scrolltext.c

早期freebsd实现

    textInfo->numLines = linenum+1;
    if (startPos == 0) {
	textInfo->startLine = 0;
    }
    textInfo->endLine = FindEndLine(textInfo, &(textInfo->bottomSpace));
    textInfo->curLine = linenum;
    /* Check to see if we are at the bottom */
    if (textInfo->endLine >= textInfo->numLines-1) {
	textInfo->curY = textInfo->h - textInfo->bottomSpace -
	  lineptr->lineHeight;
	textInfo->flagWord &= (~NOTATBOTTOM);
    } else {
	textInfo->flagWord |= NOTATBOTTOM;
    }
    return 1;
}




int TxtAddFont(display, textWin, fontNumber, newFont, newColor)
Display *display;
Window textWin;			/* Scrollable text window  */
int fontNumber;			/* Place to add font (0-7) */
XFontStruct *newFont;		/* Font to add             */
int newColor;			/* Color of font           */
/*
 * This routine loads a new font so that it can be used in a previously
 * created text window.  There are eight font slots numbered 0 through 7.
 * If there is already a font in the specified slot,  it will be replaced
 * and an automatic redraw of the window will take place.  See TxtWriteStr
 * for details on using alternate fonts.  The color specifies the foreground
 * color of the text.  The default foreground color is used if this
 * parameter is TXT_NO_COLOR.  Returns a non-zero value if
 * everything went well.
 */
{
    struct txtWin *textInfo;
    int redrawFlag;
    XGCValues gc_val;
    
    if ((fontNumber < 0) || (fontNumber >= MAXFONTS)) return 0;
    if ((textInfo = (struct txtWin *)
	 XLookUpAssoc(display, textWindows, (XID) textWin)) == 0)
      return 0;
    if (newColor == TXT_NO_COLOR) {
	newColor = textInfo->fgPix;
    }

    gc_val.font = newFont->fid;
    gc_val.foreground = newColor;
    gc_val.background = textInfo->bgPix;
    gc_val.plane_mask = AllPlanes;
    gc_val.graphics_exposures = 1;
    gc_val.function = GXcopy;
    
    if (textInfo->fontGC[fontNumber] != 0)
    {
	XChangeGC(display, textInfo->fontGC[fontNumber],
		  GCFont | GCForeground, &gc_val);
    }
    else
	textInfo->fontGC[fontNumber] = XCreateGC(display, textWin,
						 GCFont |
						 GCForeground |
						 GCBackground |
						 GCFunction |
						 GCPlaneMask |
						 GCGraphicsExposures,
						 &gc_val); 


    redrawFlag = (textInfo->theFonts[fontNumber].fid != 0) &&
      (((newFont) && (newFont->fid != textInfo->theFonts[fontNumber].fid)) ||
       (newColor != textInfo->theColors[fontNumber]));
    if (newFont) {
	textInfo->theFonts[fontNumber] = *newFont;
    }
    textInfo->theColors[fontNumber] = newColor;

    if (redrawFlag) {
	RecompBuffer(textInfo);
	XClearWindow(display, textWin);
	TxtRepaint(display, textWin);
    }
    return 1;
}



int TxtWinP(display, w)
Display *display;
Window w;
/*
 * Returns a non-zero value if the window has been previously grabbed
 * using TxtGrab and 0 if it has not.
 */
{
    if (XLookUpAssoc(display, textWindows, (XID) w))
      return(1);
    else return(0);
}



static int FindEndLine(textInfo, botSpace)
struct txtWin *textInfo;
int *botSpace;
/*
 * Given the starting line in 'textInfo->startLine',  this routine
 * determines the index of the last line that can be drawn given the
 * current size of the screen.  If there are not enough lines to
 * fill the screen,  the index of the last line will be returned.
 * The amount of empty bottom space is returned in 'botSpace'.
 */
{
    int index, height, lineHeight;

