protected override void OnMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
if (this.view == null || this.view.Element == null)
{
base.SetMeasuredDimension(widthMeasureSpec, heightMeasureSpec);
return;
}
XForms.SizeRequest measure = this.view.Element.Measure(this.initialWidth, double.PositiveInfinity, XForms.MeasureFlags.IncludeMargins);
int height = (int)Context.ToPixels(this.fastCell.Height > 0 ? this.fastCell.Height : measure.Request.Height);
this.SetMeasuredDimension((int)Context.ToPixels(this.initialWidth), height);
}
protected override SizeRequest OnSizeRequest(double widthConstraint, double heightConstraint)
{
if (!InternalChildren.Any())
{
return(new SizeRequest(new Size(0, 0)));
}
MeasureGrid(widthConstraint, heightConstraint, true);
double columnWidthSum = 0;
double nonStarColumnWidthSum = 0;
for (var index = 0; index < _columns.Count; index++)
{
ColumnDefinition c = _columns[index];
columnWidthSum += c.ActualWidth;
if (!c.Width.IsStar)
{
nonStarColumnWidthSum += c.ActualWidth;
}
}
double rowHeightSum = 0;
double nonStarRowHeightSum = 0;
for (var index = 0; index < _rows.Count; index++)
{
RowDefinition r = _rows[index];
rowHeightSum += r.ActualHeight;
if (!r.Height.IsStar)
{
nonStarRowHeightSum += r.ActualHeight;
}
}
var request = new Size(columnWidthSum + (_columns.Count - 1) * ColumnSpacing, rowHeightSum + (_rows.Count - 1) * RowSpacing);
var minimum = new Size(nonStarColumnWidthSum + (_columns.Count - 1) * ColumnSpacing, nonStarRowHeightSum + (_rows.Count - 1) * RowSpacing);
var result = new SizeRequest(request, minimum);
return(result);
}
void ExpandLastAutoRowIfNeeded(double height, bool expandToRequest)
{
for (var index = 0; index < InternalChildren.Count; index++)
{
Element element = InternalChildren[index];
var child = (View)element;
if (!child.IsVisible)
{
continue;
}
RowDefinition row = GetLastAutoRow(child);
if (row == null)
{
continue;
}
double assignedHeight = GetAssignedRowHeight(child);
var unassignedHeight = GetUnassignedHeight(height);
double h = double.IsPositiveInfinity(height) ? double.PositiveInfinity : assignedHeight + unassignedHeight;
var acw = GetAssignedColumnWidth(child);
SizeRequest sizeRequest = child.Measure(acw, h, MeasureFlags.IncludeMargins);
double requiredHeight = expandToRequest
? sizeRequest.Request.Height
: sizeRequest.Request.Height <= h ? sizeRequest.Request.Height : sizeRequest.Minimum.Height;
double deltaHeight = requiredHeight - assignedHeight - (GetRowSpan(child) - 1) * RowSpacing;
if (deltaHeight > 0)
{
row.ActualHeight += deltaHeight;
}
}
}
double MeasureStarredRows()
{
double starRowHeight;
for (var iteration = 0; iteration < 2; iteration++)
{
for (var rowspan = 1; rowspan <= _rows.Count; rowspan++)
{
for (var i = 0; i < _rows.Count; i++)
{
RowDefinition row = _rows[i];
if (!row.Height.IsStar)
{
continue;
}
if (row.ActualHeight >= 0) // if Actual is already set (by a smaller span), skip till pass 3
{
continue;
}
