/******************************************************************************* * Copyright (c) 2000, 2013 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 a surface for drawing * arbitrary graphics. *
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Styles:
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Events:
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* This class may be subclassed by custom control implementors * who are building controls that are not constructed * from aggregates of other controls. That is, they are either * painted using SWT graphics calls or are handled by native * methods. *

* * @see Composite * @see Canvas snippets * @see SWT Example: ControlExample * @see Sample code and further information */ public class Canvas extends Composite { Caret caret; IME ime; /** * Prevents uninitialized instances from being created outside the package. */ Canvas () { } /** * Constructs a new instance of this class given its parent * and a style value describing its behavior and appearance. *

* The style value is either one of the style constants defined in * class SWT which is applicable to instances of this * class, or must be built by bitwise OR'ing together * (that is, using the int "|" operator) two or more * of those SWT style constants. The class description * lists the style constants that are applicable to the class. * Style bits are also inherited from superclasses. *

* * @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 * @exception SWTException * * @see SWT * @see Widget#getStyle */ public Canvas (Composite parent, int style) { super (parent, style); } void clearArea (int x, int y, int width, int height) { checkWidget (); if (OS.IsWindowVisible (handle)) { RECT rect = new RECT (); OS.SetRect (rect, x, y, x + width, y + height); long hDC = OS.GetDCEx (handle, 0, OS.DCX_CACHE | OS.DCX_CLIPCHILDREN | OS.DCX_CLIPSIBLINGS); drawBackground (hDC, rect); OS.ReleaseDC (handle, hDC); } } /** * Fills the interior of the rectangle specified by the arguments, * with the receiver's background. * * @param gc the gc where the rectangle is to be filled * @param x the x coordinate of the rectangle to be filled * @param y the y coordinate of the rectangle to be filled * @param width the width of the rectangle to be filled * @param height the height of the rectangle to be filled * * @exception IllegalArgumentException * @exception SWTException * * @since 3.2 */ public void drawBackground (GC gc, int x, int y, int width, int height) { x = DPIUtil.autoScaleUp(x); y = DPIUtil.autoScaleUp(y); width = DPIUtil.autoScaleUp(width); height = DPIUtil.autoScaleUp(height); drawBackgroundInPixels(gc, x, y, width, height, 0, 0); } /** * Returns the caret. *

* The caret for the control is automatically hidden * and shown when the control is painted or resized, * when focus is gained or lost and when an the control * is scrolled. To avoid drawing on top of the caret, * the programmer must hide and show the caret when * drawing in the window any other time. *

