| Method from javax.swing.text.BoxView Detail: |
|---|
 protected void baselineLayout(int targetSpan,
int axis,
int[] offsets,
int[] spans) {
int totalAscent = (int)(targetSpan * getAlignment(axis));
int totalDescent = targetSpan - totalAscent;
int n = getViewCount();
for (int i = 0; i < n; i++) {
View v = getView(i);
float align = v.getAlignment(axis);
float viewSpan;
if (v.getResizeWeight(axis) > 0) {
// if resizable then resize to the best fit
// the smallest span possible
float minSpan = v.getMinimumSpan(axis);
// the largest span possible
float maxSpan = v.getMaximumSpan(axis);
if (align == 0.0f) {
// if the alignment is 0 then we need to fit into the descent
viewSpan = Math.max(Math.min(maxSpan, totalDescent), minSpan);
} else if (align == 1.0f) {
// if the alignment is 1 then we need to fit into the ascent
viewSpan = Math.max(Math.min(maxSpan, totalAscent), minSpan);
} else {
// figure out the span that we must fit into
float fitSpan = Math.min(totalAscent / align,
totalDescent / (1.0f - align));
// fit into the calculated span
viewSpan = Math.max(Math.min(maxSpan, fitSpan), minSpan);
}
} else {
// otherwise use the preferred spans
viewSpan = v.getPreferredSpan(axis);
}
offsets[i] = totalAscent - (int)(viewSpan * align);
spans[i] = (int)viewSpan;
}
}
Computes the location and extent of each child view
in this BoxView given the targetSpan,
which is the width (or height) of the region we have to
work with. |
protected SizeRequirements baselineRequirements(int axis,
SizeRequirements r) {
SizeRequirements totalAscent = new SizeRequirements();
SizeRequirements totalDescent = new SizeRequirements();
if (r == null) {
r = new SizeRequirements();
}
r.alignment = 0.5f;
int n = getViewCount();
// loop through all children calculating the max of all their ascents and
// descents at minimum, preferred, and maximum sizes
for (int i = 0; i < n; i++) {
View v = getView(i);
float align = v.getAlignment(axis);
float span;
int ascent;
int descent;
// find the maximum of the preferred ascents and descents
span = v.getPreferredSpan(axis);
ascent = (int)(align * span);
descent = (int)(span - ascent);
totalAscent.preferred = Math.max(ascent, totalAscent.preferred);
totalDescent.preferred = Math.max(descent, totalDescent.preferred);
if (v.getResizeWeight(axis) > 0) {
// if the view is resizable then do the same for the minimum and
// maximum ascents and descents
span = v.getMinimumSpan(axis);
ascent = (int)(align * span);
descent = (int)(span - ascent);
totalAscent.minimum = Math.max(ascent, totalAscent.minimum);
totalDescent.minimum = Math.max(descent, totalDescent.minimum);
span = v.getMaximumSpan(axis);
ascent = (int)(align * span);
descent = (int)(span - ascent);
totalAscent.maximum = Math.max(ascent, totalAscent.maximum);
totalDescent.maximum = Math.max(descent, totalDescent.maximum);
} else {
// otherwise use the preferred
totalAscent.minimum = Math.max(ascent, totalAscent.minimum);
totalDescent.minimum = Math.max(descent, totalDescent.minimum);
totalAscent.maximum = Math.max(ascent, totalAscent.maximum);
totalDescent.maximum = Math.max(descent, totalDescent.maximum);
}
}
// we now have an overall preferred, minimum, and maximum ascent and descent
// calculate the preferred span as the sum of the preferred ascent and preferred descent
r.preferred = (int)Math.min((long)totalAscent.preferred + (long)totalDescent.preferred,
Integer.MAX_VALUE);
// calculate the preferred alignment as the preferred ascent divided by the preferred span
if (r.preferred > 0) {
r.alignment = (float)totalAscent.preferred / r.preferred;
}
if (r.alignment == 0.0f) {
// if the preferred alignment is 0 then the minimum and maximum spans are simply
// the minimum and maximum descents since there's nothing above the baseline
r.minimum = totalDescent.minimum;
r.maximum = totalDescent.maximum;
} else if (r.alignment == 1.0f) {
// if the preferred alignment is 1 then the minimum and maximum spans are simply
// the minimum and maximum ascents since there's nothing below the baseline
r.minimum = totalAscent.minimum;
r.maximum = totalAscent.maximum;
} else {
// we want to honor the preferred alignment so we calculate two possible minimum
// span values using 1) the minimum ascent and the alignment, and 2) the minimum
// descent and the alignment. We'll choose the larger of these two numbers.