    height = YPADDING;
    index = textInfo->startLine;
    while (index < textInfo->numLines) {
	lineHeight = textInfo->txtBuffer[index]->lineHeight + INTERLINE;
	if (height + lineHeight > textInfo->h) break;
	height += lineHeight;
	index++;
    }
    if (botSpace) {
	*botSpace = textInfo->h - height;
    }
    return index - 1;
}



static int UpdateScroll(display, textInfo)
Display *display;
struct txtWin *textInfo;	/* Text window information */
/*
 * This routine computes the current extent of the scroll bar
 * indicator and repaints the bar with the correct information.
 */
{
    int top, bottom;

    if (textInfo->numLines > 1) {
	top = textInfo->startLine * (textInfo->h - 2*BARBORDER) /
	  (textInfo->numLines - 1);
	bottom = textInfo->endLine * (textInfo->h - 2*BARBORDER) /
	  (textInfo->numLines - 1);
    } else {
	top = 0;
	bottom = textInfo->h - (2*BARBORDER);
    }

    /* Draw it - make sure there is a little padding */
    if (top == 0) top++;
    if (bottom == textInfo->h-(2*BARBORDER)) bottom--;

    XFillRectangle(display, textInfo->scrollBar,
		   textInfo->bgGC, 
		   0, 0, BARSIZE, top-1);
    XFillRectangle(display, textInfo->scrollBar,
		   DEFAULT_GC, top, BARSIZE - (2*BARBORDER) - 2,
		   bottom - top);
    XFillRectangle(display, textInfo->scrollBar, DEFAULT_GC,
		   0, bottom+1, BARSIZE,
		   textInfo->h - (2 * BARBORDER) - bottom);

    return 1;
}




int TxtClear(display, w)
Display *display;
Window w;
/*
 * This routine clears a scrollable text window.  It resets the current
 * writing position to the upper left hand corner of the screen. 
 * NOTE:  THIS ALSO CLEARS THE CONTENTS OF THE TEXT WINDOW BUFFER AND
 * RESETS THE SCROLL BAR.  Returns 0 if the window is not a text window.
 * This should be used *instead* of XClear.
 */
{
    struct txtWin *textInfo;
    int index;

    if ((textInfo = (struct txtWin *) XLookUpAssoc(display, textWindows, (XID) w)) == 0)
      return 0;

    /* Zero out the arrays */
    textInfo->bufSpot = 0;
    for (index = 0;  index < textInfo->numLines;  index++) {
	InitLine(textInfo->txtBuffer[index]);
    }
    textInfo->txtBuffer[0]->lineHeight =
      textInfo->theFonts[textInfo->curFont].ascent +
	  textInfo->theFonts[textInfo->curFont].descent;

    textInfo->numLines = 1;
    textInfo->startLine = 0;
    textInfo->endLine = 0;
    textInfo->curLine = 0;
    textInfo->curX = 0;
    textInfo->curY = YPADDING + textInfo->theFonts[textInfo->curFont].ascent 
	+ textInfo->theFonts[textInfo->curFont].descent;

    textInfo->bottomSpace = textInfo->h - YPADDING -
      textInfo->theFonts[textInfo->curFont].ascent - INTERLINE -
	  textInfo->theFonts[textInfo->curFont].descent;
    /* Actually clear the window */
    XClearWindow(display, w);

    /* Draw the current cursor */
    XFillRectangle(display, w, textInfo->CursorGC,
		   XPADDING + CUROFFSET, textInfo->curY,
		   CURSORWIDTH,
		   textInfo->theFonts[textInfo->curFont].ascent +
		   textInfo->theFonts[textInfo->curFont].descent);

