Celestin Apprentice 7/Apprentice-Release7.iso/Source Code/Pascal/Code Resources/Eclectic CDEFs/Gauss CDEF Folder/NeoTextBox.p

Text File | 1997-02-25 | 19KB | 416 lines

{    NeoTextBox: Faster, script-aware alternative to TETextBox    }
{}
{    Originally written in C by Bryan K. Ressler, from Develop issue 9    }
{    Pascal conversion by Peter N. Lewis    }


{    Modifications by Sebastiano Pilla    }
{}
{    1)    Added optional saving/restoring of the clip region. This is controlled by the inSwapClipping parameter: if set to    }
{        TRUE, then NeoTextBox saves the current clip region, clips its drawing to inWrapBox, then restores the previously    }
{        saved clip region at the end of the drawing; if set to FALSE, then NeoTextBox uses whatever clip region is current    }
{}
{    2)    Added a check to avoid drawing text outside of inWrapBox, because it will be clipped anyway. However, the entire text    }
{        must still be traversed to determine the correct line breaks    }
{}
{    3)    Added a special one-line case, to avoid the wrapping loop where it is known that the text fits all into the given box }

unit NeoTextBox;


interface


    uses
        Types;


    const
        ntbJustFull = 128;


{    NeoTextBox    }
{}
{    Word-wraps text inside a given box    }
{}
{    Entry:    inTextPtr = pointer to the text we need to wrap    }
{            inTextLen = length (in bytes) of the text    }
{            inWrapBox = the box within which we're wrapping }
{            inAlign = the text alignment    }
{                        teForceLeft, teFlushLeft -> left justified    }
{                        teJustCenter, teCenter -> center justified    }
{                        teJustRight, teFlushRight -> right justified    }
{                        ntbJustFull -> full justified    }
{                        teJustLeft, teFlushDefault -> system justified    }
{            inLhCode = line height code    }
{                        < 0 -> variable - based on tallest character    }
{                        0 -> default - based on GetFontInfo    }
{                        > 0 -> fixed - use inLhCode as the line height    }
{            inSwapClipping = TRUE if NeoTextBox should save and restore the clipping, FALSE if this is unnecessary    }
{    Exit:    outEndY = vertical coordinate of the last line, if non-zero    }
{            outLhUsed = line height used to draw the text, if non-zero    }
{            function result = total number of lines drawn (even outside of the given box)    }
    function NeoTextBox (inTextPtr: Ptr;
                                    inTextLen: UInt32;
                                    inWrapBox: Rect;
                                    inAlign: SInt16;
                                    inLhCode: SInt16;
                                    var outEndY: SInt16;
                                    var outLhUsed: SInt16;
                                    inSwapClipping: Boolean): SInt16;


implementation


    uses
        Fonts, FixMath, QuickDrawText, Script, TextUtils;


    const
        kReturnChar = $D;


{    Max    }
{}
{    Returns the maximum between the two given numbers    }
{}
{    Entry:    inNum1 = first number    }
{            inNum2 = second number    }
{    Exit:    function result = maximum between inNum1 and inNum2    }
    function Max (inNum1, inNum2: SInt32): SInt32;
    inline
        $201F, $2E9F, $B097, $6F02, $2E80;


{    AddPtrLong    }
{}
{    Adds an offset to the given pointer    }
{}
{    Entry:    inPtr = pointer (first operand)    }
{            inOffset = offset (second operand) to be added to inPtr    }
{    Exit:    function result = pointer to Ord4(inPtr) + inOffset    }
    function AddPtrLong (inPtr: univ Ptr;
                                    inOffset: SInt32): Ptr;
    inline
        $201F,    { move.l    (sp)+,d0    ; pop inOffset }
        $D09F,    { add.l        (sp)+,d0    ; add inPtr to inOffset (and pop inPtr) }
        $2E80;    { move.l    d0,(sp)        ; place in result }


{     NTBLineHeight    }
{}
{    Figures line height    }
{}
{    Entry:    inTextPtr = entire text given to NeoTextBox    }
{            inTextLen = length (in bytes) of the text    }
{            inWrapBox = box within we're wrapping    }
{            inLhCode = line height code given to NeoTextBox    }
{    Exit:    outStartY = starting vertical pen location    }
{            function result = line height to use    }
    function NTBLineHeight (inTextPtr: Ptr;
                                    inTextLen: UInt32;
                                    inWrapBox: Rect;
                                    inLhCode: SInt16;
                                    var outStartY: SInt16): UInt16;
        var
            fInfo: FontInfo;                        { old-style font information record }
            frac: Point;                            { fraction for the TrueType calls }
            asc, desc: SInt16;                    { used in the OutlineMetrics calls }
            lineHeight: UInt16;                    { return value }
            err: OSErr;
    begin

