From 70cb8b24ccd9c913fdd52a99aef35d24a70c3842 Mon Sep 17 00:00:00 2001 From: tavmjong-free Date: Tue, 1 Jun 2010 12:41:52 +0200 Subject: [PATCH] Prevent vertical kerning from changing line spacing. Fixes bug 516216. Further work is needed to allow vertical kerning across multiple lines. --- src/libnrtype/Layout-TNG-Compute.cpp | 69 ++++++++++++++++++++++------ 1 file changed, 54 insertions(+), 15 deletions(-) diff --git a/src/libnrtype/Layout-TNG-Compute.cpp b/src/libnrtype/Layout-TNG-Compute.cpp index 518df152f..cad2f9b19 100644 --- a/src/libnrtype/Layout-TNG-Compute.cpp +++ b/src/libnrtype/Layout-TNG-Compute.cpp @@ -76,7 +76,14 @@ class Layout::Calculator /** for y= attributes in tspan elements et al, we do the adjustment by moving each glyph individually by this number. The spec means that this is maintained across - paragraphs. */ + paragraphs. + + To do non-flow text layout, only the first "y" attribute is normally used. If there is only one + "y" attribute in a other than the first , it is ignored. This allows Inkscape to + insert a new line anywhere. On output, the Inkscape determined "y" is written out so other SVG + viewers know where to place the . + */ + double _y_offset; /** to stop pango from hinting its output, the font factory creates all fonts very large. @@ -158,7 +165,9 @@ class Layout::Calculator void setZero(); }; - /** The definition of a chunk used here is the same as that used in Layout. */ + /** The definition of a chunk used here is the same as that used in Layout: + A collection of contiguous broken spans on the same line. (One chunk per line + unless shape splits line into several sections... then one chunk per section. */ struct ChunkInfo { std::vector broken_spans; double scanrun_width; @@ -410,6 +419,7 @@ class Layout::Calculator */ void _outputLine(ParagraphInfo const ¶, LineHeight const &line_height, std::vector const &chunk_info) { + TRACE(("Start _outputLine\n")); if (chunk_info.empty()) { TRACE(("line too short to fit anything on it, go to next\n")); return; @@ -429,19 +439,45 @@ class Layout::Calculator // add the chunk to the list Layout::Chunk new_chunk; new_chunk.in_line = _flow._lines.size() - 1; + TRACE((" New chunk: in_line: %d\n", new_chunk.in_line)); new_chunk.left_x = _getChunkLeftWithAlignment(para, it_chunk, &add_to_each_whitespace); + // we may also have y move orders to deal with here (dx, dy and rotate are done per span) - if (!it_chunk->broken_spans.empty() // this one only happens for empty paragraphs - && it_chunk->broken_spans.front().start.char_byte == 0 - && it_chunk->broken_spans.front().start.iter_span->y._set) { - // if this is the start of a line, we should change the baseline rather than each glyph individually - if (_flow._characters.empty() || _flow._characters.back().chunk(&_flow).in_line != _flow._lines.size() - 1) { - new_line.baseline_y = it_chunk->broken_spans.front().start.iter_span->y.computed; - _flow._lines.back().baseline_y = new_line.baseline_y; + + // Comment added: 1 June 2010: + // The first line in a normal object is placed by the read-in "y" value. The rest are + // determined by Inkscape. This is to allow insertation of new lines in the middle + // of a object. New "y" values are then stored in each that represents + // a new line. The line spacing should depend only on font-size and line-height (and not + // on any y-kerning). Line spacing is already handled by the calling routine. Note that + // this may render improperly any SVG with s created/edited by other programs. + if (!it_chunk->broken_spans.empty() // Not empty paragraph + && it_chunk->broken_spans.front().start.char_byte == 0 ) { // Beginning of unbroken span + + // If empty or new line + if( _flow._characters.empty() || + _flow._characters.back().chunk(&_flow).in_line != _flow._lines.size() - 1) { + + // If "y" attribute is set, use it (initial "y" attributes in + // other than the first have already been stripped). + if( it_chunk->broken_spans.front().start.iter_span->y._set ) { + + // Use set "y" attribute + new_line.baseline_y = it_chunk->broken_spans.front().start.iter_span->y.computed; + + // Save baseline + _flow._lines.back().baseline_y = new_line.baseline_y; + + // Save new y coordinate + _scanline_maker->setNewYCoordinate(new_line.baseline_y - line_height.ascent); + + } + + // Reset relative y_offset ("dy" attribute is relative but should be reset at + // the beginning of each .) _y_offset = 0.0; - _scanline_maker->setNewYCoordinate(new_line.baseline_y - line_height.ascent); - } else - _y_offset = it_chunk->broken_spans.front().start.iter_span->y.computed - new_line.baseline_y; + + } } _flow._chunks.push_back(new_chunk); @@ -466,7 +502,8 @@ class Layout::Calculator UnbrokenSpan const &unbroken_span = *it_span->start.iter_span; if (it_span->start.char_byte == 0) { - // start of an unbroken span, we might have dx, dy or rotate still to process (x and y are done per chunk) + // Start of an unbroken span, we might have dx, dy or rotate still to process + // (x and y are done per chunk) if (unbroken_span.dx._set) x += unbroken_span.dx.computed; if (unbroken_span.dy._set) _y_offset += unbroken_span.dy.computed; if (unbroken_span.rotate._set) glyph_rotate = unbroken_span.rotate.computed * (M_PI/180); @@ -984,6 +1021,7 @@ unsigned Layout::Calculator::_buildSpansForPara(ParagraphInfo *para) const } } else if (_flow._input_stream[input_index]->Type() == TEXT_SOURCE && pango_item_index < para->pango_items.size()) { Layout::InputStreamTextSource const *text_source = static_cast(_flow._input_stream[input_index]); + unsigned char_index_in_source = 0; unsigned span_start_byte_in_source = 0; @@ -1000,6 +1038,7 @@ unsigned Layout::Calculator::_buildSpansForPara(ParagraphInfo *para) const unsigned const text_source_bytes = ( text_source->text_end.base() - text_source->text_begin.base() - span_start_byte_in_source ); + TRACE(("New Span\n")); UnbrokenSpan new_span; new_span.text_bytes = std::min(text_source_bytes, pango_item_bytes); new_span.input_stream_first_character = Glib::ustring::const_iterator(text_source->text_begin.base() + span_start_byte_in_source); @@ -1385,7 +1424,7 @@ bool Layout::Calculator::calculate() _createFirstScanlineMaker(); ParagraphInfo para; - LineHeight line_height; // needs to be maintained across paragraphs to be able to deal with blank paras (this is wrong) + LineHeight line_height; // needs to be maintained across paragraphs to be able to deal with blank paras for(para.first_input_index = 0 ; para.first_input_index < _flow._input_stream.size() ; ) { // jump to the next wrap shape if this is a SHAPE_BREAK control code if (_flow._input_stream[para.first_input_index]->Type() == CONTROL_CODE) { @@ -1426,7 +1465,7 @@ bool Layout::Calculator::calculate() break; // out of shapes to wrap in to _outputLine(para, line_height, line_chunk_info); - _scanline_maker->completeLine(); + _scanline_maker->completeLine(); // Increments y by line height } while (span_pos.iter_span != para.unbroken_spans.end()); TRACE(("para %d end\n\n", _flow._paragraphs.size() - 1)); -- 2.30.2