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authorLibravatar kim <89579420+NyaaaWhatsUpDoc@users.noreply.github.com>2024-08-02 11:46:41 +0000
committerLibravatar GitHub <noreply@github.com>2024-08-02 12:46:41 +0100
commit94e87610c4ce9bbb1c614a61bab29c1422fed11b (patch)
tree2e06b8ce64212140e796f6077ba841b6cc678501 /vendor/github.com/golang/geo/s2/edge_query.go
parent[feature] Allow import of following and blocks via CSV (#3150) (diff)
downloadgotosocial-94e87610c4ce9bbb1c614a61bab29c1422fed11b.tar.xz
[chore] add back exif-terminator and use only for jpeg,png,webp (#3161)
* add back exif-terminator and use only for jpeg,png,webp * fix arguments passed to terminateExif() * pull in latest exif-terminator * fix test * update processed img --------- Co-authored-by: tobi <tobi.smethurst@protonmail.com>
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+// Copyright 2019 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package s2
+
+import (
+ "sort"
+
+ "github.com/golang/geo/s1"
+)
+
+// EdgeQueryOptions holds the options for controlling how EdgeQuery operates.
+//
+// Options can be chained together builder-style:
+//
+// opts = NewClosestEdgeQueryOptions().
+// MaxResults(1).
+// DistanceLimit(s1.ChordAngleFromAngle(3 * s1.Degree)).
+// MaxError(s1.ChordAngleFromAngle(0.001 * s1.Degree))
+// query = NewClosestEdgeQuery(index, opts)
+//
+// or set individually:
+//
+// opts = NewClosestEdgeQueryOptions()
+// opts.IncludeInteriors(true)
+//
+// or just inline:
+//
+// query = NewClosestEdgeQuery(index, NewClosestEdgeQueryOptions().MaxResults(3))
+//
+// If you pass a nil as the options you get the default values for the options.
+type EdgeQueryOptions struct {
+ common *queryOptions
+}
+
+// DistanceLimit specifies that only edges whose distance to the target is
+// within, this distance should be returned. Edges whose distance is equal
+// are not returned. To include values that are equal, specify the limit with
+// the next largest representable distance. i.e. limit.Successor().
+func (e *EdgeQueryOptions) DistanceLimit(limit s1.ChordAngle) *EdgeQueryOptions {
+ e.common = e.common.DistanceLimit(limit)
+ return e
+}
+
+// IncludeInteriors specifies whether polygon interiors should be
+// included when measuring distances.
+func (e *EdgeQueryOptions) IncludeInteriors(x bool) *EdgeQueryOptions {
+ e.common = e.common.IncludeInteriors(x)
+ return e
+}
+
+// UseBruteForce sets or disables the use of brute force in a query.
+func (e *EdgeQueryOptions) UseBruteForce(x bool) *EdgeQueryOptions {
+ e.common = e.common.UseBruteForce(x)
+ return e
+}
+
+// MaxError specifies that edges up to dist away than the true
+// matching edges may be substituted in the result set, as long as such
+// edges satisfy all the remaining search criteria (such as DistanceLimit).
+// This option only has an effect if MaxResults is also specified;
+// otherwise all edges closer than MaxDistance will always be returned.
+func (e *EdgeQueryOptions) MaxError(dist s1.ChordAngle) *EdgeQueryOptions {
+ e.common = e.common.MaxError(dist)
+ return e
+}
+
+// MaxResults specifies that at most MaxResults edges should be returned.
+// This must be at least 1.
+func (e *EdgeQueryOptions) MaxResults(n int) *EdgeQueryOptions {
+ e.common = e.common.MaxResults(n)
+ return e
+}
+
+// NewClosestEdgeQueryOptions returns a set of edge query options suitable
+// for performing closest edge queries.
+func NewClosestEdgeQueryOptions() *EdgeQueryOptions {
+ return &EdgeQueryOptions{
+ common: newQueryOptions(minDistance(0)),
+ }
+}
+
+// NewFurthestEdgeQueryOptions returns a set of edge query options suitable
+// for performing furthest edge queries.
+func NewFurthestEdgeQueryOptions() *EdgeQueryOptions {
+ return &EdgeQueryOptions{
+ common: newQueryOptions(maxDistance(0)),
+ }
+}
+
+// EdgeQueryResult represents an edge that meets the target criteria for the
+// query. Note the following special cases:
+//
+// - ShapeID >= 0 && EdgeID < 0 represents the interior of a shape.
