fltk/src/fl_draw.cxx

//
// "$Id$"
//
// Label drawing code for the Fast Light Tool Kit (FLTK).
//
// Copyright 1998-2009 by Bill Spitzak and others.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
// USA.
//
// Please report all bugs and problems on the following page:
//
//     http://www.fltk.org/str.php
//

// Implementation of fl_draw(const char*,int,int,int,int,Fl_Align)
// Used to draw all the labels and text, this routine:
// Word wraps the labels to fit into their bounding box.
// Breaks them into lines at the newlines.
// Expands all unprintable characters to ^X or \nnn notation
// Aligns them against the inside of the box.

#define min(a,b) ((a)<(b)?(a):(b))
#include <FL/fl_utf8.h>
#include <FL/Fl.H>
#include <FL/fl_draw.H>
#include <FL/Fl_Image.H>

#include "flstring.h"
#include <ctype.h>
#include <math.h>

#define MAXBUF 1024

char fl_draw_shortcut;	// set by fl_labeltypes.cxx

static char* underline_at;

/** 
    utf8 multibyte char seq. detection an pass-thru routine.
    \retval false if no utf8 seq detected, no change made. true if utf8 and d copied with s seq.
    note that for n bytes copied dest incremented of n, but s of n-1 for compatible loop use see below.
*/
#define C_IN(c,a,b) ((c)>=(a) && (c)<=(b)) 
#define C_UTF8(c)   C_IN(c,0x80,0xBF)

static bool handle_utf8_seq(const char * &s,char * &d) {
  register const unsigned char* p=(const unsigned char*)s;
  if (p[0] < 0xc2 || p[0] > 0xf4)
    return false; // not adressed in this function
  else if ( C_IN(p[0], 0xc2, 0xdf) && C_UTF8(p[1]) ) {
    d[0]=s[0]; d[1]=s[1];
    d+=2; s++;
    // non-overlong 2-byte
  }
  else if ( p[0]==0xe0 && C_IN(p[1], 0xa0, 0xbf) && C_UTF8(p[2]) ) {
    d[0]=s[0]; d[1]=s[1];d[2]=s[2];
    d+=3; s+=2;
    //  excluding overlongs
  }
  else if (p[0]==0xed && C_IN(p[1], 0x80, 0x9f) && C_UTF8(p[2]) ) {
    d[0]=s[0]; d[1]=s[1];d[2]=s[2];
    d+=3; s+=2;
    //  excluding surrogates
  }
  else if (p[0]!=0xed && C_IN(p[0], 0xe1, 0xef) && C_UTF8(p[1]) && C_UTF8(p[2]) ) {
    d[0]=s[0]; d[1]=s[1];d[2]=s[2];
    d+=3; s+=2;
    // straight 3-byte
  }
  else if (p[0]==0xf0 && C_IN(p[1], 0x90, 0xbf)   && C_UTF8(p[2]) && C_UTF8(p[3]) ) {
    d[0]=s[0]; d[1]=s[1]; d[2]=s[2]; d[3]=s[3];
    d+=4; s+=3;
    // planes 1-3
  }
  else if (C_IN(p[0], 0xf1, 0xf3) && C_UTF8(p[1]) && C_UTF8(p[2]) && C_UTF8(p[3]) ) {
    d[0]=s[0]; d[1]=s[1]; d[2]=s[2]; d[3]=s[3];
    d+=4; s+=3;
    // planes 4-15
  }
  else if (p[0]==0xf4 && C_IN(p[1], 0x80, 0x8f)   && C_UTF8(p[2]) && C_UTF8(p[3]) ) {
    d[0]=s[0]; d[1]=s[1]; d[2]=s[2]; d[3]=s[3];
    d+=4; s+=3;
    // planes 16
  } else { // non utf8 compliant, maybe CP125x or broken utf8 string
    // fprintf(stderr, "Not UTF8 char \n");
    return false; 
  }
  return true; //  we did handled and copied the utf8 multibyte char seq.
}

/**
 Copy \p from to \p buf, replacing unprintable characters with ^X and \\nnn.