* * @return the caret for the receiver, may be null * * @exception SWTException */ public Caret getCaret () { checkWidget (); return caret; } /** * Returns the IME. * * @return the IME * * @exception SWTException * * @since 3.4 */ public IME getIME () { checkWidget (); return ime; } @Override void releaseChildren (boolean destroy) { if (caret != null) { caret.release (false); caret = null; } if (ime != null) { ime.release (false); ime = null; } super.releaseChildren (destroy); } @Override void reskinChildren (int flags) { if (caret != null) caret.reskin (flags); if (ime != null) ime.reskin (flags); super.reskinChildren (flags); } /** * Scrolls a rectangular area of the receiver by first copying * the source area to the destination and then causing the area * of the source which is not covered by the destination to * be repainted. Children that intersect the rectangle are * optionally moved during the operation. In addition, all outstanding * paint events are flushed before the source area is copied to * ensure that the contents of the canvas are drawn correctly. * * @param destX the x coordinate of the destination * @param destY the y coordinate of the destination * @param x the x coordinate of the source * @param y the y coordinate of the source * @param width the width of the area * @param height the height of the area * @param all trueif children should be scrolled, and false otherwise * * @exception SWTException */ public void scroll (int destX, int destY, int x, int y, int width, int height, boolean all) { checkWidget (); destX = DPIUtil.autoScaleUp(destX); destY = DPIUtil.autoScaleUp(destY); x = DPIUtil.autoScaleUp(x); y = DPIUtil.autoScaleUp(y); width = DPIUtil.autoScaleUp(width); height = DPIUtil.autoScaleUp(height); scrollInPixels(destX, destY, x, y, width, height, all); } void scrollInPixels (int destX, int destY, int x, int y, int width, int height, boolean all) { forceResize (); boolean isFocus = caret != null && caret.isFocusCaret (); if (isFocus) caret.killFocus (); RECT sourceRect = new RECT (); OS.SetRect (sourceRect, x, y, x + width, y + height); RECT clientRect = new RECT (); OS.GetClientRect (handle, clientRect); if (OS.IntersectRect (clientRect, sourceRect, clientRect)) { int flags = OS.RDW_UPDATENOW | OS.RDW_ALLCHILDREN; OS.RedrawWindow (handle, null, 0, flags); } int deltaX = destX - x, deltaY = destY - y; if (findImageControl () != null) { int flags = OS.RDW_ERASE | OS.RDW_FRAME | OS.RDW_INVALIDATE; if (all) flags |= OS.RDW_ALLCHILDREN; OS.RedrawWindow (handle, sourceRect, 0, flags); OS.OffsetRect (sourceRect, deltaX, deltaY); OS.RedrawWindow (handle, sourceRect, 0, flags); } else { int flags = OS.SW_INVALIDATE | OS.SW_ERASE; /* * Feature in Windows. If any child in the widget tree partially * intersects the scrolling rectangle, Windows moves the child * and copies the bits that intersect the scrolling rectangle but * does not redraw the child. * * Feature in Windows. When any child in the widget tree does not * intersect the scrolling rectangle but the parent does intersect, * Windows does not move the child. This is the documented (but * strange) Windows behavior. * * The fix is to not use SW_SCROLLCHILDREN and move the children * explicitly after scrolling. */ // if (all) flags |= OS.SW_SCROLLCHILDREN; OS.ScrollWindowEx (handle, deltaX, deltaY, sourceRect, null, 0, null, flags); } if (all) { Control [] children = _getChildren (); for (int i=0; i= Math.max (x, rect.x) && Math.min (y + height, rect.y + rect.height) >= Math.max (y, rect.y)) { child.setLocationInPixels (rect.x + deltaX, rect.y + deltaY); } } } if (isFocus) caret.setFocus (); } /** * Sets the receiver's caret. *

* The caret for the control is automatically hidden * and shown when the control is painted or resized, * when focus is gained or lost and when an the control * is scrolled. To avoid drawing on top of the caret, * the programmer must hide and show the caret when * drawing in the window any other time. *

