org.geotools.styling.Graphic Maven / Gradle / Ivy
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/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2002-2008, Open Source Geospatial Foundation (OSGeo)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
package org.geotools.styling;
import java.util.Collections;
import java.util.List;
import org.geotools.filter.ConstantExpression;
import org.opengis.filter.expression.Expression;
import org.opengis.style.GraphicalSymbol;
/**
* A Graphic is a "graphical symbol" with an inherent shape, color(s), and possibly size.
*
* A "graphic" can very informally be defined as "a little picture" and can be of either a raster
* or vector graphic source type. The term graphic is used since the term "symbol" is similar to
* "symbolizer" which is used in a difference context in SLD. The graphical symbol to display can be
* provided either as an external graphical resource or as a Mark.
* Multiple external URLs and marks can be referenced with the proviso that they all provide
* equivalent graphics in different formats. The 'hot spot' to use for positioning the rendering at
* a point must either be inherent from the external format or be defined to be the "central point"
* of the graphic.
*
*
The details of this object are taken from the OGC Styled-Layer Descriptor
* Report (OGC 02-070) version 1.0.0.:
*
*
* <xsd:element name="Graphic">
* <xsd:annotation>
* <xsd:documentation>
* A "Graphic" specifies or refers to a "graphic symbol" with inherent
* shape, size, and coloring.
* </xsd:documentation>
* </xsd:annotation>
* <xsd:complexType>
* <xsd:sequence>
* <xsd:choice minOccurs="0" maxOccurs="unbounded">
* <xsd:element ref="sld:ExternalGraphic"/>
* <xsd:element ref="sld:Mark"/>
* </xsd:choice>
* <xsd:sequence>
* <xsd:element ref="sld:Opacity" minOccurs="0"/>
* <xsd:element ref="sld:Size" minOccurs="0"/>
* <xsd:element ref="sld:Rotation" minOccurs="0"/>
* </xsd:sequence>
* </xsd:sequence>
* </xsd:complexType>
* </xsd:element>
*
*
* Renderers can ue this information when displaying styled features, though it must be
* remembered that not all renderers will be able to fully represent strokes as set out by this
* interface. For example, opacity may not be supported.
*
*
Notes:
*
*
* - The graphical parameters and their values are derived from SVG/CSS2 standards with names
* and semantics which are as close as possible.
*
*
* @task REVISIT: There are no setter methods in this interface, is this a problem?
*/
public interface Graphic
extends GraphicLegend,
org.opengis.style.Graphic,
org.opengis.style.GraphicFill,
org.opengis.style.GraphicStroke {
/**
* A default Graphic instance.
*
* For some attributes the standard does not define a default, so a reasonable value is
* supplied.
*/
public static final Graphic DEFAULT =
new ConstantGraphic() {
public List graphicalSymbols() {
return Collections.emptyList();
}
public Expression getOpacity() {
return ConstantExpression.ONE;
}
public Expression getSize() {
// default size is unknown, it depends on the target
return Expression.NIL;
}
public Displacement getDisplacement() {
return Displacement.DEFAULT;
}
public Expression getRotation() {
return ConstantExpression.ZERO;
}
};
/**
* Indicates an absense of graphic.
*
* This value is used to indicate that the Graphics based opperation should be skipped. Aka
* this is used by Stroke.Stroke as place holders for GRAPHIC_FILL and GRAPHIC_STROKE.
*/
public static final Graphic NULL =
new ConstantGraphic() {
public List graphicalSymbols() {
return Collections.emptyList();
}
public Expression getOpacity() {
return ConstantExpression.NULL;
}
public Expression getSize() {
return ConstantExpression.NULL;
}
public Displacement getDisplacement() {
return Displacement.NULL;
}
public Expression getRotation() {
return ConstantExpression.NULL;
}
// public String getGeometryPropertyName() {
// return "";
// }
};
/**
* List of all symbols used to represent this graphic.
*
* @return List of ExternalGraphic or Mark in the order provided.
*/
List graphicalSymbols();
/**
* Location inside of the Graphic (or Label) to position the main-geometry point.
*
* The coordinates are provided as 0.0 to 1.0 range amounting to a percentage of the graphic
* width/height. So the default of 0.5/0.5 indicates that the graphic would be centered.
*
*
Please keep in mind that a system may shuffle things around a bit in order to prevent
* graphics from overlapping (so this AnchorPoint is only a hint about how things should be if
* there is enough room).
