Extracting OpenGL text calls. This is a minimum implementation for te…

…sting. Don;t worry. I have a cunning plan for rendering perfect antialiased text into OpenGL contexts quickly on all platforms.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3-porting@11048 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

FL/Fl_Device.H

@@ -113,9 +113,11 @@ public:
  to support all FLTK drawing functions.
   */
 class FL_EXPORT Fl_Graphics_Driver : public Fl_Device {
+  friend class Fl_Pixmap;
+  friend class Fl_Bitmap;
+  friend class Fl_RGB_Image;
 public:
-  /** A 2D coordinate transformation matrix
-   */
+  /** A 2D coordinate transformation matrix */
   struct matrix {double a, b, c, d, x, y;};
 protected:
   static const matrix m0;
@@ -134,64 +136,16 @@ protected:
   static const int region_stack_max = FL_REGION_STACK_SIZE - 1;
   Fl_Region rstack[FL_REGION_STACK_SIZE];
   Fl_Font_Descriptor *font_descriptor_;
-
-protected:
 #ifndef FL_DOXYGEN
   enum {LINE, LOOP, POLYGON, POINT_};
   inline int vertex_no() { return n; }
   inline XPOINT *vertices() {return p;}
   inline int vertex_kind() {return what;}
 #endif
-/*  ** \brief red color for background and/or mixing if device does not support masking or alpha *
-  uchar bg_r_; 
-  ** \brief green color for background and/or mixing if device does not support masking or alpha *
-  uchar bg_g_; 
-  ** \brief blue color for background and/or mixing if device does not support masking or alpha *
-  uchar bg_b_; */
-  friend class Fl_Pixmap;
-  friend class Fl_Bitmap;
-  friend class Fl_RGB_Image;
-  friend void fl_draw(const char *str, int n, int x, int y);
-#ifdef __APPLE__
-  friend void fl_draw(const char *str, int n, float x, float y);
-#elif defined(WIN32)
-  // not needed
-#elif defined(FL_PORTING)
-# pragma message "FL_PORTING: add floating point text positioning if your platform supports it"
-#else 
-  // not needed
-#endif
-  friend void fl_draw(int angle, const char *str, int n, int x, int y);
-  friend void fl_rtl_draw(const char *str, int n, int x, int y);
-  friend void fl_font(Fl_Font face, Fl_Fontsize size);
-
-  friend void fl_draw_image(const uchar* buf, int X,int Y,int W,int H, int D, int L);
-  friend void fl_draw_image_mono(const uchar* buf, int X,int Y,int W,int H, int D, int L);
-  friend void fl_draw_image(Fl_Draw_Image_Cb cb, void* data, int X,int Y,int W,int H, int D);
-  friend FL_EXPORT void fl_draw_image_mono(Fl_Draw_Image_Cb cb, void* data, int X,int Y,int W,int H, int D);
-  friend FL_EXPORT void gl_start();
-  friend void fl_copy_offscreen(int x, int y, int w, int h, Fl_Offscreen pixmap, int srcx, int srcy);
   matrix *fl_matrix; /**< Points to the current coordinate transformation matrix */
 