double actualHeight = row.ActualHeight;
double minimumHeight = row.MinimumHeight;
for (var index = 0; index < InternalChildren.Count; index++)
{
var child = (View)InternalChildren[index];
if (!child.IsVisible || GetRowSpan(child) != rowspan || !IsInRow(child, i) || NumberOfUnsetRowHeight(child) > 1)
{
continue;
}
double assignedHeight = GetAssignedRowHeight(child);
double assignedWidth = GetAssignedColumnWidth(child);
SizeRequest sizeRequest = child.Measure(assignedWidth, double.PositiveInfinity, MeasureFlags.IncludeMargins);
actualHeight = Math.Max(actualHeight, sizeRequest.Request.Height - assignedHeight - RowSpacing * (GetRowSpan(child) - 1));
minimumHeight = Math.Max(minimumHeight, sizeRequest.Minimum.Height - assignedHeight - RowSpacing * (GetRowSpan(child) - 1));
}
if (actualHeight >= 0)
{
row.ActualHeight = actualHeight;
}
if (minimumHeight >= 0)
{
row.MinimumHeight = minimumHeight;
}
}
}
}
// 3. Star columns:
//Measure the stars
starRowHeight = 1;
for (var index = 0; index < _rows.Count; index++)
{
RowDefinition row = _rows[index];
if (!row.Height.IsStar)
{
continue;
}
starRowHeight = row.Height.Value != 0 ? Math.Max(starRowHeight, row.ActualHeight / row.Height.Value) : 0;
}
return(starRowHeight);
}
double MeasuredStarredColumns(double widthConstraint, double heightConstraint)
{
double starColWidth;
for (var iteration = 0; iteration < 2; iteration++)
{
for (var colspan = 1; colspan <= _columns.Count; colspan++)
{
for (var i = 0; i < _columns.Count; i++)
{
ColumnDefinition col = _columns[i];
if (!col.Width.IsStar)
{
continue;
}
if (col.ActualWidth >= 0) // if Actual is already set (by a smaller span), skip
{
continue;
}
double actualWidth = col.ActualWidth;
double minimumWidth = col.MinimumWidth;
for (var index = 0; index < InternalChildren.Count; index++)
{
var child = (View)InternalChildren[index];
if (!child.IsVisible || GetColumnSpan(child) != colspan || !IsInColumn(child, i) || NumberOfUnsetColumnWidth(child) > 1)
{
continue;
}
double assignedWidth = GetAssignedColumnWidth(child);
SizeRequest sizeRequest = child.Measure(widthConstraint, heightConstraint, MeasureFlags.IncludeMargins);
actualWidth = Math.Max(actualWidth, sizeRequest.Request.Width - assignedWidth - (GetColumnSpan(child) - 1) * ColumnSpacing);
minimumWidth = Math.Max(minimumWidth, sizeRequest.Minimum.Width - assignedWidth - (GetColumnSpan(child) - 1) * ColumnSpacing);
}
if (actualWidth >= 0)
{
col.ActualWidth = actualWidth;
}
if (minimumWidth >= 0)
{
col.MinimumWidth = minimumWidth;
}
}
}
}
//Measure the stars
starColWidth = 1;
for (var index = 0; index < _columns.Count; index++)
{
ColumnDefinition col = _columns[index];
if (!col.Width.IsStar)
{
continue;
}
starColWidth = col.Width.Value != 0 ? Math.Max(starColWidth, col.ActualWidth / col.Width.Value) : 0;
}
return(starColWidth);
}
void CalculateAutoCells(double width, double height)
{
// this require multiple passes. First process the 1-span, then 2, 3, ...
