Developer CD Series 1996 February: Tool Chest/Apple Developer CD Series Tool Chest February 1996 (Apple Computer)(1996).iso/Tool Chest/Text/WASTE/WASTE 1.2a2/WELineLayout.c

C/C++ Source or Header | 1995-10-12 | 15.7 KB | 559 lines | [TEXT/CWIE]

/*
 *    WELineLayout.c
 *
 *    WASTE PROJECT
 *  Line Layout, Getting and Setting Variables, etc.
 *
 *  Copyright (c) 1993-1995 Marco Piovanelli
 *    All Rights Reserved
 *
 *  C port by Dan Crevier
 *
 */


#include "WASTEIntf.h"

#ifndef __PALETTES__
#include <Palettes.h>
#endif

#ifndef __QDOFFSCREEN__
#include <QDOffscreen.h>
#endif

#ifndef __GESTALT__
#include <Gestalt.h>
#endif

pascal void WEStopInlineSession(WEHandle hWE)
{
    WEPtr pWE = *hWE;

// call FixTSMDocument() only if the inlint input area is actually "open"
    if ((pWE->tsmAreaStart != kInvalidOffset) && (pWE->tsmReference != NULL))
        FixTSMDocument(pWE->tsmReference);
}

/*inline*/ pascal void _WERemoveLine(long lineIndex, WEPtr pWE)
{
    // remove the line
    _WERemoveBlock((Handle) pWE->hLines, sizeof(LineRec), lineIndex * sizeof(LineRec));

    // decrement line count
    pWE->nLines--;
}

pascal OSErr _WEInsertLine(long lineIndex, const LineRec *theLine, WEPtr pWE)
{
    // insert the specified element in the line array
    OSErr err;

    // do the insertion
    if ((err = _WEInsertBlock((Handle) pWE->hLines, theLine, sizeof(LineRec), lineIndex * sizeof(LineRec))) != noErr)
        return err;

    // increment line count
    pWE->nLines++;
    return noErr;
}

pascal void _WEBumpOrigin(long lineIndex, long deltaOrigin, WEPtr pWE)
{
    LineRec *pLine = *pWE->hLines + lineIndex;
    long nLines = pWE->nLines;

    // loop through the line run array adjusting the lineOrigin fields
    for ( ; lineIndex <= nLines; lineIndex++ )
    {
        pLine->lineOrigin += deltaOrigin;
        pLine++;
    }
}

pascal long _WEFindLineBreak(long lineStart, WEHandle hWE)
{
    // Find where to break the line beginning at lineStart
    // the current graphics port must be already set up correctly

    WEPtr pWE = *hWE;    // assume WE record is already locked
    Ptr pText;
    long offset, breakOffset;
    long textLength;
    long remainingLength;
    long segmentStart, segmentEnd;
    long runIndex;
    WERunInfo runInfo;
    Fixed pixelWidth;
    ScriptCode script, previousScript;
    Boolean isBreak = false;

    offset = lineStart;
    pText = *pWE->hText + offset;
    remainingLength = pWE->textLength - offset;

    // find the style run index corresponding to the first segment on this line
    runIndex = _WEOffsetToRun(offset, hWE);

    // initialize pixelWidth to the width of the destination rectangle, as a Fixed quantity
    pixelWidth = BSL((pWE->destRect.right - pWE->destRect.left), 16);

    // STYLE SEGMENT LOOP
    do
    {

        // get style run information for the current style run
        _WEGetIndStyle(runIndex, &runInfo, hWE);
        runIndex++;

        // set text attributes in the graphics port
        TextFont(runInfo.runAttrs.runStyle.tsFont);
        TextFace(runInfo.runAttrs.runStyle.tsFace);
        TextSize(runInfo.runAttrs.runStyle.tsSize);

        // if we're handling multiscript text, keep track of script boundaries
        if (BTST(pWE->flags, weFNonRoman))
        {
            // what is the script for this segment?
            script = FontToScript(runInfo.runAttrs.runStyle.tsFont);

            // have we crossed a script run boundary in the middle of a line?
            if ((runInfo.runStart > offset) && (script != previousScript))
            {
                // leave behind the all previous segments on this line
                offset = runInfo.runStart;
                pText = *pWE->hText + offset;
                remainingLength = pWE->textLength - offset;
            }
            previousScript = script;
        } // if non-Roman

        // we'll pass textLength as the second parameter to the line break hook
        // although this parameter is declared as a long, StyledLineBreak uses only
        // the low word, so make sure it doesn't trespass the 32,767 byte threshold!
        textLength = _WEPinInRange(remainingLength, 0, SHRT_MAX);

        // calculate segmentStart and segmentEnd relative to offset
        segmentStart = _WEPinInRange(runInfo.runStart - offset, 0, textLength);
        segmentEnd = _WEPinInRange(runInfo.runEnd - offset, 0, textLength);

