Android: Fl_Android_Graphics_Driver now derives from Fl_Graphics_Driver and no longer from the dpi-aware scaling version. I may add this level of complexity later, but for now, unscaled drivers are difficult enough. Also, the new setup lets me easily find unimplemented methods of the driver.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.4@12809 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

1 files changed, 347 insertions, 116 deletions

diff --git a/src/drivers/Android/Fl_Android_Graphics_Driver.H b/src/drivers/Android/Fl_Android_Graphics_Driver.H
index e6b4991a2..0b67e8c7a 100644
--- a/src/drivers/Android/Fl_Android_Graphics_Driver.H
+++ b/src/drivers/Android/Fl_Android_Graphics_Driver.H
@@ -39,149 +39,370 @@ class Fl_Android_Bytemap;
 
   This class is implemented only on the Windows platform.
 */
-class FL_EXPORT Fl_Android_Graphics_Driver : public Fl_Scalable_Graphics_Driver
+class FL_EXPORT Fl_Android_Graphics_Driver : public Fl_Graphics_Driver
 {
-  class Vertex {
-  public:
-    void set(float x, float y, bool gap = false) { pX = x; pY = y; pIsGap = gap; }
-    float pX, pY;
-    bool pIsGap;
-  };
+  // easy access to the super class
+  typedef Fl_Graphics_Driver super;
 
-public:
-  Fl_Android_Graphics_Driver();
-  virtual ~Fl_Android_Graphics_Driver() override;
+protected:
+  class Vertex; // see below
 
-  void make_current(Fl_Window*);
+  // --- this is a copy of Fl_Graphics_Driver ----------------------------------
+  // - use this to find unimplementet calls in the derived driver
+  // - excluded by #if/#endif means that we have not implemneted this yet
+  // - methods marked with // super: use the implemnetation of the super class
+  // - virtual ... override functions are implemented for Android
+#if 0
+private:
+  // some platforms may need to reimplement this
+  virtual void set_current_();
+protected:
+  float scale_; // scale between user and graphical coordinates: graphical = user * scale_
+  /** Sets the current value of the scaling factor */
+  virtual void scale(float f) { scale_ = f; }
+public:
+  // The following functions create the various graphics drivers that are required
+  // for core operations. They must be implemented as members of Fl_Graphics_Driver,
+  // but located in the device driver module that is linked to the core library
+  /** Instantiate the graphics driver adequate to draw to the platform's display driver.
+   Each platform implements this method its own way.
+   */
+  static Fl_Graphics_Driver *newMainGraphicsDriver();
+  /** A 2D coordinate transformation matrix */
+  struct matrix {double a, b, c, d, x, y;};
+  /** Features that a derived class may possess.  */
+  typedef enum {
+    NATIVE = 1, /**< native graphics driver for the platform */
+    PRINTER = 2 /**< graphics driver for a printer drawing surface */
+  } driver_feature;
 