// And this needs to be run twice, just in case a lower-span column can be determined by a larger span
for (var iteration = 0; iteration < 2; iteration++)
{
for (var rowspan = 1; rowspan <= _rows.Count; rowspan++)
{
for (var i = 0; i < _rows.Count; i++)
{
RowDefinition row = _rows[i];
if (!row.Height.IsAuto)
{
continue;
}
if (row.ActualHeight >= 0) // if Actual is already set (by a smaller span), skip till pass 3
{
continue;
}
double actualHeight = row.ActualHeight;
double minimumHeight = row.MinimumHeight;
for (var index = 0; index < InternalChildren.Count; index++)
{
var child = (View)InternalChildren[index];
if (!child.IsVisible || GetRowSpan(child) != rowspan || !IsInRow(child, i) || NumberOfUnsetRowHeight(child) > 1)
{
continue;
}
double assignedWidth = GetAssignedColumnWidth(child);
double assignedHeight = GetAssignedRowHeight(child);
double widthRequest = assignedWidth + GetUnassignedWidth(width);
double heightRequest = double.IsPositiveInfinity(height) ? double.PositiveInfinity : assignedHeight + GetUnassignedHeight(height);
SizeRequest sizeRequest = child.Measure(widthRequest, heightRequest, MeasureFlags.IncludeMargins);
actualHeight = Math.Max(actualHeight, sizeRequest.Request.Height - assignedHeight - RowSpacing * (GetRowSpan(child) - 1));
minimumHeight = Math.Max(minimumHeight, sizeRequest.Minimum.Height - assignedHeight - RowSpacing * (GetRowSpan(child) - 1));
}
if (actualHeight >= 0)
{
row.ActualHeight = actualHeight;
}
if (minimumHeight >= 0)
{
row.MinimumHeight = minimumHeight;
}
}
}
for (var colspan = 1; colspan <= _columns.Count; colspan++)
{
for (var i = 0; i < _columns.Count; i++)
{
ColumnDefinition col = _columns[i];
if (!col.Width.IsAuto)
{
continue;
}
if (col.ActualWidth >= 0) // if Actual is already set (by a smaller span), skip
{
continue;
}
double actualWidth = col.ActualWidth;
double minimumWidth = col.MinimumWidth;
for (var index = 0; index < InternalChildren.Count; index++)
{
var child = (View)InternalChildren[index];
if (!child.IsVisible || GetColumnSpan(child) != colspan || !IsInColumn(child, i) || NumberOfUnsetColumnWidth(child) > 1)
{
continue;
}
double assignedWidth = GetAssignedColumnWidth(child);
double assignedHeight = GetAssignedRowHeight(child);
double widthRequest = double.IsPositiveInfinity(width) ? double.PositiveInfinity : assignedWidth + GetUnassignedWidth(width);
double heightRequest = assignedHeight + GetUnassignedHeight(height);
SizeRequest sizeRequest = child.Measure(widthRequest, heightRequest, MeasureFlags.IncludeMargins);
actualWidth = Math.Max(actualWidth, sizeRequest.Request.Width - assignedWidth - (GetColumnSpan(child) - 1) * ColumnSpacing);
minimumWidth = Math.Max(minimumWidth, sizeRequest.Minimum.Width - assignedWidth - (GetColumnSpan(child) - 1) * ColumnSpacing);
}
if (actualWidth >= 0)
{
col.ActualWidth = actualWidth;
}
if (minimumWidth >= 0)
{
col.MinimumWidth = actualWidth;
}
}
}
}
}
protected override SizeRequest OnMeasure(double widthConstraint, double heightConstraint)
{
SizeRequest desiredSize = base.OnMeasure(double.PositiveInfinity, double.PositiveInfinity);
return(ImageElement.Measure(this, desiredSize, widthConstraint, heightConstraint));
}
public virtual SizeRequest GetSizeRequest(double widthConstraint, double heightConstraint)
{
SizeRequest cachedResult;
var constraintSize = new Size(widthConstraint, heightConstraint);
if (_measureCache.TryGetValue(constraintSize, out cachedResult))
{
return(cachedResult);
}
double widthRequest = WidthRequest;
double heightRequest = HeightRequest;
if (widthRequest >= 0)
{
