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/*******************************************************************************
 * 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.cairo.*;
import org.eclipse.swt.internal.gtk.*;

/**
 * Instances of this class provide an i-beam that is typically used
 * as the insertion point for text.
 * 
 * Styles:
 * (none)
 * Events:
 * (none)
 * 
 * 
 * IMPORTANT: This class is not intended to be subclassed.
 * 
 *
 * @see Caret snippets
 * @see SWT Example: ControlExample, Canvas tab
 * @see Sample code and further information
 * @noextend This class is not intended to be subclassed by clients.
 */
public class Caret extends Widget {
	Canvas parent;
	// Table or Tree the parent might be embedded into (also indirectly)
	Composite embeddedInto;
	int x, y, width, height;
	boolean isVisible, isShowing;
	int blinkRate;
	Image image;
	Font font;

	static final int DEFAULT_WIDTH = 1;

/**
 * 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 
 *    ERROR_NULL_ARGUMENT - if the parent is null
 * 
 * @exception SWTException 
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent
 *    ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass
 * 
 *
 * @see SWT
 * @see Widget#checkSubclass
 * @see Widget#getStyle
 */
public Caret (Canvas parent, int style) {
	super (parent, style);
	this.parent = parent;
	createWidget (0);
	Composite p = parent.getParent();
	while (p != null) {
		if (p instanceof Tree || p instanceof Table) {
			embeddedInto = p;
			break;
		}
		p = p.getParent();
	}
}

boolean blinkCaret () {
	if (!isVisible) return true;
	if (!isShowing) return showCaret ();
	if (blinkRate == 0) return true;
	return hideCaret ();
}

@Override
void createWidget (int index) {
	super.createWidget (index);
	blinkRate = display.getCaretBlinkTime ();
	isVisible = true;
	if (parent.getCaret () == null) {
		parent.setCaret (this);
	}
}

boolean drawCaret () {
	if (parent == null) return false;
	if (parent.isDisposed ()) return false;
	if (embeddedInto != null && !embeddedInto.isDisposed() && isFocusCaret()) {
		// Draw differently if we are in the embedded cell editor
		// See Table.setParentGdkResource() and Tree.setParentGdkResource()
		drawInCellEditor(embeddedInto.paintWindow());
	} else {
		GTK.gtk_widget_queue_draw(parent.handle);
	}
	return true;
}

private void drawInCellEditor(long window) {
	long cairo = GDK.gdk_cairo_create(window);
	Point pt = display.map(parent, embeddedInto, new Point(0,0));
	Cairo.cairo_translate (cairo, pt.x, pt.y);
	parent.drawCaretInFocus(parent.handle, cairo);
	Cairo.cairo_destroy(cairo);
}

/**
 * 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 
 *    ERROR_WIDGET_DISPOSED - if the receiver has been disposed
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
 * 
 */
public Rectangle getBounds () {
	checkWidget();
	return DPIUtil.autoScaleDown(getBoundsInPixels());
}

Rectangle getBoundsInPixels () {
	checkWidget();
	if (image != null) {
		Rectangle rect = image.getBoundsInPixels ();
		return new Rectangle (x, y, rect.width, rect.height);
	} else {
		if (width == 0) {
			return new Rectangle (x, y, DEFAULT_WIDTH, 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 
 *    ERROR_WIDGET_DISPOSED - if the receiver has been disposed
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
 * 
 */
public Font getFont () {
	checkWidget();
	if (font != null) return font;
	return parent.getFont ();
}

/**
 * Returns the image that the receiver will use to paint the caret.
 *
 * @return the receiver's image
 *
 * @exception SWTException 
 *    ERROR_WIDGET_DISPOSED - if the receiver has been disposed
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
 * 
 */
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 
 *    ERROR_WIDGET_DISPOSED - if the receiver has been disposed
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
 * 
 */
public Point getLocation () {
	checkWidget();
	return DPIUtil.autoScaleDown(getLocationInPixels());
}

Point getLocationInPixels () {
	checkWidget();
	return new Point (x, y);
}

/**
 * Returns the receiver's parent, which must be a Canvas.
 *
 * @return the receiver's parent
 *
 * @exception SWTException 
 *    ERROR_WIDGET_DISPOSED - if the receiver has been disposed
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
 * 
 */
public Canvas getParent () {
	checkWidget();
	return parent;
}

/**
 * Returns a point describing the receiver's size.
 *
 * @return the receiver's size
 *
 * @exception SWTException 
 *    ERROR_WIDGET_DISPOSED - if the receiver has been disposed
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
 * 
 */
public Point getSize () {
	checkWidget();
	return DPIUtil.autoScaleDown(getSizeInPixels());
}

Point getSizeInPixels () {
	checkWidget();
	if (image != null) {
		Rectangle rect = image.getBoundsInPixels ();
		return new Point (rect.width, rect.height);
	} else {
		if (width == 0) {
			return new Point (DEFAULT_WIDTH, height);
		}
	}
	return new Point (width, height);
}

/**
 * Returns true if the receiver is visible, and
 * false otherwise.
 * 
 * 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.
 * 
 *
 * @return the receiver's visibility state
 *
 * @exception SWTException 
 *    ERROR_WIDGET_DISPOSED - if the receiver has been disposed
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
 * 
 */
public boolean getVisible () {
	checkWidget();
	return isVisible;
}

boolean hideCaret () {
	if (!isShowing) return true;
	isShowing = false;
	return drawCaret ();
}

