textblock.hh

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#ifndef __DW_TEXTBLOCK_HH__
#define __DW_TEXTBLOCK_HH__

#include <limits.h>

#include "core.hh"
#include "../lout/misc.hh"

// These were used when improved line breaking and hyphenation were
// implemented. Should be cleaned up; perhaps reactivate RTFL again.
#define PRINTF(fmt, ...)
#define PUTCHAR(ch)

namespace dw {

class Textblock: public core::Widget
{
private:
   class BadnessAndPenalty
   {
   private:
      enum { NOT_STRETCHABLE, QUITE_LOOSE, BADNESS_VALUE, TOO_TIGHT }
         badnessState;
      enum { FORCE_BREAK, PROHIBIT_BREAK, PENALTY_VALUE } penaltyState;
      int ratio; // ratio is only defined when badness is defined
      int badness, penalty;
      
      // for debugging:
      int totalWidth, idealWidth, totalStretchability, totalShrinkability;

      // "Infinity levels" are used to represent very large numbers,
      // including "quasi-infinite" numbers. A couple of infinity
      // level and number can be mathematically represented as
      //
      //    number * N ^ (infinity level)
      //
      // where N is a number which is large enough. Practically,
      // infinity levels are used to circumvent limited ranges for
      // integer numbers.

      // Here, all infinity levels have got special meanings.
      enum {
         INF_VALUE = 0,        /* simple values */
         INF_LARGE,            /* large values, like QUITE_LOOSE */
         INF_NOT_STRETCHABLE,  /* reserved for NOT_STRECTHABLE */
         INF_TOO_TIGHT,        /* used for lines, which are too tight */
         INF_PENALTIES,        /* used for penalties */
         INF_MAX = INF_PENALTIES

         // That INF_PENALTIES is the last value means that an
         // infinite penalty (breaking is prohibited) makes a break
         // not possible at all, so that pre-formatted text
         // etc. works.
      };

      int badnessValue (int infLevel);
      int penaltyValue (int infLevel);
      
   public:
      void calcBadness (int totalWidth, int idealWidth,
                        int totalStretchability, int totalShrinkability);
      void setPenalty (int penalty);
      void setPenaltyProhibitBreak ();
      void setPenaltyForceBreak ();

      bool lineLoose ();
      bool lineTight ();
      bool lineTooTight ();
      bool lineMustBeBroken ();
      bool lineCanBeBroken ();
      int compareTo (BadnessAndPenalty *other);

      void print ();
   };

protected:
   enum {
      HYPHEN_BREAK = 100
   };

   struct Line
   {
      int firstWord;    /* first word's index in word vector */
      int lastWord;     /* last word's index in word vector */

      /* "top" is always relative to the top of the first line, i.e.
       * page->lines[0].top is always 0. */
      int top, boxAscent, boxDescent, contentAscent, contentDescent,
          breakSpace, leftOffset;

      /* This is similar to descent, but includes the bottom margins of the
       * widgets within this line. */
      int marginDescent;

      /* The following members contain accumulated values, from the
       * top down to this line. Please notice a change: until
       * recently, the values were accumulated up to the last line,
       * not this line.
       *
       * Also, keep in mind that at the end of a line, the space of
       * the last word is ignored, but instead, the hyphen width must
       * be considered.*/

      int maxLineWidth; /* Maximum of all line widths, including this
                         * line. Does not include the last space, but
                         * the last hyphen width. */
      int maxParMin;    /* Maximum of all paragraph minima, including
                         * this line. */
      int maxParMax;    /* Maximum of all paragraph maxima. This line
                         * is only included, if it is the last line of
                         * the paragraph (last word is a forced
                         * break); otherwise, it is the value of the
                         * last paragraph. For this reason, consider
                         * also parMax. */
      int parMax;       /* The maximal total width down from the last
                         * paragraph start, to the *end* of this line.
                         * The space at the end of this line is
                         * included, but not the hyphen width (as
                         * opposed to the other values). So, in some
                         * cases, the space has to be subtracted and
                         * the hyphen width to be added, to compare it
                         * to maxParMax. (Search the code for
                         * occurances.) */
   };

   struct Word
   {
      /* TODO: perhaps add a xLeft? */
      core::Requisition size;
      /* Space after the word, only if it's not a break: */
      short origSpace; /* from font, set by addSpace */
      short stretchability, shrinkability;
      short effSpace;  /* effective space, set by wordWrap,
                        * used for drawing etc. */
      short hyphenWidth; /* Additional width, when a word is part
                          * (except the last part) of a hyphenationed
                          * word. Has to be added to the width, when
                          * this is the last word of the line, and
                          * "hyphenWidth > 0" is also used to decide
                          * whether to draw a hyphen. */
      core::Content content;
      bool canBeHyphenated;