widthConstraint = Math.Min(widthConstraint, widthRequest);
}
if (heightRequest >= 0)
{
heightConstraint = Math.Min(heightConstraint, heightRequest);
}
SizeRequest result = OnMeasure(widthConstraint, heightConstraint);
bool hasMinimum = result.Minimum != result.Request;
Size request = result.Request;
Size minimum = result.Minimum;
if (heightRequest != -1)
{
request.Height = heightRequest;
if (!hasMinimum)
{
minimum.Height = heightRequest;
}
}
if (widthRequest != -1)
{
request.Width = widthRequest;
if (!hasMinimum)
{
minimum.Width = widthRequest;
}
}
double minimumHeightRequest = MinimumHeightRequest;
double minimumWidthRequest = MinimumWidthRequest;
if (minimumHeightRequest != -1)
{
minimum.Height = minimumHeightRequest;
}
if (minimumWidthRequest != -1)
{
minimum.Width = minimumWidthRequest;
}
minimum.Height = Math.Min(request.Height, minimum.Height);
minimum.Width = Math.Min(request.Width, minimum.Width);
var r = new SizeRequest(request, minimum);
if (r.Request.Width > 0 && r.Request.Height > 0)
{
_measureCache[constraintSize] = r;
}
return(r);
}
void CalculateNaiveLayout(LayoutInformation layout, StackOrientation orientation, double x, double y, double widthConstraint, double heightConstraint)
{
layout.CompressionSpace = 0;
double xOffset = x;
double yOffset = y;
double boundsWidth = 0;
double boundsHeight = 0;
double minimumWidth = 0;
double minimumHeight = 0;
double spacing = Spacing;
if (orientation == StackOrientation.Vertical)
{
View expander = null;
for (var i = 0; i < LogicalChildrenInternal.Count; i++)
{
var child = (View)LogicalChildrenInternal[i];
if (!child.IsVisible)
{
continue;
}
if (child.VerticalOptions.Expands)
{
layout.Expanders++;
if (expander != null)
{
// we have multiple expanders, make sure previous expanders are reset to not be fixed because they no logner are
ComputeConstraintForView(child, false);
}
expander = child;
}
SizeRequest request = child.Measure(widthConstraint, double.PositiveInfinity, MeasureFlags.IncludeMargins);
var bounds = new Rectangle(x, yOffset, request.Request.Width, request.Request.Height);
layout.Plots[i] = bounds;
layout.Requests[i] = request;
layout.CompressionSpace += Math.Max(0, request.Request.Height - request.Minimum.Height);
yOffset = bounds.Bottom + spacing;
boundsWidth = Math.Max(boundsWidth, request.Request.Width);
boundsHeight = bounds.Bottom - y;
minimumHeight += request.Minimum.Height + spacing;
minimumWidth = Math.Max(minimumWidth, request.Minimum.Width);
}
minimumHeight -= spacing;
if (expander != null)
{
ComputeConstraintForView(expander, layout.Expanders == 1); // warning : slightly obtuse, but we either need to setup the expander or clear the last one
}
}
else
{
View expander = null;
for (var i = 0; i < LogicalChildrenInternal.Count; i++)
{
var child = (View)LogicalChildrenInternal[i];
if (!child.IsVisible)
{
continue;
}
if (child.HorizontalOptions.Expands)
{
layout.Expanders++;
if (expander != null)
{
ComputeConstraintForView(child, false);
}
expander = child;
}
SizeRequest request = child.Measure(double.PositiveInfinity, heightConstraint, MeasureFlags.IncludeMargins);
var bounds = new Rectangle(xOffset, y, request.Request.Width, request.Request.Height);
layout.Plots[i] = bounds;
layout.Requests[i] = request;
layout.CompressionSpace += Math.Max(0, request.Request.Width - request.Minimum.Width);
xOffset = bounds.Right + spacing;
boundsWidth = bounds.Right - x;
boundsHeight = Math.Max(boundsHeight, request.Request.Height);
minimumWidth += request.Minimum.Width + spacing;
minimumHeight = Math.Max(minimumHeight, request.Minimum.Height);
}
minimumWidth -= spacing;