        // set breakOffset to a non-zero value for the first script run on the line,
        // set it to zero for all subsequent script runs
        breakOffset = (offset == lineStart);

#if WASTE_OBJECTS
        if (runInfo.runAttrs.runStyle.tsObject != NULL)
        {
            // EMBEDDED OBJECT
            // subtract object width from pixelWidth
            pixelWidth -= BSL((*runInfo.runAttrs.runStyle.tsObject)->objectSize.h, 16);

            // stop looping if pixelWidth has gone negative
            isBreak = (pixelWidth < 0);
            breakOffset = isBreak ? segmentStart : segmentEnd;
        }
        else
#endif
        {
            // REGULAR TEXT
            isBreak = (CallWELineBreakProc(pText, textLength, segmentStart, segmentEnd,
                &pixelWidth, &breakOffset, hWE, pWE->lineBreakHook) != smBreakOverflow);
        }

        // break the line anyway when we reach the end of the text
        if (segmentEnd >= remainingLength)
            isBreak = true;

    } while (!isBreak);

    // return the offset from lineStart to the break point
    return (offset - lineStart) + breakOffset;
}

pascal void _WECalcHeights(long rangeStart, long rangeEnd, short *lineAscent, short *lineDescent,
        WEHandle hWE)
{
    // Find the maximum ascent and descent values between rangeStart and rangeEnd
    // the WE record must be already locked
    // the current graphics port must be already set up correctly

    long runIndex;
    WERunInfo runInfo;
    short runAscent, runDescent;

    *lineAscent = 1;
    *lineDescent = 1;

    // find the style run index corresponding to the first segment on this line
    runIndex = _WEOffsetToRun(rangeStart, hWE);

    // STYLE SEGMENT LOOP
    do
    {
        // get style run information for the current style run
        _WEGetIndStyle(runIndex, &runInfo, hWE);
        runIndex++;

        // calculate ascent and descent (actually, descent + leading) values for this style run

#if WASTE_OBJECTS
        if (runInfo.runAttrs.runStyle.tsObject != NULL)
        {
            // EMBEDDED OBJECT
            runAscent = (*runInfo.runAttrs.runStyle.tsObject)->objectSize.v;
            runDescent = 0;
        }
        else
#endif
        {
            // REGULAR TEXT
            runAscent = runInfo.runAttrs.runAscent;
            runDescent = runInfo.runAttrs.runHeight - runAscent;
        }

        // save the maximum values in lineAscent and lineDescent
        if (runAscent > *lineAscent)
            *lineAscent = runAscent;

        if (runDescent > *lineDescent)
            *lineDescent = runDescent;

        // keep looping until we reach rangeEnd
    } while (runInfo.runEnd < rangeEnd);
}

pascal OSErr _WERecalBreaks(long *startLine, long *endLine, WEHandle hWE)
{
    // Recalculates line breaks, line heights and ascents for all the text or for a portion of it.
    // On entry, startLine and endLine define a range of lines to recalculate.
    // On exit, startLine to endLine defines the range of lines actually recalculated
    // the WE record must already be locked

    WEPtr pWE = *hWE;
    LinePtr pLine;
    LineRec lineInfo, oldLineInfo;
    long lineIndex;
    long recalThreshold;
    long lineOffset;
    short lineAscent, lineDescent;
    long textHeight;
    Boolean saveTextLock;
    QDEnvironment saveEnvironment;
    OSErr err = noErr;

    // lock the text
    saveTextLock = _WESetHandleLock(pWE->hText, true);

    // find the character offset that must be necessarily reached before we can
    // even consider the possibility of stopping the recalculation process
    // this offset, recalThreshold, is the last character on endLine _before_ recalculation
    lineIndex = _WEPinInRange(*endLine, 0, pWE->nLines - 1);
    recalThreshold = (*pWE->hLines)[lineIndex + 1].lineStart;

    // we start recalculating line breaks from the line actually _preceding_ startLine,
    // since editing startLine may cause part of its text to fit on the preceding line
    lineIndex = _WEPinInRange(*startLine - 1, 0, pWE->nLines - 1);

    // find where in the text recalculation should begin
    lineInfo = (*pWE->hLines)[lineIndex];

    // save the QuickDraw environment
    _WESaveQDEnvironment(pWE->port, false, &saveEnvironment);

    // MAIN LINE BREAKING LOOP
    do
    {
        // find where to break the current line
        lineOffset = _WEFindLineBreak(lineInfo.lineStart, hWE);

        // make sure we advance at least by one character (unless we reached the end of text)
        if ((lineOffset <= 0) && (lineInfo.lineStart < pWE->textLength))
            lineOffset = 1;

