measure.md

Pipeline

Tapin Order

• validate
• validateVisibility
• applyTemplate
• checkNeedMeasure
• invalidateFuture
• prepareOverride
• doOverride
  • Assign desiredSize based on compilation of child desiredSize.
• completeOverride
• finishDesired

Legacy

_DoMeasureWithError

• Use PreviousConstraint as availableSize to initiate start of measure traversal
• Fall back to infinite size for availableSize if root layout container is not attached and no PreviousConstraint
• [#_Measure]
• Invalidates visual parent's measure if DesiredSize changed
• Clear dirty flags

_Measure

• Validate availableSize isn't NaN
• If Collapsed: set PreviousConstraint to availableSize, clear DesiredSize, skip out
• Memoized ApplyTemplate
• If does not have dirty measure flag and PreviousConstraint equals null or availableSize: skip out
• Save availableSize to PreviousConstraint
• Invalidate Arrange
• Update Bounds
• Shrink available by Margin
• Coerce availableSize (Width, MinWidth, MaxWidth, Height, MinHeight, MaxHeight, UseLayoutRounding)
• [#MeasureOverride] -> response
• Save response as HiddenDesire
• Clear dirty flags
• If root or parent is Canvas and is Canvas: clear DesiredSize, skip out
• Coerce response
• Grow by Margin
• Set response to min of response and availableSize
• Round if UseLayoutRounding
• Set DesiredSize to response

MeasureOverride

• Control-specific layout
• Falls into children [#_Measure]