/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Eclipse Public License, Version 1.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.eclipse.org/org/documents/epl-v10.php
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.ide.common.layout.relative;
import static com.android.ide.common.api.DrawingStyle.DEPENDENCY;
import static com.android.ide.common.api.DrawingStyle.GUIDELINE;
import static com.android.ide.common.api.DrawingStyle.GUIDELINE_DASHED;
import static com.android.ide.common.api.SegmentType.BASELINE;
import static com.android.ide.common.api.SegmentType.BOTTOM;
import static com.android.ide.common.api.SegmentType.CENTER_HORIZONTAL;
import static com.android.ide.common.api.SegmentType.CENTER_VERTICAL;
import static com.android.ide.common.api.SegmentType.LEFT;
import static com.android.ide.common.api.SegmentType.RIGHT;
import static com.android.ide.common.api.SegmentType.TOP;
import static com.android.ide.common.api.SegmentType.UNKNOWN;
import static com.android.ide.common.layout.relative.ConstraintType.ALIGN_BASELINE;
import static com.android.ide.common.layout.relative.ConstraintType.ALIGN_BOTTOM;
import static com.android.ide.common.layout.relative.ConstraintType.LAYOUT_ABOVE;
import static com.android.ide.common.layout.relative.ConstraintType.LAYOUT_BELOW;
import static com.android.ide.common.layout.relative.ConstraintType.LAYOUT_LEFT_OF;
import static com.android.ide.common.layout.relative.ConstraintType.LAYOUT_RIGHT_OF;
import com.android.ide.common.api.DrawingStyle;
import com.android.ide.common.api.IGraphics;
import com.android.ide.common.api.INode;
import com.android.ide.common.api.Margins;
import com.android.ide.common.api.Rect;
import com.android.ide.common.api.SegmentType;
import com.android.ide.common.layout.relative.DependencyGraph.Constraint;
import com.android.ide.common.layout.relative.DependencyGraph.ViewData;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
/**
* The {@link ConstraintPainter} is responsible for painting relative layout constraints -
* such as a source node having its top edge constrained to a target node with a given margin.
* This painter is used both to show static constraints, as well as visualizing proposed
* constraints during a move or resize operation.
*/
public class ConstraintPainter {
/** The size of the arrow head */
private static final int ARROW_SIZE = 5;
/** Size (height for horizontal, and width for vertical) parent feedback rectangles */
private static final int PARENT_RECT_SIZE = 12;
/**
* Paints a given match as a constraint.
*
* @param graphics the graphics context
* @param sourceBounds the source bounds
* @param match the match
*/
static void paintConstraint(IGraphics graphics, Rect sourceBounds, Match match) {
Rect targetBounds = match.edge.node.getBounds();
ConstraintType type = match.type;
assert type != null;
paintConstraint(graphics, type, match.with.node, sourceBounds, match.edge.node,
targetBounds, null /* allConstraints */, true /* highlightTargetEdge */);
}
/**
* Paints a constraint.
* <p>
* TODO: when there are multiple links originating in the same direction from
* center, maybe offset them slightly from each other?
