有什么方法可以自动在WrapPanel中占据空白吗? [英] Is there any way to occupy blank space in WrapPanel automatically?
问题描述
WrapPanel的子级像附件的屏幕截图一样顺序填充.
The Children of WrapPanel are populated sequentially like attached screenshot.
因此,面板根据每个孩子的身长,留出了较长的空白.
Therefore, according to the length of each child, the Panel makes long blank space.
我如何利用空白重新安排孩子们?
How can I utilize the blank space with re-arrangng the children ?
到目前为止,似乎只有少数人使用WrapPanel,并且没有足够的示例.
It seems only few people use WrapPanel so far and no sufficient examples.
有一些自动的方法吗? 还是我只需要制定自己的算法?
Is there some automatic way for this ? Or do I only need to make own algorithm ?
WrapPanel在显示事物方面起着非常重要的作用,但显示空间有限.
The WrapPanel plays a very important role to display things but has limited space to display.
谢谢!
推荐答案
这里是WrapPanel,可以选择使用 FFDH算法,并可以选择拉伸它们以删除空白区域(示例).
Here is a WrapPanel which can optionally rearrange elements using FFDH algorithm, as well as optionally stretch them to remove blank areas (example).
public class StretchyWrapPanel : Panel {
public static readonly DependencyProperty ItemWidthProperty = DependencyProperty.Register(nameof(ItemWidth), typeof(double),
typeof(StretchyWrapPanel), new FrameworkPropertyMetadata(double.NaN, FrameworkPropertyMetadataOptions.AffectsMeasure, (o, e) => {
((StretchyWrapPanel)o)._itemWidth = (double)e.NewValue;
}));
private double _itemWidth = double.NaN;
[TypeConverter(typeof(LengthConverter))]
public double ItemWidth {
get => _itemWidth;
set => SetValue(ItemWidthProperty, value);
}
public static readonly DependencyProperty ItemHeightProperty = DependencyProperty.Register(nameof(ItemHeight), typeof(double),
typeof(StretchyWrapPanel), new FrameworkPropertyMetadata(double.NaN, FrameworkPropertyMetadataOptions.AffectsMeasure, (o, e) => {
((StretchyWrapPanel)o)._itemHeight = (double)e.NewValue;
}));
private double _itemHeight = double.NaN;
[TypeConverter(typeof(LengthConverter))]
public double ItemHeight {
get => _itemHeight;
set => SetValue(ItemHeightProperty, value);
}
public static readonly DependencyProperty OrientationProperty = DependencyProperty.Register(nameof(Orientation), typeof(Orientation),
typeof(StretchyWrapPanel), new FrameworkPropertyMetadata(Orientation.Horizontal, FrameworkPropertyMetadataOptions.AffectsArrange, (o, e) => {
((StretchyWrapPanel)o)._orientation = (Orientation)e.NewValue;
}));
private Orientation _orientation = Orientation.Horizontal;
public Orientation Orientation {
get => _orientation;
set => SetValue(OrientationProperty, value);
}
public static readonly DependencyProperty StretchToFillProperty = DependencyProperty.Register(nameof(StretchToFill), typeof(bool),
typeof(StretchyWrapPanel), new FrameworkPropertyMetadata(true, FrameworkPropertyMetadataOptions.AffectsArrange, (o, e) => {
((StretchyWrapPanel)o)._stretchToFill = (bool)e.NewValue;
}));
private bool _stretchToFill = true;
public bool StretchToFill {
get => _stretchToFill;
set => SetValue(StretchToFillProperty, value);
}
public static readonly DependencyProperty StretchProportionallyProperty = DependencyProperty.Register(nameof(StretchProportionally), typeof(bool),
typeof(StretchyWrapPanel), new FrameworkPropertyMetadata(true, FrameworkPropertyMetadataOptions.AffectsArrange, (o, e) => {
((StretchyWrapPanel)o)._stretchProportionally = (bool)e.NewValue;
}));
private bool _stretchProportionally = true;
public bool StretchProportionally {
get => _stretchProportionally;
set => SetValue(StretchProportionallyProperty, value);
}
public static readonly DependencyProperty RearrangeForBestFitProperty = DependencyProperty.Register(nameof(RearrangeForBestFit), typeof(bool),
typeof(StretchyWrapPanel), new FrameworkPropertyMetadata(false, FrameworkPropertyMetadataOptions.AffectsMeasure, (o, e) => {
((StretchyWrapPanel)o)._rearrangeForBestFit = (bool)e.NewValue;
