WIP: Pitched label legibility #4682
Commits on May 1, 2017
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Introduce 'text/icon-pitch-scale' property which controls how
symbols scale relative to the rest of the map as tiles are tilted and panned. - '1' = previous behavior (symbols have same scale as the surrounding features) - '0' = symbols maintain the same size no matter what distance they're at - fraction values = split the difference - Curved labels currently use a broken approximation to determine glyph position. - This approach makes collision detection much more expensive because we pre-calculate collisions over a much greater scale range to account for pan operations changing the effective scale of tiles.
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'text-pitch-scaling' calculations must be based on label anchors
instead of glyph anchors in order to keep all glyphs in sync.
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Fix "labelMinScale" logic in getGlyphQuads:
No glyph should be able to show if any one of the glyphs in the label can't show.
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Calculate line collision boxes over a wider range to account for label
expansion in the distance.
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Make pitched collision detection more conservative:
When doing collision detection, assume all labels are scaled the same as the least scaled label in the tile.
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Adjust collision tile scale range based on tile distance from camera.
Update collision tiles whenever the map moves because tile distance changes.
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'max-camera-distance' style property allows selective hiding of labels
as they move into the distance.
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Explain obscure difference between collision grid bounding boxes
and boxes for collision scale calculation.
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Make render test summary failures searchable
(and accessible to color blind folk)
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Fix some tests: we create more line collision boxes now at the edge of
labels now, but make sure the position of the central boxes doesn't change.
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Keep track of "maximum pitch scaling" as well as minimum pitch scaling
Necessary so that we can make collision detection conservative in the near field as well as the far field.
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min/max pitch scaling needs to be calculated over the whole tile
before placement starts.
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Get debug collision boxes closer in sync with actual labels:
Must do pitch scaling based on label anchor point, not box anchor point.
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Bring collision debug boxes into line with symbols that aren't added …
…to buffers because their placementScale is above the maxScale for the collision tile.
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Eliminate major source of label flicker: "minimum pitch scale" setting
was unpredictably shared across tiles.
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- Don't show boxes over maxScale (it was getting too confusing) - Use green background for test so white boxes are visible.
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Commits on May 2, 2017
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Fix 'symbol-avoid-edges', which relies on edge collision boxes being
inserted before first CollisionFeature is added to a CollisionBoxArray.
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Temporarily fix tests by rolling back extended collision boxes for
line labels. This could lead to label collisions in the distant field.
Commits on May 3, 2017
Commits on May 4, 2017
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Standardizing vertex shader precision on "highp" following discussion…
… in: #2096 Change some variable names from camel-case to underscore-separated.
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Only redo placement on pan operations if the map is tilted enough for
perspective to make a significant difference in collision detection.
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New approach to tilted curved labels with viewport pitch alignment:
- Lay out glyphs in tile space so we can use existing curve following logic - Space glyphs out based on the incidence angle of the middle of the label and the orientation of the middle of the label (So that a vertical line in the distance gets spaced out a lot) - Apply glyph rotation in projected space. Significant problems: - "We're out of space on this line" logic is mixed with collision detection logic, and they no longer stay in sync perfectly, so it's possible to have individual glyphs clipped before the whole label is clipped. - The spacing approximation doesn't work for highly curved labels, and you end up with silly looking results.