*
* @param graphics the graphics context to draw into
* @param constraint The constraint to be drawn
*/
private static void paintConstraint(IGraphics graphics, Constraint constraint,
Set<Constraint> allConstraints) {
ViewData source = constraint.from;
ViewData target = constraint.to;
INode sourceNode = source.node;
INode targetNode = target.node;
if (sourceNode == targetNode) {
// Self reference - don't visualize
return;
}
Rect sourceBounds = sourceNode.getBounds();
Rect targetBounds = targetNode.getBounds();
paintConstraint(graphics, constraint.type, sourceNode, sourceBounds, targetNode,
targetBounds, allConstraints, false /* highlightTargetEdge */);
}
/**
* Paint selection feedback by painting constraints for the selected nodes
*
* @param graphics the graphics context
* @param parentNode the parent relative layout
* @param childNodes the nodes whose constraints should be painted
* @param showDependents whether incoming constraints should be shown as well
*/
public static void paintSelectionFeedback(IGraphics graphics, INode parentNode,
List<? extends INode> childNodes, boolean showDependents) {
DependencyGraph dependencyGraph = new DependencyGraph(parentNode);
Set<INode> horizontalDeps = dependencyGraph.dependsOn(childNodes, false /* vertical */);
Set<INode> verticalDeps = dependencyGraph.dependsOn(childNodes, true /* vertical */);
Set<INode> deps = new HashSet<INode>(horizontalDeps.size() + verticalDeps.size());
deps.addAll(horizontalDeps);
deps.addAll(verticalDeps);
if (deps.size() > 0) {
graphics.useStyle(DEPENDENCY);
for (INode node : deps) {
// Don't highlight the selected nodes themselves
if (childNodes.contains(node)) {
continue;
}
Rect bounds = node.getBounds();
graphics.fillRect(bounds);
}
}
graphics.useStyle(GUIDELINE);
for (INode childNode : childNodes) {
ViewData view = dependencyGraph.getView(childNode);
if (view == null) {
continue;
}
// Paint all incoming constraints
if (showDependents) {
paintConstraints(graphics, view.dependedOnBy);
}
// Paint all outgoing constraints
paintConstraints(graphics, view.dependsOn);
}
}
/**
* Paints a set of constraints.
*/
private static void paintConstraints(IGraphics graphics, List<Constraint> constraints) {
Set<Constraint> mutableConstraintSet = new HashSet<Constraint>(constraints);
// WORKAROUND! Hide alignBottom attachments if we also have a alignBaseline
// constraint; this is because we also *add* alignBottom attachments when you add
// alignBaseline constraints to work around a surprising behavior of baseline
// constraints.
for (Constraint constraint : constraints) {
if (constraint.type == ALIGN_BASELINE) {
// Remove any baseline
for (Constraint c : constraints) {
if (c.type == ALIGN_BOTTOM && c.to.node == constraint.to.node) {
mutableConstraintSet.remove(c);
}
}
}
}
for (Constraint constraint : constraints) {
// paintConstraint can digest more than one constraint, so we need to keep
// checking to see if the given constraint is still relevant.
if (mutableConstraintSet.contains(constraint)) {
paintConstraint(graphics, constraint, mutableConstraintSet);
}
}
}
/**
* Paints a constraint of the given type from the given source node, to the
* given target node, with the specified bounds.
*/
private static void paintConstraint(IGraphics graphics, ConstraintType type, INode sourceNode,
Rect sourceBounds, INode targetNode, Rect targetBounds,
Set<Constraint> allConstraints, boolean highlightTargetEdge) {
SegmentType sourceSegmentTypeX = type.sourceSegmentTypeX;
SegmentType sourceSegmentTypeY = type.sourceSegmentTypeY;
SegmentType targetSegmentTypeX = type.targetSegmentTypeX;
SegmentType targetSegmentTypeY = type.targetSegmentTypeY;
// Horizontal center constraint?
if (sourceSegmentTypeX == CENTER_VERTICAL && targetSegmentTypeX == CENTER_VERTICAL) {
paintHorizontalCenterConstraint(graphics, sourceBounds, targetBounds);
return;
}
// Vertical center constraint?
if (sourceSegmentTypeY == CENTER_HORIZONTAL && targetSegmentTypeY == CENTER_HORIZONTAL) {
paintVerticalCenterConstraint(graphics, sourceBounds, targetBounds);
return;
}
// Corner constraint?
if (allConstraints != null
&& (type == LAYOUT_ABOVE || type == LAYOUT_BELOW
|| type == LAYOUT_LEFT_OF || type == LAYOUT_RIGHT_OF)) {
if (paintCornerConstraint(graphics, type, sourceNode, sourceBounds, targetNode,
targetBounds, allConstraints)) {
return;
}
}
// Vertical constraint?
if (sourceSegmentTypeX == UNKNOWN) {
paintVerticalConstraint(graphics, type, sourceNode, sourceBounds, targetNode,
targetBounds, highlightTargetEdge);
return;
}
// Horizontal constraint?
if (sourceSegmentTypeY == UNKNOWN) {
paintHorizontalConstraint(graphics, type, sourceNode, sourceBounds, targetNode,
targetBounds, highlightTargetEdge);
return;
}
// This shouldn't happen - it means we have a constraint that defines all sides
// and is not a centering constraint
assert false;
}
/**
* Paints a corner constraint, or returns false if this constraint is not a corner.