    /* Update the scroll bar */
    UpdateScroll(display, textInfo);
    return 1;
}


static int WarpToBottom(display, textInfo)
Display *display;
struct txtWin *textInfo;	/* Text Information */
/*
 * This routine causes the specified text window to display its
 * last screen of information.   It updates the scroll bar
 * to the appropriate spot.  The implementation scans backward
 * through the buffer to find an appropriate starting spot for
 * the window.
 */
{
    int index, height, lineHeight;

    index = textInfo->numLines-1;
    height = 0;
    while (index >= 0) {
	lineHeight = textInfo->txtBuffer[index]->lineHeight + INTERLINE;
	if (height + lineHeight > textInfo->h) break;
	height += lineHeight;
	index--;
    }
    textInfo->startLine = index + 1;
    textInfo->endLine = FindEndLine(textInfo, &(textInfo->bottomSpace));
    textInfo->curY = textInfo->h - textInfo->bottomSpace -
      textInfo->txtBuffer[textInfo->endLine]->lineHeight;
    XClearWindow(display, textInfo->mainWindow);
    TxtRepaint(display, textInfo->mainWindow);
    return 1;
}



static int UpdateExposures(display, textInfo)
Display *display;
struct txtWin *textInfo;	/* Text window information */
/*
 * Before a new scrolling action occurs,  the text window package
 * must handle all COPYEXPOSE events generated by the last scrolling
 * action.  This routine is called to do this.  Foreign events (those
 * not handled by TxtFilter) are queued up and replaced on the queue
 * after the processing of the exposure events is complete.
 */
{
#if 0
    XEvent foreignQueue[MAXFOREIGN];
    int index, lastItem = 0;

    while (textInfo->flagWord & COPYEXPOSE) {
	XNextEvent(display, &(foreignQueue[lastItem]));
	if (!TxtFilter(display, &(foreignQueue[lastItem])))
	  lastItem++;
	if (lastItem >= MAXFOREIGN) {
	    printf("Too many foreign events to queue!\n");
	    textInfo->flagWord &= (~COPYEXPOSE);
	}
    }
    for (index = 0;  index < lastItem;  index++) {
	XPutBackEvent(display, &(foreignQueue[index]));
    }
#endif
    return 1;
}


static int ScrollDown(display,textInfo)
Display *display;
struct txtWin *textInfo;	/* Text window information */
/*
 * This routine scrolls the indicated text window down by one
 * line.  The line below the current line must exist.  The window
 * is scrolled so that the line below the last line is fully
 * displayed.  This may cause many lines to scroll off the top.
 * Scrolling is done using XCopyArea.  The exposure events should
 * be caught using ExposeCopy.
 */
{
    int lineSum, index, targetSpace, freeSpace, updateFlag;

    lineSum = 0;
    if (textInfo->endLine + 1 >= textInfo->numLines) return 0;
    targetSpace = textInfo->txtBuffer[textInfo->endLine+1]->lineHeight +
      INTERLINE;
    if (textInfo->bottomSpace < targetSpace) {
	index = textInfo->startLine;
	while (index < textInfo->endLine) {
	    lineSum += (textInfo->txtBuffer[index]->lineHeight + INTERLINE);
	    if (textInfo->bottomSpace + lineSum >= targetSpace) break;
	    index++;
	}

	/* Must move upward by 'lineSum' pixels */
	XCopyArea(display, textInfo->mainWindow, textInfo->mainWindow,
		  DEFAULT_GC, 0, lineSum,
		  textInfo->w - BARSIZE, textInfo->h,
		  0, 0);

	textInfo->flagWord |= COPYEXPOSE;
	/* Repair the damage to the structures */
	textInfo->startLine = index + 1;
	updateFlag = 1;
    } else {
	updateFlag = 0;
    }
    /* More lines might be able to fit.  Let's check. */
    freeSpace = textInfo->bottomSpace + lineSum - targetSpace;
    index = textInfo->endLine + 1;
    while (index < textInfo->numLines-1) {
	if (freeSpace - textInfo->txtBuffer[index+1]->lineHeight - INTERLINE < 0)
	  break;
	freeSpace -= (textInfo->txtBuffer[index+1]->lineHeight + INTERLINE);
	index++;
    }
    textInfo->endLine = index;
    textInfo->bottomSpace = freeSpace;
    if (updateFlag) {
	UpdateExposures(display, textInfo);
    }
    UpdateScroll(display, textInfo);
    return 1;
}