r.minimum = Math.round(Math.max(totalAscent.minimum / r.alignment,
totalDescent.minimum / (1.0f - r.alignment)));
// a similar calculation is made for the maximum but we choose the smaller number.
r.maximum = Math.round(Math.min(totalAscent.maximum / r.alignment,
totalDescent.maximum / (1.0f - r.alignment)));
}
return r;
} Calculates the size requirements for this BoxView
by examining the size of each child view. |
protected SizeRequirements calculateMajorAxisRequirements(int axis,
SizeRequirements r) {
// calculate tiled request
float min = 0;
float pref = 0;
float max = 0;
int n = getViewCount();
for (int i = 0; i < n; i++) {
View v = getView(i);
min += v.getMinimumSpan(axis);
pref += v.getPreferredSpan(axis);
max += v.getMaximumSpan(axis);
}
if (r == null) {
r = new SizeRequirements();
}
r.alignment = 0.5f;
r.minimum = (int) min;
r.preferred = (int) pref;
r.maximum = (int) max;
return r;
} Calculates the size requirements for the major axis
axis. |
protected SizeRequirements calculateMinorAxisRequirements(int axis,
SizeRequirements r) {
int min = 0;
long pref = 0;
int max = Integer.MAX_VALUE;
int n = getViewCount();
for (int i = 0; i < n; i++) {
View v = getView(i);
min = Math.max((int) v.getMinimumSpan(axis), min);
pref = Math.max((int) v.getPreferredSpan(axis), pref);
max = Math.max((int) v.getMaximumSpan(axis), max);
}
if (r == null) {
r = new SizeRequirements();
r.alignment = 0.5f;
}
r.preferred = (int) pref;
r.minimum = min;
r.maximum = max;
return r;
} Calculates the size requirements for the minor axis
axis. |
void checkRequests(int axis) {
if ((axis != X_AXIS) && (axis != Y_AXIS)) {
throw new IllegalArgumentException("Invalid axis: " + axis);
}
if (axis == majorAxis) {
if (!majorReqValid) {
majorRequest = calculateMajorAxisRequirements(axis,
majorRequest);
majorReqValid = true;
}
} else if (! minorReqValid) {
minorRequest = calculateMinorAxisRequirements(axis, minorRequest);
minorReqValid = true;
}
} Checks the request cache and update if needed. |
protected void childAllocation(int index,
Rectangle alloc) {
alloc.x += getOffset(X_AXIS, index);
alloc.y += getOffset(Y_AXIS, index);
alloc.width = getSpan(X_AXIS, index);
alloc.height = getSpan(Y_AXIS, index);
} Allocates a region for a child view. |
protected boolean flipEastAndWestAtEnds(int position,
Bias bias) {
if(majorAxis == Y_AXIS) {
int testPos = (bias == Position.Bias.Backward) ?
Math.max(0, position - 1) : position;
int index = getViewIndexAtPosition(testPos);
if(index != -1) {
View v = getView(index);
if(v != null && v instanceof CompositeView) {
return ((CompositeView)v).flipEastAndWestAtEnds(position,
bias);
}
}
}
return false;
} Determines in which direction the next view lays.
Consider the View at index n. Typically the Views
are layed out from left to right, so that the View
to the EAST will be at index n + 1, and the View
to the WEST will be at index n - 1. In certain situations,
such as with bidirectional text, it is possible
that the View to EAST is not at index n + 1,
but rather at index n - 1, or that the View
to the WEST is not at index n - 1, but index n + 1.
In this case this method would return true,
indicating the Views are layed out in
descending order. Otherwise the method would return false
indicating the Views are layed out in ascending order.
