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.accessibility.*; import org.eclipse.swt.graphics.*; import org.eclipse.swt.internal.cocoa.*; import org.eclipse.swt.internal.graphics.*; /** * Instances of this class provide a surface for drawing * arbitrary graphics. * <dl> * <dt><b>Styles:</b></dt> * <dd>(none)</dd> * <dt><b>Events:</b></dt> * <dd>(none)</dd> * </dl> * <p> * This class may be subclassed by custom control implementors * who are building controls that are <em>not</em> constructed * from aggregates of other controls. That is, they are either * painted using SWT graphics calls or are handled by native * methods. * </p> * * @see Composite * @see <a href="http://www.eclipse.org/swt/snippets/#canvas">Canvas snippets</a> * @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: ControlExample</a> * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a> */ public class Canvas extends Composite { Caret caret; IME ime; NSOpenGLContext glcontext; NSBezierPath visiblePath; static NSMutableArray supportedPboardTypes; static { // This array is leaked. supportedPboardTypes = NSMutableArray.arrayWithCapacity(1); supportedPboardTypes.retain(); supportedPboardTypes.addObject(OS.NSPasteboardTypeString); //supportedPboardTypes.addObject(OS.NSRTFPboardType); }; Canvas() { /* Do nothing */ } @Override long attributedSubstringFromRange(long id, long sel, long range) { if (ime != null) return ime.attributedSubstringFromRange(id, sel, range); return super.attributedSubstringFromRange(id, sel, range); } @Override void sendFocusEvent(int type) { if (caret != null) { if (type == SWT.FocusIn) { caret.setFocus(); } else { caret.killFocus(); } } super.sendFocusEvent(type); } /** * 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> * </ul> * * @see SWT * @see Widget#getStyle */ public Canvas(Composite parent, int style) { super(parent, style); } @Override long characterIndexForPoint(long id, long sel, long point) { if (ime != null) return ime.characterIndexForPoint(id, sel, point); return super.characterIndexForPoint(id, sel, point); } /** * 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 <ul> * <li>ERROR_NULL_ARGUMENT - if the gc is null</li> * <li>ERROR_INVALID_ARGUMENT - if the gc 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> * * @since 3.2 */ public void drawBackground(GC gc, int x, int y, int width, int height) { drawBackground(gc, x, y, width, height, 0, 0); } @Override void drawBackground(long id, NSGraphicsContext context, NSRect rect) { super.drawBackground(id, context, rect); if (glcontext != null) { if (isObscured()) { glcontext.setValues(new int[] { -1 }, OS.NSOpenGLCPSurfaceOrder); context.saveGraphicsState(); context.setCompositingOperation(OS.NSCompositeClear); if (visiblePath == null) { long visibleRegion = getVisibleRegion(); visiblePath = getPath(visibleRegion); OS.DisposeRgn(visibleRegion); } visiblePath.addClip(); NSBezierPath.fillRect(rect); context.restoreGraphicsState(); } else { glcontext.setValues(new int[] { 1 }, OS.NSOpenGLCPSurfaceOrder); } } } @Override void drawRect(long id, long sel, NSRect rect) { if (glcontext != null && glcontext.view() == null) glcontext.setView(view); super.drawRect(id, sel, rect); } @Override void drawWidget(long id, NSGraphicsContext context, NSRect rect) { if (id != view.id) return; super.drawWidget(id, context, rect); if (caret == null) return; if (caret.isShowing) { long ctx = context.graphicsPort(); OS.CGContextSaveGState(ctx); OS.CGContextSetBlendMode(ctx, OS.kCGBlendModeDifference); Image image = caret.image; if (image != null) { NSImage imageHandle = image.handle; NSSize size = imageHandle.size(); NSImageRep imageRep = ImageUtil.createImageRep(image, size); if (!imageRep.isKindOfClass(OS.class_NSBitmapImageRep)) return; NSBitmapImageRep rep = new NSBitmapImageRep(imageRep); CGRect destRect = new CGRect(); destRect.origin.x = caret.x; destRect.origin.y = caret.y; destRect.size.width = size.width; destRect.size.height = size.height; long data = rep.bitmapData(); long format = rep.bitmapFormat(); long bpr = rep.bytesPerRow(); int alphaInfo; if (rep.hasAlpha()) { alphaInfo = (format & OS.NSAlphaFirstBitmapFormat) != 