static int ExpandLines(textInfo)
struct txtWin *textInfo;	/* Text Information */
/*
 * This routine allocates and initializes additional space in
 * the line start array (txtBuffer).  The new space
 * is allocated using realloc.  The expansion factor is a percentage
 * given by EXPANDPERCENT.
 */
{
    int newSize, index;

    newSize = textInfo->allocLines;
    newSize += (newSize * EXPANDPERCENT) / 100;

    textInfo->txtBuffer = (struct txtLine **)
      realloc((char *) textInfo->txtBuffer,
	      (unsigned) (newSize * sizeof(struct txtLine *)));
    for (index = textInfo->allocLines;  index < newSize;  index++) {
	textInfo->txtBuffer[index] = alloc(struct txtLine);
	InitLine(textInfo->txtBuffer[index]);
    }
    textInfo->allocLines = newSize;
    return 1;
}

static int ExpandBuffer(textInfo)
struct txtWin *textInfo;	/* Text information */
/*
 * Expands the basic character buffer using realloc.  The expansion
 * factor is a percentage given by EXPANDPERCENT.
 */
{
    int newSize;

    newSize = textInfo->bufAlloc + (textInfo->bufAlloc * EXPANDPERCENT) / 100;
    textInfo->mainBuffer = (short *)
      realloc((char *) textInfo->mainBuffer, (unsigned) newSize * sizeof(short));
    textInfo->bufAlloc = newSize;
    return 1;
}



static int HandleNewLine(display, textInfo, flagWord)
Display *display;
struct txtWin *textInfo;	/* Text Information            */
int flagWord;			/* DODISP or NONEWLINE or both */
/*
 * This routine initializes the next line for drawing by setting
 * its height to the current font height,  scrolls the screen down
 * one line,  and updates the current drawing position to the
 * left edge of the newly cleared line.  If DODISP is specified,
 * the screen will be updated (otherwise not).  If NONEWLINE is
 * specified,  no newline character will be added to the text buffer
 * (this is for line wrap).
 */
{
    struct txtLine *curLine, *nextLine;

    /* Check to see if a new line must be allocated */
    if (textInfo->curLine >= textInfo->allocLines-1)
      /* Expand the number of lines */
      ExpandLines(textInfo);
    textInfo->numLines += 1;

    /* Then we initialize the next line */
    nextLine = textInfo->txtBuffer[textInfo->numLines-1];
    nextLine->lineHeight =
	textInfo->theFonts[textInfo->curFont].ascent +
	    textInfo->theFonts[textInfo->curFont].descent;

    curLine = textInfo->txtBuffer[textInfo->curLine];
    if (flagWord & DODISP) {
	/* Scroll down a line if required */
	if ((textInfo->curY + curLine->lineHeight +
	     nextLine->lineHeight + (INTERLINE * 2)) > textInfo->h)
	  {
	      ScrollDown(display, textInfo);
	  }
	else
	  {
	      /* Update the bottom space appropriately */
	      textInfo->bottomSpace -= (nextLine->lineHeight + INTERLINE);
	      textInfo->endLine += 1;
	  }
	/* Update drawing position */
	textInfo->curY = textInfo->h -
	  (textInfo->bottomSpace  + nextLine->lineHeight);
    }

    /* Move down a line */
    textInfo->curLine += 1;
    if (!(flagWord & NONEWLINE)) {
	/* Append end-of-line to text buffer */
	if (textInfo->bufSpot >= textInfo->bufAlloc) {
	    /* Allocate more space in main text buffer */
	    ExpandBuffer(textInfo);
	}
	textInfo->mainBuffer[(textInfo->bufSpot)++] =
	  (textInfo->curFont << FONTSHIFT) | '\n';
    }
    nextLine->lineText = textInfo->bufSpot;
    textInfo->curX = 0;
    return 1;
}



static int CharSize(textInfo, lineNum, charNum)
struct txtWin *textInfo;	/* Current Text Information */
int lineNum;			/* Line in buffer           */
int charNum;			/* Character in line        */
/*
 * This routine determines the size of the specified character.