Fltk Labeltypes

• FL_NORMAL_LABEL (0) draws the text.
• FL_NO_LABEL (1) does nothing
• FL_SYMBOL_LABEL draws "@xyz" labels, see "Symbol"
• FL_SHADOW_LABEL draws a drop shadow under the text
• FL_ENGRAVED_LABEL draws edges as though the text is engraved
• FL_EMBOSSED_LABEL draws edges as thought the text is raised
• The label may be an XBM bitmap.
• The label may be an XPM pixmap.
• The label may be an 8-bit image.

Only the first two are actual constants. The other symbols are macros so the code is not linked in if not used. To make bitmaps or pixmaps you use a method on the Fl_Bitmap or Fl_Pixmap object, see those pages for details.

Making your own Labeltypes

Labeltypes are actually indexes into a table of functions to draw them. The primary purpose of this is to let you reuse the label() pointer as a pointer to arbitrary data such as a bitmap or pixmap. You can also use this to draw the labels in ways inaccessible through the fl_font mechanisim, such as engraved, or with program-generated letters, or with GL display lists.

typedef void (Fl_Label_Draw_F)(const Fl_Label*, int,int,int,int, Fl_Align align);
typedef void (Fl_Label_Measure_F)(const Fl_Label*, int&, int&);

An Fl_Label is a small structure imbedded in Fl_Widget containing:

struct Fl_Label {
  const char* value;
  uchar type;
  uchar font;
  uchar size;
  uchar color;
  void draw(int,int,int,int, Fl_Font align) const ;
};

Fltk calls the labeltype function with a pointer to this structure and a a bounding box and alignment. The label should be drawn inside this bounding box, even though FL_ALIGN_INSIDE may not be on. The function is not called if value is null.

The "measure" function is called to measure the size of the label. It sets the w and h to the size it will occupy. For future compatability, w and h should be preset to zero before calling this.

See <FL/fl_draw.H> for the available drawing functions.

void Fl::set_labeltype(Fl_Labeltype n, Fl_Label_Draw_F*, Fl_Label_Measure_F*);

Replace the functions for labeltype n.

void Fl::set_labeltype(Fl_Labeltype n, Fl_Labeltype from);

Copy one labeltype to another.

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