After testing, I have applied ucko's latest patch for providing access

to "core" fonts when XFT is selected. This allows contexts that need
bitmapped fonts (e.g. GL) to access a bitmap core font, even though
XFT2 does not generally provide bitmap font access.

STR #2214 refers.


git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@7474 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

FL/x.H

@@ -65,11 +65,35 @@ extern FL_EXPORT int fl_screen;
 extern FL_EXPORT XVisualInfo *fl_visual;
 extern FL_EXPORT Colormap fl_colormap;
 
+// access to core fonts:
+// This class provides a "smart pointer" that returns a pointer to an XFontStruct.
+// The global variable fl_xfont can be called wherever a bitmap "core" font is
+// needed, e.g. when rendering to a GL context under X11.
+// With Xlib / X11 fonts, fl_xfont will return the current selected font.
+// With XFT / X11 fonts, fl_xfont will attempt to return the bitmap "core" font most
+// similar to (usually the same as) the current XFT font.
+class Fl_XFont_On_Demand
+{
+public:
+  Fl_XFont_On_Demand(XFontStruct* p = NULL) : ptr(p) { }
+  Fl_XFont_On_Demand& operator=(const Fl_XFont_On_Demand& x)
+    { ptr = x.ptr;  return *this; }
+  Fl_XFont_On_Demand& operator=(XFontStruct* p)
+    { ptr = p;  return *this; }
+  XFontStruct* value();
+  operator XFontStruct*() { return value(); }
+  XFontStruct& operator*() { return *value(); }
+  XFontStruct* operator->() { return value(); }
+  bool operator==(const Fl_XFont_On_Demand& x) { return ptr == x.ptr; }
+  bool operator!=(const Fl_XFont_On_Demand& x) { return ptr != x.ptr; }
+private:
+  XFontStruct *ptr;
+};
+extern FL_EXPORT Fl_XFont_On_Demand fl_xfont;
+
 // drawing functions:
 extern FL_EXPORT GC fl_gc;
 extern FL_EXPORT Window fl_window;
-//extern FL_EXPORT XFontStruct* fl_xfont;
-extern FL_EXPORT XUtf8FontStruct* fl_xfont;
 extern FL_EXPORT void *fl_xftfont;
 FL_EXPORT ulong fl_xpixel(Fl_Color i);
 FL_EXPORT ulong fl_xpixel(uchar r, uchar g, uchar b);

src/fl_font_x.cxx

@@ -39,6 +39,7 @@ Fl_Font_Descriptor::Fl_Font_Descriptor(const char* name) {
 }
 
 Fl_Font_Descriptor* fl_fontsize;
+Fl_XFont_On_Demand fl_xfont;
 
 Fl_Font_Descriptor::~Fl_Font_Descriptor() {
 #  if HAVE_GL
@@ -52,7 +53,10 @@ Fl_Font_Descriptor::~Fl_Font_Descriptor() {
 //  glDeleteLists(listbase+base,size);
 // }
 #  endif
-  if (this == fl_fontsize) fl_fontsize = 0;
+  if (this == fl_fontsize) {
+    fl_fontsize = 0;
+    fl_xfont = 0;
+  }
   XFreeUtf8FontStruct(fl_display, font);
 }
 
@@ -83,6 +87,8 @@ Fl_Fontdesc* fl_fonts = built_in_table;
 
 #define MAXSIZE 32767
 
+#define current_font (fl_fontsize->font)
+
 // return dash number N, or pointer to ending null if none:
 const char* fl_font_word(const char* p, int n) {
   while (*p) {if (*p=='-') {if (!--n) break;} p++;}
@@ -256,11 +262,13 @@ static Fl_Font_Descriptor* find(int fnum, int size) {
 
 Fl_Font fl_font_ = 0;
 Fl_Fontsize fl_size_ = 0;
-//XFontStruct* fl_xfont = 0;
-XUtf8FontStruct* fl_xfont;
 void *fl_xftfont = 0;
 static GC font_gc;
 
+XFontStruct* Fl_XFont_On_Demand::value() {
+  return ptr;
+}
+
 void Fl_Device::font(Fl_Font fnum, Fl_Fontsize size) {
   if (fnum==-1) {
     fl_font_ = 0; fl_size_ = 0;
@@ -271,28 +279,28 @@ void Fl_Device::font(Fl_Font fnum, Fl_Fontsize size) {
   Fl_Font_Descriptor* f = find(fnum, size);
   if (f != fl_fontsize) {
     fl_fontsize = f;
-    fl_xfont = f->font;
+    fl_xfont = current_font->fonts[0];
     font_gc = 0;
   }
 }
 
 int fl_height() {
-  if (fl_xfont) return (fl_xfont->ascent + fl_xfont->descent);
+  if (current_font) return (current_font->ascent + current_font->descent);
   else return -1;
 }
 
 int fl_descent() {
-  if (fl_xfont) return fl_xfont->descent;
+  if (current_font) return current_font->descent;
   else return -1;
 }
 
 double fl_width(const char* c, int n) {
-  if (fl_xfont) return (double) XUtf8TextWidth(fl_xfont, c, n);
+  if (current_font) return (double) XUtf8TextWidth(current_font, c, n);
   else return -1;
 }
 
 double fl_width(unsigned int c) {
-  if (fl_xfont) return (double) XUtf8UcsWidth(fl_xfont, c);
+  if (current_font) return (double) XUtf8UcsWidth(current_font, c);
   else return -1;
 }
 