if (expander != null)
{
ComputeConstraintForView(expander, layout.Expanders == 1);
}
}
layout.Bounds = new Rectangle(x, y, boundsWidth, boundsHeight);
layout.MinimumSize = new Size(minimumWidth, minimumHeight);
}
static double GetMaxWidth(double width, SizeRequest size)
{
return(Math.Max(size.Request.Width, width));
}
static double GetMaxHeight(double height, SizeRequest size)
{
return(Math.Max(size.Request.Height, height));
}
double MeasureStarredRows(double widthConstraint, double heightConstraint, double totalStarsHeight)
{
double starRowHeight;
for (var iteration = 0; iteration < 2; iteration++)
{
for (var rowspan = 1; rowspan <= _rows.Count; rowspan++)
{
for (var i = 0; i < _rows.Count; i++)
{
RowDefinition row = _rows[i];
if (!row.Height.IsStar)
{
continue;
}
if (row.ActualHeight >= 0) // if Actual is already set (by a smaller span), skip till pass 3
{
continue;
}
double actualHeight = row.ActualHeight;
double minimumHeight = row.MinimumHeight;
for (var index = 0; index < InternalChildren.Count; index++)
{
var child = (View)InternalChildren[index];
if (!child.IsVisible || GetRowSpan(child) != rowspan || !IsInRow(child, i) || NumberOfUnsetRowHeight(child) > 1)
{
continue;
}
double assignedHeight = GetAssignedRowHeight(child);
// If we already have column width info, use it when measuring
double assignedWidth = GetAssignedColumnWidth(child);
var wConstraint = assignedWidth > 0 ? assignedWidth : widthConstraint;
SizeRequest sizeRequest = child.Measure(wConstraint, heightConstraint, MeasureFlags.IncludeMargins);
var rowSpacing = (GetRowSpan(child) - 1) * RowSpacing;
actualHeight = Math.Max(actualHeight, sizeRequest.Request.Height - assignedHeight - rowSpacing);
minimumHeight = Math.Max(minimumHeight, sizeRequest.Minimum.Height - assignedHeight - rowSpacing);
}
if (actualHeight >= 0)
{
row.ActualHeight = actualHeight;
}
if (minimumHeight >= 0)
{
row.MinimumHeight = minimumHeight;
}
}
}
}
starRowHeight = 0;
for (var index = 0; index < _rows.Count; index++)
{
RowDefinition row = _rows[index];
if (!row.Height.IsStar || row.Height.Value == 0 || row.ActualHeight <= 0)
{
continue;
}
starRowHeight += row.ActualHeight;
}
return(Math.Max(starRowHeight / totalStarsHeight, 1));
}
double MeasuredStarredColumns(double widthConstraint, double heightConstraint, double totalStarsWidth)
{
double starColWidth;
for (var iteration = 0; iteration < 2; iteration++)
{
for (var colspan = 1; colspan <= _columns.Count; colspan++)
{
for (var i = 0; i < _columns.Count; i++)
{
ColumnDefinition col = _columns[i];
if (!col.Width.IsStar)
{
continue;
}
if (col.ActualWidth >= 0) // if Actual is already set (by a smaller span), skip
{
continue;
}
double actualWidth = col.ActualWidth;
double minimumWidth = col.MinimumWidth;
for (var index = 0; index < InternalChildren.Count; index++)
{
var child = (View)InternalChildren[index];
if (!child.IsVisible || GetColumnSpan(child) != colspan || !IsInColumn(child, i) || NumberOfUnsetColumnWidth(child) > 1)
{
continue;
}
double assignedWidth = GetAssignedColumnWidth(child);
// If we already have row height info, use it when measuring
double assignedHeight = GetAssignedRowHeight(child);
var hConstraint = assignedHeight > 0 ? assignedHeight : heightConstraint;
SizeRequest sizeRequest = child.Measure(widthConstraint, hConstraint, MeasureFlags.IncludeMargins);
var columnSpacing = (GetColumnSpan(child) - 1) * ColumnSpacing;
actualWidth = Math.Max(actualWidth, sizeRequest.Request.Width - assignedWidth - columnSpacing);
minimumWidth = Math.Max(minimumWidth, sizeRequest.Minimum.Width - assignedWidth - columnSpacing);