        // calculate ascent and descent values for this line
        _WECalcHeights(lineInfo.lineStart, lineInfo.lineStart + lineOffset, &lineAscent, &lineDescent, hWE);

        // save the maximum line ascent for this line in the line array
        pLine = *pWE->hLines + lineIndex;
        pLine->lineAscent = lineAscent;

        // increment counters (go to the next line array entry)
        lineIndex++;
        lineInfo.lineStart += lineOffset;
        lineInfo.lineOrigin += (lineAscent + lineDescent);
        pLine++;

        // compare the newly calculated line start with the old value
        // if the new line start comes before the old line start, insert a new element
        oldLineInfo = *pLine;
        if ((lineIndex > pWE->nLines) || (lineInfo.lineStart < oldLineInfo.lineStart))
        {
            if ((err = _WEInsertLine(lineIndex, &lineInfo, pWE)) != noErr)
                goto cleanup;
        }
        else
        {
            // overwrite the old element
            pLine->lineStart = lineInfo.lineStart;
            pLine->lineOrigin = lineInfo.lineOrigin;

            // remove all further elements which have a lineStart field
            // less than or equal to the current one
            while((lineIndex < pWE->nLines) && (lineInfo.lineStart >= (pLine + 1)->lineStart))
                _WERemoveLine(lineIndex + 1, pWE);

            // if the new line start is the same as the old one...
            if (lineInfo.lineStart == oldLineInfo.lineStart)
            {
                // ...and recalThreshold has been reached, we can stop recalculating line breaks
                if (lineInfo.lineStart >= recalThreshold)
                {
                    // although line breaks need not be changed from lineIndex on,
                    // the lineOrigin fields may need to be changed
                    if (lineInfo.lineOrigin != oldLineInfo.lineOrigin)
                        _WEBumpOrigin(lineIndex + 1, lineInfo.lineOrigin - oldLineInfo.lineOrigin, pWE);

                    // exit from the line breaking loop
                    goto cleanup;
                }
            }
            else
            {
                // otherwise, the new line start comes after the old line start...
                // if the current line is the one preceding startLine, warn our caller about this
                if ((lineIndex > 0) && (lineIndex == *startLine))
                    *startLine = lineIndex - 1;
            }
        }
    } while(lineInfo.lineStart < pWE->textLength);

cleanup:
    // calculate total text height
    textHeight = WEGetHeight(0, pWE->nLines, hWE);

    // quirk: if the last character in the text is a carriage return, the caret appears
    // below the last line, so in this case we need to add the extra height to textHeight
    if (WEGetChar(pWE->textLength - 1, hWE) == kEOL)
        textHeight += WEGetHeight(pWE->nLines - 1, pWE->nLines, hWE);

    // if total text height has changed, remember to call the scroll callback later
    if (textHeight != pWE->destRect.bottom - pWE->destRect.top)
        BSET(pWE->flags, weFDestRectChanged);

    // set destRect.bottom to destRect.top + total text height
    pWE->destRect.bottom = pWE->destRect.top + textHeight;

    // return through endLine the index of the last line affected by recalculation
    *endLine = lineIndex - 1;

    // make sure startLine isn't greater than endLine
    if (*startLine > *endLine)
        *startLine = *endLine;

    // unlock the text
    _WESetHandleLock(pWE->hText, saveTextLock);

    // restore the QuickDraw environment
    _WERestoreQDEnvironment(&saveEnvironment);

    // return result code
    return err;
}

static Boolean SLCalcSlop(LinePtr pLine, const WERunAttributes *pAttrs,
        Ptr pSegment, long segmentStart, long segmentLength,
        JustStyleCode styleRunPosition, void *callbackData);

static Boolean SLCalcSlop(LinePtr pLine, const WERunAttributes *pAttrs,
        Ptr pSegment, long segmentStart, long segmentLength,
        JustStyleCode styleRunPosition, void *callbackData)
{
    struct SLCalcSlopData *p = (struct SLCalcSlopData *) callbackData;
    short segmentWidth;
    Fixed segmentProportion;
    Boolean isEndOfLine;

    // see if this text segment ends with a carriage return, or if we've reached the
    // end of the text (in which case we don't want any justification to take place)
    isEndOfLine = (segmentStart + segmentLength >= p->pWE->textLength) ||
                    ( *((Ptr)pSegment + segmentLength - 1) == kEOL);

    // if this is the first segment on the line, reset line totals
    if (IS_FIRST_RUN(styleRunPosition))
    {
        p->totalSlop = p->lineWidth;
        p->totalProportion = 0;
    }

#if WASTE_OBJECTS
    if (pAttrs->runStyle.tsObject != NULL)
    {
        // EMBEDDED OBJECT
        // segment width is just object width; no extra space can be applied for justification
        segmentWidth = (*pAttrs->runStyle.tsObject)->objectSize.h;
        segmentProportion = 0;
    }
    else
#endif
    {
        // REGULAR TEXT