* @param caret the new caret for the receiver, may be null * * @exception IllegalArgumentException * @exception SWTException */ public void setCaret (Caret caret) { checkWidget (); Caret newCaret = caret; Caret oldCaret = this.caret; this.caret = newCaret; if (hasFocus ()) { if (oldCaret != null) oldCaret.killFocus (); if (newCaret != null) { if (newCaret.isDisposed()) error(SWT.ERROR_INVALID_ARGUMENT); newCaret.setFocus (); } } } @Override public void setFont (Font font) { checkWidget (); if (caret != null) caret.setFont (font); super.setFont (font); } /** * Sets the receiver's IME. * * @param ime the new IME for the receiver, may be null * * @exception IllegalArgumentException * @exception SWTException * * @since 3.4 */ public void setIME (IME ime) { checkWidget (); if (ime != null && ime.isDisposed()) error(SWT.ERROR_INVALID_ARGUMENT); this.ime = ime; } @Override TCHAR windowClass () { if (display.useOwnDC) return display.windowOwnDCClass; return super.windowClass (); } @Override long windowProc (long hwnd, int msg, long wParam, long lParam) { if (msg == Display.SWT_RESTORECARET) { if ((state & CANVAS) != 0) { if (caret != null) { caret.killFocus (); caret.setFocus (); return 1; } } } return super.windowProc (hwnd, msg, wParam, lParam); } @Override LRESULT WM_CHAR (long wParam, long lParam) { LRESULT result = super.WM_CHAR (wParam, lParam); if (result != null) return result; if (caret != null) { switch ((int)wParam) { case SWT.DEL: case SWT.BS: case SWT.ESC: break; default: { if (OS.GetKeyState (OS.VK_CONTROL) >= 0) { int [] value = new int [1]; if (OS.SystemParametersInfo (OS.SPI_GETMOUSEVANISH, 0, value, 0)) { if (value [0] != 0) OS.SetCursor (0); } } } } } return result; } @Override LRESULT WM_IME_COMPOSITION (long wParam, long lParam) { if (ime != null) { LRESULT result = ime.WM_IME_COMPOSITION (wParam, lParam); if (result != null) return result; } return super.WM_IME_COMPOSITION (wParam, lParam); } @Override LRESULT WM_IME_COMPOSITION_START (long wParam, long lParam) { if (ime != null) { LRESULT result = ime.WM_IME_COMPOSITION_START (wParam, lParam); if (result != null) return result; } return super.WM_IME_COMPOSITION_START (wParam, lParam); } @Override LRESULT WM_IME_ENDCOMPOSITION (long wParam, long lParam) { if (ime != null) { LRESULT result = ime.WM_IME_ENDCOMPOSITION (wParam, lParam); if (result != null) return result; } return super.WM_IME_ENDCOMPOSITION (wParam, lParam); } @Override LRESULT WM_INPUTLANGCHANGE (long wParam, long lParam) { LRESULT result = super.WM_INPUTLANGCHANGE (wParam, lParam); if (caret != null && caret.isFocusCaret ()) { caret.setIMEFont (); caret.resizeIME (); } return result; } @Override LRESULT WM_KEYDOWN (long wParam, long lParam) { LRESULT result = super.WM_KEYDOWN (wParam, lParam); if (result != null) return result; if (ime != null) { ime.WM_KEYDOWN (wParam, lParam); } return result; } @Override LRESULT WM_KILLFOCUS (long wParam, long lParam) { if (ime != null) { LRESULT result = ime.WM_KILLFOCUS (wParam, lParam); if (result != null) return result; } Caret caret = this.caret; LRESULT result = super.WM_KILLFOCUS (wParam, lParam); if (caret != null) caret.killFocus (); return result; } @Override LRESULT WM_LBUTTONDOWN (long wParam, long lParam) { if (ime != null) { LRESULT result = ime.WM_LBUTTONDOWN (wParam, lParam); if (result != null) return result; } return super.WM_LBUTTONDOWN (wParam, lParam); } @Override LRESULT WM_SETFOCUS (long wParam, long lParam) { LRESULT result = super.WM_SETFOCUS (wParam, lParam); if (caret != null && caret.isFocusCaret ()) caret.setFocus (); return result; } @Override LRESULT WM_SIZE (long wParam, long lParam) { LRESULT result = super.WM_SIZE (wParam, lParam); if (caret != null && caret.isFocusCaret ()) caret.resizeIME (); return result; } @Override LRESULT WM_WINDOWPOSCHANGED (long wParam, long lParam) { LRESULT result = super.WM_WINDOWPOSCHANGED (wParam, lParam); //if (result != null) return result; /* * Bug in Windows. When a window with style WS_EX_LAYOUTRTL * that contains a caret is resized, Windows does not move the * caret in relation to the mirrored origin in the top right. * The fix is to hide the caret in WM_WINDOWPOSCHANGING and * show the caret in WM_WINDOWPOSCHANGED. */ boolean isFocus = (style & SWT.RIGHT_TO_LEFT) != 0 && caret != null && caret.isFocusCaret (); if (isFocus) caret.setFocus (); return result; } @Override LRESULT WM_WINDOWPOSCHANGING (long wParam, long lParam) { LRESULT result = super.WM_WINDOWPOSCHANGING (wParam, lParam); if (result != null) return result; /* * Bug in Windows. When a window with style WS_EX_LAYOUTRTL * that contains a caret is resized, Windows does not move the * caret in relation to the mirrored origin in the top right. * The fix is to hide the caret in WM_WINDOWPOSCHANGING and * show the caret in WM_WINDOWPOSCHANGED. */ boolean isFocus = (style & SWT.RIGHT_TO_LEFT) != 0 && caret != null && caret.isFocusCaret (); if (isFocus) caret.killFocus (); return result; } }