 Stop at a newline or if MAXBUF characters written to buffer.
 Also word-wrap if width exceeds maxw.
 Returns a pointer to the start of the next line of characters.
 Sets n to the number of characters put into the buffer.
 Sets width to the width of the string in the current font.
*/
const char*
fl_expand_text(const char* from, char* buf, int maxbuf, double maxw, int& n, 
	double &width, int wrap, int draw_symbols) {
  char* o = buf;
  char* e = buf+(maxbuf-4);
  underline_at = 0;
  char* word_end = o;
  const char* word_start = from;
  double w = 0;

  const char* p = from;
  for (;; p++) {

    int c = *p & 255;

    if (!c || c == ' ' || c == '\n') {
      // test for word-wrap:
      if (word_start < p && wrap) {
	double newwidth = w + fl_width(word_end, o-word_end);
	if (word_end > buf && newwidth > maxw) { // break before this word
	  o = word_end;
	  p = word_start;
	  break;
	}
	word_end = o;
	w = newwidth;
      }
      if (!c) break;
      else if (c == '\n') {p++; break;}
      word_start = p+1;
    }

    if (o > e) break; // don't overflow buffer

    if (c == '\t') {
      for (c = fl_utf_nb_char((uchar*)buf, o-buf)%8; c<8 && o<e; c++) 
           *o++ = ' ';
    } else if (c == '&' && fl_draw_shortcut && *(p+1)) {
      if (*(p+1) == '&') {p++; *o++ = '&';}
      else if (fl_draw_shortcut != 2) underline_at = o;
    } else if (c < ' ' || c == 127) { // ^X
      *o++ = '^';
      *o++ = c ^ 0x40;
    } else  if (handle_utf8_seq(p, o)) { // figure out if we have an utf8 valid sequence before we determine the nbsp test validity:
#ifdef __APPLE__
    } else if (c == 0xCA) { // non-breaking space in MacRoman
#else
    } else if (c == 0xA0) { // non-breaking space in ISO 8859
#endif
      *o++ = ' ';
       
    } else if (c == '@' && draw_symbols) { // Symbol???
      if (p[1] && p[1] != '@')  break;
      *o++ = c;
      if (p[1]) p++;
    } else {
      *o++ = c;
    }
  }

  width = w + fl_width(word_end, o-word_end);
  *o = 0;
  n = o-buf;
  return p;
}

/**
  The same as fl_draw(const char*,int,int,int,int,Fl_Align,Fl_Image*,int) with
  the addition of the \p callthis parameter, which is a pointer to a text drawing
  function such as fl_draw(const char*, int, int, int) to do the real work
*/
void fl_draw(
    const char* str,	// the (multi-line) string
    int x, int y, int w, int h,	// bounding box
    Fl_Align align,
    void (*callthis)(const char*,int,int,int),
    Fl_Image* img, int draw_symbols) {
  const char* p;
  const char* e;
  char buf[MAXBUF];
  int buflen;
  char symbol[2][255], *symptr;
  int symwidth[2], symoffset, symtotal;

  // count how many lines and put the last one into the buffer:
  int lines;
  double width;

  symbol[0][0] = '\0';
  symwidth[0]  = 0;

  symbol[1][0] = '\0';
  symwidth[1]  = 0;

  if (draw_symbols) {
    if (str && str[0] == '@' && str[1] && str[1] != '@') {
      // Start with a symbol...
      for (symptr = symbol[0];
           *str && !isspace(*str) && symptr < (symbol[0] + sizeof(symbol[0]) - 1);
           *symptr++ = *str++);
      *symptr = '\0';
      if (isspace(*str)) str++;
      symwidth[0] = min(w,h);
    }

    if (str && (p = strrchr(str, '@')) != NULL && p > (str + 1) && p[-1] != '@') {
      strlcpy(symbol[1], p, sizeof(symbol[1]));
      symwidth[1] = min(w,h);
    }
  }

  symtotal = symwidth[0] + symwidth[1];

  if (str) {
  for (p = str, lines=0; p;) {
      e = fl_expand_text(p, buf, MAXBUF, w - symtotal, buflen, width, 
		align&FL_ALIGN_WRAP, draw_symbols);
    lines++;
    if (!*e || (*e == '@' && e[1] != '@' && draw_symbols)) break;
    p = e;
  }
  } else lines = 0;

  if ((symwidth[0] || symwidth[1]) && lines) {
    if (symwidth[0]) symwidth[0] = lines * fl_height();
    if (symwidth[1]) symwidth[1] = lines * fl_height();
  }

  symtotal = symwidth[0] + symwidth[1];
  