0 ? OS.kCGImageAlphaFirst : OS.kCGImageAlphaLast; } else { alphaInfo = (format & OS.NSAlphaFirstBitmapFormat) != 0 ? OS.kCGImageAlphaNoneSkipFirst : OS.kCGImageAlphaNoneSkipLast; } long provider = OS.CGDataProviderCreateWithData(0, data, bpr * (int) size.height, 0); long colorspace = OS.CGColorSpaceCreateDeviceRGB(); long cgImage = OS.CGImageCreate((int) size.width, (int) size.height, rep.bitsPerSample(), rep.bitsPerPixel(), bpr, colorspace, alphaInfo, provider, 0, true, 0); OS.CGColorSpaceRelease(colorspace); OS.CGDataProviderRelease(provider); OS.CGContextScaleCTM(ctx, 1, -1); OS.CGContextTranslateCTM(ctx, 0, -(size.height + 2 * destRect.origin.y)); OS.CGContextSetBlendMode(ctx, OS.kCGBlendModeDifference); OS.CGContextDrawImage(ctx, destRect, cgImage); OS.CGImageRelease(cgImage); } else { CGRect drawRect = new CGRect(); drawRect.origin.x = caret.x; drawRect.origin.y = caret.y; drawRect.size.width = caret.width != 0 ? caret.width : Caret.DEFAULT_WIDTH; drawRect.size.height = caret.height; long colorspace = OS.CGColorSpaceCreateDeviceRGB(); OS.CGContextSetFillColorSpace(ctx, colorspace); OS.CGColorSpaceRelease(colorspace); OS.CGContextSetFillColor(ctx, new double[] { 1, 1, 1, 1 }); OS.CGContextFillRect(ctx, drawRect); } OS.CGContextRestoreGState(ctx); } } @Override NSRect firstRectForCharacterRange(long id, long sel, long range) { if (ime != null) return ime.firstRectForCharacterRange(id, sel, range); return super.firstRectForCharacterRange(id, sel, range); } /** * Returns the caret. * <p> * 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. * </p> * * @return the caret for the receiver, may be null * * @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 Caret getCaret() { checkWidget(); return caret; } /** * Returns the IME. * * @return the IME * * @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> * * @since 3.4 */ public IME getIME() { checkWidget(); return ime; } @Override boolean hasMarkedText(long id, long sel) { if (ime != null) return ime.hasMarkedText(id, sel); return super.hasMarkedText(id, sel); } @Override boolean imeInComposition() { return ime != null && ime.isInlineEnabled() && ime.startOffset != -1; } @Override boolean insertText(long id, long sel, long string) { if (ime != null) { if (!ime.insertText(id, sel, string)) return false; } return super.insertText(id, sel, string); } @Override boolean isOpaque(long id, long sel) { if (glcontext != null) return true; return super.isOpaque(id, sel); } @Override NSRange markedRange(long id, long sel) { if (ime != null) return ime.markedRange(id, sel); return super.markedRange(id, sel); } @Override boolean readSelectionFromPasteboard(long id, long sel, long pasteboard) { boolean result = false; NSPasteboard pboard = new NSPasteboard(pasteboard); NSArray availableTypes = pboard.types(); NSString type; for (long i = 0; i < supportedPboardTypes.count(); i++) { if (result) break; type = new NSString(supportedPboardTypes.objectAtIndex(i)); if (availableTypes.containsObject(type)) { result = readSelectionFromPasteboard(pboard, type); } } return result; } boolean readSelectionFromPasteboard(NSPasteboard pboard, NSString type) { boolean result = false; NSString newSelection = null; if (type.isEqualToString(OS.NSPasteboardTypeString)) { NSString string = pboard.stringForType(OS.NSPasteboardTypeString); if (string != null && string.length() > 0) { newSelection = string; } } if (newSelection != null) { Accessible acc = getAccessible(); acc.internal_accessibilitySetValue_forAttribute(newSelection, OS.NSAccessibilitySelectedTextAttribute, ACC.CHILDID_SELF); result = true; } return result; } @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); } @Override void releaseWidget() { super.releaseWidget(); if (visiblePath != null) visiblePath.release(); visiblePath = null; } @Override void resetVisibleRegion() { super.resetVisibleRegion(); if (visiblePath != null) visiblePath.release(); visiblePath = null; } /** * 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 <code>true</code>if children should be scrolled, and <code>false</code> otherwise * * @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 scroll(int destX, int