diff options
Diffstat (limited to 'src/mbgl/text/quads.cpp')
| -rw-r--r-- | src/mbgl/text/quads.cpp | 320 |
1 files changed, 54 insertions, 266 deletions
diff --git a/src/mbgl/text/quads.cpp b/src/mbgl/text/quads.cpp index ab10c5a6b7..0014ae8d01 100644 --- a/src/mbgl/text/quads.cpp +++ b/src/mbgl/text/quads.cpp @@ -13,14 +13,9 @@ namespace mbgl { using namespace style; -const float globalMinScale = 0.5f; // underscale by 1 zoom level - -SymbolQuad getIconQuad(const Anchor& anchor, - const PositionedIcon& shapedIcon, - const GeometryCoordinates& line, +SymbolQuad getIconQuad(const PositionedIcon& shapedIcon, const SymbolLayoutProperties::Evaluated& layout, const float layoutTextSize, - const style::SymbolPlacementType placement, const Shaping& shapedText) { const ImagePosition& image = shapedIcon.image(); @@ -71,18 +66,7 @@ SymbolQuad getIconQuad(const Anchor& anchor, bl = {left, bottom}; } - float angle = shapedIcon.angle(); - if (placement == style::SymbolPlacementType::Line) { - assert(static_cast<unsigned int>(anchor.segment) < line.size()); - const GeometryCoordinate &prev= line[anchor.segment]; - if (anchor.point.y == prev.y && anchor.point.x == prev.x && - static_cast<unsigned int>(anchor.segment + 1) < line.size()) { - const GeometryCoordinate &next= line[anchor.segment + 1]; - angle += std::atan2(anchor.point.y - next.y, anchor.point.x - next.x) + M_PI; - } else { - angle += std::atan2(anchor.point.y - prev.y, anchor.point.x - prev.x); - } - } + const float angle = shapedIcon.angle(); if (angle) { // Compute the transformation matrix. @@ -104,212 +88,19 @@ SymbolQuad getIconQuad(const Anchor& anchor, static_cast<uint16_t>(image.textureRect.h + border * 2) }; - return SymbolQuad { tl, tr, bl, br, textureRect, 0, 0, anchor.point, globalMinScale, std::numeric_limits<float>::infinity(), shapedText.writingMode }; -} - -struct GlyphInstance { - explicit GlyphInstance(Point<float> anchorPoint_) : anchorPoint(std::move(anchorPoint_)) {} - explicit GlyphInstance(Point<float> anchorPoint_, bool upsideDown_, float minScale_, float maxScale_, - float angle_) - : anchorPoint(std::move(anchorPoint_)), upsideDown(upsideDown_), minScale(minScale_), maxScale(maxScale_), angle(angle_) {} - - const Point<float> anchorPoint; - const bool upsideDown = false; - const float minScale = globalMinScale; - const float maxScale = std::numeric_limits<float>::infinity(); - const float angle = 0.0f; -}; - -using GlyphInstances = std::vector<GlyphInstance>; - -struct VirtualSegment { - Point<float> anchor; - Point<float> end; - size_t index; - float minScale; - float maxScale; -}; - -inline void insertSegmentGlyph(std::back_insert_iterator<GlyphInstances> glyphs, - const VirtualSegment& virtualSegment, - const bool glyphIsLogicallyForward, - const bool upsideDown) { - float segmentAngle = std::atan2(virtualSegment.end.y - virtualSegment.anchor.y, virtualSegment.end.x - virtualSegment.anchor.x); - // If !glyphIsLogicallyForward, we're iterating through the segments in reverse logical order as well, so we need to flip the segment angle - float glyphAngle = glyphIsLogicallyForward ? segmentAngle : segmentAngle + M_PI; - - // Insert a glyph rotated at this angle for display in the range from [scale, previous(larger) scale]. - glyphs = GlyphInstance{ - /* anchor */ virtualSegment.anchor, - /* upsideDown */ upsideDown, - /* minScale */ virtualSegment.minScale, - /* maxScale */ virtualSegment.maxScale, - /* angle */ static_cast<float>(std::fmod((glyphAngle + 2.0 * M_PI), (2.0 * M_PI)))}; -} - -/** - Given the distance along the line from the label anchor to the beginning of the current segment, - project a "virtual anchor" point at the same distance along the line extending out from this segment. - - B <-- beginning of current segment -* . . . . . . . *--------* E <-- end of current segment -VA | - / VA = "virtual segment