/// <summary>
/// Initialises a new instance of the <see cref="CanvasItemLayout"/> class
/// for the specified container and using the given client bounds.
/// </summary>
/// <param name="container">The CanvasItem to which this layout belongs</param>
/// <param name="clientBounds">A rectangle that indicates the client boundaries</param>
public CanvasItemLayout(CanvasItem container, Rectangle clientBounds)
{
_backColor = SystemColors.Control;
Container = container;
ResetPosition(clientBounds);
Padding = new Size(4, 4);
}
/// <summary>
/// Remove the selection from the specified item.
/// </summary>
private void ClearSelection()
{
if (_selectedItemIndex >= 0)
{
CanvasItem item = (CanvasItem)Controls[_selectedItemIndex];
item.Selected = false;
_selectedItemIndex = -1;
}
}
/// <summary>
/// Respond to a hover over a link in a static text item
/// </summary>
/// <param name="item">The item that raised this event</param>
/// <param name="args">The hover arguments</param>
public void HandleHover(CanvasItem item, CanvasHoverArgs args)
{
Point scrollOffset = AutoScrollPosition;
args.Location = new Point(args.Location.X + scrollOffset.X, args.Location.Y + scrollOffset.Y);
if (LinkHover != null)
{
LinkHover(item, args);
}
}
/// <summary>
/// Override the resize event to force a re-layout of the content.
/// </summary>
/// <param name="e">Resize event arguments</param>
protected override void OnResize(EventArgs e)
{
if (!_inLayout)
{
int index = 0;
while (index < Controls.Count)
{
CanvasItem item = (CanvasItem)Controls[index];
item.SetBounds(0, 0, ClientRectangle.Width, 0, BoundsSpecified.Width);
++index;
}
LayoutControls(null);
}
}
/// <summary>
/// If the container control gets focus, set the focus explicitly on the selected
/// item. Otherwise set it on the first visible item.
/// </summary>
/// <param name="e">Focus event arguments</param>
protected override void OnGotFocus(EventArgs e)
{
if (_selectedItemIndex >= 0)
{
CanvasItem item = (CanvasItem)Controls[_selectedItemIndex];
item.Focus();
}
else
{
CanvasItem item = (CanvasItem)GetChildAtPoint(new Point(0, 0));
if (item != null)
{
item.Focus();
}
}
}
/// <summary>
/// Called when the Items collection is changed. We make the necessary modifications to the
/// Controls collection.
/// </summary>
private void ItemsOnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
switch (e.Action)
{
case NotifyCollectionChangedAction.Reset:
_selectedItemIndex = -1;
TextSelectedItem = null;
Controls.Clear();
break;
case NotifyCollectionChangedAction.Remove:
foreach (CanvasItem item in e.OldItems)
{
if (item.Selected)
{
_selectedItemIndex = -1;
}
if (_selectedItemIndex >= e.OldStartingIndex)
{
--_selectedItemIndex;
}
Controls.Remove(item);
}
_displayRectUpdate = true;
if (!IsLayoutSuspended)
{
LayoutControls(null);
}
break;
case NotifyCollectionChangedAction.Add:
int index = e.NewStartingIndex;
foreach (CanvasItem item in e.NewItems)
{
Controls.Add(item);
Controls.SetChildIndex(item, index);
if (_selectedItemIndex >= index)
{
++_selectedItemIndex;
}
++index;
}
_displayRectUpdate = true;
if (!IsLayoutSuspended)
{
LayoutControls((CanvasItem) e.NewItems[0]);
}
break;
}
}
/// <summary>
/// A selection was made on an item. We keep track of the item with the selection
/// separately from the selected item.
/// </summary>
internal void HandleSelection(CanvasItem canvasItem)
{
if (TextSelectedItem != null && canvasItem != TextSelectedItem)
{
TextSelectedItem.ClearSelection();
}
TextSelectedItem = canvasItem;
}
/// <summary>
/// Respond to a canvas item component being selected. ComponentID is the ID
/// of the actual component under the mouse cursor.
/// </summary>
/// <param name="item">The item that raised this select</param>
/// <param name="component">The component selected</param>
internal void HandleSelect(CanvasItem item, CanvasElementBase component)
{
if (component == null || component.ID == ActionID.None)
{
if (AllowSelection)
{
Focus();
int selectedItem = Controls.IndexOf(item);
if (selectedItem != _selectedItemIndex)
{
SelectItem(selectedItem, true);
}
}
}
if (CanvasItemAction != null)
{
CanvasItemAction(this, new CanvasItemArgs
{
Item = (component != null) ? component.ID : ActionID.None,
Tag = (component != null) ? component.Tag : null,
Control = item
});
}
}
/// <summary>
/// Layout all the canvas items from either the given item or from
/// the start if null is specified.