  // figure out vertical position of the first line:
  int xpos;
  int ypos;
  int height = fl_height();
  int imgh = img ? img->h() : 0;

  symoffset = 0;

  if (align & FL_ALIGN_BOTTOM) ypos = y+h-(lines-1)*height-imgh;
  else if (align & FL_ALIGN_TOP) ypos = y+height;
  else ypos = y+(h-lines*height-imgh)/2+height;

  // draw the image unless the "text over image" alignment flag is set...
  if (img && !(align & FL_ALIGN_TEXT_OVER_IMAGE)) {
    if (img->w() > symoffset) symoffset = img->w();

    if (align & FL_ALIGN_LEFT) xpos = x + symwidth[0];
    else if (align & FL_ALIGN_RIGHT) xpos = x + w - img->w() - symwidth[1];
    else xpos = x + (w - img->w() - symtotal) / 2 + symwidth[0];

    img->draw(xpos, ypos - height);
    ypos += img->h();
  }

  // now draw all the lines:
  if (str) {
    int desc = fl_descent();
    for (p=str; ; ypos += height) {
      if (lines>1) e = fl_expand_text(p, buf, MAXBUF, w - symtotal, buflen, 
				width, align&FL_ALIGN_WRAP, draw_symbols);
      else e = "";

      if (width > symoffset) symoffset = (int)(width + 0.5);

      if (align & FL_ALIGN_LEFT) xpos = x + symwidth[0];
      else if (align & FL_ALIGN_RIGHT) xpos = x + w - (int)(width + .5) - symwidth[1];
      else xpos = x + (w - (int)(width + .5) - symtotal) / 2 + symwidth[0];

      callthis(buf,buflen,xpos,ypos-desc);

      if (underline_at && underline_at >= buf && underline_at < (buf + buflen))
	callthis("_",1,xpos+int(fl_width(buf,underline_at-buf)),ypos-desc);

      if (!*e || (*e == '@' && e[1] != '@')) break;
      p = e;
    }
  }

  // draw the image if the "text over image" alignment flag is set...
  if (img && (align & FL_ALIGN_TEXT_OVER_IMAGE)) {
    if (img->w() > symoffset) symoffset = img->w();

    if (align & FL_ALIGN_LEFT) xpos = x + symwidth[0];
    else if (align & FL_ALIGN_RIGHT) xpos = x + w - img->w() - symwidth[1];
    else xpos = x + (w - img->w() - symtotal) / 2 + symwidth[0];

    img->draw(xpos, ypos);
  }

  // draw the symbols, if any...
  if (symwidth[0]) {
    // draw to the left
    if (align & FL_ALIGN_LEFT) xpos = x;
    else if (align & FL_ALIGN_RIGHT) xpos = x + w - symtotal - symoffset;
    else xpos = x + (w - symoffset - symtotal) / 2;

    if (align & FL_ALIGN_BOTTOM) ypos = y + h - symwidth[0];
    else if (align & FL_ALIGN_TOP) ypos = y;
    else ypos = y + (h - symwidth[0]) / 2;

    fl_draw_symbol(symbol[0], xpos, ypos, symwidth[0], symwidth[0], fl_color());
  }

  if (symwidth[1]) {
    // draw to the right
    if (align & FL_ALIGN_LEFT) xpos = x + symoffset + symwidth[0];
    else if (align & FL_ALIGN_RIGHT) xpos = x + w - symwidth[1];
    else xpos = x + (w - symoffset - symtotal) / 2 + symoffset + symwidth[0];

    if (align & FL_ALIGN_BOTTOM) ypos = y + h - symwidth[1];
    else if (align & FL_ALIGN_TOP) ypos = y;
    else ypos = y + (h - symwidth[1]) / 2;

    fl_draw_symbol(symbol[1], xpos, ypos, symwidth[1], symwidth[1], fl_color());
  }
}

/**
  Fancy string drawing function which is used to draw all the labels.