}));
private bool _rearrangeForBestFit;
public bool RearrangeForBestFit {
get => _rearrangeForBestFit;
set => SetValue(RearrangeForBestFitProperty, value);
}
private struct UVSize {
internal UVSize(Orientation orientation, Size size) {
U = V = 0d;
_isHorizontal = orientation == Orientation.Horizontal;
Width = size.Width;
Height = size.Height;
}
internal UVSize(Orientation orientation, double width, double height) {
U = V = 0d;
_isHorizontal = orientation == Orientation.Horizontal;
Width = width;
Height = height;
}
internal UVSize(Orientation orientation) {
U = V = 0d;
_isHorizontal = orientation == Orientation.Horizontal;
}
internal double U;
internal double V;
private bool _isHorizontal;
internal double Width {
get => _isHorizontal ? U : V;
set {
if (_isHorizontal) {
U = value;
} else {
V = value;
}
}
}
internal double Height {
get => _isHorizontal ? V : U;
set {
if (_isHorizontal) {
V = value;
} else {
U = value;
}
}
}
}
protected override Size MeasureOverride(Size constraint) {
return RearrangeForBestFit ? MeasureBestFit(constraint) : MeasureKeepInOrder(constraint);
}
private Size MeasureKeepInOrder(Size constraint) {
var orientation = Orientation;
var uLimit = new UVSize(orientation, constraint.Width, constraint.Height).U;
var curLineSize = new UVSize(orientation);
var panelSize = new UVSize(orientation);
var itemWidth = ItemWidth;
var itemHeight = ItemHeight;
var itemWidthSet = !double.IsNaN(itemWidth);
var itemHeightSet = !double.IsNaN(itemHeight);
var childConstraint = new Size(
itemWidthSet ? itemWidth : constraint.Width,
itemHeightSet ? itemHeight : constraint.Height);
var children = InternalChildren;
for (int i = 0, count = children.Count; i < count; i++) {
var child = children[i];
if (child == null) continue;
// Flow passes its own constrint to children
child.Measure(childConstraint);
// This is the size of the child in UV space
var sz = new UVSize(orientation,
itemWidthSet ? itemWidth : child.DesiredSize.Width,
itemHeightSet ? itemHeight : child.DesiredSize.Height);
if (curLineSize.U + sz.U > uLimit) {
// Need to switch to another line
panelSize.U = Math.Max(curLineSize.U, panelSize.U);
panelSize.V += curLineSize.V;
curLineSize = sz;
if (sz.U > uLimit) {
// The element is wider then the constrint - give it a separate line
panelSize.U = Math.Max(sz.U, panelSize.U);
panelSize.V += sz.V;
curLineSize = new UVSize(orientation);
}
} else {
// Continue to accumulate a line
curLineSize.U += sz.U;
curLineSize.V = Math.Max(sz.V, curLineSize.V);
}
}
// The last line size, if any should be added
panelSize.U = Math.Max(curLineSize.U, panelSize.U);
panelSize.V += curLineSize.V;
// Go from UV space to W/H space
return new Size(panelSize.Width, panelSize.Height);
}
private Size MeasureBestFit(Size constraint) {
var orientation = Orientation;
var uLimit = new UVSize(orientation, constraint.Width, constraint.Height).U;
var itemWidth = ItemWidth;
var itemHeight = ItemHeight;
var itemWidthSet = !double.IsNaN(itemWidth);
var itemHeightSet = !double.IsNaN(itemHeight);
var childConstraint = new Size(
itemWidthSet ? itemWidth : constraint.Width,
itemHeightSet ? itemHeight : constraint.Height);
var children = InternalChildren;
// First-Fit Decreasing Height (FFDH) algorithm
var lines = new List<UVSize>();
for (int i = 0, count = children.Count; i < count; i++) {
var child = children[i];
if (child == null) continue;
// Flow passes its own constrint to children
child.Measure(childConstraint);
// This is the size of the child in UV space
var childSize = new UVSize(orientation,
itemWidthSet ? itemWidth : child.DesiredSize.Width,
itemHeightSet ? itemHeight : child.DesiredSize.Height);
for (var j = 0; j < lines.Count; j++) {
var line = lines[j];
if (line.U + childSize.U <= uLimit) {
