Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2019 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.widgets; import org.eclipse.swt.*; import org.eclipse.swt.graphics.*; import org.eclipse.swt.internal.*; import org.eclipse.swt.internal.win32.*; /** * Instances of this class provide an i-beam that is typically used * as the insertion point for text. * <dl> * <dt><b>Styles:</b></dt> * <dd>(none)</dd> * <dt><b>Events:</b></dt> * <dd>(none)</dd> * </dl> * <p> * IMPORTANT: This class is <em>not</em> intended to be subclassed. * </p> * * @see <a href="http://www.eclipse.org/swt/snippets/#caret">Caret snippets</a> * @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: ControlExample, Canvas tab</a> * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a> * @noextend This class is not intended to be subclassed by clients. */ public class Caret extends Widget { Canvas parent; int x, y, width, height; boolean moved, resized; boolean isVisible; Image image; Font font; LOGFONT oldFont; /** * Constructs a new instance of this class given its parent * and a style value describing its behavior and appearance. * <p> * The style value is either one of the style constants defined in * class <code>SWT</code> which is applicable to instances of this * class, or must be built by <em>bitwise OR</em>'ing together * (that is, using the <code>int</code> "|" operator) two or more * of those <code>SWT</code> style constants. The class description * lists the style constants that are applicable to the class. * Style bits are also inherited from superclasses. * </p> * * @param parent a composite control which will be the parent of the new instance (cannot be null) * @param style the style of control to construct * * @exception IllegalArgumentException <ul> * <li>ERROR_NULL_ARGUMENT - if the parent is null</li> * </ul> * @exception SWTException <ul> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li> * <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li> * </ul> * * @see SWT * @see Widget#checkSubclass * @see Widget#getStyle */ public Caret(Canvas parent, int style) { super(parent, style); this.parent = parent; createWidget(); } void createWidget() { isVisible = true; if (parent.getCaret() == null) { parent.setCaret(this); } } long defaultFont() { long hwnd = parent.handle; long hwndIME = OS.ImmGetDefaultIMEWnd(hwnd); long hFont = 0; if (hwndIME != 0) { hFont = OS.SendMessage(hwndIME, OS.WM_GETFONT, 0, 0); } if (hFont == 0) { hFont = OS.SendMessage(hwnd, OS.WM_GETFONT, 0, 0); } if (hFont == 0) return parent.defaultFont(); return hFont; } /** * Returns a rectangle describing the receiver's size and location * relative to its parent (or its display if its parent is null). * * @return the receiver's bounding rectangle * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public Rectangle getBounds() { checkWidget(); return DPIUtil.autoScaleDown(getBoundsInPixels()); } Rectangle getBoundsInPixels() { if (image != null) { Rectangle rect = image.getBoundsInPixels(); return new Rectangle(x, y, rect.width, rect.height); } if (width == 0) { int[] buffer = new int[1]; if (OS.SystemParametersInfo(OS.SPI_GETCARETWIDTH, 0, buffer, 0)) { return new Rectangle(x, y, buffer[0], height); } } return new Rectangle(x, y, width, height); } /** * Returns the font that the receiver will use to paint textual information. * * @return the receiver's font * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public Font getFont() { checkWidget(); if (font == null) { long hFont = defaultFont(); return Font.win32_new(display, hFont); } return font; } /** * Returns the image that the receiver will use to paint the caret. * * @return the receiver's image * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public Image getImage() { checkWidget(); return image; } /** * Returns a point describing the receiver's location relative * to its parent (or its display if its parent is null). * * @return the receiver's location * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public Point getLocation() { checkWidget(); return DPIUtil.autoScaleDown(getLocationInPixels()); } Point getLocationInPixels() { return new Point(x, y); } /** * Returns the receiver's parent, which must be a <code>Canvas</code>. * * @return the receiver's parent * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public Canvas getParent() { checkWidget(); return parent; } /** * Returns a point describing the receiver's size. * * @return the receiver's size * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public Point getSize() { checkWidget(); return DPIUtil.autoScaleDown(getSizeInPixels()); } Point getSizeInPixels() { if (image != null) { Rectangle rect = image.getBoundsInPixels(); return new Point(rect.width, rect.height); } if (width == 0) { int[] buffer = new int[1]; if (OS.SystemParametersInfo(OS.SPI_GETCARETWIDTH, 0, buffer, 