        GetFontInfo(fInfo);
        if inLhCode < 0 then
            begin

        { -------------------------------------------------------------------------------------------------- }
        { If the user has specified variable-height lines, we need to try to determine the tallest ascent in the given text. }
        { We can only really do this if the font is a TrueType font.  Otherwise, we punt and use }
        { old - fashioned GetFontInfo numbers . }
        { -------------------------------------------------------------------------------------------------- }

                frac.h := 1;
                frac.v := 1;
                if IsOutline(frac, frac) then
                    begin

            { ---------------------------------------------------------------------------------------------- }
            { At this Point we know the current font is a TrueType font, so we do an OutlineMetrics call with our full text. }
            { It will put the tallest character ascent into asc, and the deepest descent into desc. Then we choose between }
            { whichever's most between the old-style ascent/descent and the numbers we get from the OutlineMetrics call. }
            { ---------------------------------------------------------------------------------------------- }

                        err := OutlineMetrics(UInt16(inTextLen), inTextPtr, frac, frac, asc, desc, nil, nil, nil);
                        lineHeight := Max(fInfo.ascent, asc) + Max(fInfo.descent, -desc) + fInfo.leading;
                        outStartY := inWrapBox.top + Max(fInfo.ascent, asc) + fInfo.leading;
                    end

                else
                    begin

            { ------------------------------------------------------------------------------------------------- }
            { At this Point we know the current font isn't TrueType, so we just use the old way of calculating line height. }
            { ------------------------------------------------------------------------------------------------- }

                        lineHeight := Max(fInfo.ascent, asc) + Max(fInfo.descent, -desc) + fInfo.leading;
                        outStartY := inWrapBox.top + Max(fInfo.ascent, asc) + fInfo.leading;
                    end;
            end

        else if inLhCode = 0 then
            begin

        { ---------------------------------------------------------------------------------------------------- }
        { If the user has specified "default" line height, he just wants us to get the line height from the FontInfo record.    }
        { ---------------------------------------------------------------------------------------------------- }

                lineHeight := fInfo.ascent + fInfo.descent + fInfo.leading;
                outStartY := inWrapBox.top + fInfo.ascent + fInfo.leading;

            end
        else
            begin

        { ----------------------------------------------------------------------------------------------------- }
        { If the user has provided a specific line height, we just trust them.  We can't really generate too good of a }
        { starting vertical coordinate, but we munge one together anyway. }
        { ----------------------------------------------------------------------------------------------------- }

                lineHeight := inLhCode;
                outStartY := inWrapBox.top + inLhCode + fInfo.leading;

            end;

        NTBLineHeight := lineHeight;
    end;


{    NTBDraw    }
{}
{    Draws a line with appropriate justification    }
{}
{    Entry:    inLineStartPtr = pointer to the beginning of the text for the current line    }
{            inLineBytes = length (in bytes) of the text for this line    }
{            inWrapBox = box within which we're wrapping    }
{            inAlign = text alignment as specified by the user    }
{            inCurY = our current vertical pen coordinate    }
{            inBoxWidth = width of inWrapBox (since NeoTextBox already calculated it)    }
{            inBreakCode = break code returned from StyledLineBreak    }
    procedure NTBDraw (inLineStartPtr: Ptr;
                                    inLineBytes: SInt32;
                                    inWrapBox: Rect;
                                    inAlign, inCurY, inBoxWidth: SInt16;
                                    inBreakCode: StyledLineBreakCode);
        var
            blackLen: UInt32;    { length of non-white characters }
            slop: SInt16;        { number of pixels of slop for full just }
    begin

    { ------------------------------------------------------------------------------------------------------------ }
    { The first thing we do here is determine the length of the "black" part of the current line.  This excludes spaces, carriage }
    { returns, and other white stuff depending on the language.  How do we know what to eliminate?  We DON'T!  So we ask our }
    { friend the Script Manager to do it for us.  VisibleLength returns the number of bytes that we should use for pixel width }
    { calculations. }
    { ------------------------------------------------------------------------------------------------------------ }

        blackLen := VisibleLength(inLineStartPtr, inLineBytes);

        if inAlign = ntbJustFull then
            begin

        { --------------------------------------------------------------------------------------------------------- }
        { For full justification, we need to calculate the "slop" space on the line that's not filled up by the text.  Then we }
        { move to the margin and get ready to draw BUT WAIT! If this is the last line of a paragraph, we need to draw it with }
        { whatever the system justification is. So if the break code indicates we're at the end of the text, or we can find a }
        { carriage return there ourselves, we just change the text alignment to the current default system text alignment and }
        { fall through without drawing. If it's just another line within a paragraph, we use the handy Script Manager routine }
        { DrawJust to draw it justified. In languages like Arabic, full justification is performed differently than just spacing }
        { out the words. DrawJust handles cases like these correctly. }
        { Note that when we go looking for the carriage return at the end of the line, it's okay to simply index to the last Byte }
        { of the string. This is because the carriage return character, 0x0d, is in the control-code range, which is defined to }
        { never be the low Byte of a two Byte character. }
        { --------------------------------------------------------------------------------------------------------- }