* A corner is one where there are two constraints from this source node to the
* same target node, one horizontal and one vertical, to the closest edges on
* the target node.
* <p>
* Corners are a common occurrence. If we treat the horizontal and vertical
* constraints separately (below & toRightOf), then we end up with a lot of
* extra lines and arrows -- e.g. two shared edges and arrows pointing to these
* shared edges:
*
* <pre>
* +--------+ |
* | Target -->
* +----|---+ |
* v
* - - - - - -|- - - - - -
* ^
* | +---|----+
* <-- Source |
* | +--------+
*
* Instead, we can simply draw a diagonal arrow here to represent BOTH constraints and
* reduce clutter:
*
* +---------+
* | Target _|
* +-------|\+
* \
* \--------+
* | Source |
* +--------+
* </pre>
*
* @param graphics the graphics context to draw
* @param type the constraint to be drawn
* @param sourceNode the source node
* @param sourceBounds the bounds of the source node
* @param targetNode the target node
* @param targetBounds the bounds of the target node
* @param allConstraints the set of all constraints; if a corner is found and painted the
* matching corner constraint is removed from the set
* @return true if the constraint was handled and painted as a corner, false otherwise
*/
private static boolean paintCornerConstraint(IGraphics graphics, ConstraintType type,
INode sourceNode, Rect sourceBounds, INode targetNode, Rect targetBounds,
Set<Constraint> allConstraints) {
SegmentType sourceSegmentTypeX = type.sourceSegmentTypeX;
SegmentType sourceSegmentTypeY = type.sourceSegmentTypeY;
SegmentType targetSegmentTypeX = type.targetSegmentTypeX;
SegmentType targetSegmentTypeY = type.targetSegmentTypeY;
ConstraintType opposite1 = null, opposite2 = null;
switch (type) {
case LAYOUT_BELOW:
case LAYOUT_ABOVE:
opposite1 = LAYOUT_LEFT_OF;
opposite2 = LAYOUT_RIGHT_OF;
break;
case LAYOUT_LEFT_OF:
case LAYOUT_RIGHT_OF:
opposite1 = LAYOUT_ABOVE;
opposite2 = LAYOUT_BELOW;
break;
default:
return false;
}
Constraint pair = null;
for (Constraint constraint : allConstraints) {
if ((constraint.type == opposite1 || constraint.type == opposite2) &&
constraint.to.node == targetNode && constraint.from.node == sourceNode) {
pair = constraint;
break;
}
}
// TODO -- ensure that the nodes are adjacent! In other words, that
// their bounds are within N pixels.
if (pair != null) {
// Visualize the corner constraint
if (sourceSegmentTypeX == UNKNOWN) {
sourceSegmentTypeX = pair.type.sourceSegmentTypeX;
}
if (sourceSegmentTypeY == UNKNOWN) {
sourceSegmentTypeY = pair.type.sourceSegmentTypeY;
}
if (targetSegmentTypeX == UNKNOWN) {
targetSegmentTypeX = pair.type.targetSegmentTypeX;
}
if (targetSegmentTypeY == UNKNOWN) {
targetSegmentTypeY = pair.type.targetSegmentTypeY;
}
int x1, y1, x2, y2;
if (sourceSegmentTypeX == LEFT) {
x1 = sourceBounds.x + 1 * sourceBounds.w / 4;
} else {
x1 = sourceBounds.x + 3 * sourceBounds.w / 4;
}
if (sourceSegmentTypeY == TOP) {
y1 = sourceBounds.y + 1 * sourceBounds.h / 4;
} else {
y1 = sourceBounds.y + 3 * sourceBounds.h / 4;
}
if (targetSegmentTypeX == LEFT) {
x2 = targetBounds.x + 1 * targetBounds.w / 4;
} else {
x2 = targetBounds.x + 3 * targetBounds.w / 4;
}
if (targetSegmentTypeY == TOP) {
y2 = targetBounds.y + 1 * targetBounds.h / 4;
} else {
y2 = targetBounds.y + 3 * targetBounds.h / 4;
}
graphics.useStyle(GUIDELINE);
graphics.drawArrow(x1, y1, x2, y2, ARROW_SIZE);
// Don't process this constraint on its own later.
allConstraints.remove(pair);
return true;
}
return false;
}
/**
* Paints a vertical constraint, handling the various scenarios where there are
* margins, or where the two nodes overlap horizontally and where they don't, etc.
