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Improved path text placing

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This commit is contained in:
Roman Kuznetsov 2015-12-05 15:18:45 +03:00
parent 4179b9abdc
commit 6156bb3182
1 changed files with 19 additions and 33 deletions
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52
drape_frontend/path_text_shape.cpp
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@ -111,7 +111,15 @@ PathTextShape::PathTextShape(m2::SharedSpline const & spline,
uint64_t PathTextShape::GetOverlayPriority() const
{
return dp::CalculateOverlayPriority(m_params.m_minVisibleScale, m_params.m_rank, m_params.m_depth);
// Overlay priority for path text shapes considers length of the text.
// Greater test length has more priority, because smaller texts have more chances to be shown along the road.
// [6 bytes - standard overlay priority][1 byte - reserved][1 byte - length].
static uint64_t constexpr kMask = ~static_cast<uint64_t>(0xFF);
uint64_t priority = dp::CalculateOverlayPriority(m_params.m_minVisibleScale, m_params.m_rank, m_params.m_depth);
priority &= kMask;
priority |= (static_cast<uint8_t>(m_params.m_text.size()));
return priority;
}
void PathTextShape::Draw(ref_ptr<dp::Batcher> batcher, ref_ptr<dp::TextureManager> textures) const
@ -125,56 +133,34 @@ void PathTextShape::Draw(ref_ptr<dp::Batcher> batcher, ref_ptr<dp::TextureManage
//we leave a little space on either side of the text that would
//remove the comparison for equality of spline portions
float const TextBorder = 4.0f;
float const textLength = TextBorder + layout->GetPixelLength();
float const textHalfLength = textLength / 2.0f;
float const kTextBorder = 4.0f;
float const textLength = kTextBorder + layout->GetPixelLength();
float const pathGlbLength = m_spline->GetLength();
// on next readable scale m_scaleGtoP will be twice
if (textLength > pathGlbLength * 2 * m_params.m_baseGtoPScale)
if (textLength > pathGlbLength * 2.0 * m_params.m_baseGtoPScale)
return;
float const pathLength = m_params.m_baseGtoPScale * m_spline->GetLength();
float const kPathLengthScalar = 0.75;
float const pathLength = kPathLengthScalar * m_params.m_baseGtoPScale * pathGlbLength;
/// copied from old code
/// @todo Choose best constant for minimal space.
float const etalonEmpty = max(200 * df::VisualParams::Instance().GetVisualScale(), (double)textLength);
float const etalonEmpty = max(300 * df::VisualParams::Instance().GetVisualScale(), (double)textLength);
float const minPeriodSize = etalonEmpty + textLength;
float const twoTextAndEmpty = minPeriodSize + textLength;
buffer_vector<float, 32> offsets;
float const scalePtoG = 1.0f / m_params.m_baseGtoPScale;
if (pathLength < twoTextAndEmpty)
{
// if we can't place 2 text and empty part on path
// we place only one text on center of path
offsets.push_back(pathGlbLength / 2.0f);
}
else if (pathLength < twoTextAndEmpty + minPeriodSize)
{
// if we can't place 3 text and 2 empty path
// we place 2 text with empty space beetwen
// and some offset from path end
float const endOffset = (pathLength - (2 * textLength + etalonEmpty)) / 2;
// division on m_scaleGtoP give as global coord frame (Mercator)
offsets.push_back((endOffset + textHalfLength) * scalePtoG);
offsets.push_back((pathLength - (textHalfLength + endOffset)) * scalePtoG);
}
else
{
// here we place 2 text on the ends of path
// then we place as much as possible text on center path uniformly
offsets.push_back(textHalfLength * scalePtoG);
offsets.push_back((pathLength - textHalfLength) * scalePtoG);
float const emptySpace = pathLength - 2 * textLength;
uint32_t textCount = static_cast<uint32_t>(ceil(emptySpace / minPeriodSize));
float const offset = (emptySpace - textCount * textLength) / (textCount + 1);
for (size_t i = 0; i < textCount; ++i)
offsets.push_back((textHalfLength + (textLength + offset) * (i + 1)) * scalePtoG);
double const textCount = max(floor(pathLength / minPeriodSize), 1.0);
double const glbTextLen = pathGlbLength / textCount;
for (double offset = 0.5 * glbTextLen; offset < pathGlbLength; offset += glbTextLen)
offsets.push_back(offset);
}
dp::TextureManager::ColorRegion color;