anchor" - / - ---*-----` - A = label anchor - - Distance _along line_ from A to B == straight-line distance from VA to B. - */ -inline Point<float> getVirtualSegmentAnchor(const Point<float>& segmentBegin, const Point<float>& segmentEnd, float distanceFromAnchorToSegmentBegin) { - Point<float> segmentDirectionUnitVector = util::normal<float>(segmentBegin, segmentEnd); - return segmentBegin - (segmentDirectionUnitVector * distanceFromAnchorToSegmentBegin); -} - -/* - Given the segment joining `segmentAnchor` and `segmentEnd` and a desired offset - `glyphDistanceFromAnchor` at which a glyph is to be placed, calculate the minimum - "scale" at which the glyph will fall on the segment (i.e., not past the end) - - "Scale" here refers to the ratio between the *rendered* zoom level and the text-layout - zoom level, which is 1 + (source tile's zoom level). `glyphDistanceFromAnchor`, although - passed in units consistent with the text-layout zoom level, is based on text size. So - when the tile is being rendered at z < text-layout zoom, the glyph's actual distance from - the anchor is larger relative to the segment's length than at layout time: - - - GLYPH - z == layout-zoom, scale == 1: segmentAnchor *--------------^-------------* segmentEnd - z == layout-zoom - 1, scale == 0.5: segmentAnchor *--------------^* segmentEnd - - <--------------> - Anchor-to-glyph distance stays visually fixed, - so it changes relative to the segment. -*/ -inline float getMinScaleForSegment(const float glyphDistanceFromAnchor, - const Point<float>& segmentAnchor, - const Point<float>& segmentEnd) { - const auto distanceFromAnchorToEnd = util::dist<float>(segmentAnchor, segmentEnd); - return glyphDistanceFromAnchor / distanceFromAnchorToEnd; -} - -inline Point<float> getSegmentEnd(const bool glyphIsLogicallyForward, - const GeometryCoordinates& line, - const size_t segmentIndex) { - return convertPoint<float>(glyphIsLogicallyForward ? line[segmentIndex+1] : line[segmentIndex]); -} - -optional<VirtualSegment> getNextVirtualSegment(const VirtualSegment& previousVirtualSegment, - const GeometryCoordinates& line, - const float glyphDistanceFromAnchor, - const bool glyphIsLogicallyForward) { - auto nextSegmentBegin = previousVirtualSegment.end; - - auto end = nextSegmentBegin; - size_t index = previousVirtualSegment.index; - - // skip duplicate nodes - while (end == nextSegmentBegin) { - // look ahead by 2 points in the line because the segment index refers to the beginning - // of the segment, and we need an endpoint too - if (glyphIsLogicallyForward && (index + 2 < line.size())) { - index += 1; - } else if (!glyphIsLogicallyForward && index != 0) { - index -= 1; - } else { - return {}; - } - - end = getSegmentEnd(glyphIsLogicallyForward, line, index); - } - - const auto anchor = getVirtualSegmentAnchor(nextSegmentBegin, end, - util::dist<float>(previousVirtualSegment.anchor, - previousVirtualSegment.end)); - return VirtualSegment { - anchor, - end, - index, - getMinScaleForSegment(glyphDistanceFromAnchor, anchor, end), - previousVirtualSegment.minScale - }; -} - -/* - Given (1) a glyph positioned relative to an anchor point and (2) a line to follow, - calculates which segment of the line the glyph will fall on for each possible - scale range, and for each range produces a "virtual" anchor point and an angle that will - place the glyph on the right segment and rotated to the correct angle. - - Because one glyph quad is made ahead of time for each possible orientation, the - symbol_sdf shader can quickly handle changing layout as we zoom in and out - - If the "keepUpright" property is set, we call getLineGlyphs twice (once upright and - once "upside down"). This will generate two sets of glyphs following the line in opposite - directions. Later, SymbolLayout::place will look at the glyphs and based on the placement - angle determine