Hi Marcel,

Wouldn't it be better to skip the extra variable?

 	arrangement ifNotEmpty: [arrangement first addExtraSpace: 0 @ extra]

vs

 	arrangement ifNotEmpty: [:cells | cells first addExtraSpace: 0 @ extra]


Levente

On Sat, 4 Apr 2020, commits at source.squeak.org wrote:

> Marcel Taeumel uploaded a new version of Morphic to project The Trunk:
> http://source.squeak.org/trunk/Morphic-mt.1643.mcz
>
> ==================== Summary ====================
>
> Name: Morphic-mt.1643
> Author: mt
> Time: 4 April 2020, 11:06:42.760864 am
> UUID: 81efe0e9-ec69-1b45-ba8e-b81bbb649355
> Ancestors: Morphic-mt.1642
>
> Fixes the recently discovered layout bug. Thanks to Christoph (ct)!
>
> =============== Diff against Morphic-mt.1642 ===============
>
> Item was changed:
>  ----- Method: TableLayout>>computeExtraSpacing:in:horizontal:target: (in category 'layout') -----
>  computeExtraSpacing: arrangement in: newBounds horizontal: aBool target: aMorph
>  	"Compute the required extra spacing for laying out the cells"
>
>  	"match newBounds extent with arrangement's orientation"
>
>  	| extent extra centering n extraPerCell cell last hFill vFill max amount allow |
>  	extent := newBounds extent.
>  	aBool ifFalse: [extent := extent transposed].
>
>  	"figure out if we have any horizontal or vertical space fillers"
>  	hFill := vFill := false.
>  	max := 0 @ 0.
>  	arrangement do:
>  			[:c |
>  			max := (max x max: c cellSize x) @ (max y + c cellSize y).
>  			max := max max: c cellSize.
>  			hFill := hFill or: [c hSpaceFill].
>  			vFill := vFill or: [c vSpaceFill]].
>
>  	"Take client's shrink wrap constraints into account.
>  	Note: these are only honored when there are no #spaceFill children,
>  	or when #rubberBandCells is set."
>  	allow := properties rubberBandCells not.
>  	aMorph hResizing == #shrinkWrap
>  		ifTrue:
>  			[aBool
>  				ifTrue: [allow & hFill ifFalse: [extent := max x @ (max y max: extent y)]]
>  				ifFalse: [allow & vFill ifFalse: [extent := (max x max: extent x) @ max y]]].
>  	aMorph vResizing == #shrinkWrap
>  		ifTrue:
>  			[aBool
>  				ifFalse: [allow & hFill ifFalse: [extent := max x @ (max y max: extent y)]]
>  				ifTrue: [allow & vFill ifFalse: [extent := (max x max: extent x) @ max y]]].
>
>  	"Now compute the extra v space"
>  	extra := extent y
>  				- (arrangement inject: 0 into: [:sum :c | sum + c cellSize y]).
>  	extra > 0
>  		ifTrue:
>  			["Check if we have any #spaceFillers"
>
>  			vFill
>  				ifTrue:
>  					["use only #spaceFillers"
>
>  					n := arrangement inject: 0
>  								into: [:sum :c | c vSpaceFill ifTrue: [sum + 1] ifFalse: [sum]].
>  					n isZero ifFalse: [extraPerCell := extra asFloat / n asFloat].
>  					extra := last := 0.
>  					arrangement do:
>  							[:c |
>  							c vSpaceFill
>  								ifTrue:
>  									[extra := (last := extra) + extraPerCell.
>  									amount := 0 @ (extra truncated - last truncated).
>  									c do: [:cc | cc cellSize: cc cellSize + amount]]]]
>  				ifFalse:
>  					["no #spaceFillers; distribute regularly"
>
>  					centering := properties wrapCentering.
>  					"centering == #topLeft ifTrue:[]."	"add all extra space to the last cell; e.g., do nothing"
>  					centering == #bottomRight
>  						ifTrue:
>  							["add all extra space to the first cell"
> 
> + 							arrangement ifNotEmpty: [:cells | cells first addExtraSpace: 0 @ extra]].
> - 							arrangement first addExtraSpace: 0 @ extra].
>  					centering == #center
>  						ifTrue:
>  							["add 1/2 extra space to the first and last cell"
> 
> + 							arrangement ifNotEmpty: [:cells | cells first addExtraSpace: 0 @ (extra // 2)]].
> - 							arrangement first addExtraSpace: 0 @ (extra // 2)].
>  					centering == #justified
>  						ifTrue:
>  							["add extra space equally distributed to each cell"
>
>  							n := arrangement size - 1 max: 1.
>  							extraPerCell := extra asFloat / n asFloat.
>  							extra := last := 0.
>  							arrangement do:
>  									[:c |
>  									c addExtraSpace: 0 @ (extra truncated - last truncated).
>  									extra := (last := extra) + extraPerCell]]]].
>
>  	"Now compute the extra space for the primary direction"
>  	centering := properties listCentering.
>  	1 to: arrangement size
>  		do:
>  			[:i |
>  			cell := arrangement at: i.
>  			extra := extent x - cell cellSize x.
>  			extra > 0
>  				ifTrue:
>  					["Check if we have any #spaceFillers"
>  					cell := cell nextCell.
>  					cell hSpaceFill
>  						ifTrue:
>  							["use only #spaceFillers"
>
>
>  							n := cell inject: 0
>  										into: [:sum :c | c hSpaceFill ifTrue: [sum + c target spaceFillWeight] ifFalse: [sum]].
>  							n isZero ifFalse: [extraPerCell := extra asFloat / n asFloat].
>  							extra := last := 0.
>  							cell do:
>  									[:c |
>  									c hSpaceFill
>  										ifTrue:
>  											[extra := (last := extra) + (extraPerCell * c target spaceFillWeight).
>  											amount := extra truncated - last truncated.
>  											c cellSize: c cellSize + (amount @ 0)]]]
>  						ifFalse:
>  							["no #spaceFiller; distribute regularly"
>
>
>  							"centering == #topLeft ifTrue:[]"	"add all extra space to the last cell; e.g., do nothing"
>  							centering == #bottomRight
>  								ifTrue:
>  									["add all extra space to the first cell"
>
>  									cell addExtraSpace: extra @ 0].
>  							centering == #center
>  								ifTrue:
>  									["add 1/2 extra space to the first and last cell"
>
>  									cell addExtraSpace: (extra // 2) @ 0].
>  							centering == #justified
>  								ifTrue:
>  									["add extra space equally distributed to each cell"
>
>  									n := cell size - 1 max: 1.
>  									extraPerCell := extra asFloat / n asFloat.
>  									extra := last := 0.
>  									cell do:
>  											[:c |
>  											c addExtraSpace: (extra truncated - last truncated) @ 0.
>  											extra := (last := extra) + extraPerCell]]]]]!