"requires: graphics."

Graphics addSlot: #SpaceRequirement valued: Object derive.
SpaceRequirement addSlot: #preferredWidth valued: 0.
SpaceRequirement addSlot: #preferredHeight valued: 0.
SpaceRequirement addSlot: #maxX.
SpaceRequirement addSlot: #maxY.
SpaceRequirement addSlot: #minX.
SpaceRequirement addSlot: #minY.
"The size slots are points specifying (width,height) parameters for each
requested option. The coordinates may be dimensioned, but if not, are
interpreted as fractions of the container size. If Nil, min and max default
to the preferred values. Don't access the fooX slots directly, as they have
wrappers to handle defaults."

sr@(SpaceRequirement traits) newPreferred: pref max: max min: min
[| newSR |
  newSR: sr clone.
  newSR preferredWidth: pref x.
  newSR preferredHeight: pref y.
  newSR maxX: max x.
  newSR maxY: max y.
  newSR minX: min x.
  newSR minY: min y.
  newSR
].

Graphics addSlot: #EmptySpaceRequirement
	 valued: (SpaceRequirement newPreferred: Point origin
	    max: Point origin min: Point origin).

sr@(SpaceRequirement traits) zero
"A convenient accessor."
[EmptySpaceRequirement].

sr@(SpaceRequirement traits) reset
"Resets all parameters, causing the defaults to be active."
[
  sr preferredWidth: Nil.
  sr preferredHeight: Nil.
  sr maxX: Nil.
  sr maxY: Nil.
  sr minX: Nil.
  sr minY: Nil.
  sr
].

sr@(SpaceRequirement traits) minWidth
[
  sr minX ifNil: [sr preferredWidth]
].

sr@(SpaceRequirement traits) minHeight
[
  sr minY ifNil: [sr preferredHeight]
].

sr@(SpaceRequirement traits) maxWidth
[
  sr maxX ifNil: [sr preferredWidth]
].

sr@(SpaceRequirement traits) maxHeight
[
  sr maxY ifNil: [sr preferredHeight]
].

sr@(SpaceRequirement traits) minWidth: n
[
  sr minX: n
].

sr@(SpaceRequirement traits) minHeight: n
[
  sr minY: n
].

sr@(SpaceRequirement traits) maxWidth: n
[
  sr maxX: n
].

sr@(SpaceRequirement traits) maxHeight: n
[
  sr maxY: n
].

sr@(SpaceRequirement traits) preferredSize
[
  Point x: sr preferredWidth y: sr preferredHeight
].

sr@(SpaceRequirement traits) preferredSize: n@(Number traits)
[
  sr preferredX: n.
  sr preferredY: n.
  n
].

sr@(SpaceRequirement traits) preferredSize: p@(Point traits)
[
  sr preferredX: p x.
  sr preferredY: p y.
  p
].

sr1@(SpaceRequirement traits) with: sr2@(SpaceRequirement traits) collect: block
"Returns a new SpaceRequirement, whose slots are the results of applying the
given block to each pair of slots from the originals."
[| r |
  r: sr1 clone.
  r preferredWidth: (block value: r preferredWidth value: sr2 preferredWidth).
  r preferredHeight: (block value: r preferredHeight value: sr2 preferredHeight).
  r maxX: (block value: r maxWidth value: sr2 maxWidth).
  r maxY: (block value: r maxHeight value: sr2 maxHeight).
  r minX: (block value: r maxWidth value: sr2 maxWidth).
  r minY: (block value: r maxHeight value: sr2 maxHeight).
  r
].

sr@(SpaceRequirement traits) collect: block
"Returns a new SpaceRequirement, whose slots are the results of applying the
given block to each slot value in the original."
[| r |
  r: sr clone.
  r preferredWidth: (block value: r preferredWidth).
  r preferredHeight: (block value: r preferredHeight).
  r maxX: (block value: r maxWidth).
  r maxY: (block value: r maxHeight).
  r minX: (block value: r maxWidth).
  r minY: (block value: r maxHeight).
  r
].

sr1@(SpaceRequirement traits) + sr2@(SpaceRequirement traits)
[sr1 with: sr2 collect: [| :a :b | a + b]].

sr1@(SpaceRequirement traits) - sr2@(SpaceRequirement traits)
[sr1 with: sr2 collect: [| :a :b | a - b]].

sr@(SpaceRequirement traits) * n
[sr collect: [| :dim | dim * n]].

sr@(SpaceRequirement traits) / n
[sr collect: [| :dim | dim / n]].

sr@(SpaceRequirement traits) + n@(Magnitude traits)
[sr collect: [| :dim | dim * n]].

sr@(SpaceRequirement traits) - n@(Magnitude traits)
[sr collect: [| :dim | dim - n]].