destY, int x, int y, int width, int height, boolean all) { checkWidget(); if (width <= 0 || height <= 0) return; int deltaX = destX - x, deltaY = destY - y; if (deltaX == 0 && deltaY == 0) return; if (!isDrawing()) return; NSRect visibleRect = view.visibleRect(); if (visibleRect.width <= 0 || visibleRect.height <= 0) return; boolean isFocus = caret != null && caret.isFocusCaret(); if (isFocus) caret.killFocus(); Rectangle clientRect = getClientArea(); Rectangle sourceRect = new Rectangle(x, y, width, height); Control control = findBackgroundControl(); boolean redraw = control != null && control.backgroundImage != null; if (!redraw) redraw = hasRegion(); if (!redraw) redraw = isObscured(); if (!redraw && sourceRect.intersects(clientRect)) { getShell().setScrolling(); redraw = !update(all); } if (redraw) { redrawWidget(view, x, y, width, height, false); redrawWidget(view, destX, destY, width, height, false); } else { NSRect damage = new NSRect(); damage.x = x; damage.y = y; damage.width = width; damage.height = height; NSPoint dest = new NSPoint(); dest.x = destX; dest.y = destY; view.lockFocus(); NSSize delta = new NSSize(); delta.width = deltaX; delta.height = deltaY; view.scrollRect(damage, delta); view.unlockFocus(); boolean disjoint = (destX + width < x) || (x + width < destX) || (destY + height < y) || (y + height < destY); if (disjoint) { view.setNeedsDisplayInRect(damage); } else { if (deltaX != 0) { int newX = destX - deltaX; if (deltaX < 0) newX = destX + width; damage.x = newX; damage.width = Math.abs(deltaX); view.setNeedsDisplayInRect(damage); } if (deltaY != 0) { int newY = destY - deltaY; if (deltaY < 0) newY = destY + height; damage.x = x; damage.y = newY; damage.width = width; damage.height = Math.abs(deltaY); view.setNeedsDisplayInRect(damage); } } NSRect srcRect = new NSRect(); srcRect.x = sourceRect.x; srcRect.y = sourceRect.y; srcRect.width = sourceRect.width; srcRect.height = sourceRect.height; OS.NSIntersectionRect(visibleRect, visibleRect, srcRect); if (!OS.NSEqualRects(visibleRect, srcRect)) { if (srcRect.x != visibleRect.x) { damage.x = srcRect.x + deltaX; damage.y = srcRect.y + deltaY; damage.width = visibleRect.x - srcRect.x; damage.height = srcRect.height; view.setNeedsDisplayInRect(damage); } if (visibleRect.x + visibleRect.width != srcRect.x + srcRect.width) { damage.x = srcRect.x + visibleRect.width + deltaX; damage.y = srcRect.y + deltaY; damage.width = srcRect.width - visibleRect.width; damage.height = srcRect.height; view.setNeedsDisplayInRect(damage); } if (visibleRect.y != srcRect.y) { damage.x = visibleRect.x + deltaX; damage.y = srcRect.y + deltaY; damage.width = visibleRect.width; damage.height = visibleRect.y - srcRect.y; view.setNeedsDisplayInRect(damage); } if (visibleRect.y + visibleRect.height != srcRect.y + srcRect.height) { damage.x = visibleRect.x + deltaX; damage.y = visibleRect.y + visibleRect.height + deltaY; damage.width = visibleRect.width; damage.height = srcRect.y + srcRect.height - (visibleRect.y + visibleRect.height); view.setNeedsDisplayInRect(damage); } } } if (all) { Control[] children = _getChildren(); for (int i = 0; i < children.length; i++) { Control child = children[i]; Rectangle rect = child.getBounds(); if (Math.min(x + width, rect.x + rect.width) >= Math.max(x, rect.x) && Math.min(y + height, rect.y + rect.height) >= Math.max(y, rect.y)) { child.setLocation(rect.x + deltaX, rect.y + deltaY); } } } if (isFocus) caret.setFocus(); } @Override NSRange selectedRange(long id, long sel) { if (ime != null) return ime.selectedRange(id, sel); return super.selectedRange(id, sel); } @Override boolean sendKeyEvent(NSEvent nsEvent, int type) { if (caret != null) NSCursor.setHiddenUntilMouseMoves(true); return super.sendKeyEvent(nsEvent, type); } /** * Sets the receiver's caret. * <p> * 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. * </p> * @param caret the new caret for the receiver, may be null * * @exception IllegalArgumentException <ul> * <li>ERROR_INVALID_ARGUMENT - if the caret 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 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); } @Override void