                slop := inBoxWidth - TextWidth(inLineStartPtr, 0, blackLen);
                MoveTo(inWrapBox.left, inCurY);
                if (inBreakCode = smBreakOverflow) | (AddPtrLong(inLineStartPtr, inLineBytes - 1)^ = kReturnChar) then
                    inAlign := GetSysDirection
                else
                    DrawJust(inLineStartPtr, blackLen, slop);
            end;

    { ------------------------------------------------------------------------------------------------------------ }
    { For the rest of the text alignments (left, center, and right), we just move the pen to the right place and draw the text }
    { with DrawText.  Note that the alignments that could have come into the NeoTextBox call have been resolved down to one }
    { of the four constants teForceLeft, teJustRight, teJustCenter, or ntbJustFull. }
    { ------------------------------------------------------------------------------------------------------------ }

        case inAlign of
            teForceLeft, teJustLeft:
                MoveTo(inWrapBox.left, inCurY);
            teJustRight:
                MoveTo(inWrapBox.right - TextWidth(inLineStartPtr, 0, blackLen), inCurY);
            teJustCenter:
                MoveTo(inWrapBox.left + (inBoxWidth - TextWidth(inLineStartPtr, 0, blackLen)) div 2, inCurY);
            otherwise
                ;
        end;

        if inAlign <> ntbJustFull then
            DrawText(inLineStartPtr, 0, inLineBytes);
    end;


{    NeoTextBox    }
{}
{    Word-wraps text inside a given box    }
{}
{    Entry:    inTextPtr = pointer to the text we need to wrap    }
{            inTextLen = length (in bytes) of the text    }
{            inWrapBox = the box within which we're wrapping }
{            inAlign = the text alignment    }
{            inLhCode = line height code    }
{            inSwapClipping = TRUE if NeoTextBox should save and restore the clipping    }
{    Exit:    outEndY = vertical coordinate of the last line, if non-zero    }
{            outLhUsed = line height used to draw the text, if non-zero    }
{            function result = total number of lines drawn (even outside of the given box)    }
    function NeoTextBox (inTextPtr: Ptr;
                                    inTextLen: UInt32;
                                    inWrapBox: Rect;
                                    inAlign: SInt16;
                                    inLhCode: SInt16;
                                    var outEndY: SInt16;
                                    var outLhUsed: SInt16;
                                    inSwapClipping: Boolean): SInt16;
        var
            oldClip: RgnHandle;                        { saved clipping region }
            lineStartPtr: Ptr;                        { pointer to beginning of a line }
            textEndPtr: Ptr;                        { pointer to the end of input text }
            fixedMax: Fixed;                        { boxWidth converted to fixed point }
            wrapWid: Fixed;                        { width to wrap to }
            lineBytes: SInt32;                        { number of bytes in one line }
            textLeft: UInt32;                        { pointer to remaining bytes of text }
            boxWidth: SInt16;                        { width of the wrapBox }
            lineHeight: UInt16;                        { calculated line height }
            curY: SInt16;                            { current vertical pen location }
            lineCount: UInt16;                        { number of lines we've drawn }
            breakCode: StyledLineBreakCode;        { returned code from StyledLineBreak }
    begin

    { ---------------------------------------------------------------------------------------------------------- }
    { Check the parameters we're given, and exit immediately if they're wrong. }
    { ---------------------------------------------------------------------------------------------------------- }
        if (inTextPtr = nil) or (inTextLen = 0) then
            Exit(NeoTextBox);

    { ---------------------------------------------------------------------------------------------------------- }
    { First, we save the old clipping region and clip to wrapBox, if requested. Then, figure the width of wrapBox, and make }
    { a fixed point version of it. Also, resolve the text alignment teFlushDefault to be the default system text alignment. }
    { ---------------------------------------------------------------------------------------------------------- }

        if inSwapClipping then
            begin
                oldClip := NewRgn;
                GetClip(oldClip);
                ClipRect(inWrapBox);
            end;
        boxWidth := inWrapBox.right - inWrapBox.left;
        if inAlign = teFlushDefault then
            inAlign := GetSysDirection;

