Java example source code file (PlainView.java)
The PlainView.java Java example source code
/*
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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
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* 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.
*
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package javax.swing.text;
import java.util.Vector;
import java.util.Properties;
import java.awt.*;
import javax.swing.event.*;
/**
* Implements View interface for a simple multi-line text view
* that has text in one font and color. The view represents each
* child element as a line of text.
*
* @author Timothy Prinzing
* @see View
*/
public class PlainView extends View implements TabExpander {
/**
* Constructs a new PlainView wrapped on an element.
*
* @param elem the element
*/
public PlainView(Element elem) {
super(elem);
}
/**
* Returns the tab size set for the document, defaulting to 8.
*
* @return the tab size
*/
protected int getTabSize() {
Integer i = (Integer) getDocument().getProperty(PlainDocument.tabSizeAttribute);
int size = (i != null) ? i.intValue() : 8;
return size;
}
/**
* Renders a line of text, suppressing whitespace at the end
* and expanding any tabs. This is implemented to make calls
* to the methods <code>drawUnselectedText and
* <code>drawSelectedText so that the way selected and
* unselected text are rendered can be customized.
*
* @param lineIndex the line to draw >= 0
* @param g the <code>Graphics context
* @param x the starting X position >= 0
* @param y the starting Y position >= 0
* @see #drawUnselectedText
* @see #drawSelectedText
*/
protected void drawLine(int lineIndex, Graphics g, int x, int y) {
Element line = getElement().getElement(lineIndex);
Element elem;
try {
if (line.isLeaf()) {
drawElement(lineIndex, line, g, x, y);
} else {
// this line contains the composed text.
int count = line.getElementCount();
for(int i = 0; i < count; i++) {
elem = line.getElement(i);
x = drawElement(lineIndex, elem, g, x, y);
}
}
} catch (BadLocationException e) {
throw new StateInvariantError("Can't render line: " + lineIndex);
}
}
private int drawElement(int lineIndex, Element elem, Graphics g, int x, int y) throws BadLocationException {
int p0 = elem.getStartOffset();
int p1 = elem.getEndOffset();
p1 = Math.min(getDocument().getLength(), p1);
if (lineIndex == 0) {
x += firstLineOffset;
}
AttributeSet attr = elem.getAttributes();
if (Utilities.isComposedTextAttributeDefined(attr)) {
g.setColor(unselected);
x = Utilities.drawComposedText(this, attr, g, x, y,
p0-elem.getStartOffset(),
p1-elem.getStartOffset());
} else {
if (sel0 == sel1 || selected == unselected) {
// no selection, or it is invisible
x = drawUnselectedText(g, x, y, p0, p1);
} else if ((p0 >= sel0 && p0 <= sel1) && (p1 >= sel0 && p1 <= sel1)) {
x = drawSelectedText(g, x, y, p0, p1);
} else if (sel0 >= p0 && sel0 <= p1) {
if (sel1 >= p0 && sel1 <= p1) {
x = drawUnselectedText(g, x, y, p0, sel0);
x = drawSelectedText(g, x, y, sel0, sel1);
x = drawUnselectedText(g, x, y, sel1, p1);
} else {
x = drawUnselectedText(g, x, y, p0, sel0);
x = drawSelectedText(g, x, y, sel0, p1);
}
} else if (sel1 >= p0 && sel1 <= p1) {
x = drawSelectedText(g, x, y, p0, sel1);
x = drawUnselectedText(g, x, y, sel1, p1);
} else {
x = drawUnselectedText(g, x, y, p0, p1);
}
}
return x;
}
/**
* Renders the given range in the model as normal unselected
* text. Uses the foreground or disabled color to render the text.
