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/*******************************************************************************
* Copyright (c) 2018 Remain Software
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* wim.jongman@remainsoftware.com - initial API and implementation
*******************************************************************************/
package org.eclipse.tips.ui.internal.util;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Base64;
import java.util.Base64.Decoder;
import java.util.Base64.Encoder;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.ImageData;
import org.eclipse.swt.graphics.ImageLoader;
/**
* Image helper class.
*
*/
public class ImageUtil {
private static final String COMMA = ",";
/**
* Calculate a height that will fit in the proposed rectangle given the passed
* aspect ratio.
*
* @param aspectRatio
* the aspect ration, e.g. 1.5 for a 3/2 ratio (width/height).
* @param widthHint
* the available width in the viewport
* @param heightHint
* the available height in the viewport
* @return the maximum height that will fit in the passed rectangle.
*/
public static int getHeight(double aspectRatio, int widthHint, int heightHint) {
return (int) Math.min(heightHint, widthHint / aspectRatio);
}
/**
* Calculate a width that will fit in the proposed rectangle given the passed
* aspect ratio.
*
* @param aspectRatio
* the aspect ration, e.g. 1.5 for a 3/2 ratio (width/height).
* @param widthHint
* the available width in the viewport
* @param heightHint
* the available height in the viewport
* @return the maximum width that will fit in the rectangle.
*/
public static int getWidth(double aspectRatio, int widthHint, int heightHint) {
return (int) Math.min(widthHint, heightHint * aspectRatio);
}
/**
* Converts a base 64 encoded image into and ImageData object.
*
* @param base64Image
* the images as a base64 string.
* @return the image decoded as base64
* @throws IOException
* in case of IO problems
*/
public static ImageData decodeToImage(String base64Image) throws IOException {
if (base64Image == null) {
return null;
}
String image = processB64String(base64Image);
Decoder decoder = Base64.getDecoder();
byte[] imageByte = decoder.decode(image);
try (ByteArrayInputStream bis = new ByteArrayInputStream(imageByte)) {
ImageData imageData = new ImageData(bis);
return imageData;
}
}
/**
* Transforms the passed image to a Base64 String.
*
* @param image
* the image to convert, null in is null out.
* @param format
* see {@link ImageLoader#save(java.io.OutputStream, int)}
* @return The encoded image in base 64 or null if the passed image was null.
*/
public static String decodeFromImage(Image image, int format) {
if (image == null) {
return null;
}
ImageLoader loader = new ImageLoader();
loader.data = new ImageData[] { image.getImageData() };
ByteArrayOutputStream bos = new ByteArrayOutputStream();
loader.save(bos, format);
Encoder encoder = Base64.getEncoder();
return getHeader(format) + encoder.encodeToString(bos.toByteArray());
}
private static String getHeader(int format) {
return "data:image/" + getExtension(format) + ";base64,";
}
private static String getExtension(int format) {
switch (format) {
case SWT.IMAGE_BMP:
return "bmp";
case SWT.IMAGE_BMP_RLE:
return "bmp";
case SWT.IMAGE_GIF:
return "gif";
case SWT.IMAGE_ICO:
return "ico";
case SWT.IMAGE_JPEG:
return "jpeg";
default:
return "png";
}
}
private static String processB64String(String base64Image) {
int index = base64Image.substring(0, 50).indexOf(COMMA) + 1;
return base64Image.substring(index);
}
}
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