+// Such results may be returned when the option IncludeInteriors is true.
+//
+// - ShapeID < 0 && EdgeID < 0 is returned to indicate that no edge
+// satisfies the requested query options.
+type EdgeQueryResult struct {
+ distance distance
+ shapeID int32
+ edgeID int32
+}
+
+// Distance reports the distance between the edge in this shape that satisfied
+// the query's parameters.
+func (e EdgeQueryResult) Distance() s1.ChordAngle { return e.distance.chordAngle() }
+
+// ShapeID reports the ID of the Shape this result is for.
+func (e EdgeQueryResult) ShapeID() int32 { return e.shapeID }
+
+// EdgeID reports the ID of the edge in the results Shape.
+func (e EdgeQueryResult) EdgeID() int32 { return e.edgeID }
+
+// newEdgeQueryResult returns a result instance with default values.
+func newEdgeQueryResult(target distanceTarget) EdgeQueryResult {
+ return EdgeQueryResult{
+ distance: target.distance().infinity(),
+ shapeID: -1,
+ edgeID: -1,
+ }
+}
+
+// IsInterior reports if this result represents the interior of a Shape.
+func (e EdgeQueryResult) IsInterior() bool {
+ return e.shapeID >= 0 && e.edgeID < 0
+}
+
+// IsEmpty reports if this has no edge that satisfies the given edge query options.
+// This result is only returned in one special case, namely when FindEdge() does
+// not find any suitable edges.
+func (e EdgeQueryResult) IsEmpty() bool {
+ return e.shapeID < 0
+}
+
+// Less reports if this results is less that the other first by distance,
+// then by (shapeID, edgeID). This is used for sorting.
+func (e EdgeQueryResult) Less(other EdgeQueryResult) bool {
+ if e.distance.less(other.distance) {
+ return true
+ }
+ if other.distance.less(e.distance) {
+ return false
+ }
+ if e.shapeID < other.shapeID {
+ return true
+ }
+ if other.shapeID < e.shapeID {
+ return false
+ }
+ return e.edgeID < other.edgeID
+}
+
+// EdgeQuery is used to find the edge(s) between two geometries that match a
+// given set of options. It is flexible enough so that it can be adapted to
+// compute maximum distances and even potentially Hausdorff distances.
+//
+// By using the appropriate options, this type can answer questions such as:
+//
+// - Find the minimum distance between two geometries A and B.
+// - Find all edges of geometry A that are within a distance D of geometry B.
+// - Find the k edges of geometry A that are closest to a given point P.
+//
+// You can also specify whether polygons should include their interiors (i.e.,
+// if a point is contained by a polygon, should the distance be zero or should
+// it be measured to the polygon boundary?)
+//
+// The input geometries may consist of any number of points, polylines, and
+// polygons (collectively referred to as "shapes"). Shapes do not need to be
+// disjoint; they may overlap or intersect arbitrarily. The implementation is
+// designed to be fast for both simple and complex geometries.
+type EdgeQuery struct {
+ index *ShapeIndex
+ opts *queryOptions
+ target distanceTarget
+
+ // True if opts.maxError must be subtracted from ShapeIndex cell distances
+ // in order to ensure that such distances are measured conservatively. This
+ // is true only if the target takes advantage of maxError in order to
+ // return faster results, and 0 < maxError < distanceLimit.
+ useConservativeCellDistance bool
+
+ // The decision about whether to use the brute force algorithm is based on
+ // counting the total number of edges in the index. However if the index
+ // contains a large number of shapes, this in itself might take too long.
+ // So instead we only count edges up to (maxBruteForceIndexSize() + 1)
+ // for the current target type (stored as indexNumEdgesLimit).
+ indexNumEdges int
+ indexNumEdgesLimit int
+
+ // The distance beyond which we can safely ignore further candidate edges.
+ // (Candidates that are exactly at the limit are ignored; this is more
+ // efficient for UpdateMinDistance and should not affect clients since
+ // distance measurements have a small amount of error anyway.)
+ //
+ // Initially this is the same as the maximum distance specified by the user,
+ // but it can also be updated by the algorithm (see maybeAddResult).
+ distanceLimit distance
+
+ // The current set of results of the query.
+ results []EdgeQueryResult
+
+ // This field is true when duplicates must be avoided explicitly. This
+ // is achieved by maintaining a separate set keyed by (shapeID, edgeID)
+ // only, and checking whether each edge is in that set before computing the
+ // distance to it.