If the receiver is laying its Views along the
Y_AXIS, this will will return the value from
invoking the same method on the View
responsible for rendering position and
bias. Otherwise this will return false. |
protected void forwardUpdate(ElementChange ec,
DocumentEvent e,
Shape a,
ViewFactory f) {
boolean wasValid = isLayoutValid(majorAxis);
super.forwardUpdate(ec, e, a, f);
// determine if a repaint is needed
if (wasValid && (! isLayoutValid(majorAxis))) {
// Repaint is needed because one of the tiled children
// have changed their span along the major axis. If there
// is a hosting component and an allocated shape we repaint.
Component c = getContainer();
if ((a != null) && (c != null)) {
int pos = e.getOffset();
int index = getViewIndexAtPosition(pos);
Rectangle alloc = getInsideAllocation(a);
if (majorAxis == X_AXIS) {
alloc.x += majorOffsets[index];
alloc.width -= majorOffsets[index];
} else {
alloc.y += minorOffsets[index];
alloc.height -= minorOffsets[index];
}
c.repaint(alloc.x, alloc.y, alloc.width, alloc.height);
}
}
} Forwards the given DocumentEvent to the child views
that need to be notified of the change to the model.
If a child changed its requirements and the allocation
was valid prior to forwarding the portion of the box
from the starting child to the end of the box will
be repainted. |
public float getAlignment(int axis) {
checkRequests(axis);
if (axis == majorAxis) {
return majorRequest.alignment;
} else {
return minorRequest.alignment;
}
} Determines the desired alignment for this view along an
axis. This is implemented to give the total alignment
needed to position the children with the alignment points
lined up along the axis orthoginal to the axis that is
being tiled. The axis being tiled will request to be
centered (i.e. 0.5f). |
public int getAxis() {
return majorAxis;
} Fetches the tile axis property. This is the axis along which
the child views are tiled. |
public Shape getChildAllocation(int index,
Shape a) {
if (a != null) {
Shape ca = super.getChildAllocation(index, a);
if ((ca != null) && (! isAllocationValid())) {
// The child allocation may not have been set yet.
Rectangle r = (ca instanceof Rectangle) ?
(Rectangle) ca : ca.getBounds();
if ((r.width == 0) && (r.height == 0)) {
return null;
}
}
return ca;
}
return null;
} Fetches the allocation for the given child view.
This enables finding out where various views
are located. This is implemented to return
null if the layout is invalid,
otherwise the superclass behavior is executed. |
public int getHeight() {
int span;
if (majorAxis == Y_AXIS) {
span = majorSpan;
} else {
span = minorSpan;
}
span += getTopInset() - getBottomInset();
return span;
} Returns the current height of the box. This is the height that
it was last allocated. |
public float getMaximumSpan(int axis) {
checkRequests(axis);
float marginSpan = (axis == X_AXIS) ? getLeftInset() + getRightInset() :
getTopInset() + getBottomInset();
if (axis == majorAxis) {
return ((float)majorRequest.maximum) + marginSpan;
} else {
return ((float)minorRequest.maximum) + marginSpan;
}
} Determines the maximum span for this view along an
axis. |
public float getMinimumSpan(int axis) {
checkRequests(axis);
float marginSpan = (axis == X_AXIS) ? getLeftInset() + getRightInset() :
getTopInset() + getBottomInset();
if (axis == majorAxis) {
return ((float)majorRequest.minimum) + marginSpan;
} else {
return ((float)minorRequest.minimum) + marginSpan;
}
} Determines the minimum span for this view along an
axis. |
protected int getOffset(int axis,
int childIndex) {
int[] offsets = (axis == majorAxis) ? majorOffsets : minorOffsets;
return offsets[childIndex];
} Fetches the offset of a particular child's current layout. |
public float getPreferredSpan(int axis) {
checkRequests(axis);
float marginSpan = (axis == X_AXIS) ? getLeftInset() + getRightInset() :
getTopInset() + getBottomInset();