if their original anchor was "upright" or not -- based on that, it throws - away one set of glyphs or the other (this work has to be done in the CPU, but it's just a - filter so it's fast) - */ -void getLineGlyphs(std::back_insert_iterator<GlyphInstances> glyphs, - Anchor& anchor, - float glyphHorizontalOffsetFromAnchor, - const GeometryCoordinates& line, - size_t anchorSegment, - bool upsideDown) { - assert(line.size() > anchorSegment+1); - - // This is true if the glyph is "logically forward" of the anchor point, based on the ordering of line segments - // The actual angle of the line is irrelevant - // If "upsideDown" is set, everything is flipped - const bool glyphIsLogicallyForward = (glyphHorizontalOffsetFromAnchor >= 0) ^ upsideDown; - const float glyphDistanceFromAnchor = std::fabs(glyphHorizontalOffsetFromAnchor); - - const auto initialSegmentEnd = getSegmentEnd(glyphIsLogicallyForward, line, anchorSegment); - VirtualSegment virtualSegment = { - anchor.point, - initialSegmentEnd, - anchorSegment, - getMinScaleForSegment(glyphDistanceFromAnchor, anchor.point, initialSegmentEnd), - std::numeric_limits<float>::infinity() - }; - - while (true) { - insertSegmentGlyph(glyphs, - virtualSegment, - glyphIsLogicallyForward, - upsideDown); - - if (virtualSegment.minScale <= anchor.scale) { - // No need to calculate below the scale where the label starts showing - return; - } - - optional<VirtualSegment> nextVirtualSegment = getNextVirtualSegment(virtualSegment, - line, - glyphDistanceFromAnchor, - glyphIsLogicallyForward); - if (!nextVirtualSegment) { - // There are no more segments, so we can't fit this glyph on the line at a lower scale - // This implies we can't show the label at all at lower scale, so we update the anchor's min scale - anchor.scale = virtualSegment.minScale; - return; - } else { - virtualSegment = *nextVirtualSegment; - } - } - + return SymbolQuad { tl, tr, bl, br, textureRect, shapedText.writingMode, { 0.0f, 0.0f } }; } -SymbolQuads getGlyphQuads(Anchor& anchor, - const Shaping& shapedText, - const float boxScale, - const GeometryCoordinates& line, +SymbolQuads getGlyphQuads(const Shaping& shapedText, const SymbolLayoutProperties::Evaluated& layout, const style::SymbolPlacementType placement, const GlyphPositionMap& positions) { const float textRotate = layout.get<TextRotate>() * util::DEG2RAD; - const bool keepUpright = layout.get<TextKeepUpright>(); + + const float oneEm = 24.0; + std::array<float, 2> textOffset = layout.get<TextOffset>(); + textOffset[0] *= oneEm; + textOffset[1] *= oneEm; SymbolQuads quads; @@ -320,67 +111,64 @@ SymbolQuads getGlyphQuads(Anchor& anchor, const GlyphPosition& glyph = positionsIt->second; const Rect<uint16_t>& rect = glyph.rect; - const float centerX = (positionedGlyph.x + glyph.metrics.advance / 2.0f) * boxScale; - - GlyphInstances glyphInstances; - if (placement == style::SymbolPlacementType::Line) { - getLineGlyphs(std::back_inserter(glyphInstances), anchor, centerX, line, anchor.segment, false); - if (keepUpright) - getLineGlyphs(std::back_inserter(glyphInstances), anchor, centerX, line, anchor.segment, true); - } else { - glyphInstances.emplace_back(GlyphInstance{anchor.point}); - } // The rects have an addditional buffer that is not included in their size; const float glyphPadding = 1.0f; const float rectBuffer = 3.0f + glyphPadding; - const float x1 = positionedGlyph.x + glyph.metrics.left - rectBuffer; - const float y1 = positionedGlyph.y - glyph.metrics.top - rectBuffer; - const float x2 = x1 + rect.w; - const float y2 = y1 + rect.h; + const float halfAdvance = glyph.metrics.advance / 2.0; + const bool alongLine = layout.get<TextRotationAlignment>() == AlignmentType::Map && placement == SymbolPlacementType::Line; - const Point<float> center{positionedGlyph.x, static_cast<float>(static_cast<float>(glyph.metrics.advance) / 