+ avoidDuplicates bool
+
+ // testedEdges tracks the set of shape and edges that have already been tested.
+ testedEdges map[ShapeEdgeID]uint32
+}
+
+// NewClosestEdgeQuery returns an EdgeQuery that is used for finding the
+// closest edge(s) to a given Point, Edge, Cell, or geometry collection.
+//
+// You can find either the k closest edges, or all edges within a given
+// radius, or both (i.e., the k closest edges up to a given maximum radius).
+// E.g. to find all the edges within 5 kilometers, set the DistanceLimit in
+// the options.
+//
+// By default *all* edges are returned, so you should always specify either
+// MaxResults or DistanceLimit options or both.
+//
+// Note that by default, distances are measured to the boundary and interior
+// of polygons. For example, if a point is inside a polygon then its distance
+// is zero. To change this behavior, set the IncludeInteriors option to false.
+//
+// If you only need to test whether the distance is above or below a given
+// threshold (e.g., 10 km), you can use the IsDistanceLess() method. This is
+// much faster than actually calculating the distance with FindEdge,
+// since the implementation can stop as soon as it can prove that the minimum
+// distance is either above or below the threshold.
+func NewClosestEdgeQuery(index *ShapeIndex, opts *EdgeQueryOptions) *EdgeQuery {
+ if opts == nil {
+ opts = NewClosestEdgeQueryOptions()
+ }
+ return &EdgeQuery{
+ testedEdges: make(map[ShapeEdgeID]uint32),
+ index: index,
+ opts: opts.common,
+ }
+}
+
+// NewFurthestEdgeQuery returns an EdgeQuery that is used for finding the
+// furthest edge(s) to a given Point, Edge, Cell, or geometry collection.
+//
+// The furthest edge is defined as the one which maximizes the
+// distance from any point on that edge to any point on the target geometry.
+//
+// Similar to the example in NewClosestEdgeQuery, to find the 5 furthest edges
+// from a given Point:
+func NewFurthestEdgeQuery(index *ShapeIndex, opts *EdgeQueryOptions) *EdgeQuery {
+ if opts == nil {
+ opts = NewFurthestEdgeQueryOptions()
+ }
+ return &EdgeQuery{
+ testedEdges: make(map[ShapeEdgeID]uint32),
+ index: index,
+ opts: opts.common,
+ }
+}
+
+// FindEdges returns the edges for the given target that satisfy the current options.
+//
+// Note that if opts.IncludeInteriors is true, the results may include some
+// entries with edge_id == -1. This indicates that the target intersects
+// the indexed polygon with the given ShapeID.
+func (e *EdgeQuery) FindEdges(target distanceTarget) []EdgeQueryResult {
+ return e.findEdges(target, e.opts)
+}
+
+// Distance reports the distance to the target. If the index or target is empty,
+// returns the EdgeQuery's maximal sentinel.
+//
+// Use IsDistanceLess()/IsDistanceGreater() if you only want to compare the
+// distance against a threshold value, since it is often much faster.
+func (e *EdgeQuery) Distance(target distanceTarget) s1.ChordAngle {
+ return e.findEdge(target, e.opts).Distance()
+}
+
+// IsDistanceLess reports if the distance to target is less than the given limit.
+//
+// This method is usually much faster than Distance(), since it is much
+// less work to determine whether the minimum distance is above or below a
+// threshold than it is to calculate the actual minimum distance.
+//
+// If you wish to check if the distance is less than or equal to the limit, use:
+//
+// query.IsDistanceLess(target, limit.Successor())
+//
+func (e *EdgeQuery) IsDistanceLess(target distanceTarget, limit s1.ChordAngle) bool {
+ opts := e.opts
+ opts = opts.MaxResults(1).
+ DistanceLimit(limit).
+ MaxError(s1.StraightChordAngle)
+ return !e.findEdge(target, opts).IsEmpty()
+}
+
+// IsDistanceGreater reports if the distance to target is greater than limit.
+//
+// This method is usually much faster than Distance, since it is much
+// less work to determine whether the maximum distance is above or below a
+// threshold than it is to calculate the actual maximum distance.