setOpenGLContext(Object value) { glcontext = (NSOpenGLContext) value; Shell shell = getShell(); if (glcontext != null) { shell.glContextCount++; } else { shell.glContextCount--; } shell.updateOpaque(); } /** * Sets the receiver's IME. * * @param ime the new IME for the receiver, may be null * * @exception IllegalArgumentException <ul> * <li>ERROR_INVALID_ARGUMENT - if the IME 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> * * @since 3.4 */ public void setIME(IME ime) { checkWidget(); if (ime != null && ime.isDisposed()) error(SWT.ERROR_INVALID_ARGUMENT); this.ime = ime; } @Override boolean setMarkedText_selectedRange(long id, long sel, long string, long range) { if (ime != null) { if (!ime.setMarkedText_selectedRange(id, sel, string, range)) return false; } return super.setMarkedText_selectedRange(id, sel, string, range); } @Override long validAttributesForMarkedText(long id, long sel) { if (ime != null) return ime.validAttributesForMarkedText(id, sel); return super.validAttributesForMarkedText(id, sel); } @Override long validRequestorForSendType(long id, long sel, long sendType, long returnType) { if (id == view.id) { Accessible acc = getAccessible(); if (acc != null) { // This returns null if there are no additional overrides. Since this is only checked to see if there is // a StyledText or other control that supports reading and writing of the selection there's no need to bother // with checking the default values. They will be picked up in the default implementation. NSArray attributes = acc.internal_accessibilityAttributeNames(ACC.CHILDID_SELF); if (attributes != null) { boolean canReturn = attributes.containsObject(OS.NSAccessibilitySelectedTextAttribute); boolean canSend = acc.internal_accessibilityIsAttributeSettable( OS.NSAccessibilitySelectedTextAttribute, ACC.CHILDID_SELF); boolean canHandlePBoardType = supportedPboardTypes.containsObject(new id(sendType)) && supportedPboardTypes.containsObject(new id(returnType)); if (canReturn && canSend && canHandlePBoardType) { id selection = acc.internal_accessibilityAttributeValue( OS.NSAccessibilitySelectedTextAttribute, ACC.CHILDID_SELF); if (selection != null) { NSString selectionString = new NSString(selection); if (selectionString.length() > 0) return view.id; } } } } } return super.validRequestorForSendType(id, sel, sendType, returnType); } @Override void updateOpenGLContext(long id, long sel, long notification) { if (glcontext != null) ((NSOpenGLContext) glcontext).update(); } @Override void viewWillMoveToWindow(long id, long sel, long arg0) { super.viewWillMoveToWindow(id, sel, arg0); if (glcontext != null && id == view.id && arg0 != 0) { Widget newShell = display.getWidget(new NSWindow(arg0).contentView()); if (newShell instanceof Shell) { ((Shell) newShell).glContextCount++; ((Shell) newShell).updateOpaque(); } Shell shell = getShell(); shell.glContextCount--; shell.updateOpaque(); } } @Override boolean writeSelectionToPasteboard(long id, long sel, long pasteboardObj, long typesObj) { boolean result = false; NSPasteboard pboard = new NSPasteboard(pasteboardObj); NSArray types = new NSArray(typesObj); NSMutableArray typesToDeclare = NSMutableArray.arrayWithCapacity(2); NSString type; for (long i = 0; i < supportedPboardTypes.count(); i++) { type = new NSString(supportedPboardTypes.objectAtIndex(i)); if (types.containsObject(type)) typesToDeclare.addObject(type); } if (typesToDeclare.count() > 0) { pboard.declareTypes(typesToDeclare, view); for (long i = 0; i < typesToDeclare.count(); i++) { type = new NSString(typesToDeclare.objectAtIndex(i)); if (writeSelectionToPasteboard(pboard, type)) result = true; } } return result; } boolean writeSelectionToPasteboard(NSPasteboard pboard, NSString type) { boolean result = false; if (type.isEqualToString(OS.NSPasteboardTypeString)) { Accessible acc = getAccessible(); id selection = acc.internal_accessibilityAttributeValue(OS.NSAccessibilitySelectedTextAttribute, ACC.CHILDID_SELF); if (selection != null) { NSString selectionString = new NSString(selection); if (selectionString.length() > 0) result = pboard.setString(selectionString, OS.NSPasteboardTypeString); } } return result; } }