-  // --- text and font stuff
-  virtual void draw_unscaled(const char* str, int n, int x, int y) override;
-  virtual double width_unscaled(const char *str, int n) override;
-  virtual double width_unscaled(unsigned int c) override;
-  virtual Fl_Fontsize size_unscaled() override;
-  virtual void text_extents_unscaled(const char *str, int n, int &dx, int &dy, int &w, int &h) override;
-  virtual int height_unscaled() override;
-  virtual int descent_unscaled() override;
-  virtual void font_unscaled(Fl_Font face, Fl_Fontsize size) override;
-  virtual const char *get_font_name(Fl_Font fnum, int* ap) override;
-  virtual const char *font_name(int num) override;
-  virtual int get_font_sizes(Fl_Font fnum, int*& sizep) override;
-  virtual Fl_Font set_fonts(const char *name) override;
-  virtual void font_name(int num, const char *name) override;
+protected:
+  int fl_clip_state_number; ///< For internal use by FLTK
+  static const matrix m0; ///< For internal use by FLTK
+  Fl_Font font_; ///< current font
+  Fl_Fontsize size_; ///< current font size
+  Fl_Color color_; ///< current color
+  int sptr;///< For internal use by FLTK
+  static const int matrix_stack_size = FL_MATRIX_STACK_SIZE; ///< For internal use by FLTK
+  matrix stack[FL_MATRIX_STACK_SIZE]; ///< For internal use by FLTK
+  matrix m; ///< current transformation matrix
+  int n; ///< For internal use by FLTK
+  int gap_; ///< For internal use by FLTK
+  int what; ///< For internal use by FLTK
+  int rstackptr; ///< For internal use by FLTK
+  static const int region_stack_max = FL_REGION_STACK_SIZE - 1; ///< For internal use by FLTK
+  Fl_Region rstack[FL_REGION_STACK_SIZE]; ///< For internal use by FLTK
+  Fl_Font_Descriptor *font_descriptor_; ///< For internal use by FLTK
+#ifndef FL_DOXYGEN
+  enum {LINE, LOOP, POLYGON, POINT_};
+  inline int vertex_no() { return n; }
+  inline int vertex_kind() {return what;}
+#endif
+  matrix *fl_matrix; /**< Points to the current coordinate transformation matrix */
+  virtual void global_gc();
+  /** Support function for Fl_Pixmap drawing */
+  virtual fl_uintptr_t cache(Fl_Pixmap *img) { return 0; }
+#endif
+  /** Support function for Fl_Bitmap drawing */
+  virtual fl_uintptr_t cache(Fl_Bitmap *img) override;
+#if 0
+  /** Support function for Fl_RGB_Image drawing */
+  virtual void uncache(Fl_RGB_Image *img, fl_uintptr_t &id_, fl_uintptr_t &mask_) { }
+  // --- implementation is in src/drivers/xxx/Fl_xxx_Graphics_Driver_image.cxx
+  /** 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) {}
+  /** see fl_draw_image_mono(const uchar* buf, int X,int Y,int W,int H, int D, int L) */
+  virtual void draw_image_mono(const uchar* buf, int X,int Y,int W,int H, int D=1, int L=0) {}
+  /** see fl_draw_image(Fl_Draw_Image_Cb cb, void* data, int X,int Y,int W,int H, int D) */
+  virtual void draw_image(Fl_Draw_Image_Cb cb, void* data, int X,int Y,int W,int H, int D=3) {}
+  /** see fl_draw_image_mono(Fl_Draw_Image_Cb cb, void* data, int X,int Y,int W,int H, int D) */
+  virtual void draw_image_mono(Fl_Draw_Image_Cb cb, void* data, int X,int Y,int W,int H, int D=1) {}
+  /** \brief Draws an Fl_RGB_Image object using this graphics driver.
+   *
+   Specifies a bounding box for the image, with the origin (upper left-hand corner) of
+   the image offset by the cx and cy arguments.
+   */
+  virtual void draw(Fl_RGB_Image * rgb,int XP, int YP, int WP, int HP, int cx, int cy) {}
+  /** \brief Draws an Fl_Pixmap object using this graphics driver.
+   *
+   Specifies a bounding box for the image, with the origin (upper left-hand corner) of
+   the image offset by the cx and cy arguments.
+   */
+  virtual void draw(Fl_Pixmap * pxm,int XP, int YP, int WP, int HP, int cx, int cy) {}
+#endif
+  /** \brief Draws an Fl_Bitmap object using this graphics driver.
+   *
+   Specifies a bounding box for the image, with the origin (upper left-hand corner) of
+   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) override;
+#if 0
+  virtual void copy_offscreen(int x, int y, int w, int h, Fl_Offscreen pixmap, int srcx, int srcy);
 