@@ -312,12 +320,12 @@ void fl_text_extents(const char *c, int n, int &dx, int &dy, int &W, int &H) {
 
 void Fl_Device::draw(const char* c, int n, int x, int y) {
   if (font_gc != fl_gc) {
-    if (!fl_xfont) fl_font(FL_HELVETICA, 14);
+    if (!current_font) fl_font(FL_HELVETICA, 14);
     font_gc = fl_gc;
-    XSetFont(fl_display, fl_gc, fl_xfont->fid);
+    XSetFont(fl_display, fl_gc, current_font->fid);
   }
 //  XDrawString(fl_display, fl_window, fl_gc, x, y, c, n);
-  XUtf8DrawString(fl_display, fl_window, fl_xfont, fl_gc, x, y, c, n);
+  XUtf8DrawString(fl_display, fl_window, current_font, fl_gc, x, y, c, n);
 }
 void Fl_Device::draw(int angle, const char *str, int n, int x, int y) {
   fprintf(stderr,"ROTATING TEXT NOT IMPLIMENTED\n");
@@ -329,10 +337,10 @@ void Fl_Device::draw(int angle, const char *str, int n, int x, int y) {
 
 void fl_rtl_draw(const char* c, int n, int x, int y) {
   if (font_gc != fl_gc) {
-    if (!fl_xfont) fl_font(FL_HELVETICA, 12);
+    if (!current_font) fl_font(FL_HELVETICA, 12);
     font_gc = fl_gc;
   }
-  XUtf8DrawRtlString(fl_display, fl_window, fl_xfont, fl_gc, x, y, c, n);
+  XUtf8DrawRtlString(fl_display, fl_window, current_font, fl_gc, x, y, c, n);
 }
 #endif // FL_DOXYGEN
 //

src/fl_font_xft.cxx

@@ -94,8 +94,7 @@ Fl_Fontdesc* fl_fonts = built_in_table;
 Fl_Font fl_font_ = 0;
 Fl_Fontsize fl_size_ = 0;
 int fl_angle_ = 0; // internal for rotating text support
-//XFontStruct* fl_xfont = 0;
-XUtf8FontStruct* fl_xfont = 0;
+Fl_XFont_On_Demand fl_xfont;
 void *fl_xftfont = 0;
 //const char* fl_encoding_ = "iso8859-1";
 const char* fl_encoding_ = "iso10646-1";
@@ -128,6 +127,8 @@ void fl_font(Fl_Font fnum, Fl_Fontsize size, int angle) {
   fl_fontsize = f;
 #if XFT_MAJOR < 2
   fl_xfont    = f->font->u.core.font;
+#else
+  fl_xfont    = NULL; // invalidate
 #endif // XFT_MAJOR < 2
   fl_xftfont = (void*)f->font;
 }
@@ -372,17 +373,16 @@ void fl_text_extents(const char *c, int n, int &dx, int &dy, int &w, int &h) {
 } // fl_text_extents
 
 
-#if HAVE_GL
-/* This code is used by opengl to get a bitmapped font. The original XFT-1 code
- * used XFT's "core" fonts methods to load an XFT font that was actually a
- * X-bitmap font, that could then be readily used with GL.
- * But XFT-2 does not provide that ability, and there is no easy method to use
- * an XFT font directly with GL. So...
+/* This code is used (mainly by opengl) to get a bitmapped font. The
+ * original XFT-1 code used XFT's "core" fonts methods to load an XFT
+ * font that was actually a X-bitmap font, that could then be readily
+ * used with GL.  But XFT-2 does not provide that ability, and there
+ * is no easy method to use an XFT font directly with GL. So...
 */
 
 #  if XFT_MAJOR > 1
 // This function attempts, on XFT2 systems, to find a suitable "core" Xfont
-// for GL to use, since we dont have an XglUseXftFont(...) function.
+// for GL or other bitmap font needs (we dont have an XglUseXftFont(...) function.)
 // There's probably a better way to do this. I can't believe it is this hard...
 // Anyway... This code attempts to make an XLFD out of the fltk-style font
 // name it is passed, then tries to load that font. Surprisingly, this quite
@@ -392,8 +392,8 @@ void fl_text_extents(const char *c, int n, int &dx, int &dy, int &w, int &h) {
 // If this code fails to load the requested font, it falls back through a
 // series of tried 'n tested alternatives, ultimately resorting to what the
 // original fltk code did.
-// NOTE: On my test boxes (FC6, FC7, FC8, ubuntu8.04) this works well for the 
-//       fltk "built-in" font names.
+// NOTE: On my test boxes (FC6, FC7, FC8, ubuntu8.04, 9.04, 9.10) this works 
+//       well for the fltk "built-in" font names.
 static XFontStruct* load_xfont_for_xft2(void) {
   XFontStruct* xgl_font = 0;
   int size = fl_size_;
@@ -468,7 +468,11 @@ XFontStruct* fl_xxfont() {
   return xftfont->u.core.font;
 #  endif // XFT_MAJOR > 1
 }
-#endif // HAVE_GL
+
+XFontStruct* Fl_XFont_On_Demand::value() {
+  if (!ptr) ptr = fl_xxfont();
+  return ptr;
+}
 
 #if USE_OVERLAY
 // Currently Xft does not work with colormapped visuals, so this probably