if (axis == majorAxis) {
return ((float)majorRequest.preferred) + marginSpan;
} else {
return ((float)minorRequest.preferred) + marginSpan;
}
} Determines the preferred span for this view along an
axis. |
public int getResizeWeight(int axis) {
checkRequests(axis);
if (axis == majorAxis) {
if ((majorRequest.preferred != majorRequest.minimum) ||
(majorRequest.preferred != majorRequest.maximum)) {
return 1;
}
} else {
if ((minorRequest.preferred != minorRequest.minimum) ||
(minorRequest.preferred != minorRequest.maximum)) {
return 1;
}
}
return 0;
} Gets the resize weight. A value of 0 or less is not resizable. |
protected int getSpan(int axis,
int childIndex) {
int[] spans = (axis == majorAxis) ? majorSpans : minorSpans;
return spans[childIndex];
} Fetches the span of a particular childs current layout. |
float getSpanOnAxis(int axis) {
if (axis == majorAxis) {
return majorSpan;
} else {
return minorSpan;
}
} Returns the size of the view along an axis. This is implemented
to return zero. |
protected View getViewAtPoint(int x,
int y,
Rectangle alloc) {
int n = getViewCount();
if (majorAxis == View.X_AXIS) {
if (x < (alloc.x + majorOffsets[0])) {
childAllocation(0, alloc);
return getView(0);
}
for (int i = 0; i < n; i++) {
if (x < (alloc.x + majorOffsets[i])) {
childAllocation(i - 1, alloc);
return getView(i - 1);
}
}
childAllocation(n - 1, alloc);
return getView(n - 1);
} else {
if (y < (alloc.y + majorOffsets[0])) {
childAllocation(0, alloc);
return getView(0);
}
for (int i = 0; i < n; i++) {
if (y < (alloc.y + majorOffsets[i])) {
childAllocation(i - 1, alloc);
return getView(i - 1);
}
}
childAllocation(n - 1, alloc);
return getView(n - 1);
}
} Fetches the child view at the given coordinates. |
public int getWidth() {
int span;
if (majorAxis == X_AXIS) {
span = majorSpan;
} else {
span = minorSpan;
}
span += getLeftInset() - getRightInset();
return span;
} Returns the current width of the box. This is the width that
it was last allocated. |
protected boolean isAfter(int x,
int y,
Rectangle innerAlloc) {
if (majorAxis == View.X_AXIS) {
return (x > (innerAlloc.width + innerAlloc.x));
} else {
return (y > (innerAlloc.height + innerAlloc.y));
}
} Determines if a point falls after an allocated region. |
protected boolean isAllocationValid() {
return (majorAllocValid && minorAllocValid);
} Are the allocations for the children still
valid? |
protected boolean isBefore(int x,
int y,
Rectangle innerAlloc) {
if (majorAxis == View.X_AXIS) {
return (x < innerAlloc.x);
} else {
return (y < innerAlloc.y);
}
} Determines if a point falls before an allocated region. |
protected boolean isLayoutValid(int axis) {
if (axis == majorAxis) {
return majorAllocValid;
} else {
return minorAllocValid;
}
} Determines if the layout is valid along the given axis. |
protected void layout(int width,
int height) {
setSpanOnAxis(X_AXIS, width);
setSpanOnAxis(Y_AXIS, height);
} Perform layout on the box |
public void layoutChanged(int axis) {
if (axis == majorAxis) {
majorAllocValid = false;
} else {
minorAllocValid = false;
}
} Invalidates the layout along an axis. This happens
automatically if the preferences have changed for
any of the child views. In some cases the layout
may need to be recalculated when the preferences
have not changed. The layout can be marked as
invalid by calling this method. The layout will
be updated the next time the setSize method
is called on this view (typically in paint). |
protected void layoutMajorAxis(int targetSpan,
int axis,
int[] offsets,
int[] spans) {
/*
* first pass, calculate the preferred sizes
* and the flexibility to adjust the sizes.
*/
long preferred = 0;
int n = getViewCount();
for (int i = 0; i < n; i++) {
View v = getView(i);
spans[i] = (int) v.getPreferredSpan(axis);
preferred += spans[i];
}
/*
* Second pass, expand or contract by as much as possible to reach
* the target span.