-  /** \brief The constructor. */
-  Fl_Graphics_Driver();
-  /** \brief see fl_draw(const char *str, int n, int x, int y). */
-  virtual void draw(const char *str, int n, int x, int y) {}
-#ifdef __APPLE__
-  virtual void draw(const char *str, int n, float x, float y) { draw(str, n, (int)(x+0.5), (int)(y+0.5));}
-#elif defined(WIN32)
-  // not needed
-#elif defined(FL_PORTING)
-# pragma message "FL_PORTING: add floating point text positioning if your platform supports it"
-#else
-  // not needed
-#endif
-  /** \brief see fl_draw(int angle, const char *str, int n, int x, int y). */
-  virtual void draw(int angle, const char *str, int n, int x, int y) {}
-  /** \brief see fl_rtl_draw(const char *str, int n, int x, int y). */
-  virtual void rtl_draw(const char *str, int n, int x, int y) {};
-
-  // Images
+public:
+  // ---- Images
   /** \brief see fl_draw_image(const uchar* buf, int X,int Y,int W,int H, int D, int L). */
   virtual   void draw_image(const uchar* buf, int X,int Y,int W,int H, int D=3, int L=0) {}
   /** \brief see fl_draw_image_mono(const uchar* buf, int X,int Y,int W,int H, int D, int L). */
@@ -219,42 +173,16 @@ protected:
    the image offset by the cx and cy arguments.
    */
   virtual void draw(Fl_Bitmap *bm, int XP, int YP, int WP, int HP, int cx, int cy) {}
-#if FLTK_ABI_VERSION >= 10301
-  virtual
-#endif
-  void copy_offscreen(int x, int y, int w, int h, Fl_Offscreen pixmap, int srcx, int srcy);
-
+  virtual int draw_scaled(Fl_Image *img, int X, int Y, int W, int H);
+  virtual void copy_offscreen(int x, int y, int w, int h, Fl_Offscreen pixmap, int srcx, int srcy);
+
+
+  // === all code below in this class has been to the reorganisation FL_PORTING process
 public:
   static const char *class_id;
   virtual const char *class_name() {return class_id;};
-  /** \brief see fl_font(Fl_Font face, Fl_Fontsize size). */
-  virtual void font(Fl_Font face, Fl_Fontsize fsize) {font_ = face; size_ = fsize;}
-  /** \brief see fl_font(void). */
-  Fl_Font font() {return font_; }
-  /** \brief see fl_size(). */
-  Fl_Fontsize size() {return size_; }
-  /** \brief see fl_width(const char *str, int n). */
-  virtual double width(const char *str, int n) {return 0;}
-  /** \brief see fl_width(unsigned int n). */
-  virtual inline double width(unsigned int c) { char ch = (char)c; return width(&ch, 1); }
-  /** \brief see fl_text_extents(const char*, int n, int& dx, int& dy, int& w, int& h). */
-  virtual void text_extents(const char*, int n, int& dx, int& dy, int& w, int& h);
-  /** \brief see fl_height(). */
-  virtual int height() {return size();}
-  /** \brief see fl_descent(). */
-  virtual int descent() {return 0;}
-  /** Returns a pointer to the current Fl_Font_Descriptor for the graphics driver */
-  inline Fl_Font_Descriptor *font_descriptor() { return font_descriptor_;}
-  /** Sets the current Fl_Font_Descriptor for the graphics driver */
-  inline void font_descriptor(Fl_Font_Descriptor *d) { font_descriptor_ = d;}
-#if FLTK_ABI_VERSION >= 10304 || defined(FL_DOXYGEN)
-  virtual
-#endif
-  int draw_scaled(Fl_Image *img, int X, int Y, int W, int H);
-  /** \brief The destructor */
+  Fl_Graphics_Driver();
   virtual ~Fl_Graphics_Driver() { if (p) free(p); }
-
-  // === all code below in this class has been to the reorganisation FL_PORTING process
 public:
   // --- implementation is in src/fl_rect.cxx which includes src/cfg_gfx/xxx_rect.cxx
   virtual void point(int x, int y) = 0;
@@ -320,6 +248,21 @@ public:
   virtual void color(Fl_Color c) { color_ = c; }
   virtual Fl_Color color() { return color_; }
   virtual void color(uchar r, uchar g, uchar b) = 0;
+  // --- implementation is in src/fl_font.cxx which includes src/cfg_gfx/xxx_font.cxx
+  virtual void draw(const char *str, int n, int x, int y) = 0;
+  virtual void draw(const char *str, int n, float x, float y) { draw(str, n, (int)(x+0.5), (int)(y+0.5));}
+  virtual void draw(int angle, const char *str, int n, int x, int y) { draw(str, n, x, y); }
+  virtual void rtl_draw(const char *str, int n, int x, int y) { draw(str, n, x, y); }
+  virtual void font(Fl_Font face, Fl_Fontsize fsize) {font_ = face; size_ = fsize;}
+  virtual Fl_Font font() {return font_; }
+  virtual Fl_Fontsize size() {return size_; }
+  virtual double width(const char *str, int n) { return 0; }
+  virtual double width(unsigned int c) { char ch = (char)c; return width(&ch, 1); }
+  virtual void text_extents(const char*, int n, int& dx, int& dy, int& w, int& h);
+  virtual int height() { return size(); }
+  virtual int descent() { return 0; }
+  virtual Fl_Font_Descriptor *font_descriptor() { return font_descriptor_;}
+  virtual void font_descriptor(Fl_Font_Descriptor *d) { font_descriptor_ = d;}
 
 protected:
   // --- implementation is in src/fl_vertex.cxx which includes src/cfg_gfx/xxx_rect.cxx

src/Fl_Gl_Device_Plugin.cxx

@@ -55,6 +55,7 @@ const char *Fl_OpenGL_Display_Device::class_id = "Fl_OpenGL_Display_Device";
 