* <p>
* Here's an example of what will be shown for a "below" constraint where the
* nodes do not overlap horizontally and the target node has a bottom margin:
* <pre>
* +--------+
* | Target |
* +--------+
* |
* v
* - - - - - - - - - - - - - -
* ^
* |
* +--------+
* | Source |
* +--------+
* </pre>
*/
private static void paintVerticalConstraint(IGraphics graphics, ConstraintType type,
INode sourceNode, Rect sourceBounds, INode targetNode, Rect targetBounds,
boolean highlightTargetEdge) {
SegmentType sourceSegmentTypeY = type.sourceSegmentTypeY;
SegmentType targetSegmentTypeY = type.targetSegmentTypeY;
Margins targetMargins = targetNode.getMargins();
assert sourceSegmentTypeY != UNKNOWN;
assert targetBounds != null;
int sourceY = sourceSegmentTypeY.getY(sourceNode, sourceBounds);
int targetY = targetSegmentTypeY ==
UNKNOWN ? sourceY : targetSegmentTypeY.getY(targetNode, targetBounds);
if (highlightTargetEdge && type.isRelativeToParentEdge()) {
graphics.useStyle(DrawingStyle.DROP_ZONE_ACTIVE);
graphics.fillRect(targetBounds.x, targetY - PARENT_RECT_SIZE / 2,
targetBounds.x2(), targetY + PARENT_RECT_SIZE / 2);
}
// First see if the two views overlap horizontally. If so, we can just draw a direct
// arrow from the source up to (or down to) the target.
//
// +--------+
// | Target |
// +--------+
// ^
// |
// |
// +--------+
// | Source |
// +--------+
//
int maxLeft = Math.max(sourceBounds.x, targetBounds.x);
int minRight = Math.min(sourceBounds.x2(), targetBounds.x2());
int center = (maxLeft + minRight) / 2;
if (center > sourceBounds.x && center < sourceBounds.x2()) {
// Yes, the lines overlap -- just draw a straight arrow
//
//
// If however there is a margin on the target edge, it should be drawn like this:
//
// +--------+
// | Target |
// +--------+
// |
// |
// v
// - - - - - - -
// ^
// |
// |
// +--------+
// | Source |
// +--------+
//
// Use a minimum threshold for this visualization since it doesn't look good
// for small margins
if (targetSegmentTypeY == BOTTOM && targetMargins.bottom > 5) {
int sharedY = targetY + targetMargins.bottom;
if (sourceY > sharedY + 2) { // Skip when source falls on the margin line
graphics.useStyle(GUIDELINE_DASHED);
graphics.drawLine(targetBounds.x, sharedY, targetBounds.x2(), sharedY);
graphics.useStyle(GUIDELINE);
graphics.drawArrow(center, sourceY, center, sharedY + 2, ARROW_SIZE);
graphics.drawArrow(center, targetY, center, sharedY - 3, ARROW_SIZE);
} else {
graphics.useStyle(GUIDELINE);
// Draw reverse arrow to make it clear the node is as close
// at it can be
graphics.drawArrow(center, targetY, center, sourceY, ARROW_SIZE);
}
return;
} else if (targetSegmentTypeY == TOP && targetMargins.top > 5) {
int sharedY = targetY - targetMargins.top;
if (sourceY < sharedY - 2) {
graphics.useStyle(GUIDELINE_DASHED);
graphics.drawLine(targetBounds.x, sharedY, targetBounds.x2(), sharedY);
graphics.useStyle(GUIDELINE);
graphics.drawArrow(center, sourceY, center, sharedY - 3, ARROW_SIZE);
graphics.drawArrow(center, targetY, center, sharedY + 3, ARROW_SIZE);
} else {
graphics.useStyle(GUIDELINE);