*
* @param g the graphics context
* @param x the starting X coordinate >= 0
* @param y the starting Y coordinate >= 0
* @param p0 the beginning position in the model >= 0
* @param p1 the ending position in the model >= 0
* @return the X location of the end of the range >= 0
* @exception BadLocationException if the range is invalid
*/
protected int drawUnselectedText(Graphics g, int x, int y,
int p0, int p1) throws BadLocationException {
g.setColor(unselected);
Document doc = getDocument();
Segment s = SegmentCache.getSharedSegment();
doc.getText(p0, p1 - p0, s);
int ret = Utilities.drawTabbedText(this, s, x, y, g, this, p0);
SegmentCache.releaseSharedSegment(s);
return ret;
}
/**
* Renders the given range in the model as selected text. This
* is implemented to render the text in the color specified in
* the hosting component. It assumes the highlighter will render
* the selected background.
*
* @param g the graphics context
* @param x the starting X coordinate >= 0
* @param y the starting Y coordinate >= 0
* @param p0 the beginning position in the model >= 0
* @param p1 the ending position in the model >= 0
* @return the location of the end of the range
* @exception BadLocationException if the range is invalid
*/
protected int drawSelectedText(Graphics g, int x,
int y, int p0, int p1) throws BadLocationException {
g.setColor(selected);
Document doc = getDocument();
Segment s = SegmentCache.getSharedSegment();
doc.getText(p0, p1 - p0, s);
int ret = Utilities.drawTabbedText(this, s, x, y, g, this, p0);
SegmentCache.releaseSharedSegment(s);
return ret;
}
/**
* Gives access to a buffer that can be used to fetch
* text from the associated document.
*
* @return the buffer
*/
protected final Segment getLineBuffer() {
if (lineBuffer == null) {
lineBuffer = new Segment();
}
return lineBuffer;
}
/**
* Checks to see if the font metrics and longest line
* are up-to-date.
*
* @since 1.4
*/
protected void updateMetrics() {
Component host = getContainer();
Font f = host.getFont();
if (font != f) {
// The font changed, we need to recalculate the
// longest line.
calculateLongestLine();
tabSize = getTabSize() * metrics.charWidth('m');
}
}
// ---- View methods ----------------------------------------------------
/**
* 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.
* @exception IllegalArgumentException for an invalid axis
*/
public float getPreferredSpan(int axis) {
updateMetrics();
switch (axis) {
case View.X_AXIS:
return getLineWidth(longLine);
case View.Y_AXIS:
return getElement().getElementCount() * metrics.getHeight();
default:
throw new IllegalArgumentException("Invalid axis: " + axis);
}
}
/**
* 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) {
Shape originalA = a;
a = adjustPaintRegion(a);
Rectangle alloc = (Rectangle) a;
tabBase = alloc.x;
JTextComponent host = (JTextComponent) getContainer();
Highlighter h = host.getHighlighter();
g.setFont(host.getFont());
sel0 = host.getSelectionStart();
sel1 = host.getSelectionEnd();
unselected = (host.isEnabled()) ?
host.getForeground() : host.getDisabledTextColor();
Caret c = host.getCaret();
selected = c.isSelectionVisible() && h != null ?
host.getSelectedTextColor() : unselected;
updateMetrics();
// If the lines are clipped then we don't expend the effort to
// try and paint them. Since all of the lines are the same height
// with this object, determination of what lines need to be repainted
// is quick.
Rectangle clip = g.getClipBounds();
int fontHeight = metrics.getHeight();
int heightBelow = (alloc.y + alloc.height) - (clip.y + clip.height);
int heightAbove = clip.y - alloc.y;
int linesBelow, linesAbove, linesTotal;
if (fontHeight > 0) {
linesBelow = Math.max(0, heightBelow / fontHeight);
linesAbove = Math.max(0, heightAbove / fontHeight);
linesTotal = alloc.height / fontHeight;
if (alloc.height % fontHeight != 0) {
linesTotal++;
}
} else {
linesBelow = linesAbove = linesTotal = 0;
}
// update the visible lines
Rectangle lineArea = lineToRect(a, linesAbove);
int y = lineArea.y + metrics.getAscent();
int x = lineArea.x;
Element map = getElement();
int lineCount = map.getElementCount();
int endLine = Math.min(lineCount, linesTotal - linesBelow);
lineCount--;
LayeredHighlighter dh = (h instanceof LayeredHighlighter) ?
