display->screenInfo(_screen);
+
+    XColor xcol;    // convert from 0-0xff to 0-0xffff
+    xcol.red = _red; xcol.red |= xcol.red << 8;
+    xcol.green = _green; xcol.green |= xcol.green << 8;
+    xcol.blue = _blue; xcol.blue |= xcol.blue << 8;
+    xcol.pixel = 0;
+
+    if (! XAllocColor(**display, info->colormap(), &xcol)) {
+      fprintf(stderr, "RenderColor: color alloc error: rgb:%x/%x/%x\n",
+	      _red, _green, _blue);
+      xcol.pixel = 0;
+    }
+
+    gcv.foreground = xcol.pixel;
+    _gc = XCreateGC(**display, info->rootWindow(), GCForeground, &gcv);
+    assert(_gc);
+
+    // insert into the cache
+    _cache[_screen][color] = new CacheItem(_gc);
+  }
+}
+
+RenderColor::~RenderColor()
+{
+  unsigned long color = _blue | _green << 8 | _red << 16;
+  
+  CacheItem *item = _cache[_screen][color];
+  assert(item); // it better be in the cache ...
+
+  if (--item->count <= 0) {
+    // remove from the cache
+    XFreeGC(**display, _gc);
+    _cache[_screen][color] = 0;
+    delete item;
+  }
+}
+
+}