0)) { return new Point(buffer[0], height); } } return new Point(width, height); } /** * Returns <code>true</code> if the receiver is visible, and * <code>false</code> otherwise. * <p> * If one of the receiver's ancestors is not visible or some * other condition makes the receiver not visible, this method * may still indicate that it is considered visible even though * it may not actually be showing. * </p> * * @return the receiver's visibility state * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public boolean getVisible() { checkWidget(); return isVisible; } boolean hasFocus() { return parent.handle == OS.GetFocus(); } boolean isFocusCaret() { return parent.caret == this && hasFocus(); } /** * Returns <code>true</code> if the receiver is visible and all * of the receiver's ancestors are visible and <code>false</code> * otherwise. * * @return the receiver's visibility state * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> * * @see #getVisible */ public boolean isVisible() { checkWidget(); return isVisible && parent.isVisible() && hasFocus(); } void killFocus() { OS.DestroyCaret(); restoreIMEFont(); } void move() { moved = false; if (!OS.SetCaretPos(x, y)) return; resizeIME(); } void resizeIME() { if (!OS.IsDBLocale) return; POINT ptCurrentPos = new POINT(); if (!OS.GetCaretPos(ptCurrentPos)) return; long hwnd = parent.handle; long hIMC = OS.ImmGetContext(hwnd); IME ime = parent.getIME(); if (ime != null && ime.isInlineEnabled()) { Point size = getSizeInPixels(); CANDIDATEFORM lpCandidate = new CANDIDATEFORM(); lpCandidate.dwStyle = OS.CFS_EXCLUDE; lpCandidate.ptCurrentPos = ptCurrentPos; lpCandidate.rcArea = new RECT(); OS.SetRect(lpCandidate.rcArea, ptCurrentPos.x, ptCurrentPos.y, ptCurrentPos.x + size.x, ptCurrentPos.y + size.y); OS.ImmSetCandidateWindow(hIMC, lpCandidate); } else { RECT rect = new RECT(); OS.GetClientRect(hwnd, rect); COMPOSITIONFORM lpCompForm = new COMPOSITIONFORM(); lpCompForm.dwStyle = OS.CFS_RECT; lpCompForm.x = ptCurrentPos.x; lpCompForm.y = ptCurrentPos.y; lpCompForm.left = rect.left; lpCompForm.right = rect.right; lpCompForm.top = rect.top; lpCompForm.bottom = rect.bottom; OS.ImmSetCompositionWindow(hIMC, lpCompForm); } OS.ImmReleaseContext(hwnd, hIMC); } @Override void releaseParent() { super.releaseParent(); if (parent != null && this == parent.caret) { if (!parent.isDisposed()) parent.setCaret(null); else parent.caret = null; } } @Override void releaseWidget() { super.releaseWidget(); parent = null; image = null; font = null; oldFont = null; } void resize() { resized = false; long hwnd = parent.handle; OS.DestroyCaret(); long hBitmap = image != null ? image.handle : 0; int width = this.width; if (image == null && width == 0) { int[] buffer = new int[1]; if (OS.SystemParametersInfo(OS.SPI_GETCARETWIDTH, 0, buffer, 0)) { width = buffer[0]; } } OS.CreateCaret(hwnd, hBitmap, width, height); OS.SetCaretPos(x, y); OS.ShowCaret(hwnd); move(); } void restoreIMEFont() { if (!OS.IsDBLocale) return; if (oldFont == null) return; long hwnd = parent.handle; long hIMC = OS.ImmGetContext(hwnd); OS.ImmSetCompositionFont(hIMC, oldFont); OS.ImmReleaseContext(hwnd, hIMC); oldFont = null; } /** * Sets the receiver's size and location to the rectangular * area specified by the arguments. The <code>x</code> and * <code>y</code> arguments are relative to the receiver's * parent (or its display if its parent is null). * * @param x the new x coordinate for the receiver * @param y the new y coordinate for the receiver * @param width the new width for the receiver * @param height the new height for the receiver * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public void setBounds(int x, int y, int width, int height) { checkWidget(); setBoundsInPixels(DPIUtil.autoScaleUp(x), DPIUtil.autoScaleUp(y), DPIUtil.autoScaleUp(width), DPIUtil.autoScaleUp(height)); } void setBoundsInPixels(int x, int y, int width, int height) { boolean samePosition = this.x == x && this.y == y; boolean sameExtent = this.width == width && this.height == height; if (samePosition && sameExtent) return; this.x = x; this.y = y; this.width = width; this.height = height; if (sameExtent) { moved = true; if (isVisible && hasFocus()) move(); } else { resized = true; if (isVisible && hasFocus()) resize(); } } /** * Sets the receiver's size and location to the rectangular * area specified by the argument. The <code>x</code> and * <code>y</code> fields of the rectangle are relative to * the receiver's parent (or its display if its parent is null). * * @param rect the new bounds for the receiver * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public void setBounds(Rectangle rect) { if (rect == null) error(SWT.ERROR_NULL_ARGUMENT); setBoundsInPixels(DPIUtil.autoScaleUp(rect)); } void setBoundsInPixels(Rectangle rect) { setBoundsInPixels(rect.x, rect.y, rect.width, rect.height); } void