(LayeredHighlighter)h : null;
for (int line = linesAbove; line < endLine; line++) {
if (dh != null) {
Element lineElement = map.getElement(line);
if (line == lineCount) {
dh.paintLayeredHighlights(g, lineElement.getStartOffset(),
lineElement.getEndOffset(),
originalA, host, this);
}
else {
dh.paintLayeredHighlights(g, lineElement.getStartOffset(),
lineElement.getEndOffset() - 1,
originalA, host, this);
}
}
drawLine(line, g, x, y);
y += fontHeight;
if (line == 0) {
// This should never really happen, in so far as if
// firstLineOffset is non 0, there should only be one
// line of text.
x -= firstLineOffset;
}
}
}
/**
* Should return a shape ideal for painting based on the passed in
* Shape <code>a. This is useful if painting in a different
* region. The default implementation returns <code>a.
*/
Shape adjustPaintRegion(Shape a) {
return a;
}
/**
* 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 {
// line coordinates
Document doc = getDocument();
Element map = getElement();
int lineIndex = map.getElementIndex(pos);
if (lineIndex < 0) {
return lineToRect(a, 0);
}
Rectangle lineArea = lineToRect(a, lineIndex);
// determine span from the start of the line
tabBase = lineArea.x;
Element line = map.getElement(lineIndex);
int p0 = line.getStartOffset();
Segment s = SegmentCache.getSharedSegment();
doc.getText(p0, pos - p0, s);
int xOffs = Utilities.getTabbedTextWidth(s, metrics, tabBase, this,p0);
SegmentCache.releaseSharedSegment(s);
// fill in the results and return
lineArea.x += xOffs;
lineArea.width = 1;
lineArea.height = metrics.getHeight();
return lineArea;
}
/**
* Provides a mapping from the view coordinate space to the logical
* coordinate space of the model.
*
* @param fx the X coordinate >= 0
* @param fy the Y coordinate >= 0
* @param a the allocated region to render into
* @return the location within the model that best represents the
* given point in the view >= 0
* @see View#viewToModel
*/
public int viewToModel(float fx, float fy, Shape a, Position.Bias[] bias) {
// PENDING(prinz) properly calculate bias
bias[0] = Position.Bias.Forward;
Rectangle alloc = a.getBounds();
Document doc = getDocument();
int x = (int) fx;
int y = (int) fy;
if (y < alloc.y) {
// above the area covered by this icon, so the the position
// is assumed to be the start of the coverage for this view.
return getStartOffset();
} else if (y > alloc.y + alloc.height) {
// below the area covered by this icon, so the the position
// is assumed to be the end of the coverage for this view.
return getEndOffset() - 1;
} else {
// positioned within the coverage of this view vertically,
// so we figure out which line the point corresponds to.
// if the line is greater than the number of lines contained, then
// simply use the last line as it represents the last possible place
// we can position to.
Element map = doc.getDefaultRootElement();
int fontHeight = metrics.getHeight();
int lineIndex = (fontHeight > 0 ?
Math.abs((y - alloc.y) / fontHeight) :
map.getElementCount() - 1);
if (lineIndex >= map.getElementCount()) {
return getEndOffset() - 1;
}
Element line = map.getElement(lineIndex);
int dx = 0;
if (lineIndex == 0) {
alloc.x += firstLineOffset;
alloc.width -= firstLineOffset;
}
if (x < alloc.x) {
// point is to the left of the line
return line.getStartOffset();
} else if (x > alloc.x + alloc.width) {
// point is to the right of the line
return line.getEndOffset() - 1;
} else {
// Determine the offset into the text
try {
int p0 = line.getStartOffset();
int p1 = line.getEndOffset() - 1;
Segment s = SegmentCache.getSharedSegment();
doc.getText(p0, p1 - p0, s);
tabBase = alloc.x;
int offs = p0 + Utilities.getTabbedTextOffset(s, metrics,
tabBase, x, this, p0);
SegmentCache.releaseSharedSegment(s);
return offs;
} catch (BadLocationException e) {
// should not happen
return -1;
}
}
}
}
/**
* Gives notification that something was inserted into the document
* in a location that this view is responsible for.