-  // --- line drawing stuff
-  virtual void rectf_unscaled(float x, float y, float w, float h) override;
-  void rectf_unclipped(float x, float y, float w, float h);
-  virtual void point_unscaled(float x, float y) override;
-  virtual void rect_unscaled(float x, float y, float w, float h) override;
-  virtual void xyline_unscaled(float x, float y, float x1) override;
-  void xyline_unclipped(float x, float y, float x1);
-  virtual void yxline_unscaled(float x, float y, float y1) override;
-  void yxline_unclipped(float x, float y, float y1);
-  virtual void line_unscaled(float  x, float y, float x1, float y1) override;
-  virtual void line_unscaled(float x, float y, float x1, float y1, float x2, float y2) override;
-  virtual void loop_unscaled(float x0, float y0, float x1, float y1, float x2, float y2) override;
-  virtual void loop_unscaled(float x0, float y0, float x1, float y1, float x2, float y2, float x3, float y3) override;
-  virtual void polygon_unscaled(float x0, float y0, float x1, float y1, float x2, float y2) override;
-  virtual void polygon_unscaled(float x0, float y0, float x1, float y1, float x2, float y2, float x3, float y3) override;
-  virtual void arc_unscaled(float x, float y, float w, float h, double a1, double a2) override;
-  virtual void pie_unscaled(float x, float y, float w, float h, double a1, double a2) override;
-  virtual void ellipse_unscaled(double xt, double yt, double rx, double ry) override;
-
-  // --- implementation is in src/fl_vertex.cxx which includes src/cfg_gfx/xxx_rect.cxx
+  /** Support function for image drawing */
+  virtual Fl_Bitmask create_bitmask(int w, int h, const uchar *array) {return 0; }
+  /** Support function for image drawing */
+  virtual void delete_bitmask(Fl_Bitmask bm) {}
+  /** For internal library use only */
+  static void change_image_size(Fl_Image *img, int W, int H) {
+    img->w(W);
+    img->h(H);
+  }
+  // Support function for image drawing
+  virtual void uncache_pixmap(fl_uintptr_t p);
+  // accessor functions to protected image members
+  int start_image(Fl_Image *img, int XP, int YP, int WP, int HP, int &cx, int &cy,
+                  int &X, int &Y, int &W, int &H);
+  /** Accessor to a private member variable of Fl_RGB_Image */
+  static fl_uintptr_t* id(Fl_RGB_Image *rgb) {return &(rgb->id_);}
+  /** Accessor to a private member variable of Fl_Pixmap */
+  static fl_uintptr_t* id(Fl_Pixmap *pm) {return &(pm->id_);}
+  /** Accessor to a private member variable of Fl_Bitmap */
+  static fl_uintptr_t* id(Fl_Bitmap *bm) {return &(bm->id_);}
+  /** Accessor to a private member variable of Fl_RGB_Image */
+  static fl_uintptr_t* mask(Fl_RGB_Image *rgb) {return &(rgb->mask_);}
+  /** Accessor to a private member variable of Fl_Pixmap */
+  static fl_uintptr_t* mask(Fl_Pixmap *pm) {return &(pm->mask_);}
+  /** Accessor to a private member variable of Fl_Pixmap */
+  static float* cache_scale(Fl_Pixmap *pm) {return &(pm->cache_scale_);}
+  /** Accessor to a private member variable of Fl_Bitmap */
+  static float* cache_scale(Fl_Bitmap *bm) {return &(bm->cache_scale_);}
+  /** Accessor to a private member variable of Fl_RGB_Image */
+  static float* cache_scale(Fl_RGB_Image *rgb) {return &(rgb->cache_scale_);}
+  /** Accessor to a private member variable of Fl_Pixmap */
+  static Fl_Color* pixmap_bg_color(Fl_Pixmap *pm) {return &(pm->pixmap_bg_color);}
+  /** For internal library use only */
+  static void draw_empty(Fl_Image* img, int X, int Y) {img->draw_empty(X, Y);}
+  /** Accessor to a private member function of Fl_Bitmap */
+  static int prepare(Fl_Bitmap *bm, int XP, int YP, int WP, int HP, int &cx, int &cy,
+                     int &X, int &Y, int &W, int &H) {
+    return bm->prepare(XP,YP,WP,HP,cx,cy,X,Y,W,H);
+  }
+  /** Accessor to a private member function of Fl_Pixmap */
+  static int prepare(Fl_Pixmap *pm, int XP, int YP, int WP, int HP, int &cx, int &cy,
+                     int &X, int &Y, int &W, int &H) {
+    return pm->prepare(XP,YP,WP,HP,cx,cy,X,Y,W,H);
+  }
+#endif
+public:
+  /** Constructor, C++11 initialises member variables in-line */
+  Fl_Android_Graphics_Driver();
+  /** destructor */
+  virtual ~Fl_Android_Graphics_Driver() override;
+  /** Return whether the graphics driver can do alpha blending */
+  virtual char can_do_alpha_blending() override { return 0; }
+  // --- implementation is in src/fl_rect.cxx which includes src/drivers/xxx/Fl_xxx_Graphics_Driver_rect.cxx
+  /** see fl_point() */
+  virtual void point(int x, int y) override;