/**
 * Returns true if the receiver is visible and all
 * of the receiver's ancestors are visible and false
 * otherwise.
 *
 * @return the receiver's visibility state
 *
 * @exception SWTException 
 *    ERROR_WIDGET_DISPOSED - if the receiver has been disposed
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
 * 
 *
 * @see #getVisible
 */
public boolean isVisible () {
	checkWidget();
	return isVisible && parent.isVisible () && parent.hasFocus ();
}

boolean isFocusCaret () {
	return this == display.currentCaret;
}

void killFocus () {
	if (display.currentCaret != this) return;
	display.setCurrentCaret (null);
	if (isVisible) hideCaret ();
}

@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 ();
	if (display.currentCaret == this) {
		hideCaret ();
		display.setCurrentCaret (null);
	}
	parent = null;
	image = null;
	embeddedInto = null;
}

/**
 * Sets the receiver's size and location to the rectangular
 * area specified by the arguments. The x and
 * y 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 
 *    ERROR_WIDGET_DISPOSED - if the receiver has been disposed
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
 * 
 */
public void setBounds (int x, int y, int width, int height) {
	checkWidget();
	setBounds (new Rectangle (x, y, width, height));
}

void setBoundsInPixels (int x, int y, int width, int height) {
	checkWidget();
	if (this.x == x && this.y == y && this.width == width && this.height == height) return;
	boolean isFocus = isFocusCaret ();
	if (isFocus && isVisible) hideCaret ();
	this.x = x; this.y = y;
	this.width = width; this.height = height;
	parent.updateCaret ();
	if (isFocus && isVisible) showCaret ();
}

/**
 * Sets the receiver's size and location to the rectangular
 * area specified by the argument. The x and
 * y 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 
 *    ERROR_WIDGET_DISPOSED - if the receiver has been disposed
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
 * 
 */
public void setBounds (Rectangle rect) {
	checkWidget();
	rect = DPIUtil.autoScaleUp(rect);
	setBoundsInPixels(rect);
}

void setBoundsInPixels (Rectangle rect) {
	checkWidget();
	if (rect == null) error (SWT.ERROR_NULL_ARGUMENT);
	setBoundsInPixels (rect.x, rect.y, rect.width, rect.height);
}

void setFocus () {
	if (display.currentCaret == this) return;
	display.setCurrentCaret (this);
	if (isVisible) showCaret ();
}

/**
 * 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 
 *    ERROR_INVALID_ARGUMENT - if the font has been disposed
 * 
 * @exception SWTException 
 *    ERROR_WIDGET_DISPOSED - if the receiver has been disposed
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
 * 
 */
public void setFont (Font font) {
	checkWidget();
	if (font != null && font.isDisposed ()) {
		error (SWT.ERROR_INVALID_ARGUMENT);
	}
	this.font = font;
}

/**
 * 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 
 *    ERROR_INVALID_ARGUMENT - if the image has been disposed
 * 
 * @exception SWTException 
 *    ERROR_WIDGET_DISPOSED - if the receiver has been disposed
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
 * 
 */
public void setImage (Image image) {
	checkWidget();
	if (image != null && image.isDisposed ()) {
		error (SWT.ERROR_INVALID_ARGUMENT);
	}
	boolean isFocus = isFocusCaret ();
	if (isFocus && isVisible) hideCaret ();
	this.image = image;
	if (isFocus && isVisible) showCaret ();
}

/**
 * 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 
 *    ERROR_WIDGET_DISPOSED - if the receiver has been disposed
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
 * 
 */
public void setLocation (int x, int y) {
	checkWidget();
	setLocation (new Point (x, y));
}

void setLocationInPixels (int x, int y) {
	checkWidget();
	setBoundsInPixels (x, y, width, height);
}

/**
 * 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 
 *    ERROR_WIDGET_DISPOSED - if the receiver has been disposed
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
 * 
 */
public void setLocation (Point location) {
	checkWidget();
	setLocationInPixels (DPIUtil.autoScaleUp (location));
}

void setLocationInPixels (Point location) {
	checkWidget();
	if (location == null) error (SWT.ERROR_NULL_ARGUMENT);
	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 
 *    ERROR_WIDGET_DISPOSED - if the receiver has been disposed
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
 * 
 */
public void setSize (int width, int height) {
	checkWidget();
	setSize (new Point (width,height));
}

void setSizeInPixels (int width, int height) {
	checkWidget();
	setBoundsInPixels (x, y, width, height);
}

/**
 * Sets the receiver's size to the point specified by the argument.
 *
 * @param size the new extent for the receiver
 *
 * @exception IllegalArgumentException 
 *    ERROR_NULL_ARGUMENT - if the point is null
 * 
 * @exception SWTException 
 *    ERROR_WIDGET_DISPOSED - if the receiver has been disposed
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
 * 
 */
public void setSize (Point size) {
	checkWidget();
	setSizeInPixels(DPIUtil.autoScaleUp (size));
}

void setSizeInPixels (Point size) {
	checkWidget();
	if (size == null) error (SWT.ERROR_NULL_ARGUMENT);
	setSizeInPixels (size.x, size.y);
}

/**
 * Marks the receiver as visible if the argument is true,
 * and marks it invisible otherwise.
 * 
 * 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.
 * 
 *
 * @param visible the new visibility state
 *
 * @exception SWTException 
 *    ERROR_WIDGET_DISPOSED - if the receiver has been disposed
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
 * 
 */
public void setVisible (boolean visible) {
	checkWidget();
	Canvas canvas = getParent();
	canvas.blink = true;
	canvas.drawFlag = visible;
	display.resetCaretTiming();
	if (visible == isVisible) return;
	isVisible = visible;
	if (!isFocusCaret ()) return;
	if (isVisible) {
		showCaret ();
	} else {
		hideCaret ();
	}
}

boolean showCaret () {
	if (isShowing) return true;
	isShowing = true;
	return drawCaret ();
}

}