graphics.drawArrow(center, targetY, center, sourceY, ARROW_SIZE);
}
return;
}
// TODO: If the center falls smack in the center of the sourceBounds,
// AND the source node is part of the selection, then adjust the
// center location such that it is off to the side, let's say 1/4 or 3/4 of
// the overlap region, to ensure that it does not overlap the center selection
// handle
// When the constraint is for two immediately adjacent edges, we
// need to make some adjustments to make sure the arrow points in the right
// direction
if (sourceY == targetY) {
if (sourceSegmentTypeY == BOTTOM || sourceSegmentTypeY == BASELINE) {
sourceY -= 2 * ARROW_SIZE;
} else if (sourceSegmentTypeY == TOP) {
sourceY += 2 * ARROW_SIZE;
} else {
assert sourceSegmentTypeY == CENTER_HORIZONTAL : sourceSegmentTypeY;
sourceY += sourceBounds.h / 2 - 2 * ARROW_SIZE;
}
} else if (sourceSegmentTypeY == BASELINE) {
sourceY = targetY - 2 * ARROW_SIZE;
}
// Center the vertical line in the overlap region
graphics.useStyle(GUIDELINE);
graphics.drawArrow(center, sourceY, center, targetY, ARROW_SIZE);
return;
}
// If there is no horizontal overlap in the vertical constraints, then we
// will show the attachment relative to a dashed line that extends beyond
// the target bounds, like this:
//
// +--------+
// | Target |
// +--------+ - - - - - - - - -
// ^
// |
// +--------+
// | Source |
// +--------+
//
// However, if the target node has a vertical margin, we may need to offset
// the line:
//
// +--------+
// | Target |
// +--------+
// |
// v
// - - - - - - - - - - - - - -
// ^
// |
// +--------+
// | Source |
// +--------+
//
// If not, we'll need to indicate a shared edge. This is the edge that separate
// them (but this will require me to evaluate margins!)
// Compute overlap region and pick the middle
int sharedY = targetSegmentTypeY ==
UNKNOWN ? sourceY : targetSegmentTypeY.getY(targetNode, targetBounds);
if (type.relativeToMargin) {
if (targetSegmentTypeY == TOP) {
sharedY -= targetMargins.top;
} else if (targetSegmentTypeY == BOTTOM) {
sharedY += targetMargins.bottom;
}
}
int startX;
int endX;
if (center <= sourceBounds.x) {
startX = targetBounds.x + targetBounds.w / 4;
endX = sourceBounds.x2();
} else {
assert (center >= sourceBounds.x2());
startX = sourceBounds.x;
endX = targetBounds.x + 3 * targetBounds.w / 4;
}
// Must draw segmented line instead
// Place the arrow 1/4 instead of 1/2 in the source to avoid overlapping with the
// selection handles
graphics.useStyle(GUIDELINE_DASHED);
graphics.drawLine(startX, sharedY, endX, sharedY);
// Adjust position of source arrow such that it does not sit across edge; it
// should point directly at the edge
if (Math.abs(sharedY - sourceY) < 2 * ARROW_SIZE) {
if (sourceSegmentTypeY == BASELINE) {
sourceY = sharedY - 2 * ARROW_SIZE;
} else if (sourceSegmentTypeY == TOP) {
sharedY = sourceY;
sourceY = sharedY + 2 * ARROW_SIZE;
} else {
sharedY = sourceY;
sourceY = sharedY - 2 * ARROW_SIZE;
}
}
graphics.useStyle(GUIDELINE);
// Draw the line from the source anchor to the shared edge
int x = sourceBounds.x + ((sourceSegmentTypeY == BASELINE) ?
