SCViewer/plugins/com.minres.scviewer.databas.../src/com/minres/scviewer/database/ui/swt/sb/ComponentDistribution.java

105 lines
3.6 KiB
Java

package com.minres.scviewer.database.ui.swt.sb;
import static java.lang.Math.max;
import java.math.BigDecimal;
import java.math.RoundingMode;
class ComponentDistribution {
private static final int MIN_DRAG_LENGTH = 17;
final int upFastLength;
final int dragStart;
final int dragLength;
final int downFastStart;
final int downFastLength;
final int downStart;
final int buttonLen;
ComponentDistribution( int buttonLen, int len, int range, int pos, int thumb ) {
int slideLen = slideLen( buttonLen, len );
int relDragLen = relDragLen( slideLen, range, thumb );
int minDragLength = max( MIN_DRAG_LENGTH, buttonLen );
int interval = interval( range, relDragLen, minDragLength );
this.dragLength = dragLen( minDragLength, relDragLen );
this.upFastLength = upFastLen( minDragLength, interval, pos, slideLen, relDragLen, dragLength );
this.downStart = downStart( buttonLen, len );
this.downFastStart = downFastStart( buttonLen, upFastLength, dragLength );
this.dragStart = dragStart( buttonLen, upFastLength );
this.downFastLength = downFastLen( minDragLength, interval, pos, slideLen, relDragLen, dragLength, upFastLength );
this.buttonLen = buttonLen;
}
private static int slideLen( int buttonLen, int len ) {
return len - buttonLen * 2;
}
private static int relDragLen( int slideLen, int range, int thumb ) {
return divide( slideLen * thumb, range );
}
private static int interval( int range, int relDragLen, int minDragLength ) {
int result = range;
if( useMinDragLen( minDragLength, relDragLen ) ) {
result += minDragLength - relDragLen / 2;
}
return result;
}
private static int dragLen( int buttonLen, int relDragLen ) {
return max( relDragLen, buttonLen );
}
private static int upFastLen( int buttonLen, int range, int pos, int slideLen, int relDragLen, int dragLen ) {
int result = slideLen * pos / range;
if( useMinDragLen( buttonLen, relDragLen ) ) {
result -= divide( ( dragLen - relDragLen ) * pos, range );
}
return result;
}
private static int downStart( int buttonLen, int len ) {
return len - buttonLen;
}
private static int downFastStart( int buttonLen, int upFastLength, int dragLength ) {
return buttonLen + upFastLength + dragLength;
}
private static int dragStart( int buttonLen, int upFastLen ) {
return buttonLen + upFastLen;
}
private static int downFastLen(
int buttonLen, int range, int pos, int slideLen, int relDragLen, int dragLen, int upFastLen )
{
int result = divide( slideLen * ( range - pos ), range ) - dragLen;
if( useMinDragLen( buttonLen, relDragLen ) ) {
result += divide( ( dragLen - relDragLen ) * pos, range );
}
return adjustDownFastLen( result, slideLen, dragLen, upFastLen );
}
private static boolean useMinDragLen( int buttonLen, int relDragLen ) {
return relDragLen < buttonLen;
}
static int divide( int dividend, int divisor ) {
BigDecimal bigDividend = new BigDecimal( dividend );
BigDecimal bigDivisor = new BigDecimal( divisor );
return bigDividend .divide( bigDivisor, 0, RoundingMode.HALF_EVEN ) .intValue();
}
private static int adjustDownFastLen( int tentative, int slideLen, int dragLen, int upFastLen ) {
// TODO [fappel]: Without this there is a flickering of the downFast label of one pixel.
// Check whether this can be resolved by better rounding or whatsoever.
int result = tentative;
if( slideLen < upFastLen + dragLen + result ) {
result--;
} else if( slideLen > upFastLen + dragLen + result ) {
result++;
}
return result;
}
}