        // if this is the last segment on the line, strip trailing spaces
        if (IS_LAST_RUN(styleRunPosition))
        {
            segmentLength = VisibleLength(pSegment, segmentLength);
        }
        // measure this segment
        segmentWidth = TextWidth(pSegment, 0, segmentLength);

        // calculate the proportion of extra space to apply to this text segment
        segmentProportion = PortionLine(pSegment, segmentLength,
                            styleRunPosition, kOneToOneScaling, kOneToOneScaling);
    }

    // keep track of line totals
    p->totalSlop -= segmentWidth;
    p->totalProportion += segmentProportion;

    // if this is the last segment on the line, save values in the line array
    if (IS_LAST_RUN(styleRunPosition))
    {
        // make sure slop is non-negative
        if (p->totalSlop < 0)
            p->totalSlop = 0;
        pLine->lineSlop = p->totalSlop;

        if (isEndOfLine)
        {
            pLine->lineJustAmount = 0;
        }
        else
        {
            pLine->lineJustAmount = FixDiv(BSL(p->totalSlop, 16), p->totalProportion);
        }
    }
    return false;    // keep looping
}

pascal void _WERecalSlops(long firstLine, long lastLine, WEHandle hWE)
{
    // Calculates the lineSlop and lineJustAmount fields
    // of the line array for the specified lines

    WEPtr pWE = *hWE;
    struct SLCalcSlopData callbackData;

    // we only need to bother if the user isn't using left justification
    if (pWE->alignment == weFlushLeft)
        return;

    // calculate slop and normalized slop proportion for all lines
    callbackData.pWE = pWE;
    callbackData.lineWidth = pWE->destRect.right - pWE->destRect.left;
    _WESegmentLoop(firstLine, lastLine, SLCalcSlop, (void *) &callbackData, hWE);
}

pascal OSErr WEUseText(Handle text, WEHandle hWE)
{
    WEPtr pWE;
    long textLength;
    Boolean saveWELock;

    // lock the WE record
    saveWELock = _WESetHandleLock((Handle) hWE, true);
    pWE = *hWE;

    // install the text
    _WEForgetHandle(&pWE->hText);
    pWE->hText = text;
    textLength = GetHandleSize(text);
    pWE->textLength = textLength;
    (*pWE->hRuns)[pWE->nRuns].runStart = textLength + 1;
    (*pWE->hLines)[pWE->nLines].lineStart = textLength;

    // unlock the WE record
    _WESetHandleLock((Handle) hWE, saveWELock);

    return noErr;
}

pascal char WEGetAlignment(WEHandle hWE)
{
    return (*hWE)->alignment;
}

pascal void WEGetSelection(long *selStart, long *selEnd, WEHandle hWE)
{
    WEPtr pWE = *hWE;

    *selStart = pWE->selStart;
    *selEnd = pWE->selEnd;
}

pascal void WESetDestRect(const LongRect *destRect, WEHandle hWE)
{
    (*hWE)->destRect = *destRect;
}

pascal void WEGetDestRect(LongRect *destRect, WEHandle hWE)
{
    *destRect = (*hWE)->destRect;
}

pascal void WESetViewRect(const LongRect *viewRect, WEHandle hWE)
{
    WEPtr pWE = *hWE;
    Rect r;

    pWE->viewRect = *viewRect;

    // keep the viewRgn in sync with the view rectangle
    WELongRectToRect(viewRect, &r);
    RectRgn(pWE->viewRgn, &r);
}

pascal void WEGetViewRect(LongRect *viewRect, WEHandle hWE)
{
    *viewRect = (*hWE)->viewRect;
}

pascal long WEGetTextLength(WEHandle hWE)
{
    return (*hWE)->textLength;
}

pascal long WECountLines(WEHandle hWE)
{
    return (*hWE)->nLines;
}

pascal long WEGetHeight(long startLine, long endLine, WEHandle hWE)
{
    WEPtr pWE = *hWE;
    LineArrayPtr pLines = *pWE->hLines;
    long nLines = pWE->nLines;

    startLine = _WEPinInRange(startLine, 0, nLines);
    endLine = _WEPinInRange(endLine, 0, nLines);
    _WEReorder(&startLine, &endLine);
    return pLines[endLine].lineOrigin - pLines[startLine].lineOrigin;
}

pascal Handle WEGetText(WEHandle hWE)
{
    return (*hWE)->hText;
}

pascal short WEGetChar(long offset, WEHandle hWE)
{
    WEPtr pWE = *hWE;

    // sanity check: make sure offset is withing allowed bounds
    if ((offset < 0) || (offset >= pWE->textLength))
    {
        return 0;
    }

    // get the specified character (actually, byte)
    return (*pWE->hText)[offset];
}