2.0)}; + const Point<float> glyphOffset = alongLine ? + Point<float>{ positionedGlyph.x + halfAdvance, positionedGlyph.y } : + Point<float>{ 0.0f, 0.0f }; - Point<float> otl{x1, y1}; - Point<float> otr{x2, y1}; - Point<float> obl{x1, y2}; - Point<float> obr{x2, y2}; - - if (positionedGlyph.angle != 0) { - otl = util::rotate(otl - center, positionedGlyph.angle) + center; - otr = util::rotate(otr - center, positionedGlyph.angle) + center; - obl = util::rotate(obl - center, positionedGlyph.angle) + center; - obr = util::rotate(obr - center, positionedGlyph.angle) + center; - } + const Point<float> builtInOffset = alongLine ? + Point<float>{ 0.0f, 0.0f } : + Point<float>{ positionedGlyph.x + halfAdvance + textOffset[0], positionedGlyph.y + textOffset[1] }; - for (const GlyphInstance &instance : glyphInstances) { - Point<float> tl = otl; - Point<float> tr = otr; - Point<float> bl = obl; - Point<float> br = obr; - if (textRotate) { - // Compute the transformation matrix. - float angle_sin = std::sin(textRotate); - float angle_cos = std::cos(textRotate); - std::array<float, 4> matrix = {{angle_cos, -angle_sin, angle_sin, angle_cos}}; + const float x1 = glyph.metrics.left - rectBuffer - halfAdvance + builtInOffset.x; + const float y1 = -glyph.metrics.top - rectBuffer + builtInOffset.y; + const float x2 = x1 + rect.w; + const float y2 = y1 + rect.h; - tl = util::matrixMultiply(matrix, tl); - tr = util::matrixMultiply(matrix, tr); - bl = util::matrixMultiply(matrix, bl); - br = util::matrixMultiply(matrix, br); - } + Point<float> tl{x1, y1}; + Point<float> tr{x2, y1}; + Point<float> bl{x1, y2}; + Point<float> br{x2, y2}; + + if (alongLine && positionedGlyph.vertical) { + // Vertical-supporting glyphs are laid out in 24x24 point boxes (1 square em) + // In horizontal orientation, the y values for glyphs are below the midline + // and we use a "yOffset" of -17 to pull them up to the middle. + // By rotating counter-clockwise around the point at the center of the left + // edge of a 24x24 layout box centered below the midline, we align the center + // of the glyphs with the horizontal midline, so the yOffset is no longer + // necessary, but we also pull the glyph to the left along the x axis + const Point<float> center{-halfAdvance, halfAdvance}; + const float verticalRotation = -M_PI_2; + const Point<float> xOffsetCorrection{5, 0}; + + tl = util::rotate(tl - center, verticalRotation) + center + xOffsetCorrection; + tr = util::rotate(tr - center, verticalRotation) + center + xOffsetCorrection; + bl = util::rotate(bl - center, verticalRotation) + center + xOffsetCorrection; + br = util::rotate(br - center, verticalRotation) + center + xOffsetCorrection; + } - // Prevent label from extending past the end of the line - const float glyphMinScale = std::max(instance.minScale, anchor.scale); + if (textRotate) { + // Compute the transformation matrix. + float angle_sin = std::sin(textRotate); + float angle_cos = std::cos(textRotate); + std::array<float, 4> matrix = {{angle_cos, -angle_sin, angle_sin, angle_cos}}; - // All the glyphs for a label are tagged with either the "right side up" or "upside down" anchor angle, - // which is used at placement time to determine which set to show - const float anchorAngle = std::fmod((anchor.angle + (instance.upsideDown ? M_PI : 0.0) + 2 * M_PI), (2 * M_PI)); - const float glyphAngle = std::fmod((instance.angle + (instance.upsideDown ? M_PI : 0.0) + 2 * M_PI), (2 * M_PI)); - quads.emplace_back(tl, tr, bl, br, rect, anchorAngle, glyphAngle, instance.anchorPoint, glyphMinScale, instance.maxScale, shapedText.writingMode); + tl = util::matrixMultiply(matrix, tl); + tr = util::matrixMultiply(matrix, tr); + bl = util::matrixMultiply(matrix, bl); + br = util::matrixMultiply(matrix, br); } + + quads.emplace_back(tl, tr, bl, br, rect, shapedText.writingMode, glyphOffset); } return quads; |