JDK14/Java14源码在线阅读
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package javax.swing.text;
import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;
/**
* Extends the multi-line plain text view to be suitable
* for a single-line editor view. If the view is
* allocated extra space, the field must adjust for it.
* If the hosting component is a JTextField, this view
* will manage the ranges of the associated BoundedRangeModel
* and will adjust the horizontal allocation to match the
* current visibility settings of the JTextField.
*
* @author Timothy Prinzing
* @see View
*/
public class FieldView extends PlainView {
/**
* Constructs a new FieldView wrapped on an element.
*
* @param elem the element
*/
public FieldView(Element elem) {
super(elem);
}
/**
* Fetches the font metrics associated with the component hosting
* this view.
*
* @return the metrics
*/
protected FontMetrics getFontMetrics() {
Component c = getContainer();
return c.getFontMetrics(c.getFont());
}
/**
* Adjusts the allocation given to the view
* to be a suitable allocation for a text field.
* If the view has been allocated more than the
* preferred span vertically, the allocation is
* changed to be centered vertically. Horizontally
* the view is adjusted according to the horizontal
* alignment property set on the associated JTextField
* (if that is the type of the hosting component).
*
* @param a the allocation given to the view, which may need
* to be adjusted.
* @return the allocation that the superclass should use.
*/
protected Shape adjustAllocation(Shape a) {
if (a != null) {
Rectangle bounds = a.getBounds();
int vspan = (int) getPreferredSpan(Y_AXIS);
int hspan = (int) getPreferredSpan(X_AXIS);
if (bounds.height != vspan) {
int slop = bounds.height - vspan;
bounds.y += slop / 2;
bounds.height -= slop;
}
// horizontal adjustments
Component c = getContainer();
if (c instanceof JTextField) {
JTextField field = (JTextField) c;
BoundedRangeModel vis = field.getHorizontalVisibility();
int max = Math.max(hspan, bounds.width);
int value = vis.getValue();
int extent = Math.min(max, bounds.width - 1);
if ((value + extent) > max) {
value = max - extent;
}
vis.setRangeProperties(value, extent, vis.getMinimum(),
max, false);
if (hspan < bounds.width) {
// horizontally align the interior
int slop = bounds.width - 1 - hspan;
int align = ((JTextField)c).getHorizontalAlignment();
if(Utilities.isLeftToRight(c)) {
if(align==LEADING) {
align = LEFT;
}
else if(align==TRAILING) {
align = RIGHT;
}
}
else {
if(align==LEADING) {
align = RIGHT;
}
else if(align==TRAILING) {
align = LEFT;
}
}
switch (align) {
case SwingConstants.CENTER:
bounds.x += slop / 2;
bounds.width -= slop;
break;
case SwingConstants.RIGHT:
bounds.x += slop;
bounds.width -= slop;
break;
}
} else {
// adjust the allocation to match the bounded range.
bounds.width = hspan;
bounds.x -= vis.getValue();
}
}
return bounds;
}
return null;
}
/**
* Update the visibility model with the associated JTextField
* (if there is one) to reflect the current visibility as a
* result of changes to the document model. The bounded
* range properties are updated. If the view hasn't yet been
* shown the extent will be zero and we just set it to be full
* until determined otherwise.
*/
void updateVisibilityModel() {
Component c = getContainer();
if (c instanceof JTextField) {
JTextField field = (JTextField) c;
BoundedRangeModel vis = field.getHorizontalVisibility();
int hspan = (int) getPreferredSpan(X_AXIS);
int extent = vis.getExtent();
int maximum = Math.max(hspan, extent);
extent = (extent == 0) ? maximum : extent;
int value = maximum - extent;
int oldValue = vis.getValue();
if ((oldValue + extent) > maximum) {
oldValue = maximum - extent;
}
value = Math.max(0, Math.min(value, oldValue));
vis.setRangeProperties(value, extent, 0, maximum, false);
}
}
// --- View methods -------------------------------------------
/**
* Renders using the given rendering surface and area on that surface.
* The view may need to do layout and create child views to enable
* itself to render into the given allocation.
*
* @param g the rendering surface to use
* @param a the allocated region to render into
*
* @see View#paint
*/
public void paint(Graphics g, Shape a) {
Rectangle r = (Rectangle) a;
g.clipRect(r.x, r.y, r.width, r.height);
super.paint(g, a);
}
/**
* Adjusts <code>a</code> based on the visible region and returns it.
*/
Shape adjustPaintRegion(Shape a) {
return adjustAllocation(a);
}
/**
* Determines the preferred span for this view along an
* axis.
*
* @param axis may be either View.X_AXIS or View.Y_AXIS
* @return the span the view would like to be rendered into >= 0.
* Typically the view is told to render into the span
* that is returned, although there is no guarantee.
* The parent may choose to resize or break the view.
*/
@SuppressWarnings("deprecation")
public float getPreferredSpan(int axis) {
switch (axis) {
case View.X_AXIS:
Segment buff = SegmentCache.getSharedSegment();
Document doc = getDocument();
int width;
try {
FontMetrics fm = getFontMetrics();
doc.getText(0, doc.getLength(), buff);
width = Utilities.getTabbedTextWidth(buff, fm, 0, this, 0);
if (buff.count > 0) {
Component c = getContainer();
firstLineOffset = sun.swing.SwingUtilities2.
getLeftSideBearing((c instanceof JComponent) ?
(JComponent)c : null, fm,
buff.array[buff.offset]);
firstLineOffset = Math.max(0, -firstLineOffset);
}
else {
firstLineOffset = 0;
}
} catch (BadLocationException bl) {
width = 0;
}
SegmentCache.releaseSharedSegment(buff);
return width + firstLineOffset;
default:
return super.getPreferredSpan(axis);
}
}
/**
* Determines the resizability of the view along the
* given axis. A value of 0 or less is not resizable.
*
* @param axis View.X_AXIS or View.Y_AXIS
* @return the weight -> 1 for View.X_AXIS, else 0
*/
public int getResizeWeight(int axis) {
if (axis == View.X_AXIS) {
return 1;
}
return 0;
}
/**
* Provides a mapping from the document model coordinate space
* to the coordinate space of the view mapped to it.
*
* @param pos the position to convert >= 0
* @param a the allocated region to render into
* @return the bounding box of the given position
* @exception BadLocationException if the given position does not
* represent a valid location in the associated document
* @see View#modelToView
*/
public Shape modelToView(int pos, Shape a, Position.Bias b) throws BadLocationException {
return super.modelToView(pos, adjustAllocation(a), b);
}
/**
* Provides a mapping from the view coordinate space to the logical
* coordinate space of the model.
*
* @param fx the X coordinate >= 0.0f
* @param fy the Y coordinate >= 0.0f
* @param a the allocated region to render into
* @return the location within the model that best represents the
* given point in the view
* @see View#viewToModel
*/
public int viewToModel(float fx, float fy, Shape a, Position.Bias[] bias) {
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