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Fixed|Client|FontLineWrapping: Wrapping tabbed lines
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Now the line wrapper correctly takes tab stops into account when
determining wrapped rich text lines.

Also added some more comments and cleaned up the code a little.
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@skyjake
skyjake committed Jul 25, 2013
1 parent c594f2f commit 645911f
Showing 1 changed file with 77 additions and 44 deletions.
121 changes: 77 additions & 44 deletions doomsday/client/src/ui/widgets/fontlinewrapping.cpp
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Expand Up @@ -33,15 +33,17 @@ DENG2_PIMPL_NOREF(FontLineWrapping)
{
Font const *font;

/**
* A wrapped line of text.
*/
struct Line
{
WrappedLine line;
LineInfo info;
int width; ///< Total width of the line (in pixels).
bool isTabbed;

Line(WrappedLine const &ln = WrappedLine(Rangei()), int lineWidth = 0, int leftIndent = 0)
: line(ln), width(lineWidth), isTabbed(false)
: line(ln), width(lineWidth)
{
info.indent = leftIndent;
}
Expand Down Expand Up @@ -109,10 +111,14 @@ DENG2_PIMPL_NOREF(FontLineWrapping)
}

/**
* Constructs a wrapped line. Note that indent and tabStop are modified.
* @param range
* @param width
* @return Caller gets ownership of the Line.
* Constructs a wrapped line. Note that indent and tabStop are modified;
* this is expected to be called in the right order as lines are being
* processed.
*
* @param range Range in the content for the line.
* @param width Width of the line in pixel. If -1, will be calculated.
*
* @return Line instance. Caller gets ownership.
*/
Line *makeLine(Rangei const &range, int width = -1)
{
Expand All @@ -130,6 +136,7 @@ DENG2_PIMPL_NOREF(FontLineWrapping)
Font::RichFormat rich = format.subRange(range);
Font::RichFormat::Iterator iter(rich);

// Divide the line into segments based on tab stops.
while(iter.hasNext())
{
iter.next();
Expand Down Expand Up @@ -159,10 +166,7 @@ DENG2_PIMPL_NOREF(FontLineWrapping)
{
for(int i = 0; i < line->info.segs.size(); ++i)
{
line->info.segs[i].width = (
i < line->info.segs.size() - 1?
rangeAdvanceWidth(line->info.segs[i].range) :
rangeVisibleWidth(line->info.segs[i].range));
line->info.segs[i].width = rangeAdvanceWidth(line->info.segs[i].range);
}
}

Expand Down Expand Up @@ -204,19 +208,6 @@ DENG2_PIMPL_NOREF(FontLineWrapping)
return false;
}

QList<int> findTabsInUse(Rangei const &range) const
{
QList<int> stops;
Font::RichFormat rich = format.subRange(range);
Font::RichFormat::Iterator iter(rich);
while(iter.hasNext())
{
iter.next();
if(iter.tabStop() > 0) stops << iter.tabStop();
}
return stops;
}

int findMaxWrapWithStep(int const stepSize, int const begin, int end,
int const availableWidth,
int *wrapPosMax)
Expand Down Expand Up @@ -283,31 +274,47 @@ DENG2_PIMPL_NOREF(FontLineWrapping)
/**
* Wraps the range onto one or more lines.
*
* @param rangeToWrap Range in the content string.
* @param maxWidth Maximum width of a line.
* @param initialIndent
* @param initialTabStop
* @param rangeToWrap Range in the content string.
* @param maxWidth Maximum width of a line.
* @param subsequentMaxWidth Maximum width of lines beyond the first one.
* Note: if larger than zero, the line is considered
* to contain tabbed segments.
* @param initialIndent Initial value for the indent.
*
* @return Produced wrapped lines. Caller gets ownership.
* @return The produced wrapped lines. Caller gets ownership.
*/
Lines wrapRange(Rangei const &rangeToWrap, int maxWidth, int initialIndent = 0, int initialTabStop = 0)
Lines wrapRange(Rangei const &rangeToWrap, int maxWidth, int subsequentMaxWidth = 0,
int initialIndent = 0)
{
int const MIN_LINE_WIDTH = 120;
bool const isTabbed = (subsequentMaxWidth > 0);

indent = initialIndent;
tabStop = initialTabStop;
tabStop = 0;
int begin = rangeToWrap.start;

Lines wrappedLines;
forever
{
int mw = maxWidth;
if(!wrappedLines.isEmpty() && subsequentMaxWidth > 0) mw = subsequentMaxWidth;

// How much width is available, taking indentation into account?
if(maxWidth - indent < MIN_LINE_WIDTH)
if(mw - indent < MIN_LINE_WIDTH)
{
// There is no room for this indent...
indent = de::max(0, maxWidth - MIN_LINE_WIDTH);
if(!isTabbed)
{
// Regular non-tabbed line -- there is no room for this indent,
// so reduce it.
indent = de::max(0, mw - MIN_LINE_WIDTH);
}
else
{
// We can't alter indentation with tabs, so just extend the line instead.
mw = MIN_LINE_WIDTH + indent;
}
}
int availWidth = maxWidth - indent;
int availWidth = mw - indent;