+  /** see fl_rect() */
+  virtual void rect(int x, int y, int w, int h) override;
+  // super: virtual void focus_rect(int x, int y, int w, int h);
+  /** see fl_rectf() */
+  virtual void rectf(int x, int y, int w, int h) override;
+  /** see fl_line(int, int, int, int) */
+  virtual void line(int x, int y, int x1, int y1) override;
+  /** see fl_line(int, int, int, int, int, int) */
+  virtual void line(int x, int y, int x1, int y1, int x2, int y2) override;
+  /** see fl_xyline(int, int, int) */
+  virtual void xyline(int x, int y, int x1) override;
+  /** see fl_xyline(int, int, int, int) */
+  virtual void xyline(int x, int y, int x1, int y2) override;
+  /** see fl_xyline(int, int, int, int, int) */
+  virtual void xyline(int x, int y, int x1, int y2, int x3) override;
+  /** see fl_yxline(int, int, int) */
+  virtual void yxline(int x, int y, int y1) override;
+  /** see fl_yxline(int, int, int, int) */
+  virtual void yxline(int x, int y, int y1, int x2) override;
+  /** see fl_yxline(int, int, int, int, int) */
+  virtual void yxline(int x, int y, int y1, int x2, int y3) override;
+  /** see fl_loop(int, int, int, int, int, int) */
+  virtual void loop(int x0, int y0, int x1, int y1, int x2, int y2) override;
+  /** see fl_loop(int, int, int, int, int, int, int, int) */
+  virtual void loop(int x0, int y0, int x1, int y1, int x2, int y2, int x3, int y3) override;
+  /** see fl_polygon(int, int, int, int, int, int) */
+  virtual void polygon(int x0, int y0, int x1, int y1, int x2, int y2) override;
+  /** see fl_polygon(int, int, int, int, int, int, int, int) */
+  virtual void polygon(int x0, int y0, int x1, int y1, int x2, int y2, int x3, int y3) override;
+  // --- clipping
+  /** see fl_push_clip() */
+  virtual void push_clip(int x, int y, int w, int h) override;
+  /** see fl_clip_box() */
+  virtual int clip_box(int x, int y, int w, int h, int &X, int &Y, int &W, int &H) override;
+  /** see fl_not_clipped() */
+  virtual int not_clipped(int x, int y, int w, int h) override;
+  /** see fl_push_no_clip() */
+  virtual void push_no_clip() override;
+  /** see fl_pop_clip() */
+  virtual void pop_clip() override;
+  virtual Fl_Region clip_region() override;
+  virtual void clip_region(Fl_Region r) override;
+  virtual void restore_clip() override;
+  // --- implementation is in src/fl_vertex.cxx which includes src/drivers/xxx/Fl_xxx_Graphics_Driver_vertex.cxx
+  // super: virtual void push_matrix();
+  // super: virtual void pop_matrix();
+  // super: virtual void mult_matrix(double a, double b, double c, double d, double x, double y);
+  // super: virtual void rotate(double d);
+  // super: virtual void translate(double x,double y);
   virtual void begin_points() override;
   virtual void begin_line() override;
   virtual void begin_loop() override;
   virtual void begin_polygon() override;
   virtual void begin_complex_polygon() override;
+  // super: virtual double transform_x(double x, double y);
+  // super: virtual double transform_y(double x, double y);
+  // super: virtual double transform_dx(double x, double y);
+  // super: virtual double transform_dy(double x, double y);
+  /** see fl_transformed_vertex() */
+  virtual void transformed_vertex(double xf, double yf) override;
+  /** see fl_vertex() */
+  virtual void vertex(double x, double y) override;
+  /** see fl_end_points() */
   virtual void end_points() override;
+  /** see fl_end_line() */
   virtual void end_line() override;
+  /** see fl_end_loop() */
   virtual void end_loop() override;
+  /** see fl_end_polygon() */
   virtual void end_polygon() override;
-  void end_polygon(int begin, int end);
+  /** see fl_end_complex_polygon() */
   virtual void end_complex_polygon() override;
+  /** see fl_gap() */
   virtual void gap() override;
-  virtual void transformed_vertex0(float x, float y) override;
-
-  // --- clipping
-  virtual void push_clip(int x, int y, int w, int h) override;
-  virtual int clip_box(int x, int y, int w, int h, int &X, int &Y, int &W, int &H) override;
-  virtual int not_clipped(int x, int y, int w, int h) override;
-  virtual void push_no_clip() override;
-  virtual void pop_clip() override;
-  virtual void restore_clip() override;
-  virtual void clip_region(Fl_Region r) override;
-  virtual Fl_Region clip_region() override;
-
-  virtual void line_style_unscaled(int style, float width, char* dashes) override;
-
-  // --- matrix based drawing
-//  virtual void line_unscaled(float x, float y, float x1, float y1) override;