lines[j] = new UVSize(orientation) { U = childSize.U, V = Math.Max(childSize.V, line.V) };
goto Next;
}
}
lines.Add(childSize);
Next:
{ }
}
var panelSize = new UVSize(orientation);
for (var i = 0; i < lines.Count; i++) {
var line = lines[i];
panelSize.U = Math.Max(line.U, panelSize.U);
panelSize.V += line.V;
}
// Go from UV space to W/H space
return new Size(panelSize.Width, panelSize.Height);
}
protected override Size ArrangeOverride(Size finalSize) {
return RearrangeForBestFit ? ArrangeBestFit(finalSize) : ArrangeKeepInOrder(finalSize);
}
private static UVSize GetChildSize(Orientation orientation, UIElement child, UVSize fixedChildSize) {
var childSize = new UVSize(orientation, child.DesiredSize);
if (!double.IsNaN(fixedChildSize.U)) childSize.U = fixedChildSize.U;
if (!double.IsNaN(fixedChildSize.V)) childSize.V = fixedChildSize.V;
return childSize;
}
private Size ArrangeKeepInOrder(Size finalSize) {
var orientation = Orientation;
var fixedChildSize = new UVSize(orientation, ItemWidth, ItemHeight);
var children = InternalChildren;
var firstInLine = 0;
var uLimit = new UVSize(orientation, finalSize).U;
var currentLineSize = new UVSize(orientation);
var accumulatedV = 0d;
for (int i = 0, count = children.Count; i < count; i++) {
var child = children[i];
if (child == null) continue;
var childSize = GetChildSize(orientation, child, fixedChildSize);
if (currentLineSize.U + childSize.U > uLimit) {
// Need to switch to another line
if (!double.IsNaN(fixedChildSize.U)) {
ArrangeLineFixedSize(orientation, children, accumulatedV, currentLineSize.V, firstInLine, i, fixedChildSize.U);
} else if (!StretchToFill) {
ArrangeLineDefault(orientation, children, accumulatedV, currentLineSize.V, firstInLine, i);
} else {
ArrangeLineStretch(orientation, children, accumulatedV, currentLineSize.V, firstInLine, i, uLimit, StretchProportionally);
}
accumulatedV += currentLineSize.V;
currentLineSize = childSize;
firstInLine = i;
} else {
// Continue to accumulate a line
currentLineSize.U += childSize.U;
currentLineSize.V = Math.Max(childSize.V, currentLineSize.V);
}
}
// Arrange the last line, if any
if (!double.IsNaN(fixedChildSize.U)) {
ArrangeLineFixedSize(orientation, children, accumulatedV, currentLineSize.V, firstInLine, children.Count, fixedChildSize.U);
} else if (!StretchToFill) {
ArrangeLineDefault(orientation, children, accumulatedV, currentLineSize.V, firstInLine, children.Count);
} else {
ArrangeLineStretch(orientation, children, accumulatedV, currentLineSize.V, firstInLine, children.Count, uLimit, StretchProportionally);
}
return finalSize;
}
private static void ArrangeLineDefault(Orientation orientation, UIElementCollection children, double v, double lineV, int start, int end) {
var position = new UVSize(orientation){ U = 0d, V = v };
for (var i = start; i < end; i++) {
var child = children[i];
if (child != null) {
var childSize = new UVSize(orientation, child.DesiredSize) { V = lineV };
child.Arrange(new Rect(position.Width, position.Height, childSize.Width, childSize.Height));
position.U += childSize.U;
}
}
}
private static void ArrangeLineStretch(Orientation orientation, UIElementCollection children, double v, double lineV, int start, int end,
double limitU, bool stretchProportionally) {
var totalU = 0d;
for (var i = start; i < end; i++) {
totalU += new UVSize(orientation, children[i].DesiredSize).U;
}
var position = new UVSize(orientation) { U = 0d, V = v };
var uExtra = stretchProportionally ? limitU / totalU : (limitU - totalU) / (end - start);
for (var i = start; i < end; i++) {
var child = children[i];
if (child != null) {
var childSize = new UVSize(orientation, child.DesiredSize) { V = lineV };
childSize.U = stretchProportionally ? childSize.U * uExtra : Math.Max(childSize.U + uExtra, 1d);