sourceBounds.w / 2 : sourceBounds.w / 4);
graphics.drawArrow(x, sourceY, x, sharedY, ARROW_SIZE);
// Draw the line from the target to the horizontal shared edge
int tx = targetBounds.centerX();
if (targetSegmentTypeY == TOP) {
int ty = targetBounds.y;
int margin = targetMargins.top;
if (margin == 0 || !type.relativeToMargin) {
graphics.drawArrow(tx, ty + 2 * ARROW_SIZE, tx, ty, ARROW_SIZE);
} else {
graphics.drawArrow(tx, ty, tx, ty - margin, ARROW_SIZE);
}
} else if (targetSegmentTypeY == BOTTOM) {
int ty = targetBounds.y2();
int margin = targetMargins.bottom;
if (margin == 0 || !type.relativeToMargin) {
graphics.drawArrow(tx, ty - 2 * ARROW_SIZE, tx, ty, ARROW_SIZE);
} else {
graphics.drawArrow(tx, ty, tx, ty + margin, ARROW_SIZE);
}
} else {
assert targetSegmentTypeY == BASELINE : targetSegmentTypeY;
int ty = targetSegmentTypeY.getY(targetNode, targetBounds);
graphics.drawArrow(tx, ty - 2 * ARROW_SIZE, tx, ty, ARROW_SIZE);
}
return;
}
/**
* Paints a horizontal constraint, handling the various scenarios where there are margins,
* or where the two nodes overlap horizontally and where they don't, etc.
*/
private static void paintHorizontalConstraint(IGraphics graphics, ConstraintType type,
INode sourceNode, Rect sourceBounds, INode targetNode, Rect targetBounds,
boolean highlightTargetEdge) {
SegmentType sourceSegmentTypeX = type.sourceSegmentTypeX;
SegmentType targetSegmentTypeX = type.targetSegmentTypeX;
Margins targetMargins = targetNode.getMargins();
assert sourceSegmentTypeX != UNKNOWN;
assert targetBounds != null;
// See paintVerticalConstraint for explanations of the various cases.
int sourceX = sourceSegmentTypeX.getX(sourceNode, sourceBounds);
int targetX = targetSegmentTypeX == UNKNOWN ?
sourceX : targetSegmentTypeX.getX(targetNode, targetBounds);
if (highlightTargetEdge && type.isRelativeToParentEdge()) {
graphics.useStyle(DrawingStyle.DROP_ZONE_ACTIVE);
graphics.fillRect(targetX - PARENT_RECT_SIZE / 2, targetBounds.y,
targetX + PARENT_RECT_SIZE / 2, targetBounds.y2());
}
int maxTop = Math.max(sourceBounds.y, targetBounds.y);
int minBottom = Math.min(sourceBounds.y2(), targetBounds.y2());
// First see if the two views overlap vertically. If so, we can just draw a direct
// arrow from the source over to the target.
int center = (maxTop + minBottom) / 2;
if (center > sourceBounds.y && center < sourceBounds.y2()) {
// See if we should draw a margin line
if (targetSegmentTypeX == RIGHT && targetMargins.right > 5) {
int sharedX = targetX + targetMargins.right;
if (sourceX > sharedX + 2) { // Skip when source falls on the margin line
graphics.useStyle(GUIDELINE_DASHED);
graphics.drawLine(sharedX, targetBounds.y, sharedX, targetBounds.y2());
graphics.useStyle(GUIDELINE);
graphics.drawArrow(sourceX, center, sharedX + 2, center, ARROW_SIZE);
graphics.drawArrow(targetX, center, sharedX - 3, center, ARROW_SIZE);
} else {
graphics.useStyle(GUIDELINE);
// Draw reverse arrow to make it clear the node is as close
// at it can be
graphics.drawArrow(targetX, center, sourceX, center, ARROW_SIZE);
}
return;
} else if (targetSegmentTypeX == LEFT && targetMargins.left > 5) {
int sharedX = targetX - targetMargins.left;
if (sourceX < sharedX - 2) {
graphics.useStyle(GUIDELINE_DASHED);
graphics.drawLine(sharedX, targetBounds.y, sharedX, targetBounds.y2());
graphics.useStyle(GUIDELINE);
graphics.drawArrow(sourceX, center, sharedX - 3, center, ARROW_SIZE);
graphics.drawArrow(targetX, center, sharedX + 3, center, ARROW_SIZE);
} else {
graphics.useStyle(GUIDELINE);
graphics.drawArrow(targetX, center, sourceX, center, ARROW_SIZE);
}
return;
}
if (sourceX == targetX) {
if (sourceSegmentTypeX == RIGHT) {
sourceX -= 2 * ARROW_SIZE;
} else if (sourceSegmentTypeX == LEFT ) {
sourceX += 2 * ARROW_SIZE;
} else {
assert sourceSegmentTypeX == CENTER_VERTICAL : sourceSegmentTypeX;
sourceX += sourceBounds.w / 2 - 2 * ARROW_SIZE;
}
}
graphics.useStyle(GUIDELINE);
graphics.drawArrow(sourceX, center, targetX, center, ARROW_SIZE);
return;
}
// Segment line
// Compute overlap region and pick the middle
int sharedX = targetSegmentTypeX == UNKNOWN ?