*/
// determine the adjustment to be made
long desiredAdjustment = targetSpan - preferred;
float adjustmentFactor = 0.0f;
int[] diffs = null;
if (desiredAdjustment != 0) {
long totalSpan = 0;
diffs = new int[n];
for (int i = 0; i < n; i++) {
View v = getView(i);
int tmp;
if (desiredAdjustment < 0) {
tmp = (int)v.getMinimumSpan(axis);
diffs[i] = spans[i] - tmp;
} else {
tmp = (int)v.getMaximumSpan(axis);
diffs[i] = tmp - spans[i];
}
totalSpan += tmp;
}
float maximumAdjustment = Math.abs(totalSpan - preferred);
adjustmentFactor = desiredAdjustment / maximumAdjustment;
adjustmentFactor = Math.min(adjustmentFactor, 1.0f);
adjustmentFactor = Math.max(adjustmentFactor, -1.0f);
}
// make the adjustments
int totalOffset = 0;
for (int i = 0; i < n; i++) {
offsets[i] = totalOffset;
if (desiredAdjustment != 0) {
float adjF = adjustmentFactor * diffs[i];
spans[i] += Math.round(adjF);
}
totalOffset = (int) Math.min((long) totalOffset + (long) spans[i], Integer.MAX_VALUE);
}
} Performs layout for the major axis of the box (i.e. the
axis that it represents). The results of the layout (the
offset and span for each children) are placed in the given
arrays which represent the allocations to the children
along the major axis. |
protected void layoutMinorAxis(int targetSpan,
int axis,
int[] offsets,
int[] spans) {
int n = getViewCount();
for (int i = 0; i < n; i++) {
View v = getView(i);
int max = (int) v.getMaximumSpan(axis);
if (max < targetSpan) {
// can't make the child this wide, align it
float align = v.getAlignment(axis);
offsets[i] = (int) ((targetSpan - max) * align);
spans[i] = max;
} else {
// make it the target width, or as small as it can get.
int min = (int)v.getMinimumSpan(axis);
offsets[i] = 0;
spans[i] = Math.max(min, targetSpan);
}
}
} Performs layout for the minor axis of the box (i.e. the
axis orthoginal to the axis that it represents). The results
of the layout (the offset and span for each children) are
placed in the given arrays which represent the allocations to
the children along the minor axis. |
public Shape modelToView(int pos,
Shape a,
Bias b) throws BadLocationException {
if (! isAllocationValid()) {
Rectangle alloc = a.getBounds();
setSize(alloc.width, alloc.height);
}
return super.modelToView(pos, a, b);
} Provides a mapping from the document model coordinate space
to the coordinate space of the view mapped to it. This makes
sure the allocation is valid before calling the superclass. |
public void paint(Graphics g,
Shape allocation) {
Rectangle alloc = (allocation instanceof Rectangle) ?
(Rectangle)allocation : allocation.getBounds();
int n = getViewCount();
int x = alloc.x + getLeftInset();
int y = alloc.y + getTopInset();
Rectangle clip = g.getClipBounds();
for (int i = 0; i < n; i++) {
tempRect.x = x + getOffset(X_AXIS, i);
tempRect.y = y + getOffset(Y_AXIS, i);
tempRect.width = getSpan(X_AXIS, i);
tempRect.height = getSpan(Y_AXIS, i);
int trx0 = tempRect.x, trx1 = trx0 + tempRect.width;
int try0 = tempRect.y, try1 = try0 + tempRect.height;
int crx0 = clip.x, crx1 = crx0 + clip.width;
int cry0 = clip.y, cry1 = cry0 + clip.height;
// We should paint views that intersect with clipping region
// even if the intersection has no inside points (is a line).