child.Arrange(new Rect(position.Width, position.Height, childSize.Width, childSize.Height));
position.U += childSize.U;
}
}
}
private static void ArrangeLineFixedSize(Orientation orientation, UIElementCollection children, double v, double lineV, int start, int end, double itemU) {
var position = new UVSize(orientation) { U = 0d, V = v };
var childSize = new UVSize(orientation){ U = itemU, V = lineV };
for (var i = start; i < end; i++) {
var child = children[i];
if (child != null) {
child.Arrange(new Rect(position.Width, position.Height, childSize.Width, childSize.Height));
position.U += childSize.U;
}
}
}
private class ArrangeBestFitLine {
public UVSize Size;
public readonly List<int> ItemIndices = new List<int>();
public void ArrangeDefault(Orientation orientation, UIElementCollection children, double v) {
var position = new UVSize(orientation){ U = 0d, V = v };
for (var i = 0; i < ItemIndices.Count; i++) {
var child = children[ItemIndices[i]];
if (child != null) {
var childSize = new UVSize(orientation, child.DesiredSize) { V = Size.V };
child.Arrange(new Rect(position.Width, position.Height, childSize.Width, childSize.Height));
position.U += childSize.U;
}
}
}
public void ArrangeStretch(Orientation orientation, UIElementCollection children, double v, double limitU, bool stretchProportionally) {
var totalU = 0d;
for (var i = 0; i < ItemIndices.Count; i++) {
totalU += new UVSize(orientation, children[ItemIndices[i]].DesiredSize).U;
}
var position = new UVSize(orientation) { U = 0d, V = v };
var uExtra = stretchProportionally ? limitU / totalU : (limitU - totalU) / ItemIndices.Count;
for (var i = 0; i < ItemIndices.Count; i++) {
var child = children[ItemIndices[i]];
if (child != null) {
var childSize = new UVSize(orientation, child.DesiredSize) { V = Size.V };
childSize.U = stretchProportionally ? childSize.U * uExtra : Math.Max(childSize.U + uExtra, 1d);
child.Arrange(new Rect(position.Width, position.Height, childSize.Width, childSize.Height));
position.U += childSize.U;
}
}
}
public void ArrangeFixedSize(Orientation orientation, UIElementCollection children, double v, double itemU) {
var position = new UVSize(orientation) { U = 0d, V = v };
var childSize = new UVSize(orientation){ U = itemU, V = Size.V };
for (var i = 0; i < ItemIndices.Count; i++) {
var child = children[ItemIndices[i]];
if (child != null) {
child.Arrange(new Rect(position.Width, position.Height, childSize.Width, childSize.Height));
position.U += childSize.U;
}
}
}
}
private Size ArrangeBestFit(Size finalSize) {
var orientation = Orientation;
var fixedChildSize = new UVSize(orientation, ItemWidth, ItemHeight);
var uLimit = new UVSize(orientation, finalSize).U;
// First-Fit Decreasing Height (FFDH) algorithm
var lines = new List<ArrangeBestFitLine>();
var children = InternalChildren;
for (int i = 0, count = children.Count; i < count; i++) {
var child = children[i];
if (child == null) continue;
var childSize = GetChildSize(orientation, child, fixedChildSize);
for (var j = 0; j < lines.Count; j++) {
var line = lines[j];
if (line.Size.U + childSize.U <= uLimit) {
line.Size.U += childSize.U;
line.Size.V = Math.Max(childSize.V, line.Size.V);
line.ItemIndices.Add(i);
goto Next;
}
}
lines.Add(new ArrangeBestFitLine {
Size = childSize,
ItemIndices = { i }
});
Next:
{ }
}
var accumulatedV = 0d;
for (var i = 0; i < lines.Count; i++) {
var line = lines[i];
if (!double.IsNaN(fixedChildSize.U)) {
line.ArrangeFixedSize(orientation, children, accumulatedV, fixedChildSize.U);
} else if (!StretchToFill) {
line.ArrangeDefault(orientation, children, accumulatedV);
} else {
line.ArrangeStretch(orientation, children, accumulatedV, uLimit, StretchProportionally);
}
accumulatedV += line.Size.V;
}
return finalSize;
}
}
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