-
-  // --- image drawing
-
-  virtual void draw_unscaled(Fl_Bitmap *pxm, float s, int XP, int YP, int WP, int HP, int cx, int cy) override;
-  virtual fl_uintptr_t cache(Fl_Bitmap *img) override;
-
+  /** see fl_circle() */
+  virtual void circle(double x, double y, double r) override;
 #if 0
-  virtual int has_feature(driver_feature mask) { return mask & NATIVE; }
-  char can_do_alpha_blending();
-  // --- bitmap stuff
-  Fl_Bitmask create_bitmask(int w, int h, const uchar *array);
-  void delete_bitmask(Fl_Bitmask bm);
-  virtual void draw_unscaled(int angle, const char *str, int n, int x, int y);
-  virtual void rtl_draw_unscaled(const char* str, int n, int x, int y);
-  void draw_unscaled(Fl_Pixmap *pxm, float s, int XP, int YP, int WP, int HP, int cx, int cy);
-  void draw_unscaled(Fl_RGB_Image *img, float s, int XP, int YP, int WP, int HP, int cx, int cy);
-  int draw_scaled(Fl_Image *img, int XP, int YP, int WP, int HP);
-  virtual void draw_image_unscaled(const uchar* buf, int X,int Y,int W,int H, int D=3, int L=0);
-  virtual void draw_image_unscaled(Fl_Draw_Image_Cb cb, void* data, int X,int Y,int W,int H, int D=3);
-  virtual void draw_image_mono_unscaled(const uchar* buf, int X,int Y,int W,int H, int D=1, int L=0);
-  virtual void draw_image_mono_unscaled(Fl_Draw_Image_Cb cb, void* data, int X,int Y,int W,int H, int D=1);
-  fl_uintptr_t cache(Fl_Pixmap *img, int w, int h, const char *const*array);
-  virtual void uncache_pixmap(fl_uintptr_t p);
-  fl_uintptr_t cache(Fl_Bitmap *img, int w, int h, const uchar *array);
-  void uncache(Fl_RGB_Image *img, fl_uintptr_t &id_, fl_uintptr_t &mask_);
-  void copy_offscreen_with_alpha(int x,int y,int w,int h,HBITMAP bitmap,int srcx,int srcy);
-  virtual void copy_offscreen(int x, int y, int w, int h, Fl_Offscreen pixmap, int srcx, int srcy);
-  void add_rectangle_to_region(Fl_Region r, int x, int y, int w, int h);
-  Fl_Region XRectangleRegion(int x, int y, int w, int h);
-  void XDestroyRegion(Fl_Region r);
-  void translate_all(int x, int y);
-  void untranslate_all(void);
-  static HRGN scale_region(HRGN r, float f, Fl_GDI_Graphics_Driver *dr);
-  virtual void scale(float f);
-protected:
-  void fixloop();
-  // --- implementation is in src/fl_rect.cxx which includes src/cfg_gfx/gdi_rect.cxx
-  virtual Fl_Region scale_clip(float f);
-  // --- implementation is in src/fl_arc.cxx which includes src/cfg_gfx/xxx_arc.cxx if needed
-  // using void Fl_Graphics_Driver::arc(double x, double y, double r, double start, double end);
-  // --- implementation is in src/fl_arci.cxx which includes src/cfg_gfx/xxx_arci.cxx
+  // TODO: arc()
+  // --- implementation is in src/fl_arc.cxx which includes src/drivers/xxx/Fl_xxx_Graphics_Driver_arc.cxx if needed
+  virtual void arc(double x, double y, double r, double start, double end);
+#endif
+  // --- implementation is in src/fl_arci.cxx which includes src/drivers/xxx/Fl_xxx_Graphics_Driver_arci.cxx
+  /** see fl_arc(int x, int y, int w, int h, double a1, double a2) */
+  virtual void arc(int x, int y, int w, int h, double a1, double a2) override;
+  /** see fl_pie() */
+  virtual void pie(int x, int y, int w, int h, double a1, double a2) override;
+#if 0
+  // TODO: curve()
+  // --- implementation is in src/fl_curve.cxx which includes src/drivers/xxx/Fl_xxx_Graphics_Driver_curve.cxx if needed
+  virtual void curve(double X0, double Y0, double X1, double Y1, double X2, double Y2, double X3, double Y3);
+#endif
   // --- implementation is in src/fl_line_style.cxx which includes src/cfg_gfx/xxx_line_style.cxx
-  virtual void line_style_unscaled(int style, float width, char* dashes);
+  // TODO: line_style()
+  /** see fl_line_style() */
+  virtual void line_style(int style, int width=0, char* dashes=0) override;
   // --- implementation is in src/fl_color.cxx which includes src/cfg_gfx/xxx_color.cxx
-  void color(Fl_Color c);
-  void color(uchar r, uchar g, uchar b);
-  Fl_Color color() { return color_; }
-  void set_color(Fl_Color i, unsigned int c);
-  void free_color(Fl_Color i, int overlay);
-  void set_spot(int font, int size, int X, int Y, int W, int H, Fl_Window *win);
-  void reset_spot();
-  void global_gc();
-  virtual void overlay_rect(int x, int y, int w , int h);
-
+  /** see fl_color(Fl_Color) */
+  // super: virtual void color(Fl_Color c);
+#if 0
+  virtual void set_color(Fl_Color i, unsigned int c);
+  virtual void free_color(Fl_Color i, int overlay);
+  /** see fl_color(void) */