      // accumulated values, relative to the beginning of the line
      int totalWidth;          /* The sum of all word widths; plus all
                                  spaces, excluding the one of this
                                  word; plus the hyphen width of this
                                  word (but of course, no hyphen
                                  widths of previous words. In other
                                  words: the value compared to the
                                  ideal width of the line, if the line
                                  would be broken after this word. */
      int totalStretchability; // includes all *before* current word
      int totalShrinkability;  // includes all *before* current word
      BadnessAndPenalty badnessAndPenalty; /* when line is broken after this
                                            * word */

      core::style::Style *style;
      core::style::Style *spaceStyle; /* initially the same as of the word,
                                         later set by a_Dw_page_add_space */
   };

   void printWord (Word *word);

   struct Anchor
   {
      char *name;
      int wordIndex;
   };

   class TextblockIterator: public core::Iterator
   {
   private:
      int index;

   public:
      TextblockIterator (Textblock *textblock, core::Content::Type mask,
                         bool atEnd);
      TextblockIterator (Textblock *textblock, core::Content::Type mask,
                         int index);

      lout::object::Object *clone();
      int compareTo(lout::misc::Comparable *other);

      bool next ();
      bool prev ();
      void highlight (int start, int end, core::HighlightLayer layer);
      void unhighlight (int direction, core::HighlightLayer layer);
      void getAllocation (int start, int end, core::Allocation *allocation);
   };

   friend class TextblockIterator;

   /* These fields provide some ad-hoc-functionality, used by sub-classes. */
   bool hasListitemValue; /* If true, the first word of the page is treated
                          specially (search in source). */
   int innerPadding;    /* This is an additional padding on the left side
                            (used by ListItem). */
   int line1Offset;     /* This is an additional offset of the first line.
                           May be negative (shift to left) or positive
                           (shift to right). */
   int line1OffsetEff; /* The "effective" value of line1_offset, may
                          differ from line1_offset when
                          ignoreLine1OffsetSometimes is set to true. */

   /* The following is really hackish: It is used for DwTableCell (see
    * comment in dw_table_cell.c), to avoid too wide table columns. If
    * set to true, it has following effects:
    *
    *  (i) line1_offset is ignored in calculating the minimal width
    *      (which is used by DwTable!), and
    * (ii) line1_offset is ignored (line1_offset_eff is set to 0),
    *      when line1_offset plus the width of the first word is
    *      greater than the the available witdh.
    *
    * \todo Eliminate all these ad-hoc features by a new, simpler and
    *       more elegant design. ;-)
    */
   bool ignoreLine1OffsetSometimes;

   bool mustQueueResize;

   bool limitTextWidth; /* from preferences */

   int redrawY;
   int lastWordDrawn;

   /* These values are set by set_... */
   int availWidth, availAscent, availDescent;

   int wrapRef;  /* [0 based] */

   lout::misc::SimpleVector <Line> *lines;
   int nonTemporaryLines;
   lout::misc::NotSoSimpleVector <Word> *words;
   lout::misc::SimpleVector <Anchor> *anchors;

   struct {int index, nChar;}
      hlStart[core::HIGHLIGHT_NUM_LAYERS], hlEnd[core::HIGHLIGHT_NUM_LAYERS];

   int hoverLink;  /* The link under the mouse pointer */


   void queueDrawRange (int index1, int index2);
   void getWordExtremes (Word *word, core::Extremes *extremes);
   void markChange (int ref);
   void justifyLine (Line *line, int diff);
   Line *addLine (int firstWord, int lastWord, bool temporary);
   void calcWidgetSize (core::Widget *widget, core::Requisition *size);
   void rewrap ();
   void showMissingLines ();
   void removeTemporaryLines ();

   void decorateText (core::View *view, core::style::Style *style,
                      core::style::Color::Shading shading,
                      int x, int yBase, int width);
   void drawText (core::View *view, core::style::Style *style,
                  core::style::Color::Shading shading, int x, int y,
                  const char *text, int start, int len);
   void drawWord (Line *line, int wordIndex1, int wordIndex2, core::View *view,
                  core::Rectangle *area, int xWidget, int yWidgetBase);
   void drawWord0 (int wordIndex1, int wordIndex2,
                   const char *text, int totalWidth,
                   core::style::Style *style, core::View *view,
                   core::Rectangle *area, int xWidget, int yWidgetBase);
   void drawSpace (int wordIndex, core::View *view, core::Rectangle *area,
                   int xWidget, int yWidgetBase);
   void drawLine (Line *line, core::View *view, core::Rectangle *area);
   int findLineIndex (int y);
   int findLineOfWord (int wordIndex);
   Word *findWord (int x, int y, bool *inSpace);