*
* @param changes the change information from the associated document
* @param a the current allocation of the view
* @param f the factory to use to rebuild if the view has children
* @see View#insertUpdate
*/
public void insertUpdate(DocumentEvent changes, Shape a, ViewFactory f) {
updateDamage(changes, a, f);
}
/**
* Gives notification that something was removed from the document
* in a location that this view is responsible for.
*
* @param changes the change information from the associated document
* @param a the current allocation of the view
* @param f the factory to use to rebuild if the view has children
* @see View#removeUpdate
*/
public void removeUpdate(DocumentEvent changes, Shape a, ViewFactory f) {
updateDamage(changes, a, f);
}
/**
* Gives notification from the document that attributes were changed
* in a location that this view is responsible for.
*
* @param changes the change information from the associated document
* @param a the current allocation of the view
* @param f the factory to use to rebuild if the view has children
* @see View#changedUpdate
*/
public void changedUpdate(DocumentEvent changes, Shape a, ViewFactory f) {
updateDamage(changes, a, f);
}
/**
* Sets the size of the view. This should cause
* layout of the view along the given axis, if it
* has any layout duties.
*
* @param width the width >= 0
* @param height the height >= 0
*/
public void setSize(float width, float height) {
super.setSize(width, height);
updateMetrics();
}
// --- TabExpander methods ------------------------------------------
/**
* Returns the next tab stop position after a given reference position.
* This implementation does not support things like centering so it
* ignores the tabOffset argument.
*
* @param x the current position >= 0
* @param tabOffset the position within the text stream
* that the tab occurred at >= 0.
* @return the tab stop, measured in points >= 0
*/
public float nextTabStop(float x, int tabOffset) {
if (tabSize == 0) {
return x;
}
int ntabs = (((int) x) - tabBase) / tabSize;
return tabBase + ((ntabs + 1) * tabSize);
}
// --- local methods ------------------------------------------------
/**
* Repaint the region of change covered by the given document
* event. Damages the line that begins the range to cover
* the case when the insert/remove is only on one line.
* If lines are added or removed, damages the whole
* view. The longest line is checked to see if it has
* changed.
*
* @since 1.4
*/
protected void updateDamage(DocumentEvent changes, Shape a, ViewFactory f) {
Component host = getContainer();
updateMetrics();
Element elem = getElement();
DocumentEvent.ElementChange ec = changes.getChange(elem);
Element[] added = (ec != null) ? ec.getChildrenAdded() : null;
Element[] removed = (ec != null) ? ec.getChildrenRemoved() : null;
if (((added != null) && (added.length > 0)) ||
((removed != null) && (removed.length > 0))) {
// lines were added or removed...
if (added != null) {
int currWide = getLineWidth(longLine);
for (int i = 0; i < added.length; i++) {
int w = getLineWidth(added[i]);
if (w > currWide) {
currWide = w;
longLine = added[i];
}
}
}
if (removed != null) {
for (int i = 0; i < removed.length; i++) {
if (removed[i] == longLine) {
calculateLongestLine();
break;
}
}
}
preferenceChanged(null, true, true);
host.repaint();
} else {
Element map = getElement();
int line = map.getElementIndex(changes.getOffset());
damageLineRange(line, line, a, host);
if (changes.getType() == DocumentEvent.EventType.INSERT) {
// check to see if the line is longer than current
// longest line.
int w = getLineWidth(longLine);
Element e = map.getElement(line);
if (e == longLine) {
preferenceChanged(null, true, false);
} else if (getLineWidth(e) > w) {
longLine = e;
preferenceChanged(null, true, false);
}
} else if (changes.getType() == DocumentEvent.EventType.REMOVE) {
if (map.getElement(line) == longLine) {
// removed from longest line... recalc
calculateLongestLine();
preferenceChanged(null, true, false);
}
}
}
}
/**
* Repaint the given line range.
