Java tutorial
/******************************************************************************* * Copyright (c) 2007, 2017 IBM Corporation and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * IBM Corporation - initial API and implementation *******************************************************************************/ package org.eclipse.swt.dnd; import org.eclipse.swt.*; import org.eclipse.swt.graphics.*; import org.eclipse.swt.internal.*; import org.eclipse.swt.internal.ole.win32.*; import org.eclipse.swt.internal.win32.*; /** * The class <code>ImageTransfer</code> provides a platform specific mechanism * for converting an Image represented as a java <code>ImageData</code> to a * platform specific representation of the data and vice versa. * * <p>An example of a java <code>ImageData</code> is shown below:</p> * * <pre><code> * Image image = new Image(display, "C:\\temp\\img1.gif"); * ImageData imgData = image.getImageData(); * </code></pre> * * @see Transfer * * @since 3.4 */ public class ImageTransfer extends ByteArrayTransfer { private static ImageTransfer _instance = new ImageTransfer(); private static final String CF_DIB = "CF_DIB"; //$NON-NLS-1$ private static final int CF_DIBID = COM.CF_DIB; private ImageTransfer() { } /** * Returns the singleton instance of the ImageTransfer class. * * @return the singleton instance of the ImageTransfer class */ public static ImageTransfer getInstance() { return _instance; } /** * This implementation of <code>javaToNative</code> converts an ImageData object represented * by java <code>ImageData</code> to a platform specific representation. * * @param object a java <code>ImageData</code> containing the ImageData to be converted * @param transferData an empty <code>TransferData</code> object that will * be filled in on return with the platform specific format of the data * * @see Transfer#nativeToJava */ @Override public void javaToNative(Object object, TransferData transferData) { if (!checkImage(object) || !isSupportedType(transferData)) { DND.error(DND.ERROR_INVALID_DATA); } ImageData imgData = (ImageData) object; if (imgData == null) SWT.error(SWT.ERROR_NULL_ARGUMENT); int imageSize = imgData.data.length; int imageHeight = imgData.height; int bytesPerLine = imgData.bytesPerLine; BITMAPINFOHEADER bmiHeader = new BITMAPINFOHEADER(); bmiHeader.biSize = BITMAPINFOHEADER.sizeof; bmiHeader.biSizeImage = imageSize; bmiHeader.biWidth = imgData.width; bmiHeader.biHeight = imageHeight; bmiHeader.biPlanes = 1; bmiHeader.biBitCount = (short) imgData.depth; bmiHeader.biCompression = OS.DIB_RGB_COLORS; int colorSize = 0; if (bmiHeader.biBitCount <= 8) { colorSize += (1 << bmiHeader.biBitCount) * 4; } byte[] bmi = new byte[BITMAPINFOHEADER.sizeof + colorSize]; OS.MoveMemory(bmi, bmiHeader, BITMAPINFOHEADER.sizeof); RGB[] rgbs = imgData.palette.getRGBs(); if (rgbs != null && colorSize > 0) { int offset = BITMAPINFOHEADER.sizeof; for (int j = 0; j < rgbs.length; j++) { bmi[offset] = (byte) rgbs[j].blue; bmi[offset + 1] = (byte) rgbs[j].green; bmi[offset + 2] = (byte) rgbs[j].red; bmi[offset + 3] = 0; offset += 4; } } long newPtr = OS.GlobalAlloc(OS.GMEM_FIXED | OS.GMEM_ZEROINIT, BITMAPINFOHEADER.sizeof + colorSize + imageSize); OS.MoveMemory(newPtr, bmi, bmi.length); long pBitDest = newPtr + BITMAPINFOHEADER.sizeof + colorSize; if (imageHeight <= 0) { OS.MoveMemory(pBitDest, imgData.data, imageSize); } else { int offset = 0; pBitDest += bytesPerLine * (imageHeight - 1); byte[] scanline = new byte[bytesPerLine]; for (int i = 0; i < imageHeight; i++) { System.arraycopy(imgData.data, offset, scanline, 0, bytesPerLine); OS.MoveMemory(pBitDest, scanline, bytesPerLine); offset += bytesPerLine; pBitDest -= bytesPerLine; } } transferData.stgmedium = new STGMEDIUM(); transferData.stgmedium.tymed = COM.TYMED_HGLOBAL; transferData.stgmedium.unionField = newPtr; transferData.stgmedium.pUnkForRelease = 0; transferData.result = COM.S_OK; } /** * This implementation of <code>nativeToJava</code> converts a platform specific * representation of an image to java <code>ImageData</code>. * * @param transferData the platform specific representation of the data to be converted * @return a java <code>ImageData</code> of the image if the conversion was successful; * otherwise null * * @see Transfer#javaToNative */ @Override public Object nativeToJava(TransferData transferData) { if (!isSupportedType(transferData) || transferData.pIDataObject == 0) return null; IDataObject dataObject = new IDataObject(transferData.pIDataObject); dataObject.AddRef(); FORMATETC formatetc = new FORMATETC(); formatetc.cfFormat = COM.CF_DIB; formatetc.ptd = 0; formatetc.dwAspect = COM.DVASPECT_CONTENT; formatetc.lindex = -1; formatetc.tymed = COM.TYMED_HGLOBAL; STGMEDIUM stgmedium = new STGMEDIUM(); stgmedium.tymed = COM.TYMED_HGLOBAL; transferData.result = getData(dataObject, formatetc, stgmedium); if (transferData.result != COM.S_OK) return null; long hMem = stgmedium.unionField; dataObject.Release(); try { long ptr = OS.GlobalLock(hMem); if (ptr == 0) return null; try { BITMAPINFOHEADER bmiHeader = new BITMAPINFOHEADER(); OS.MoveMemory(bmiHeader, ptr, BITMAPINFOHEADER.sizeof); long[] pBits = new long[1]; long memDib = OS.CreateDIBSection(0, ptr, OS.DIB_RGB_COLORS, pBits, 0, 0); if (memDib == 0) SWT.error(SWT.ERROR_NO_HANDLES); long bits = ptr + bmiHeader.biSize; if (bmiHeader.biBitCount <= 8) { bits += (bmiHeader.biClrUsed == 0 ? (1 << bmiHeader.biBitCount) : bmiHeader.biClrUsed) * 4; } else if (bmiHeader.biCompression == OS.BI_BITFIELDS) { bits += 12; } if (bmiHeader.biHeight < 0) { OS.MoveMemory(pBits[0], bits, bmiHeader.biSizeImage); } else { DIBSECTION dib = new DIBSECTION(); OS.GetObject(memDib, DIBSECTION.sizeof, dib); int biHeight = dib.biHeight; int scanline = dib.biSizeImage / biHeight; long pDestBits = pBits[0]; long pSourceBits = bits + scanline * (biHeight - 1); for (int i = 0; i < biHeight; i++) { OS.MoveMemory(pDestBits, pSourceBits, scanline); pDestBits += scanline; pSourceBits -= scanline; } } Image image = Image.win32_new(null, SWT.BITMAP, memDib); ImageData data = image.getImageData(DPIUtil.getDeviceZoom()); OS.DeleteObject(memDib); image.dispose(); return data; } finally { OS.GlobalUnlock(hMem); } } finally { OS.GlobalFree(hMem); } } @Override protected int[] getTypeIds() { return new int[] { CF_DIBID }; } @Override protected String[] getTypeNames() { return new String[] { CF_DIB }; } boolean checkImage(Object object) { if (object == null || !(object instanceof ImageData)) return false; return true; } @Override protected boolean validate(Object object) { return checkImage(object); } }