setFocus() { long hwnd = parent.handle; long hBitmap = 0; if (image != null) hBitmap = image.handle; int width = this.width; if (image == null && width == 0) { int[] buffer = new int[1]; if (OS.SystemParametersInfo(OS.SPI_GETCARETWIDTH, 0, buffer, 0)) { width = buffer[0]; } } OS.CreateCaret(hwnd, hBitmap, width, height); move(); setIMEFont(); if (isVisible) OS.ShowCaret(hwnd); } /** * Sets the font that the receiver will use to paint textual information * to the font specified by the argument, or to the default font for that * kind of control if the argument is null. * * @param font the new font (or null) * * @exception IllegalArgumentException <ul> * <li>ERROR_INVALID_ARGUMENT - if the font has been disposed</li> * </ul> * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public void setFont(Font font) { checkWidget(); if (font != null && font.isDisposed()) { error(SWT.ERROR_INVALID_ARGUMENT); } this.font = font; if (hasFocus()) setIMEFont(); } /** * Sets the image that the receiver will use to paint the caret * to the image specified by the argument, or to the default * which is a filled rectangle if the argument is null * * @param image the new image (or null) * * @exception IllegalArgumentException <ul> * <li>ERROR_INVALID_ARGUMENT - if the image has been disposed</li> * </ul> * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public void setImage(Image image) { checkWidget(); if (image != null && image.isDisposed()) { error(SWT.ERROR_INVALID_ARGUMENT); } this.image = image; if (isVisible && hasFocus()) resize(); } void setIMEFont() { if (!OS.IsDBLocale) return; long hFont = 0; if (font != null) hFont = font.handle; if (hFont == 0) hFont = defaultFont(); long hwnd = parent.handle; long hIMC = OS.ImmGetContext(hwnd); /* Save the current IME font */ if (oldFont == null) { oldFont = new LOGFONT(); if (!OS.ImmGetCompositionFont(hIMC, oldFont)) oldFont = null; } /* Set new IME font */ LOGFONT logFont = new LOGFONT(); if (OS.GetObject(hFont, LOGFONT.sizeof, logFont) != 0) { OS.ImmSetCompositionFont(hIMC, logFont); } OS.ImmReleaseContext(hwnd, hIMC); } /** * Sets the receiver's location to the point specified by * the arguments which are relative to the receiver's * parent (or its display if its parent is null). * * @param x the new x coordinate for the receiver * @param y the new y coordinate for the receiver * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public void setLocation(int x, int y) { checkWidget(); setLocationInPixels(DPIUtil.autoScaleUp(x), DPIUtil.autoScaleUp(y)); } void setLocationInPixels(int x, int y) { if (this.x == x && this.y == y) return; this.x = x; this.y = y; moved = true; if (isVisible && hasFocus()) move(); } /** * Sets the receiver's location to the point specified by * the argument which is relative to the receiver's * parent (or its display if its parent is null). * * @param location the new location for the receiver * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public void setLocation(Point location) { checkWidget(); if (location == null) error(SWT.ERROR_NULL_ARGUMENT); location = DPIUtil.autoScaleUp(location); setLocationInPixels(location.x, location.y); } /** * Sets the receiver's size to the point specified by the arguments. * * @param width the new width for the receiver * @param height the new height for the receiver * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public void setSize(int width, int height) { checkWidget(); setSizeInPixels(DPIUtil.autoScaleUp(width), DPIUtil.autoScaleUp(height)); } void setSizeInPixels(int width, int height) { if (this.width == width && this.height == height) return; this.width = width; this.height = height; resized = true; if (isVisible && hasFocus()) resize(); } /** * Sets the receiver's size to the point specified by the argument. * * @param size the new extent for the receiver * * @exception IllegalArgumentException <ul> * <li>ERROR_NULL_ARGUMENT - if the point is null</li> * </ul> * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public void setSize(Point size) { checkWidget(); if (size == null) error(SWT.ERROR_NULL_ARGUMENT); size = DPIUtil.autoScaleUp(size); setSizeInPixels(size.x, size.y); } /** * Marks the receiver as visible if the argument is <code>true</code>, * and marks it invisible otherwise. * <p> * If one of the receiver's ancestors is not visible or some * other condition makes the receiver not visible, marking * it visible may not actually cause it to be displayed. * </p> * * @param visible the new visibility state * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public void setVisible(boolean visible) { checkWidget(); if (visible == isVisible) return; isVisible = visible; long hwnd = parent.handle; if (OS.GetFocus() != hwnd) return; if (!isVisible) { OS.HideCaret(hwnd); } else { if (resized) { resize(); } else { if (moved) move(); } OS.ShowCaret(hwnd); } } }