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Apache POI - Java API To Access Microsoft Format Files
/*
* ====================================================================
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.poi.sl.draw;
import java.awt.Graphics2D;
import java.awt.Insets;
import java.awt.geom.Dimension2D;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.Charset;
import org.apache.poi.common.usermodel.GenericRecord;
import org.apache.poi.util.Dimension2DDouble;
/**
* Classes can implement this interfaces to support other formats, for
* example, use Apache Batik to render WMF (since POI 4.0, there's an internal WMF/EMF/EMF+ renderer in POI),
* PICT can be rendered using Apple QuickTime API for Java:
*
*
*
* public class MyImageRendener implements ImageRendener {
* InputStream data;
*
* public boolean drawImage(Graphics2D graphics,Rectangle2D anchor,Insets clip) {
* // draw image
* DataInputStream is = new DataInputStream(data);
* org.apache.batik.transcoder.wmf.tosvg.WMFRecordStore wmfStore =
* new org.apache.batik.transcoder.wmf.tosvg.WMFRecordStore();
* try {
* wmfStore.read(is);
* } catch (IOException e){
* return;
* }
*
* float scale = (float)anchor.width/wmfStore.getWidthPixels();
*
* org.apache.batik.transcoder.wmf.tosvg.WMFPainter painter =
* new org.apache.batik.transcoder.wmf.tosvg.WMFPainter(wmfStore, 0, 0, scale);
* graphics.translate(anchor.x, anchor.y);
* painter.paint(graphics);
* }
*
* public void loadImage(InputStream data, String contentType) throws IOException {
* if ("image/wmf".equals(contentType)) {
* this.data = data;
* // use Apache Batik to handle WMF
* } else {
* super.loadImage(data,contentType);
* }
* }
* }
*
*
*
* and then pass this class to your instance of java.awt.Graphics2D:
*
*
*
* graphics.setRenderingHint(Drawable.IMAGE_RENDERER, new MyImageRendener());
*
*
*/
public interface ImageRenderer {
/**
* Determines if this image renderer implementation supports the given contentType
* @param contentType the image content type
* @return if the content type is supported
*/
boolean canRender(String contentType);
/**
* Load and buffer the image
*
* @param data the raw image stream
* @param contentType the content type
*/
void loadImage(InputStream data, String contentType) throws IOException;
/**
* Load and buffer the image
*
* @param data the raw image bytes
* @param contentType the content type
*/
void loadImage(byte[] data, String contentType) throws IOException;
/**
* @return the format-specific / not-normalized bounds of the image
*/
Rectangle2D getNativeBounds();
/**
* @return the bounds of the buffered image in pixel
*/
Rectangle2D getBounds();
/**
* @return the dimension of the buffered image in pixel
*/
default Dimension2D getDimension() {
Rectangle2D r = getBounds();
return new Dimension2DDouble(Math.abs(r.getWidth()), Math.abs(r.getHeight()));
}
/**
* @param alpha the alpha [0..1] to be added to the image (possibly already containing an alpha channel)
*/
void setAlpha(double alpha);
/**
* @return the image as buffered image or null if image could not be loaded
*/
BufferedImage getImage();
/**
* @param dim the dimension in pixels of the returned image
* @return the image as buffered image or null if image could not be loaded
*
* @since POI 3.15-beta2
*/
BufferedImage getImage(Dimension2D dim);
/**
* Render picture data into the supplied graphics
*
* @return true if the picture data was successfully rendered
*/
boolean drawImage(Graphics2D graphics, Rectangle2D anchor);
/**
* Render picture data into the supplied graphics
*
* @return true if the picture data was successfully rendered
*/
boolean drawImage(Graphics2D graphics, Rectangle2D anchor, Insets clip);
default GenericRecord getGenericRecord() { return null; }
/**
* Sets the default charset to render text elements.
* Opposed to other windows libraries in POI this simply defaults to Windows-1252.
*
* @param defaultCharset the default charset
*/
default void setDefaultCharset(Charset defaultCharset) {}
/**
* Dis-/Enables caching of input data for later retrieval.
* Opposed to {@link #getImage()}, which returns a {@link BufferedImage}, the cached image can be later
* used to embedded the original, unmodified data
* @param enable dis-/enables caching - this is an optional operation. {@code false} removes already cached data
*/
default void setCacheInput(boolean enable) {}
/**
* @return the cached image data
*/
default byte[] getCachedImage() { return null; }
/**
* @return the cached content type
*/
default String getCachedContentType() { return null; }
}