+  virtual Fl_Color color() { return color_; }
+  /** see fl_color(uchar, uchar, uchar) */
+  virtual void color(uchar r, uchar g, uchar b) {}
 #endif
+  /** see fl_draw(const char *str, int n, int x, int y) */
+  virtual void draw(const char *str, int n, int x, int y) override;
+#if 0
+  /** Draw the first \p n bytes of the string \p str starting at position \p x , \p y */
+  virtual void draw(const char *str, int n, float x, float y) { draw(str, n, (int)(x+0.5), (int)(y+0.5));}
+  /** 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) { draw(str, n, x, y); }
+  /** 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) { draw(str, n, x, y); }
+  /** Returns non-zero if the graphics driver possesses the \p feature */
+  virtual int has_feature(driver_feature feature) { return 0; }
+#endif
+  /** see fl_font(Fl_Font, Fl_Fontsize) */
+  virtual void font(Fl_Font face, Fl_Fontsize fsize) override;
+  /** see fl_font(void) */
+  // super: virtual Fl_Font font() {return font_; }
+  /** Return the current font size */
+  virtual Fl_Fontsize size() override;
+  /** Compute the width of the first \p n bytes of the string \p str if drawn with current font */
+  virtual double width(const char *str, int n) override;
+  /** Compute the width of Unicode character \p c if drawn with current font */
+  virtual double width(unsigned int c) override;
+  virtual void text_extents(const char*, int n, int& dx, int& dy, int& w, int& h) override;
+  /** Return the current line height */
+  virtual int height() override;
+  /** Return the current line descent */
+  virtual int descent() override;
+  /** Return the current Fl_Font_Descriptor */
+  // super: inline Fl_Font_Descriptor *font_descriptor() { return font_descriptor_;}
+  /** Set the current Fl_Font_Descriptor */
+  // super: virtual void font_descriptor(Fl_Font_Descriptor *d) { font_descriptor_ = d;}
+#if 0
+  /** Sets the value of the driver-specific graphics context. */
+  virtual void gc(void*) {}
+  /** Returns the driver-specific graphics context, of NULL if there's none. */
+  virtual void *gc(void) {return NULL;}
+  /** Support for pixmap drawing */
+  virtual uchar **mask_bitmap() { return 0; }
+  /** Support for pixmap drawing */
+  virtual void mask_bitmap(uchar **) {}
+  // default implementation may be enough
+  /** Support for PostScript drawing */
+  virtual float scale_font_for_PostScript(Fl_Font_Descriptor *desc, int s) { return float(s); }
+  // default implementation may be enough
+  /** Support for PostScript drawing */
+  virtual float scale_bitmap_for_PostScript() { return 2; }
+  virtual void set_spot(int font, int size, int X, int Y, int W, int H, Fl_Window *win);
+  virtual void reset_spot();
+  // each platform implements these 3 functions its own way
+  virtual void add_rectangle_to_region(Fl_Region r, int x, int y, int w, int h);
+  virtual Fl_Region XRectangleRegion(int x, int y, int w, int h);
+  virtual void XDestroyRegion(Fl_Region r);
+#endif
+  /** Support for Fl::get_font_name() */
+  virtual const char* get_font_name(Fl_Font fnum, int* ap) override;
+  /** Support for Fl::get_font_sizes() */
+  virtual int get_font_sizes(Fl_Font fnum, int*& sizep) override;
+  /** Support for Fl::set_fonts() */
+  virtual Fl_Font set_fonts(const char *name) override;
+#if 0
+  /** Some platforms may need to implement this to support fonts */
+  virtual Fl_Fontdesc* calc_fl_fonts(void) {return NULL;}
+  /** Support for Fl::set_font() */
+  virtual unsigned font_desc_size();
+#endif
+  /** Support for Fl::get_font() */
+  virtual const char *font_name(int num) override;
+  /** Support for Fl::set_font() */
+  virtual void font_name(int num, const char *name) override;
+#if 0
+  // Draws an Fl_Image scaled to width W & height H
+  virtual int draw_scaled(Fl_Image *img, int X, int Y, int W, int H);
+  /** Support function for fl_overlay_rect() and scaled GUI.
+   Defaut implementation may be enough */
+  virtual bool overlay_rect_unscaled();
+  /** Support function for fl_overlay_rect() and scaled GUI.
+   Defaut implementation may be enough */
+  virtual void overlay_rect(int x, int y, int w , int h) { loop(x, y, x+w-1, y, x+w-1, y+h-1, x, y+h-1); }
+#endif
+  // --- end of original Fl_Graphics_Driver header -----------------------------
+
+  // --- start of Android additions --------------------------------------------
+  // start drawing with this driver into the given window
+  // TODO: how is this different to Fl_Graphics_Driver::set_current_() above
+  void make_current(Fl_Window*);
 
