public class ZoomLevelFunction extends FunctionExpressionImpl
Note: EPSG:3857 is currently the only supported srid, and zoom levels are assumed to be at the
equator.
Example:
ff.function("zoomLevel", ff.function("env", ff.literal("wms_scale_denominator")), ff.literal("EPSG:3857") );The above function would evaluate to the zoomLevel that corresponds to the current environment's wms_scale_denominator, for EPSG:3857.
ff.function("zoomLevel", ff.literal(136494.693347), ff.literal("EPSG:3857") );The above function would evaluate to a zoomLevel of 12.
Modifier and Type | Field and Description |
---|---|
static double |
EPSG_3857_O_SCALE
Scale denominator of the root tile.
|
static String |
MBSTYLE_ROOT_TILE_PIXELS_KEY
Name of the system variable controlling
ROOT_TILE_PIXELS |
static FunctionName |
NAME |
static int |
ROOT_TILE_PIXELS
Number of pixels in the side of the root tile.
|
fallback, functionName, name, params
NIL
Constructor and Description |
---|
ZoomLevelFunction() |
Modifier and Type | Method and Description |
---|---|
Object |
evaluate(Object feature)
Subclass should override, default implementation returns null.
|
int |
getArgCount() |
accept, equals, functionName, getExpression, getFallbackValue, getFunctionName, getImplementationHints, getName, getParameters, hashCode, setFallbackValue, setParameters, toString
isAttributeExpression, isExpression, isFunctionExpression, isGeometryExpression, isLiteralExpression, isMathExpression
evaluate
evaluate
public static final FunctionName NAME
public static final String MBSTYLE_ROOT_TILE_PIXELS_KEY
ROOT_TILE_PIXELS
public static final int ROOT_TILE_PIXELS
public static final double EPSG_3857_O_SCALE
public int getArgCount()
public Object evaluate(Object feature)
ExpressionAbstract
evaluate
in interface Expression
evaluate
in class FunctionExpressionImpl
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