/// <summary>This is the second pass of layout requests.
/// It positions the element in global screen space and also fires the render events
/// which in turn generate or reallocates mesh blocks. This call applies to all it's
/// children elements too.</summary>
/// <param name="relativeTo">The current style we are positioning relative to.</param>
public void PositionGlobally(ComputedStyle relativeTo)
{
ComputedStyle computed = Style.Computed;
if (computed.Display == DisplayType.None)
{
// Don't draw this element or it's kids.
return;
}
// Position globally:
if (computed.Position == PositionType.Fixed)
{
// Fixed elements are nice and simple to deal with - Their essentially absolutely positioned but relative to the html tag.
ComputedStyle html = Document.html.style.Computed;
if (computed.RightPositioned)
{
// The right hand edge of parent minus how far from the edge minus the width.
computed.OffsetLeft = computed.MarginLeft + html.OffsetLeft + html.PixelWidth - computed.PositionRight - computed.PixelWidth;
}
else
{
computed.OffsetLeft = computed.MarginLeft + html.OffsetLeft + computed.PositionLeft;
}
if (computed.BottomPositioned)
{
computed.OffsetTop = computed.MarginTop + html.OffsetTop + html.PixelHeight - computed.PositionBottom - computed.PixelHeight;
}
else
{
computed.OffsetTop = computed.MarginTop + html.OffsetTop + computed.PositionTop;
}
// Change relativeTo here - we are now hopping to this fixed objects kids.
relativeTo = computed;
}
else if (computed.Position == PositionType.Relative)
{
// Relative to where they should have been. PositionLeft/PositionRight etc. may be zero, but not always.
// The width of border/padding/margin + the position of the parent + the offet from the parent.
if (relativeTo == null)
{
computed.OffsetLeft = computed.MarginLeft + computed.ParentOffsetLeft;
}
else
{
computed.OffsetLeft = computed.MarginLeft + relativeTo.StyleOffsetLeft + relativeTo.OffsetLeft + computed.ParentOffsetLeft;
}
if (computed.RightPositioned)
{
computed.OffsetLeft -= computed.PositionRight;
}
else
{
computed.OffsetLeft += computed.PositionLeft;
}
if (relativeTo == null)
{
computed.OffsetTop = computed.MarginTop + computed.ParentOffsetTop;
}
else
{
computed.OffsetTop = computed.MarginTop + relativeTo.StyleOffsetTop + relativeTo.OffsetTop + computed.ParentOffsetTop;
}
if (computed.BottomPositioned)
{
computed.OffsetTop -= computed.PositionBottom;
}
else
{
computed.OffsetTop += computed.PositionTop;
}
// Vertical alignment:
bool tableCell = (computed.Display == DisplayType.TableCell);
if (relativeTo != null || computed.AutoMarginY || tableCell)
{
if (computed.AutoMarginY || relativeTo.VerticalAlign == VerticalAlignType.Middle || (tableCell && computed.VerticalAlign == VerticalAlignType.Middle))
{
// Similar to below - we find the gap, then add *half* of that onto OffsetTop.
if (tableCell)
{
// Move upwards - we're sitting on the line and want to be above it.
computed.OffsetTop -= (relativeTo.InnerHeight - computed.PixelHeight) / 2;
}
else
{
computed.OffsetTop += (relativeTo.InnerHeight - relativeTo.ContentHeight) / 2;
}
}
else if (relativeTo.VerticalAlign == VerticalAlignType.Bottom)
{
// Find the gap - parent height-contentHeight.
// Then simply add that onto offsetTop.
computed.OffsetTop += relativeTo.InnerHeight - relativeTo.ContentHeight;
}
else if (tableCell && computed.VerticalAlign == VerticalAlignType.Top)
{
// This time we find the gap and remove it - we're at the bottom by default as a td sits on the line.
computed.OffsetTop -= relativeTo.InnerHeight - computed.PixelHeight;
}
}
// Note: relativeTo does not change here if we're in an inline element:
if (computed.Display != DisplayType.Inline)
{
relativeTo = computed;
}
}
else
{
// Absolute - relative to parent. It's ParentOffsetLeft/Top are both zero.
if (computed.RightPositioned)
{
// The right hand edge of parent minus how far from the edge minus the width.
computed.OffsetLeft = computed.MarginLeft + relativeTo.OffsetLeft - relativeTo.StyleOffsetLeft - relativeTo.ScrollLeft + relativeTo.PixelWidth - computed.PositionRight - computed.PixelWidth;
}
else
{
computed.OffsetLeft = computed.MarginLeft + relativeTo.OffsetLeft + relativeTo.StyleOffsetLeft + relativeTo.ScrollLeft + computed.PositionLeft;
}
if (computed.BottomPositioned)
{
computed.OffsetTop = computed.MarginTop + relativeTo.OffsetTop - relativeTo.StyleOffsetTop - relativeTo.ScrollTop + relativeTo.PixelHeight - computed.PositionBottom - computed.PixelHeight;
}
else
{
computed.OffsetTop = computed.MarginTop + relativeTo.OffsetTop + relativeTo.StyleOffsetTop + relativeTo.ScrollTop + computed.PositionTop;
}
// Set relativeTo to this - this is because the kids of absolute objects are relative to the absolute object itself.
relativeTo = computed;
}
// Push the transform to our stack, if we have one.
if (computed.Transform != null)
{
// Add it to the stack:
Document.Renderer.Transformations.Push(computed.Transform);
// Update it:
computed.Transform.RecalculateMatrix(computed);
}
// Great, it's good to go!
computed.Render();
if (KidsToRender != null || HScrollbar || VScrollbar)
{
BoxRegion parentBoundary = null;
if (relativeTo == computed)
{
// We changed who we're relative to.
// Change the clipping boundary:
Renderman renderer = Document.Renderer;
parentBoundary = renderer.ClippingBoundary;
renderer.SetBoundary(computed);
}
if (KidsToRender != null)
{
for (int i = 0; i < KidsToRender.Count; i++)
{
Element child = KidsToRender[i];
if (child != null)
{
child.PositionGlobally(relativeTo);
}
}
}
if (HScrollbar)
{
HorizontalScrollbar.Element.PositionGlobally(relativeTo);
}
if (VScrollbar)
{
VerticalScrollbar.Element.PositionGlobally(relativeTo);
}
if (relativeTo == computed)
{
// Restore the previous boundary before this one: [Note - can't use SetBoundary here as it would destroy the box.]
Document.Renderer.ClippingBoundary = parentBoundary;
}
}
if (computed.Transform != null)
{
// Pop it off again:
Document.Renderer.Transformations.Pop();
}
}