*
* @return AnchorPoint , if null should use a default point X=0.5 Y=0.5
*/
public AnchorPoint getAnchorPoint();
/** Anchor point (expressed as an x/y percentage of the graphic size). */
public void setAnchorPoint(org.opengis.style.AnchorPoint anchorPoint);
/**
* This specifies the level of translucency to use when rendering the graphic.
* The value is encoded as a floating-point value between 0.0 and 1.0 with 0.0 representing
* totally transparent and 1.0 representing totally opaque, with a linear scale of translucency
* for intermediate values.
* For example, "0.65" would represent 65% opacity. The default value is 1.0 (opaque).
*
* @return The opacity of the Graphic, where 0.0 is completely transparent and 1.0 is completely
* opaque.
*/
Expression getOpacity();
/** @param opacity opacity between 0 and 1 */
void setOpacity(Expression opacity);
/**
* This paramteter gives the absolute size of the graphic in pixels encoded as a floating point
* number.
*
*
The default size of an image format (such as GIFD) is the inherent size of the image. The
* default size of a format without an inherent size (such as SVG) is defined to be 16 pixels in
* height and the corresponding aspect in width. If a size is specified, the height of the
* graphic will be scaled to that size and the corresponding aspect will be used for the width.
*
* @return The size of the graphic. The default is context specific. Negative values are not
* possible.
*/
Expression getSize();
/** @param size Size of graphic */
void setSize(Expression size);
/** @return Offset of graphic */
Displacement getDisplacement();
/** @param offset Amount to offset graphic */
void setDisplacement(org.opengis.style.Displacement offset);
/**
* This parameter defines the rotation of a graphic in the clockwise direction about its centre
* point in decimal degrees. The value encoded as a floating point number.
*
* @return The angle of rotation in decimal degrees. Negative values represent counter-clockwise
* rotation. The default is 0.0 (no rotation).
*/
Expression getRotation();
/**
* This parameter defines the rotation of a graphic in the clockwise direction about its centre
* point in decimal degrees. The value encoded as a floating point number.
*
* @param rotation in decimal degrees
*/
void setRotation(Expression rotation);
Expression getGap();
void setGap(Expression gap);
Expression getInitialGap();
void setInitialGap(Expression initialGap);
/**
* accepts a StyleVisitor - used by xmlencoder and other packages which need to walk the style
* tree
*
* @param visitor - the visitor object
*/
void accept(org.geotools.styling.StyleVisitor visitor);
}
abstract class ConstantGraphic implements Graphic {
private void cannotModifyConstant() {
throw new UnsupportedOperationException("Constant Graphic may not be modified");
}
public void setDisplacement(org.opengis.style.Displacement offset) {
cannotModifyConstant();
}
public void setExternalGraphics(ExternalGraphic[] externalGraphics) {
cannotModifyConstant();
}
public void addExternalGraphic(ExternalGraphic externalGraphic) {
cannotModifyConstant();
}
public void setMarks(Mark[] marks) {
cannotModifyConstant();
}
public void addMark(Mark mark) {
cannotModifyConstant();
}
public void setGap(Expression gap) {
cannotModifyConstant();
}
public void setInitialGap(Expression initialGap) {
cannotModifyConstant();
}
public void setSymbols(Symbol[] symbols) {
cannotModifyConstant();
}
public void addSymbol(Symbol symbol) {
cannotModifyConstant();
}
public void setOpacity(Expression opacity) {
cannotModifyConstant();
}
public void setSize(Expression size) {
cannotModifyConstant();
}
public void setRotation(Expression rotation) {
cannotModifyConstant();
}
public void setAnchorPoint(AnchorPoint anchor) {
cannotModifyConstant();
}
public Object accept(org.opengis.style.StyleVisitor visitor, Object data) {
return visitor.visit((org.opengis.style.GraphicStroke) this, data);
}
public void accept(org.geotools.styling.StyleVisitor visitor) {
visitor.visit(this);
}
public List graphicalSymbols() {
return Collections.emptyList();
}
public AnchorPoint getAnchorPoint() {
return org.geotools.styling.AnchorPoint.DEFAULT;
}
public void setAnchorPoint(org.opengis.style.AnchorPoint anchorPoint) {
cannotModifyConstant();
}
public Expression getGap() {
return ConstantExpression.constant(0);
}
public Expression getInitialGap() {
return ConstantExpression.constant(0);
}
}