/**
* Draws a double headed arrow with arrow heads of a given width and height.
*
* @param aG the canvas to draw on;
* @param aX1 the starting X position of the arrow;
* @param aY1 the starting Y position of the arrow;
* @param aX2 the ending X position of the arrow;
* @param aY2 the ending Y position of the arrow;
* @param aArrowWidth the total width of the arrow head;
* @param aArrowHeight the total height of the arrow head.
*/
public static final void drawDoubleHeadedArrow(
final Graphics aG,
final int aX1,
final int aY1,
final int aX2,
final int aY2,
final int aArrowWidth,
final int aArrowHeight) {
final Graphics2D g2d = (Graphics2D) aG.create();
final int lineWidth = Math.abs(aX2 - aX1);
final int threshold = (2 * aArrowWidth) + 2;
try {
int x1 = aX1;
int x2 = aX2;
if (lineWidth > threshold) {
drawArrowHead(g2d, aX1, aY1, LEFT_FACING, aArrowWidth, aArrowHeight);
// why x2 needs to be shifted by one pixel is beyond me...
drawArrowHead(g2d, aX2 + 1, aY2, RIGHT_FACING, aArrowWidth, aArrowHeight);
x1 += aArrowWidth - 1;
x2 -= aArrowWidth + 1;
}
g2d.drawLine(x1, aY1, x2, aY2);
} finally {
g2d.dispose();
}
}
/**
* Draws a single arrow head
*
* @param aG the canvas to draw on;
* @param aXpos the X position of the arrow head;
* @param aYpos the (center) Y position of the arrow head;
* @param aFactor +1 to have a left-facing arrow head, -1 to have a right-facing arrow head;
* @param aArrowWidth the total width of the arrow head;
* @param aArrowHeight the total height of the arrow head.
*/
public static final void drawArrowHead(
final Graphics2D aG,
final int aXpos,
final int aYpos,
final int aFactor,
final int aArrowWidth,
final int aArrowHeight) {
final double halfHeight = aArrowHeight / 2.0;
final int x1 = aXpos + (aFactor * aArrowWidth);
final int y1 = (int) Math.ceil(aYpos - halfHeight);
final int y2 = (int) Math.floor(aYpos + halfHeight);
final Polygon arrowHead = new Polygon();
arrowHead.addPoint(aXpos, aYpos);
arrowHead.addPoint(x1, y1);
arrowHead.addPoint(x1, y2);
aG.fill(arrowHead);
}