  The string is formatted and aligned inside the passed box.
  Handles '\\t' and '\\n', expands all other control characters to '^X',
  and aligns inside or against the edges of the box.
  See Fl_Widget::align() for values of \p align. The value FL_ALIGN_INSIDE
  is ignored, as this function always prints inside the box.
  If \p img is provided and is not \p NULL, the image is drawn above or
  below the text as specified by the \p align value.
  The \p draw_symbols argument specifies whether or not to look for symbol
  names starting with the '\@' character'
  The text length is limited to 1024 characters per line.
*/
void fl_draw(
  const char* str,
  int x, int y, int w, int h,
  Fl_Align align,
  Fl_Image* img,
  int draw_symbols) {
  if ((!str || !*str) && !img) return;
  if (w && h && !fl_not_clipped(x, y, w, h) && (align & FL_ALIGN_INSIDE)) return;
  if (align & FL_ALIGN_CLIP) fl_push_clip(x, y, w, h);
  fl_draw(str, x, y, w, h, align, fl_draw, img, draw_symbols);
  if (align & FL_ALIGN_CLIP) fl_pop_clip();
}

/**
  Measure how wide and tall the string will be when printed by the
  fl_draw() function with \p align parameter. If the incoming \p w
  is non-zero it will wrap to that width.
  \param[in] str nul-terminated string
  \param[out] w,h width and height of string in current font
  \param[in] draw_symbols non-zero to enable @@symbol handling [default=1]
*/
void fl_measure(const char* str, int& w, int& h, int draw_symbols) {
  if (!str || !*str) {w = 0; h = 0; return;}
  h = fl_height();
  const char* p;
  const char* e;
  char buf[MAXBUF];
  int buflen;
  int lines;
  double width=0;
  int W = 0;
  char symbol[2][255], *symptr;
  int symwidth[2], symtotal;

  // count how many lines and put the last one into the buffer:
  symbol[0][0] = '\0';
  symwidth[0]  = 0;

  symbol[1][0] = '\0';
  symwidth[1]  = 0;

  if (draw_symbols) {
    if (str && str[0] == '@' && str[1] && str[1] != '@') {
      // Start with a symbol...
      for (symptr = symbol[0];
           *str && !isspace(*str) && symptr < (symbol[0] + sizeof(symbol[0]) - 1);
           *symptr++ = *str++);
      *symptr = '\0';
      if (isspace(*str)) str++;
      symwidth[0] = h;
    }

    if (str && (p = strrchr(str, '@')) != NULL && p > (str + 1) && p[-1]!='@') {
      strlcpy(symbol[1], p, sizeof(symbol[1]));
      symwidth[1] = h;
    }
  }

  symtotal = symwidth[0] + symwidth[1];
  
  for (p = str, lines=0; p;) {
//    e = expand(p, buf, w - symtotal, buflen, width, w != 0, draw_symbols);
    e = fl_expand_text(p, buf, MAXBUF, w - symtotal, buflen, width, 
			w != 0, draw_symbols);
    if ((int)ceil(width) > W) W = (int)ceil(width);
    lines++;
    if (!*e || (*e == '@' && draw_symbols)) break;
    p = e;
  }

  if ((symwidth[0] || symwidth[1]) && lines) {
    if (symwidth[0]) symwidth[0] = lines * fl_height();
    if (symwidth[1]) symwidth[1] = lines * fl_height();
  }

  symtotal = symwidth[0] + symwidth[1];

  w = W + symtotal;
  h = lines*h;
}

/**
  This function returns the actual height of the specified \p font
  and \p size. Normally the font height should always be 'size',
  but with the advent of XFT, there are (currently) complexities
  that seem to only be solved by asking the font what its actual
  font height is. (See STR#2115)
  
  This function was originally undocumented in 1.1.x, and was used
  only by Fl_Text_Display. We're now documenting it in 1.3.x so that
  apps that need precise height info can get it with this function.

  \returns the height of the font in pixels.
  
  \todo  In the future, when the XFT issues are resolved, this function
         should simply return the 'size' value.
*/
int fl_height(int font, int size) {
    if ( font == fl_font() && size == fl_size() ) return(fl_height());
    int tf = fl_font(), ts = fl_size();   // save
    fl_font(font,size);
    int height = fl_height();
    fl_font(tf,ts);                       // restore
    return(height);
}

//
// End of "$Id$".
//