 #include "cfg_gfx/opengl_arci.cxx"
 #include "cfg_gfx/opengl_color.cxx"
+#include "cfg_gfx/opengl_font.cxx"
 #include "cfg_gfx/opengl_line_style.cxx"
 #include "cfg_gfx/opengl_rect.cxx"
 #include "cfg_gfx/opengl_vertex.cxx"

src/cfg_gfx/opengl.H

@@ -35,7 +35,6 @@ class FL_EXPORT Fl_OpenGL_Graphics_Driver : public Fl_Graphics_Driver {
 public:
   static const char *class_id;
   const char *class_name() {return class_id;};
-  void draw(const char* str, int n, int x, int y);
   // --- line and polygon drawing with integer coordinates
   void point(int x, int y);
   void rect(int x, int y, int w, int h);
@@ -86,6 +85,12 @@ public:
   void color(Fl_Color c);
   Fl_Color color() { return color_; }
   void color(uchar r, uchar g, uchar b);
+  // --- implementation is in src/fl_font.cxx which includes src/cfg_gfx/xxx_font.cxx
+  void draw(const char *str, int n, int x, int y);
+  double width(const char *str, int n);
+  void text_extents(const char*, int n, int& dx, int& dy, int& w, int& h);
+  int height();
+  int descent();
 };
 
 

src/cfg_gfx/opengl_font.cxx

@@ -0,0 +1,133 @@
+//
+// "$Id$"
+//
+// Standard X11 font selection code for the Fast Light Tool Kit (FLTK).
+//
+// Copyright 1998-2016 by Bill Spitzak and others.
+//
+// This library is free software. Distribution and use rights are outlined in
+// the file "COPYING" which should have been included with this file.  If this
+// file is missing or damaged, see the license at:
+//
+//     http://www.fltk.org/COPYING.php
+//
+// Please report all bugs and problems on the following page:
+//
+//     http://www.fltk.org/str.php
+//
+
+/*
+ This module implements a lowest-common-denominator font for OpenGL.
+ It will always work, even if the main graphics library does not support
+ rendering text into a texture buffer.
+ 
+ The font is limited to a single face and ASCII characters. It is drawn using
+ lines which makes it arbitrarily scalable. I am trying to keep font data really
+ compact.
+ */
+
+
+#include <FL/gl.h>
+
+/*
+  |01234567|
+ -+--------+
+ 0|        |____
+ 1|++++++++|font
+ 2|++++++++|
+ 3|++++++++|
+ 4|++++++++|
+ 5|++++++++|____
+ 6|        |descent
+ 7|        |
+ -+--------+
+ */
+
+
+static const char *font_data[128] = {
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, /*T*/"\11\71\100\41\45", 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+
+  0, 0, 0, 0, 0, /*e*/"\55\25\14\13\22\52\63\64\14", 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, /*s*/"\62\22\13\64\55\15", /*t*/"\41\44\55\65\100\22\62", 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+};
+
+
+#if 0
+
+void Fl_OpenGL_Graphics_Driver::draw(const char* str, int n, int x, int y) {
+  gl_draw(str, n, x, y);
+}
+
+#else
+
+double Fl_OpenGL_Graphics_Driver::width(const char *str, int n) {
+  return size_*n*0.5;
+}
+
+int Fl_OpenGL_Graphics_Driver::descent() {
+  return (int)(size_ - size_*0.8);
+}
+
+int Fl_OpenGL_Graphics_Driver::height() {
+  return (int)(size_*0.8);
+}
+
+void Fl_OpenGL_Graphics_Driver::text_extents(const char *str, int n, int& dx, int& dy, int& w, int& h)
+{
+  dx = 0;
+  dy = descent();
+  w = width(str, n);
+  h = size_;
+}
+
+void Fl_OpenGL_Graphics_Driver::draw(const char *str, int n, int x, int y)
+{
+  int i;
+  for (i=0; i<n; i++) {
+    char c = str[i] & 0x7f;
+    const char *fd = font_data[(int)c];
+    if (fd) {
+      char rendering = 0;
+      float px, py;
+      for (;;) {
+        char cmd = *fd++;
+        if (cmd==0) {
+          if (rendering) {
+            glEnd();
+            glBegin(GL_POINTS); glVertex2f(px, py); glEnd();
+            rendering = 0;
+          }
+          break;
+        } else if (cmd>63) {
+          if (cmd=='\100' && rendering) {
+            glEnd();
+            glBegin(GL_POINTS); glVertex2f(px, py); glEnd();
+            rendering = 0;
+          }
+        } else {
+          if (!rendering) { glBegin(GL_LINE_STRIP); rendering = 1; }
+          int vx = (cmd & '\70')>>3;
+          int vy = (cmd & '\07');
+          px = 0.5+x+vx*size_*0.5/8.0;
+          py = 0.5+y+vy*size_/8.0-0.8*size_;
+          glVertex2f(px, py);
+        }
+      }
+    }
+    x += size_*0.5;
+  }
+}
+
+#endif
+
+
+//
+// End of "$Id$".
+//