   Word *addWord (int width, int ascent, int descent, bool canBeHyphenated,
                  core::style::Style *style);
   void fillWord (Word *word, int width, int ascent, int descent,
                  bool canBeHyphenated, core::style::Style *style);
   void fillSpace (Word *word, core::style::Style *style);
   void setBreakOption (Word *word, core::style::Style *style);
   int textWidth (const char *text, int start, int len,
                  core::style::Style *style);
   void calcTextSize (const char *text, size_t len, core::style::Style *style,
                      core::Requisition *size);

   inline int lineXOffsetContents (Line *line)
   {
      return innerPadding + line->leftOffset +
         (line == lines->getFirstRef() ? line1OffsetEff : 0);
   }

   inline int lineXOffsetWidget (Line *line)
   {
      return lineXOffsetContents (line) + getStyle()->boxOffsetX ();
   }

   inline int lineYOffsetWidgetAllocation (Line *line,
                                           core::Allocation *allocation)
   {
      return line->top + (allocation->ascent - lines->getRef(0)->boxAscent);
   }

   inline int lineYOffsetWidget (Line *line)
   {
      return lineYOffsetWidgetAllocation (line, &allocation);
   }

   inline int lineYOffsetCanvasAllocation (Line *line,
                                           core::Allocation *allocation)
   {
      return allocation->y + lineYOffsetWidgetAllocation(line, allocation);
   }

   inline int lineYOffsetCanvas (Line *line)
   {
      return lineYOffsetCanvasAllocation(line, &allocation);
   }

   inline int lineYOffsetWidgetI (int lineIndex)
   {
      return lineYOffsetWidget (lines->getRef (lineIndex));
   }

   inline int lineYOffsetCanvasI (int lineIndex)
   {
      return lineYOffsetCanvas (lines->getRef (lineIndex));
   }

   bool sendSelectionEvent (core::SelectionState::EventType eventType,
                            core::MousePositionEvent *event);

   void accumulateWordExtremes (int firstWord, int lastWord,
                                int *maxOfMinWidth, int *sumOfMaxWidth);
   virtual void wordWrap (int wordIndex, bool wrapAll);
   int hyphenateWord (int wordIndex);
   void accumulateWordForLine (int lineIndex, int wordIndex);
   void accumulateWordData(int wordIndex);
   int calcAvailWidth (int lineIndex);
   void initLine1Offset (int wordIndex);
   void alignLine (int lineIndex);

   void sizeRequestImpl (core::Requisition *requisition);
   void getExtremesImpl (core::Extremes *extremes);
   void sizeAllocateImpl (core::Allocation *allocation);
   void resizeDrawImpl ();

   void markSizeChange (int ref);
   void markExtremesChange (int ref);
   void setWidth (int width);
   void setAscent (int ascent);
   void setDescent (int descent);
   void draw (core::View *view, core::Rectangle *area);

   bool buttonPressImpl (core::EventButton *event);
   bool buttonReleaseImpl (core::EventButton *event);
   bool motionNotifyImpl (core::EventMotion *event);
   void enterNotifyImpl (core::EventCrossing *event);
   void leaveNotifyImpl (core::EventCrossing *event);

   void removeChild (Widget *child);

   void addText0 (const char *text, size_t len, bool canBeHyphenated,
                  core::style::Style *style, core::Requisition *size);
   void calcTextSizes (const char *text, size_t textLen,
                       core::style::Style *style,
                       int numBreaks, int *breakPos,
                       core::Requisition *wordSize);

public:
   static int CLASS_ID;

   Textblock(bool limitTextWidth);
   ~Textblock();

   core::Iterator *iterator (core::Content::Type mask, bool atEnd);

   void flush ();

   void addText (const char *text, size_t len, core::style::Style *style);
   inline void addText (const char *text, core::style::Style *style)
   {
      addText (text, strlen(text), style);
   }
   void addWidget (core::Widget *widget, core::style::Style *style);
   bool addAnchor (const char *name, core::style::Style *style);
   void addSpace (core::style::Style *style);

   inline void addBreakOption (core::style::Style *style)
   {
      int wordIndex = words->size () - 1;
      if (wordIndex >= 0)
         setBreakOption (words->getRef(wordIndex), style);
   }

   void addHyphen();
   void addParbreak (int space, core::style::Style *style);
   void addLinebreak (core::style::Style *style);

   core::Widget *getWidgetAtPoint (int x, int y, int level);
   void handOverBreak (core::style::Style *style);
   void changeLinkColor (int link, int newColor);
   void changeWordStyle (int from, int to, core::style::Style *style,
                         bool includeFirstSpace, bool includeLastSpace);
};

} // namespace dw

#endif // __DW_TEXTBLOCK_HH__