sourceX : targetSegmentTypeX.getX(targetNode, targetBounds);
if (type.relativeToMargin) {
if (targetSegmentTypeX == LEFT) {
sharedX -= targetMargins.left;
} else if (targetSegmentTypeX == RIGHT) {
sharedX += targetMargins.right;
}
}
int startY, endY;
if (center <= sourceBounds.y) {
startY = targetBounds.y + targetBounds.h / 4;
endY = sourceBounds.y2();
} else {
assert (center >= sourceBounds.y2());
startY = sourceBounds.y;
endY = targetBounds.y + 3 * targetBounds.h / 2;
}
// Must draw segmented line instead
// Place at 1/4 instead of 1/2 to avoid overlapping with selection handles
int y = sourceBounds.y + sourceBounds.h / 4;
graphics.useStyle(GUIDELINE_DASHED);
graphics.drawLine(sharedX, startY, sharedX, endY);
// Adjust position of source arrow such that it does not sit across edge; it
// should point directly at the edge
if (Math.abs(sharedX - sourceX) < 2 * ARROW_SIZE) {
if (sourceSegmentTypeX == LEFT) {
sharedX = sourceX;
sourceX = sharedX + 2 * ARROW_SIZE;
} else {
sharedX = sourceX;
sourceX = sharedX - 2 * ARROW_SIZE;
}
}
graphics.useStyle(GUIDELINE);
// Draw the line from the source anchor to the shared edge
graphics.drawArrow(sourceX, y, sharedX, y, ARROW_SIZE);
// Draw the line from the target to the horizontal shared edge
int ty = targetBounds.centerY();
if (targetSegmentTypeX == LEFT) {
int tx = targetBounds.x;
int margin = targetMargins.left;
if (margin == 0 || !type.relativeToMargin) {
graphics.drawArrow(tx + 2 * ARROW_SIZE, ty, tx, ty, ARROW_SIZE);
} else {
graphics.drawArrow(tx, ty, tx - margin, ty, ARROW_SIZE);
}
} else {
assert targetSegmentTypeX == RIGHT;
int tx = targetBounds.x2();
int margin = targetMargins.right;
if (margin == 0 || !type.relativeToMargin) {
graphics.drawArrow(tx - 2 * ARROW_SIZE, ty, tx, ty, ARROW_SIZE);
} else {
graphics.drawArrow(tx, ty, tx + margin, ty, ARROW_SIZE);
}
}
return;
}
/**
* Paints a vertical center constraint. The constraint is shown as a dashed line
* through the vertical view, and a solid line over the node bounds.
*/
private static void paintVerticalCenterConstraint(IGraphics graphics, Rect sourceBounds,
Rect targetBounds) {
graphics.useStyle(GUIDELINE_DASHED);
graphics.drawLine(targetBounds.x, targetBounds.centerY(),
targetBounds.x2(), targetBounds.centerY());
graphics.useStyle(GUIDELINE);
graphics.drawLine(sourceBounds.x, sourceBounds.centerY(),
sourceBounds.x2(), sourceBounds.centerY());
}
/**
* Paints a horizontal center constraint. The constraint is shown as a dashed line
* through the horizontal view, and a solid line over the node bounds.
*/
private static void paintHorizontalCenterConstraint(IGraphics graphics, Rect sourceBounds,
Rect targetBounds) {
graphics.useStyle(GUIDELINE_DASHED);
graphics.drawLine(targetBounds.centerX(), targetBounds.y,
targetBounds.centerX(), targetBounds.y2());
graphics.useStyle(GUIDELINE);
graphics.drawLine(sourceBounds.centerX(), sourceBounds.y,
sourceBounds.centerX(), sourceBounds.y2());
}
}