+// If you wish to check if the distance is less than or equal to the limit, use:
+//
+// query.IsDistanceGreater(target, limit.Predecessor())
+//
+func (e *EdgeQuery) IsDistanceGreater(target distanceTarget, limit s1.ChordAngle) bool {
+ return e.IsDistanceLess(target, limit)
+}
+
+// IsConservativeDistanceLessOrEqual reports if the distance to target is less
+// or equal to the limit, where the limit has been expanded by the maximum error
+// for the distance calculation.
+//
+// For example, suppose that we want to test whether two geometries might
+// intersect each other after they are snapped together using Builder
+// (using the IdentitySnapFunction with a given "snap radius"). Since
+// Builder uses exact distance predicates (s2predicates), we need to
+// measure the distance between the two geometries conservatively. If the
+// distance is definitely greater than "snap radius", then the geometries
+// are guaranteed to not intersect after snapping.
+func (e *EdgeQuery) IsConservativeDistanceLessOrEqual(target distanceTarget, limit s1.ChordAngle) bool {
+ return e.IsDistanceLess(target, limit.Expanded(minUpdateDistanceMaxError(limit)))
+}
+
+// IsConservativeDistanceGreaterOrEqual reports if the distance to the target is greater
+// than or equal to the given limit with some small tolerance.
+func (e *EdgeQuery) IsConservativeDistanceGreaterOrEqual(target distanceTarget, limit s1.ChordAngle) bool {
+ return e.IsDistanceGreater(target, limit.Expanded(-minUpdateDistanceMaxError(limit)))
+}
+
+// findEdges returns the closest edges to the given target that satisfy the given options.
+//
+// Note that if opts.includeInteriors is true, the results may include some
+// entries with edgeID == -1. This indicates that the target intersects the
+// indexed polygon with the given shapeID.
+func (e *EdgeQuery) findEdges(target distanceTarget, opts *queryOptions) []EdgeQueryResult {
+ e.findEdgesInternal(target, opts)
+ // TODO(roberts): Revisit this if there is a heap or other sorted and
+ // uniquing datastructure we can use instead of just a slice.
+ e.results = sortAndUniqueResults(e.results)
+ if len(e.results) > e.opts.maxResults {
+ e.results = e.results[:e.opts.maxResults]
+ }
+ return e.results
+}
+
+func sortAndUniqueResults(results []EdgeQueryResult) []EdgeQueryResult {
+ if len(results) <= 1 {
+ return results
+ }
+ sort.Slice(results, func(i, j int) bool { return results[i].Less(results[j]) })
+ j := 0
+ for i := 1; i < len(results); i++ {
+ if results[j] == results[i] {
+ continue
+ }
+ j++
+ results[j] = results[i]
+ }
+ return results[:j+1]
+}
+
+// findEdge is a convenience method that returns exactly one edge, and if no
+// edges satisfy the given search criteria, then a default Result is returned.
+//
+// This is primarily to ease the usage of a number of the methods in the DistanceTargets
+// and in EdgeQuery.
+func (e *EdgeQuery) findEdge(target distanceTarget, opts *queryOptions) EdgeQueryResult {
+ opts.MaxResults(1)
+ e.findEdges(target, opts)
+ if len(e.results) > 0 {
+ return e.results[0]
+ }
+
+ return newEdgeQueryResult(target)
+}
+
+// findEdgesInternal does the actual work for find edges that match the given options.
+func (e *EdgeQuery) findEdgesInternal(target distanceTarget, opts *queryOptions) {
+ e.target = target
+ e.opts = opts
+
+ e.testedEdges = make(map[ShapeEdgeID]uint32)
+ e.distanceLimit = target.distance().fromChordAngle(opts.distanceLimit)
+ e.results = make([]EdgeQueryResult, 0)
+
+ if e.distanceLimit == target.distance().zero() {
+ return
+ }
+
+ if opts.includeInteriors {
+ shapeIDs := map[int32]struct{}{}
+ e.target.visitContainingShapes(e.index, func(containingShape Shape, targetPoint Point) bool {
+ shapeIDs[e.index.idForShape(containingShape)] = struct{}{}
+ return len(shapeIDs) < opts.maxResults
+ })
+ for shapeID := range shapeIDs {
+ e.addResult(EdgeQueryResult{target.distance().zero(), shapeID, -1})
+ }
+
+ if e.distanceLimit == target.distance().zero() {
+ return
+ }
+ }
+
+ // If maxError > 0 and the target takes advantage of this, then we may
+ // need to adjust the distance estimates to ShapeIndex cells to ensure
+ // that they are always a lower bound on the true distance. For example,
+ // suppose max_distance == 100, maxError == 30, and we compute the distance
+ // to the target from some cell C0 as d(C0) == 80. Then because the target
+ // takes advantage of maxError, the true distance could be as low as 50.