}
if (actualWidth >= 0)
{
col.ActualWidth = actualWidth;
}
if (minimumWidth >= 0)
{
col.MinimumWidth = minimumWidth;
}
}
}
}
starColWidth = 0;
for (var index = 0; index < _columns.Count; index++)
{
ColumnDefinition col = _columns[index];
if (!col.Width.IsStar || col.Width.Value == 0 || col.ActualWidth <= 0)
{
continue;
}
starColWidth += col.ActualWidth;
}
return(Math.Max(starColWidth / totalStarsWidth, 1));
}
protected override SizeRequest OnSizeRequest(double widthConstraint, double heightConstraint)
{
SizeRequest desiredSize = base.OnSizeRequest(double.PositiveInfinity, double.PositiveInfinity);
double desiredAspect = desiredSize.Request.Width / desiredSize.Request.Height;
double constraintAspect = widthConstraint / heightConstraint;
double desiredWidth = desiredSize.Request.Width;
double desiredHeight = desiredSize.Request.Height;
if (desiredWidth == 0 || desiredHeight == 0)
{
return(new SizeRequest(new Size(0, 0)));
}
double width = desiredWidth;
double height = desiredHeight;
if (constraintAspect > desiredAspect)
{
// constraint area is proportionally wider than image
switch (Aspect)
{
case Aspect.AspectFit:
case Aspect.AspectFill:
height = Math.Min(desiredHeight, heightConstraint);
width = desiredWidth * (height / desiredHeight);
break;
case Aspect.Fill:
width = Math.Min(desiredWidth, widthConstraint);
height = desiredHeight * (width / desiredWidth);
break;
}
}
else if (constraintAspect < desiredAspect)
{
// constraint area is proportionally taller than image
switch (Aspect)
{
case Aspect.AspectFit:
case Aspect.AspectFill:
width = Math.Min(desiredWidth, widthConstraint);
height = desiredHeight * (width / desiredWidth);
break;
case Aspect.Fill:
height = Math.Min(desiredHeight, heightConstraint);
width = desiredWidth * (height / desiredHeight);
break;
}
}
else
{
// constraint area is same aspect as image
width = Math.Min(desiredWidth, widthConstraint);
height = desiredHeight * (width / desiredWidth);
}
return(new SizeRequest(new Size(width, height)));
}
public static SizeRequest Measure(
IImageController ImageElementManager,
SizeRequest desiredSize,
double widthConstraint,
double heightConstraint)
{
double desiredAspect = desiredSize.Request.Width / desiredSize.Request.Height;
double constraintAspect = widthConstraint / heightConstraint;
double desiredWidth = desiredSize.Request.Width;
double desiredHeight = desiredSize.Request.Height;
if (desiredWidth == 0 || desiredHeight == 0)
{
return(new SizeRequest(new Size(0, 0)));
}
double width = desiredWidth;
double height = desiredHeight;
if (constraintAspect > desiredAspect)
{
// constraint area is proportionally wider than image
switch (ImageElementManager.Aspect)
{
case Aspect.AspectFit:
case Aspect.AspectFill:
height = Math.Min(desiredHeight, heightConstraint);
width = desiredWidth * (height / desiredHeight);
break;
case Aspect.Fill:
width = Math.Min(desiredWidth, widthConstraint);
height = desiredHeight * (width / desiredWidth);
break;
}
}
else if (constraintAspect < desiredAspect)
{
// constraint area is proportionally taller than image
switch (ImageElementManager.Aspect)
{
case Aspect.AspectFit:
case Aspect.AspectFill:
width = Math.Min(desiredWidth, widthConstraint);
height = desiredHeight * (width / desiredWidth);
break;
case Aspect.Fill:
height = Math.Min(desiredHeight, heightConstraint);
width = desiredWidth * (height / desiredHeight);
break;
}
}
else
{
// constraint area is same aspect as image
width = Math.Min(desiredWidth, widthConstraint);
height = desiredHeight * (width / desiredWidth);
}
return(new SizeRequest(new Size(width, height)));
}