1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
|
#import <Foundation/Foundation.h>
#import "MGLFoundation.h"
#import "MGLForegroundStyleLayer.h"
NS_ASSUME_NONNULL_BEGIN
/**
`MGLVectorStyleLayer` is an abstract superclass for style layers whose content
is defined by an `MGLShapeSource` or `MGLVectorSource` object.
Create instances of `MGLCircleStyleLayer`, `MGLFillStyleLayer`,
`MGLFillExtrusionStyleLayer`, `MGLLineStyleLayer`, and `MGLSymbolStyleLayer` in
order to use `MGLVectorStyleLayer`'s properties and methods. Do not create
instances of `MGLVectorStyleLayer` directly, and do not create your own
subclasses of this class.
*/
MGL_EXPORT
@interface MGLVectorStyleLayer : MGLForegroundStyleLayer
#pragma mark Refining a Style Layer’s Content
/**
Identifier of the layer within the source identified by the `sourceIdentifier`
property from which the receiver obtains the data to style.
*/
@property (nonatomic, nullable) NSString *sourceLayerIdentifier;
/**
The style layer’s predicate.
Use the style layer’s predicate to include only the features in the source
layer that satisfy a condition that you define. If the style layer initially
comes from the style, its predicate corresponds to the
<a href="https://www.mapbox.com/mapbox-gl-style-spec/#layer-filter">`filter`</a>
property in the style JSON.
The following comparison operators are supported.
<ul>
<li><code>NSEqualToPredicateOperatorType</code> (<code>=</code>, <code>==</code>)</li>
<li><code>NSGreaterThanOrEqualToPredicateOperatorType</code> (<code>>=</code>, <code>=></code>)</li>
<li><code>NSLessThanOrEqualToPredicateOperatorType</code> (<code><=</code>, <code>=<</code>)</li>
<li><code>NSGreaterThanPredicateOperatorType</code> (<code>></code>)</li>
<li><code>NSLessThanPredicateOperatorType</code> (<code><</code>)</li>
<li><code>NSNotEqualToPredicateOperatorType</code> (<code>!=</code>, <code><></code>)</li>
<li><code>NSBetweenPredicateOperatorType</code> (<code>BETWEEN</code>)</li>
</ul>
The following compound operators are supported:
<ul>
<li><code>NSAndPredicateType</code> (<code>AND</code>, <code>&&</code>)</li>
<li><code>NSOrPredicateType</code> (<code>OR</code>, <code>||</code>)</li>
<li><code>NSNotPredicateType</code> (<code>NOT</code>, <code>!</code>)</li>
</ul>
The following aggregate operators are supported:
<ul>
<li><code>NSInPredicateOperatorType</code> (<code>IN</code>)</li>
<li><code>NSContainsPredicateOperatorType</code> (<code>CONTAINS</code>)</li>
</ul>
To test whether a feature has or lacks a specific attribute, compare the
attribute to `NULL` or `NIL`. Predicates created using the
`+[NSPredicate predicateWithValue:]` method are also supported. String
operators and custom operators are not supported.
For details about the predicate format string syntax, consult the “Predicate
Format String Syntax” chapter of the
“<a href="https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/Predicates/">Predicate Programming Guide</a>”
in Apple developer documentation.
The predicate's left-hand expression must be a string that identifies a feature
attribute or, alternatively, one of the following special attributes:
<table>
<thead>
<tr><th>Attribute</th><th>Meaning</th></tr>
</thead>
<tbody>
<tr>
<td><code>$id</code></td>
<td>
A value that uniquely identifies the feature in the containing source.
For details on the types of values that may be associated with this key,
consult the documentation for the <code>MGLFeature</code> protocol’s
<code>identifier</code> property.
</td>
</tr>
<tr>
<td><code>$type</code></td>
<td>
The type of geometry represented by the feature. A feature’s type is
guaranteed to be one of the following strings:
<ul>
<li>
<code>Point</code> for point features, corresponding to the
<code>MGLPointAnnotation</code> class
</li>
<li>
<code>LineString</code> for polyline features, corresponding to
the <code>MGLPolyline</code> class
</li>
<li>
<code>Polygon</code> for polygon features, corresponding to the
<code>MGLPolygon</code> class
</li>
</ul>
</td>
</tr>
<tr>
<td><code>point_count</code></td>
<td>The number of point features in a given cluster.</td>
</tr>
</tbody>
</table>
The predicate’s right-hand expression must be an `NSString` (to match strings)
or `NSNumber` (to match numbers, including Boolean values) or an array of
`NSString`s or `NSNumber`s, depending on the operator and the type of values
expected for the attribute being tested. For floating-point values, use
`-[NSNumber numberWithDouble:]` instead of `-[NSNumber numberWithFloat:]`
to avoid precision issues.
Automatic type casting is not performed. Therefore, a feature only matches this
predicate if its value for the attribute in question is of the same type as the
value specified in the predicate. Also, operator modifiers such as `c` (for
case insensitivity), `d` (for diacritic insensitivity), and `l` (for locale
sensitivity) are unsupported for comparison and aggregate operators that are
used in the predicate.
It is possible to create expressions that contain special characters in the
predicate format syntax. This includes the `$` in the `$id` and `$type` special
style attributes and also `hyphen-minus` and `tag:subtag`. However, you must use
`%K` in the format string to represent these variables:
`@"%K == 'LineString'", @"$type"`.
### Example
To filter the layer to include only the features whose `index` attribute is 5
or 10 and whose `ele` attribute is at least 1,500, you could create an
`NSCompoundPredicate` along these lines:
```swift
let layer = MGLLineStyleLayer(identifier: "contour", source: terrain)
layer.sourceLayerIdentifier = "contours"
layer.predicate = NSPredicate(format: "(index == 5 || index == 10) && ele >= 1500.0")
mapView.style?.addLayer(layer)
```
*/
@property (nonatomic, nullable) NSPredicate *predicate;
@end
NS_ASSUME_NONNULL_END
|