+ // In order not to miss edges contained by such cells, we need to subtract
+ // maxError from the distance estimates. This behavior is controlled by
+ // the useConservativeCellDistance flag.
+ //
+ // However there is one important case where this adjustment is not
+ // necessary, namely when distanceLimit < maxError, This is because
+ // maxError only affects the algorithm once at least maxEdges edges
+ // have been found that satisfy the given distance limit. At that point,
+ // maxError is subtracted from distanceLimit in order to ensure that
+ // any further matches are closer by at least that amount. But when
+ // distanceLimit < maxError, this reduces the distance limit to 0,
+ // i.e. all remaining candidate cells and edges can safely be discarded.
+ // (This is how IsDistanceLess() and friends are implemented.)
+ targetUsesMaxError := opts.maxError != target.distance().zero().chordAngle() &&
+ e.target.setMaxError(opts.maxError)
+
+ // Note that we can't compare maxError and distanceLimit directly
+ // because one is a Delta and one is a Distance. Instead we subtract them.
+ e.useConservativeCellDistance = targetUsesMaxError &&
+ (e.distanceLimit == target.distance().infinity() ||
+ target.distance().zero().less(e.distanceLimit.sub(target.distance().fromChordAngle(opts.maxError))))
+
+ // Use the brute force algorithm if the index is small enough. To avoid
+ // spending too much time counting edges when there are many shapes, we stop
+ // counting once there are too many edges. We may need to recount the edges
+ // if we later see a target with a larger brute force edge threshold.
+ minOptimizedEdges := e.target.maxBruteForceIndexSize() + 1
+ if minOptimizedEdges > e.indexNumEdgesLimit && e.indexNumEdges >= e.indexNumEdgesLimit {
+ e.indexNumEdges = e.index.NumEdgesUpTo(minOptimizedEdges)
+ e.indexNumEdgesLimit = minOptimizedEdges
+ }
+
+ if opts.useBruteForce || e.indexNumEdges < minOptimizedEdges {
+ // The brute force algorithm already considers each edge exactly once.
+ e.avoidDuplicates = false
+ e.findEdgesBruteForce()
+ } else {
+ // If the target takes advantage of maxError then we need to avoid
+ // duplicate edges explicitly. (Otherwise it happens automatically.)
+ e.avoidDuplicates = targetUsesMaxError && opts.maxResults > 1
+
+ // TODO(roberts): Uncomment when optimized is completed.
+ e.findEdgesBruteForce()
+ //e.findEdgesOptimized()
+ }
+}
+
+func (e *EdgeQuery) addResult(r EdgeQueryResult) {
+ e.results = append(e.results, r)
+ if e.opts.maxResults == 1 {
+ // Optimization for the common case where only the closest edge is wanted.
+ e.distanceLimit = r.distance.sub(e.target.distance().fromChordAngle(e.opts.maxError))
+ }
+ // TODO(roberts): Add the other if/else cases when a different data structure
+ // is used for the results.
+}
+
+func (e *EdgeQuery) maybeAddResult(shape Shape, edgeID int32) {
+ if _, ok := e.testedEdges[ShapeEdgeID{e.index.idForShape(shape), edgeID}]; e.avoidDuplicates && !ok {
+ return
+ }
+ edge := shape.Edge(int(edgeID))
+ dist := e.distanceLimit
+
+ if dist, ok := e.target.updateDistanceToEdge(edge, dist); ok {
+ e.addResult(EdgeQueryResult{dist, e.index.idForShape(shape), edgeID})
+ }
+}
+
+func (e *EdgeQuery) findEdgesBruteForce() {
+ // Range over all shapes in the index. Does order matter here? if so
+ // switch to for i = 0 .. n?
+ for _, shape := range e.index.shapes {
+ // TODO(roberts): can this happen if we are only ranging over current entries?
+ if shape == nil {
+ continue
+ }
+ for edgeID := int32(0); edgeID < int32(shape.NumEdges()); edgeID++ {
+ e.maybeAddResult(shape, edgeID)
+ }
+ }
+}
+
+// TODO(roberts): Remaining pieces
+// Add clear/reset/re-init method to empty out the state of the query.
+// findEdgesOptimized and related methods.
+// GetEdge
+// Project