/// </summary>
public void LayoutControls(CanvasItem firstControl)
{
if (!_inLayout)
{
bool layoutAll = (firstControl == null);
_inLayout = true;
int index = (layoutAll) ? 0 : Controls.IndexOf(firstControl);
if (index >= 0)
{
Point point;
if (index > 0)
{
point = Controls[index - 1].Location;
point.Y += Controls[index - 1].Height;
}
else
{
point = AutoScrollPosition;
}
int topOffset = Math.Abs(point.Y);
int yCount = 0;
while (index < Controls.Count && (layoutAll || yCount < ClientRectangle.Bottom * 2))
{
CanvasItem item = (CanvasItem) Controls[index];
BoundsSpecified flags = BoundsSpecified.None;
if (item.Bounds.X != point.X)
{
flags |= BoundsSpecified.X;
}
if (item.Bounds.Y != point.Y)
{
flags |= BoundsSpecified.Y;
}
if (item.Bounds.Width != ClientRectangle.Width)
{
flags |= BoundsSpecified.Width;
}
if (item.Bounds.Height != item.Height)
{
flags |= BoundsSpecified.Height;
}
item.SetBounds(point.X, point.Y, ClientRectangle.Width, item.Height, flags);
point.Y += item.Height;
yCount += item.Height - topOffset;
topOffset = 0;
++index;
}
// If the collection changed then we need to update the virtual display
// rectangle bounds too.
if (_displayRectUpdate)
{
while (index < Controls.Count)
{
CanvasItem item = (CanvasItem) Controls[index++];
point.Y += item.Height;
}
AutoScrollMinSize = new Size(DisplayRectangle.Width, point.Y);
_displayRectUpdate = false;
}
}
_inLayout = false;
}
}
/// <summary>
/// Respond to a link being clicked in a static text item.
/// </summary>
/// <param name="item">The item that raised this event</param>
/// <param name="link">The URL</param>
public void HandleLink(CanvasItem item, string link)
{
if (LinkClicked != null)
{
LinkClicked(item, new LinkClickedEventArgs(link));
}
}
/// <summary>
/// Respond to a hover over a link in a static text item
/// </summary>
/// <param name="item">The item that raised this event</param>
/// <param name="args">The hover arguments</param>
public void HandleHover(CanvasItem item, CanvasHoverArgs args)
{
Point scrollOffset = AutoScrollPosition;
args.Location = new Point(args.Location.X + scrollOffset.X, args.Location.Y + scrollOffset.Y);
if (LinkHover != null)
{
LinkHover(item, args);
}
}
/// <summary>
/// Marks the end of batch update of items and proceeds to render.
/// </summary>
public void EndUpdate(CanvasItem rootItem)
{
IsLayoutSuspended = false;
LayoutControls(rootItem);
ResumeLayout(true);
}
/// <summary>
/// If the item has selected text, extract that and use it as quotation
/// in the message body.
/// </summary>
/// <param name="item">The item</param>
/// <returns>Quoted text or an empty string</returns>
private static string GetQuotedText(CanvasItem item)
{
if (item != null)
{
string selectedText = item.Selection;
if (!string.IsNullOrWhiteSpace(selectedText))
{
return selectedText.Quoted();
}
}
return string.Empty;
}
/// <summary>
/// Layout all the canvas items from either the given item or from
/// the start if null is specified.
/// </summary>
public void LayoutControls(CanvasItem firstControl)
{
if (!_inLayout)
{
bool layoutAll = (firstControl == null);
_inLayout = true;
int index = (layoutAll) ? 0 : Controls.IndexOf(firstControl);
if (index >= 0)
{
Point point;
if (index > 0)
{
point = Controls[index - 1].Location;
point.Y += Controls[index - 1].Height;
}
else
{
point = AutoScrollPosition;
}
int topOffset = Math.Abs(point.Y);
int yCount = 0;
while (index < Controls.Count && (layoutAll || yCount < ClientRectangle.Bottom * 2))
{
CanvasItem item = (CanvasItem)Controls[index];
BoundsSpecified flags = BoundsSpecified.None;
if (item.Bounds.X != point.X)
{
flags |= BoundsSpecified.X;
}
if (item.Bounds.Y != point.Y)
{
flags |= BoundsSpecified.Y;
}
if (item.Bounds.Width != ClientRectangle.Width)
{
flags |= BoundsSpecified.Width;
}
if (item.Bounds.Height != item.Height)
{
flags |= BoundsSpecified.Height;
}
item.SetBounds(point.X, point.Y, ClientRectangle.Width, item.Height, flags);
point.Y += item.Height;
yCount += item.Height - topOffset;
topOffset = 0;
++index;
}
// If the collection changed then we need to update the virtual display
// rectangle bounds too.
if (_displayRectUpdate)
{
while (index < Controls.Count)
{
CanvasItem item = (CanvasItem)Controls[index++];
point.Y += item.Height;
}
AutoScrollMinSize = new Size(DisplayRectangle.Width, point.Y);
_displayRectUpdate = false;
}
}
_inLayout = false;
}
}
/// <summary>
/// Marks the end of batch update of items and proceeds to render.
/// </summary>
public void EndUpdate(CanvasItem rootItem)
{
IsLayoutSuspended = false;
LayoutControls(rootItem);
ResumeLayout(true);
}
