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// Protocol Version 1
package llmr.vector;
option optimize_for = LITE_RUNTIME;
enum geom_type {
Unknown = 0;
Point = 1;
LineString = 2;
Polygon = 3;
}
// Variant type encoding
message value {
// Exactly one of these values may be present in a valid message
optional string string_value = 1;
optional float float_value = 2;
optional double double_value = 3;
optional int64 int_value = 4;
optional uint64 uint_value = 5;
optional sint64 sint_value = 6;
optional bool bool_value = 7;
extensions 8 to max;
}
message feature {
optional uint64 id = 1;
// Tags of this feature. Even numbered values refer to the nth
// value in the keys list on the tile message, odd numbered
// values refer to the nth value in the values list on the tile
// message.
repeated uint32 tags = 2 [ packed = true ];
// The type of geometry stored in this feature.
optional geom_type type = 3 [ default = Unknown ];
// Contains a stream of commands and parameters (vertices). The
// repeat count is shifted to the left by 3 bits. This means
// that the command has 3 bits (0-15). The repeat count
// indicates how often this command is to be repeated. Defined
// commands are:
// - MoveTo: 1 (2 parameters follow)
// - LineTo: 2 (2 parameters follow)
// - ClosePath: 15 (no parameters follow)
//
// Ex.: MoveTo(3, 6), LineTo(8, 12), LineTo(20, 34), ClosePath
// Encoded as: [ 3 6 18 5 6 12 22 15 ]
// == command type 15 (ClosePath)
// ===== relative LineTo(+12, +22) == LineTo(20, 34)
// === relative LineTo(+5, +6) == LineTo(8, 12)
// == [00010 010] = command type 2 (LineTo), length 2
// === relative MoveTo(+3, +6)
// = implicit command type 1 (MoveTo), length 1
// Commands are encoded as uint32 varints, vertex parameters are
// encoded as sint32 varints (zigzag). Vertex parameters are
// also encoded as deltas to the previous position. The original
// position is (0,0)
repeated uint32 geometry = 4 [ packed = true ];
// A list of indices to the geometry array that specify a triangulation of
// this geometry. This must only exist if this feature is a polygon.
// These are the valid indices for the example above:
// 0 ==> (3/6)
// 1 ==> (8/12)
// 2 ==> (20/34)
// Indices beyond 2 are invalid, as the total number of vertices is 3.
repeated sint32 triangulation = 5 [ packed = true ];
// The total number of vertices encoded in the geometry field. This is can
// be deduced by manually iterating through the geometry field, but we can
// just as well store the number to avoid the overhead on parsing.
optional uint32 vertex_count = 6;
}
// Stores a glyph with metrics and optional SDF bitmap information.
message glyph {
required uint32 id = 1;
// A signed distance field of the glyph with a border of 3 pixels.
optional bytes bitmap = 2;
// Glyph metrics.
required uint32 width = 3;
required uint32 height = 4;
required sint32 left = 5;
required sint32 top = 6;
required uint32 advance = 7;
}
// Stores font face information and a list of glyphs.
message face {
required string family = 1;
required string style = 2;
repeated glyph glyphs = 5;
}
// Stores the shaping information for the label with a given text
message label {
// The original value ID this shaping information is for.
required uint32 text = 1;
// References the index of the font stack in the layer's fontstack array.
required uint32 stack = 2;
// Parallel arrays of face ID, glyph ID and position.
repeated uint32 faces = 3 [packed = true];
repeated uint32 glyphs = 4 [packed = true];
repeated uint32 x = 5 [packed = true];
repeated uint32 y = 6 [packed = true];
}
message layer {
// Any compliant implementation must first read the version
// number encoded in this message and choose the correct
// implementation for this version number before proceeding to
// decode other parts of this message.
required uint32 version = 15 [ default = 1 ];
required string name = 1;
// The actual features in this tile.
repeated feature features = 2;
// Dictionary encoding for keys
repeated string keys = 3;
// Dictionary encoding for values
repeated value values = 4;
// The bounding box in this tile spans from 0..4095 units
optional uint32 extent = 5 [ default = 4096 ];
// Total vertex count in this layer.
optional uint32 vertex_count = 6;
// Shaping information for labels contained in this tile.
repeated string faces = 7;
repeated label labels = 8;
repeated string stacks = 9;
extensions 16 to max;
}
message tile {
repeated layer layers = 3;
repeated face faces = 4;
extensions 16 to 8191;
}
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