// This is needed for supporting views that have zero width, like
// views that contain only combining marks.
if ((trx1 >= crx0) && (try1 >= cry0) && (crx1 >= trx0) && (cry1 >= try0)) {
paintChild(g, tempRect, i);
}
}
} Renders the BoxView using the given
rendering surface and area
on that surface. Only the children that intersect
the clip bounds of the given Graphics
will be rendered. |
protected void paintChild(Graphics g,
Rectangle alloc,
int index) {
View child = getView(index);
child.paint(g, alloc);
} Paints a child. By default
that is all it does, but a subclass can use this to paint
things relative to the child. |
public void preferenceChanged(View child,
boolean width,
boolean height) {
boolean majorChanged = (majorAxis == X_AXIS) ? width : height;
boolean minorChanged = (majorAxis == X_AXIS) ? height : width;
if (majorChanged) {
majorReqValid = false;
majorAllocValid = false;
}
if (minorChanged) {
minorReqValid = false;
minorAllocValid = false;
}
super.preferenceChanged(child, width, height);
} This is called by a child to indicate its
preferred span has changed. This is implemented to
throw away cached layout information so that new
calculations will be done the next time the children
need an allocation. |
public void replace(int index,
int length,
View[] elems) {
super.replace(index, length, elems);
// invalidate cache
int nInserted = (elems != null) ? elems.length : 0;
majorOffsets = updateLayoutArray(majorOffsets, index, nInserted);
majorSpans = updateLayoutArray(majorSpans, index, nInserted);
majorReqValid = false;
majorAllocValid = false;
minorOffsets = updateLayoutArray(minorOffsets, index, nInserted);
minorSpans = updateLayoutArray(minorSpans, index, nInserted);
minorReqValid = false;
minorAllocValid = false;
} Invalidates the layout and resizes the cache of
requests/allocations. The child allocations can still
be accessed for the old layout, but the new children
will have an offset and span of 0. |
public void setAxis(int axis) {
boolean axisChanged = (axis != majorAxis);
majorAxis = axis;
if (axisChanged) {
preferenceChanged(null, true, true);
}
} Sets the tile axis property. This is the axis along which
the child views are tiled. |
public void setSize(float width,
float height) {
layout(Math.max(0, (int)(width - getLeftInset() - getRightInset())),
Math.max(0, (int)(height - getTopInset() - getBottomInset())));
} Sets the size of the view. This should cause
layout of the view if the view caches any layout
information. This is implemented to call the
layout method with the sizes inside of the insets. |
void setSpanOnAxis(int axis,
float span) {
if (axis == majorAxis) {
if (majorSpan != (int) span) {
majorAllocValid = false;
}
if (! majorAllocValid) {
// layout the major axis
majorSpan = (int) span;
checkRequests(majorAxis);
layoutMajorAxis(majorSpan, axis, majorOffsets, majorSpans);
majorAllocValid = true;
// flush changes to the children
updateChildSizes();
}
} else {
if (((int) span) != minorSpan) {
minorAllocValid = false;
}
if (! minorAllocValid) {
// layout the minor axis
minorSpan = (int) span;
checkRequests(axis);
layoutMinorAxis(minorSpan, axis, minorOffsets, minorSpans);
minorAllocValid = true;
// flush changes to the children
updateChildSizes();
}
}
} Sets the size of the view along an axis. This should cause
layout of the view along the given axis. |
void updateChildSizes() {
int n = getViewCount();
if (majorAxis == X_AXIS) {
for (int i = 0; i < n; i++) {
View v = getView(i);
v.setSize((float) majorSpans[i], (float) minorSpans[i]);
}
} else {
for (int i = 0; i < n; i++) {
View v = getView(i);
v.setSize((float) minorSpans[i], (float) majorSpans[i]);
}
}
} Propagates the current allocations to the child views. |
int[] updateLayoutArray(int[] oldArray,
int offset,
int nInserted) {
int n = getViewCount();
int[] newArray = new int[n];
System.arraycopy(oldArray, 0, newArray, 0, offset);
System.arraycopy(oldArray, offset,
newArray, offset + nInserted, n - nInserted - offset);
return newArray;
} Resizes the given layout array to match the new number of
child views. The current number of child views are used to
produce the new array. The contents of the old array are
inserted into the new array at the appropriate places so that
the old layout information is transferred to the new array. |
public int viewToModel(float x,
float y,
Shape a,
Bias[] bias) {
if (! isAllocationValid()) {
Rectangle alloc = a.getBounds();
setSize(alloc.width, alloc.height);
}
return super.viewToModel(x, y, a, bias);
} Provides a mapping from the view coordinate space to the logical
coordinate space of the model. |
javax.swing.text.View