 protected:
   static uint16_t make565(Fl_Color crgba);
-
+  void rectf_unclipped(int x, int y, int w, int h);
+  void xyline_unclipped(int x, int y, int x1);
+  void yxline_unclipped(int x, int y, int y1);
+  void end_polygon(int begin, int end);
+  void ellipse(double xt, double yt, double rx, double ry);
   void render_bytemap(int x, int y, Fl_Android_Bytemap *bm, Fl_Rect_Region &r);
   int render_letter(int xx, int yy, uint32_t c, Fl_Rect_Region &r);
 
-  int32_t pStride;
-  uint16_t *pBits;
+  // pointer into the screen buffer at the top left corner of the current window
+  uint16_t *pBits = nullptr;
+
+  // advance to next line in screen buffer
+  int32_t pStride = 0;
 
+  // TODO: current line style, temp kludge to make focus rect work.
   int pLineStyle = 0;
 
   // Clipping region of the current window in window coordinates (see: pStride and pBits)
@@ -193,6 +414,14 @@ protected:
   // Final clipping region for all graphics calls to this class.
   Fl_Complex_Region pClippingRegion;
 
+  // store vertices for begin_.../end_... drawing
+  class Vertex {
+  public:
+    void set(float x, float y, bool gap = false) { pX = x; pY = y; pIsGap = gap; }
+    float pX, pY;
+    bool pIsGap;
+  };
+
   void begin_vertices();
   void add_vertex(float x, float y, bool gap=false);
   int pnVertex = 0, pNVertex = 0, pVertexGapStart = 0;
@@ -200,6 +429,7 @@ protected:
 };
 
 
+#if 0
 /**
   The graphics driver used when printing on Android.
 */
@@ -219,6 +449,7 @@ public:
 #endif
 
 };
+#endif
 
 
 #endif // FL_ANDROID_GRAPHICS_DRIVER_H