// Range for the remainder of the text.
Rangei const range(begin, rangeToWrap.end);
Expand Down Expand Up @@ -416,8 +423,7 @@ void FontLineWrapping::wrapTextToWidth(String const &text, Font::RichFormat cons
d->text = newText;
d->format = format;

// When tabs are used, we must first determine the maximum width of each
// tab stop.
// When tabs are used, we must first determine the maximum width of each tab stop.
if(d->containsTabs(Rangei(0, text.size())))
{
d->indent = 0;
Expand All @@ -429,7 +435,6 @@ void FontLineWrapping::wrapTextToWidth(String const &text, Font::RichFormat cons
Rangei const wholeLine = d->untilNextNewline(pos);
d->lines << d->makeLine(wholeLine);
pos = wholeLine.end + 1;
qDebug() << "wrapped tab line:" << wholeLine.asText();
}

// Determine the actual positions of each tab stop according to segment widths.
Expand All @@ -441,23 +446,51 @@ void FontLineWrapping::wrapTextToWidth(String const &text, Font::RichFormat cons
for(int k = 0; k < line->info.segs.size(); ++k)
{
LineInfo::Segment const &seg = line->info.segs[k];
stopMaxWidths[seg.tabStop] = de::max(stopMaxWidths[seg.tabStop], seg.width);
int sw = seg.width;

// Include overall indent into the first segment width.
if(!k) sw += line->info.indent;

stopMaxWidths[seg.tabStop] = de::max(stopMaxWidths[seg.tabStop], sw);
}
}

// Now we can wrap the lines that area too long.
for(int i = 0; i < d->lines.size(); ++i)
{
Instance::Line *line = d->lines[i];
int lineWidth = 0;
int curLeft = 0;
int prevRight = 0;
for(int k = 0; k < line->info.segs.size(); ++k)
{
lineWidth += stopMaxWidths[line->info.segs[k].tabStop];
if(lineWidth > maxWidth)
LineInfo::Segment const &seg = line->info.segs[k];
int const tab = seg.tabStop;
int const stopWidth = stopMaxWidths[tab];

if(curLeft + stopWidth >= maxWidth)
{
// Wrap the line starting from this segment.

Instance::Lines wrapped = d->wrapRange(line->line.range,
maxWidth - (curLeft - prevRight),
maxWidth - curLeft + line->info.indent,
line->info.indent);

// Replace the original line with these wrapped lines.
delete d->lines.takeAt(i);
foreach(Instance::Line *wl, wrapped)
{
d->lines.insert(i++, wl);
}
--i;
break; // Proceed to next line.
}

// Update the coordinate of the previous segment's right edge.
prevRight = curLeft + seg.width;
if(!k) prevRight += line->info.indent;

// Move on to the next segment's left edge.
curLeft += stopWidth;
}
}
}
Expand All @@ -473,7 +506,7 @@ void FontLineWrapping::wrapTextToWidth(String const &text, Font::RichFormat cons
d->lines.last()->line.isFinal = true;
}

#if 1
#if 0
qDebug() << "Wrapped:" << d->text;
foreach(Instance::Line const *ln, d->lines)
{
Expand All @@ -482,7 +515,7 @@ void FontLineWrapping::wrapTextToWidth(String const &text, Font::RichFormat cons
foreach(LineInfo::Segment const &s, ln->info.segs)
{
qDebug() << "- seg" << s.range.asText() << d->text.substr(s.range)
<< "tab:" << s.tabStop;
<< "tab:" << s.tabStop << "w:" << s.width;
}
}
#endif
Expand Down

5 comments on commit 645911f

@danij-deng
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Good work, this seems to have fixed all(?) the line wrapping issues.

How feasible is a Config option for the 'justified' scaling of lines in the console history? I'd like to either reduce or disable this personally as I find it sometimes adversely affects readability.

@skyjake
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Do you mean the slight justification that occurs when there is still plenty of room for the text (this is a bug), or the major compression that occurs when there isn't enough room to fit all the tabs?

@danij-deng
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The major compression which I believe a applies a 15% scaling 'leeway'. In traditional typesetting terms I would rather a 'ragged edge' than 'rivers' of white space (though this doesn't actually happen in our case for numerous reasons).

@skyjake
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The underlying problem here is what to do when the tab layout runs out of space. The compression is the current solution that gives the rightmost column a bit more space by sacrificing legibility. I suppose a better solution would be to instead collapse the tab column to the next line.

@danij-deng
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Perhaps the ability to break long words onto the following line with a hyphen would help? Naturally this should only be done when necessary, though.

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