    { ---------------------------------------------------------------------------------------------------------- }
    { Now we call NTBLineHeight to calculate the appropriate line height. It also figures our starting vertical pen location in }
    { curY based on the line height and other metric parameters. Clear lineCount, set lineStartPtr to point to the beginning of }
    { the text, calculate textEnd for comparison to know when we're done, and preset textLeft to be all the text. }
    { ---------------------------------------------------------------------------------------------------------- }

        lineHeight := NTBLineHeight(inTextPtr, inTextLen, inWrapBox, inLhCode, curY);
        lineCount := 0;
        lineStartPtr := inTextPtr;
        textEndPtr := AddPtrLong(inTextPtr, inTextLen);
        textLeft := inTextLen;

    { ------------------------------------------------------------------------------------------------------------ }
    { Special one-line case: if the width of the input text is less than boxWidth, we avoid the wrapping loop and call NTBDraw }
    { directly to draw the single line with the appropriate justification. }
    { Note that the TextWidth call uses a 16-bit value to specify the number of bytes, where the inTextLen parameter given }
    { to NeoTextBox is a 32-bit value. So, we hope that the width of inWrapBox is small enough to let us correctly handle this }
    { special case. }
    { ------------------------------------------------------------------------------------------------------------ }
        if boxWidth > TextWidth(inTextPtr, 0, LoWrd(inTextLen)) then
            begin
                NTBDraw(inTextPtr, inTextLen, inWrapBox, inAlign, curY, boxWidth, smBreakOverflow);
                textLeft := 0;                    { avoids entering the wrapping loop }
            end;

    { ------------------------------------------------------------------------------------------------------------ }
    { This is the main wrap-and-draw loop. I bet you never thought wrapping text could be so easy... }
    { ------------------------------------------------------------------------------------------------------------ }

        fixedMax := Long2Fix(boxWidth);
        while textLeft > 0 do
            begin

        { ------------------------------------------------------------------------------------------------------- }
        { Every line, we have to preset lineBytes to something non-zero. This tells StyledLineBreak that we're drawing the }
        { first format run on the line (of course, for us, there's only ONE format run total).  Also preset wrapWid. }
        { StyledLineBreak will always modify lineBytes (to tell you how many bytes are on this line), and will modify }
        { wrapWid, so we have to reset them each line. }
        { ------------------------------------------------------------------------------------------------------- }

                lineBytes := 1;
                wrapWid := fixedMax;

                breakCode := StyledLineBreak(lineStartPtr, textLeft, 0, textLeft, 0, wrapWid, lineBytes);

        { ------------------------------------------------------------------------------------------------------ }
        { Now that the Script Manager has done all the really hard work for us, we draw the line. We already knew lineStart, }
        { StyledLineBreak gave us lineBytes, which we pass to NTBDraw. It'll handle the different text alignments itself. }
        { Note that we really shouldn't draw text outside inWrapBox, but nonetheless it is necessary to break the entire text }
        { into lines, to have the correct line breaks: this means that we call NTBDraw only if curY <= inWrapBox.bottom + lineHeight }
        { ------------------------------------------------------------------------------------------------------ }

                if curY <= inWrapBox.bottom + lineHeight then
                    NTBDraw(lineStartPtr, lineBytes, inWrapBox, inAlign, curY, boxWidth, breakCode);

        { ------------------------------------------------------------------------------------------------------ }
        { Now we advance our vertical position down by the height of one line, advance lineStartPtr by the number of bytes }
        { we just drew, calculate a new textLeft, and increment our line count. }
        { ------------------------------------------------------------------------------------------------------ }

                curY := curY + lineHeight;
                lineStartPtr := AddPtrLong(lineStartPtr, lineBytes);
                textLeft := textLeft - lineBytes;
                lineCount := lineCount + 1;

            end;

    { --------------------------------------------------------------------------------------------------------- }
    { Well that was a job well done.  Let's return some useful values, too. Stuff our ending vertical coordinate and the line }
    { height we calculated into outEndY and outLHUsed, respectively. These allow the guy to put something after the }
    { wrapped text (or at least know the right place to put it). }
    { --------------------------------------------------------------------------------------------------------- }

        outEndY := curY - lineHeight;
        outLhUsed := lineHeight;

    { --------------------------------------------------------------------------------------------------------- }
    { Finally, restore the clipping region (if requested), dispose of the region, and return the TOTAL number of lines drawn }
    { (note that we didn't stop drawing when curY advanced past inWrapBox->bottom. This way, the user could tell that the text }
    { overflowed inWrapBox. If you want to know how many lines fit, divide inWrapBox by outLhUsed. This way, you get the }
    { best of both worlds. }
    { --------------------------------------------------------------------------------------------------------- }

        if inSwapClipping then
            begin
                SetClip(oldClip);
                DisposeRgn(oldClip);
            end;

        NeoTextBox := lineCount;
    end;


end.