*
* @param host the component hosting the view (used to call repaint)
* @param a the region allocated for the view to render into
* @param line0 the starting line number to repaint. This must
* be a valid line number in the model.
* @param line1 the ending line number to repaint. This must
* be a valid line number in the model.
* @since 1.4
*/
protected void damageLineRange(int line0, int line1, Shape a, Component host) {
if (a != null) {
Rectangle area0 = lineToRect(a, line0);
Rectangle area1 = lineToRect(a, line1);
if ((area0 != null) && (area1 != null)) {
Rectangle damage = area0.union(area1);
host.repaint(damage.x, damage.y, damage.width, damage.height);
} else {
host.repaint();
}
}
}
/**
* Determine the rectangle that represents the given line.
*
* @param a the region allocated for the view to render into
* @param line the line number to find the region of. This must
* be a valid line number in the model.
* @since 1.4
*/
protected Rectangle lineToRect(Shape a, int line) {
Rectangle r = null;
updateMetrics();
if (metrics != null) {
Rectangle alloc = a.getBounds();
if (line == 0) {
alloc.x += firstLineOffset;
alloc.width -= firstLineOffset;
}
r = new Rectangle(alloc.x, alloc.y + (line * metrics.getHeight()),
alloc.width, metrics.getHeight());
}
return r;
}
/**
* Iterate over the lines represented by the child elements
* of the element this view represents, looking for the line
* that is the longest. The <em>longLine variable is updated to
* represent the longest line contained. The <em>font variable
* is updated to indicate the font used to calculate the
* longest line.
*/
private void calculateLongestLine() {
Component c = getContainer();
font = c.getFont();
metrics = c.getFontMetrics(font);
Document doc = getDocument();
Element lines = getElement();
int n = lines.getElementCount();
int maxWidth = -1;
for (int i = 0; i < n; i++) {
Element line = lines.getElement(i);
int w = getLineWidth(line);
if (w > maxWidth) {
maxWidth = w;
longLine = line;
}
}
}
/**
* Calculate the width of the line represented by
* the given element. It is assumed that the font
* and font metrics are up-to-date.
*/
private int getLineWidth(Element line) {
if (line == null) {
return 0;
}
int p0 = line.getStartOffset();
int p1 = line.getEndOffset();
int w;
Segment s = SegmentCache.getSharedSegment();
try {
line.getDocument().getText(p0, p1 - p0, s);
w = Utilities.getTabbedTextWidth(s, metrics, tabBase, this, p0);
} catch (BadLocationException ble) {
w = 0;
}
SegmentCache.releaseSharedSegment(s);
return w;
}
// --- member variables -----------------------------------------------
/**
* Font metrics for the current font.
*/
protected FontMetrics metrics;
/**
* The current longest line. This is used to calculate
* the preferred width of the view. Since the calculation
* is potentially expensive we try to avoid it by stashing
* which line is currently the longest.
*/
Element longLine;
/**
* Font used to calculate the longest line... if this
* changes we need to recalculate the longest line
*/
Font font;
Segment lineBuffer;
int tabSize;
int tabBase;
int sel0;
int sel1;
Color unselected;
Color selected;
/**
* Offset of where to draw the first character on the first line.
* This is a hack and temporary until we can better address the problem
* of text measuring. This field is actually never set directly in
* PlainView, but by FieldView.
*/
int firstLineOffset;
}
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