src/cfg_gfx/opengl_rect.cxx

@@ -28,10 +28,6 @@
 #include <FL/gl.h>
 #include "opengl.H"
 
-void Fl_OpenGL_Graphics_Driver::draw(const char* str, int n, int x, int y) {
-  gl_draw(str, n, x, y);
-}
-
 // --- line and polygon drawing with integer coordinates
 
 void Fl_OpenGL_Graphics_Driver::point(int x, int y) {

src/cfg_gfx/quartz.H

@@ -43,13 +43,7 @@ class FL_EXPORT Fl_Quartz_Graphics_Driver : public Fl_Graphics_Driver {
 public:
   static const char *class_id;
   const char *class_name() {return class_id;};
-  void draw(const char* str, int n, int x, int y);
-#ifdef __APPLE__
-  void draw(const char *str, int n, float x, float y);
-#endif
-  void draw(int angle, const char *str, int n, int x, int y);
-  void rtl_draw(const char* str, int n, int x, int y);
-  void font(Fl_Font face, Fl_Fontsize size);
+
   void draw(Fl_Pixmap *pxm, int XP, int YP, int WP, int HP, int cx, int cy);
   void draw(Fl_Bitmap *pxm, int XP, int YP, int WP, int HP, int cx, int cy);
   void draw(Fl_RGB_Image *img, int XP, int YP, int WP, int HP, int cx, int cy);
@@ -58,11 +52,6 @@ public:
   void draw_image(Fl_Draw_Image_Cb cb, void* data, int X,int Y,int W,int H, int D=3);
   void draw_image_mono(const uchar* buf, int X,int Y,int W,int H, int D=1, int L=0);
   void draw_image_mono(Fl_Draw_Image_Cb cb, void* data, int X,int Y,int W,int H, int D=1);
-  double width(const char *str, int n);
-  double width(unsigned int c);
-  void text_extents(const char*, int n, int& dx, int& dy, int& w, int& h);
-  int height();
-  int descent();
 #if ! defined(FL_DOXYGEN)
   static Fl_Offscreen create_offscreen_with_alpha(int w, int h);
 #endif
@@ -113,6 +102,17 @@ protected:
   void color(Fl_Color c);
   Fl_Color color() { return color_; }
   void color(uchar r, uchar g, uchar b);
+  // --- implementation is in src/fl_font.cxx which includes src/cfg_gfx/xxx_font.cxx
+  void draw(const char *str, int n, int x, int y);
+  void draw(const char *str, int n, float x, float y);
+  void draw(int angle, const char *str, int n, int x, int y);
+  void rtl_draw(const char *str, int n, int x, int y);
+  void font(Fl_Font face, Fl_Fontsize fsize);
+  double width(const char *str, int n);
+  double width(unsigned int c);
+  void text_extents(const char*, int n, int& dx, int& dy, int& w, int& h);
+  int height();
+  int descent();
 };
 
 

src/fl_font_mac.cxx → src/cfg_gfx/quartz_font.cxx

@@ -3,7 +3,7 @@
 //
 // MacOS font selection routines for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 1998-2015 by Bill Spitzak and others.
+// Copyright 1998-2016 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this

src/fl_font.cxx

@@ -48,7 +48,7 @@
 #ifdef WIN32
 #  include "fl_font_win32.cxx"
 #elif defined(__APPLE__)
-#  include "fl_font_mac.cxx"
+#  include "cfg_gfx/quartz_font.cxx"
 #elif USE_XFT
 #  include "fl_font_xft.cxx"
 #elif defined(FL_PORTING)