/// レイアウト要素のBoundRelative領域の変更を試みる
/// @param layoutElement レイアウト要素
/// @param target 変更箇所
/// @param value 変更値
/// @param[out] changed 変更後、制約を満たす形に訂正されたBoundRelative領域
/// @return 試行結果（訂正箇所）
public static TryResult TryChange(
LayoutElement layoutElement, Names target, double value,
out RelativeLTRB changed)
{
// 準備
var original = BoundRelativeInputCorrector.GetOriginal(layoutElement);
// 訂正
switch (target)
{
case Names.Left:
case Names.Top: {
return(BoundRelativeInputCorrector.TryChangeLow(original, target, value,
Constants.MinimumBoundRelativeSize, out changed));
}
case Names.Right:
case Names.Bottom: {
return(BoundRelativeInputCorrector.TryChangeHigh(original, target, value,
Constants.MinimumBoundRelativeSize, out changed));
}
default: Debug.Fail("switch"); throw new System.ArgumentException();
}
}
//=================================================================
// 訂正
//=================================================================
/// BoundRelative*の値が小さい方の位置要素(Left/Top)の変更を試みる
/// @param original 変更前のBoundRelativeLTRB
/// @param target 変更箇所
/// @param value 変更値
/// @param sizeLowerBound 訂正後のサイズ要素(Width/Height)の最小値
/// @param[out] changed 変更後、制約を満たす形に訂正されたBoundRelativeLTRB
/// @return 試行結果（訂正箇所）
private static TryResult TryChangeLow(RelativeLTRB original,
Names target, double value, double sizeLowerBound,
out RelativeLTRB changed)
{
Debug.Assert(target == Names.Left || target == Names.Top);
// 準備
var onX = (target == Names.Left);
var low = value;
var high = onX ? original.Right : original.Bottom;
var result = TryResult.NothingChanged;
// highのチェック
/// @todo(me) 浮動小数点数の比較
Debug.Assert(0.0 + sizeLowerBound <= high && high <= 1.0);
// 上限・下限の補正
/// @attention 浮動小数点数の比較
if (low < 0.0)
{
low = 0.0;
result |= TryResult.TargetChanged;
}
else if (1.0 - sizeLowerBound < low)
{
low = 1.0 - sizeLowerBound;
result |= TryResult.TargetChanged;
}
// lowが大きすぎる場合、highを増やして最小幅を確保
if (high < low + sizeLowerBound)
{
high = low + sizeLowerBound;
result |= TryResult.DependentChanged;
}
// 出力
changed = onX
? new RelativeLTRB(low, original.Top, high, original.Bottom)
: new RelativeLTRB(original.Left, low, original.Right, high);
return(result);
}
/// BoundRelative*の値が大きい方の位置要素(Right/Bottom)の変更を試みる
/// @param original 変更前のBoundRelativeLTRB
/// @param target 変更箇所
/// @param value 変更値
/// @param sizeLowerBound 訂正後のサイズ要素(Width/Height)の最小値
/// @param[out] changed 変更後、制約を満たす形に訂正されたBoundRelativeLTRB
/// @return 試行結果（訂正箇所）
public static TryResult TryChangeHigh(RelativeLTRB original,
Names target, double value, double sizeLowerBound,
out RelativeLTRB changed)
{
Debug.Assert(target == Names.Right || target == Names.Bottom);
// 準備
var onX = (target == Names.Right);
var low = onX ? original.Left : original.Top;
var high = value;
var result = TryResult.NothingChanged;
// lowのチェック
/// @todo(me) 浮動小数点数の比較
Debug.Assert(0.0 <= low && low <= 1.0 - sizeLowerBound);
// 上限・下限の補正
/// @attention 浮動小数点数の比較
if (high < 0.0 + sizeLowerBound)
{
high = 0.0 + sizeLowerBound;
result |= TryResult.TargetChanged;
}
else if (1.0 < high)
{
high = 1.0;
result |= TryResult.TargetChanged;
}
// lowが大きすぎる場合、lowを減らして最小幅を確保
if (high < low + sizeLowerBound)
{
low = high - sizeLowerBound;
result |= TryResult.DependentChanged;
}
// 出力
changed = onX
? new RelativeLTRB(low, original.Top, high, original.Bottom)
: new RelativeLTRB(original.Left, low, original.Right, high);
return(result);
}
/// フィールドを初期化
private void Clear()
{
this.target = null;
this.hitMode = HitModes.Neutral;
this.mouseOffset = null;
this.originalLTRB = null;
this.snapGuide = null;
this.lastUpdateControl = 0;
this.MousePoint = null;
this.ShouldUpdateControl = false;
}
//===================================================================
// 動作
//===================================================================
/// 開始
public void Start(LayoutElement target, HitModes hitMode,
RelativePoint mousePoint, SnapGuide snapGuide)
{
this.target = target;
this.hitMode = hitMode;
this.mouseOffset = new RelativeMouseOffset(target, mousePoint);
this.originalLTRB = new RelativeLTRB(target.BoundRelativeLeft,
target.BoundRelativeTop,
target.BoundRelativeRight,
target.BoundRelativeBottom);
this.snapGuide = snapGuide;
this.lastUpdateControl = Environment.TickCount;
this.MousePoint = mousePoint;
this.ShouldUpdateControl = false;
}