SceneElement addSlot: #spaceRequirements valued: SpaceRequirement zero.

se@(SceneElement traits) emptySpaceRequirement
"This returns the default space requirements for leaf elements. Override
it as necessary."
[
  SpaceRequirement zero
].

se@(SceneElement traits) childrensSpaceRequirements
[
  se children collect: [| :each | each spaceRequirements]
].

se@(SceneElement traits) composeSpace
[| newSR |
  newSR: se emptySpaceRequirement clone.
  se childrensSpaceRequirements do: [| :each |
    newSR preferredWidth: newSR preferredWidth + each preferredWidth.
    newSR maxWidth: newSR maxWidth + each maxWidth.
    newSR minWidth: newSR minWidth + each minWidth.
    newSR preferredHeight: newSR preferredHeight + each preferredHeight.
    newSR maxHeight: newSR maxHeight + each maxHeight.
    newSR minHeight: newSR minHeight + each minHeight].
  newSR
].

se@(SceneElement traits) spaceRequirements: sr@(SpaceRequirement traits)
[
  resend.
  se treeParent ifNotNil: [se treeParent noteSpaceRequirementsChangedFor: se]
].

se@(SceneElement traits) noteSpaceRequirementsChangedFor: ch@(SceneElement traits)
"This is the size update notification handler. Override this to invoke
different sizing behaviors."
[
  se spaceRequirements: se composeSpaceRequirements
].

Graphics addSlot: #Alignment valued: SceneElement derive.

Graphics addSlot: #HorizontalAlignment valued: Alignment derive.

Graphics addSlot: #VerticalAlignment valued: Alignment derive.

Graphics addSlot: #Layout valued: Morph derive.
Layout addSlot: #xSpacing valued: 0.
Layout addSlot: #ySpacing valued: 0.
"x and y-spacing specify how much space should be between submorphs."
Layout addSlot: #alignmentX.
Layout addSlot: #alignmentY.
"Alignment values can be one of those below or Nil, which specifies none."

Graphics addSlot: #HorizontalAlignments
  valued: ({#left. #center. #right} as: ExtensibleSequence).
Graphics addSlot: #VerticalAlignments
  valued: ({#top. #center. #bottom} as: ExtensibleSequence).

lm@(Layout traits) spacing
[Point x: lm xSpacing y: lm ySpacing].

lm@(Layout traits) spacing: p@(Point traits)
[
  lm xSpacing: p x.
  lm ySpacing: p y.
  p
].

Graphics addSlot: #HBox valued: Layout derive.

hb@(HBox traits) composeSpace
[| newSR |
  newSR: hb emptySpaceRequirement clone.
  hb childrensSpaceRequirements do: [| :each |
    newSR preferredHeight: newSR preferredHeight + each preferredHeight.
    newSR preferredWidth: (newSR preferredWidth max: each preferredWidth).
    newSR maxHeight: (newSR maxHeight max: each maxHeight).
    newSR maxWidth: newSR maxWidth + each maxWidth.
    newSR minHeight: (newSR minHeight max: each minHeight).
    newSR minWidth: newSR minWidth + each minWidth].
  newSR
].

Graphics addSlot: #VBox valued: Layout derive.

vb@(VBox traits) composeSpace
[| newSR |
  newSR: vb emptySpaceRequirement clone.
  vb childrensSpaceRequirements do: [| :each |
    newSR preferredHeight: newSR preferredHeight + each preferredHeight.
    newSR preferredWidth: (newSR preferredWidth max: each preferredWidth).
    newSR maxHeight: newSR maxHeight + each maxHeight.
    newSR maxWidth: (newSR maxWidth max: each maxWidth).
    newSR minHeight: newSR minHeight + each minHeight.
    newSR minWidth: (newSR minWidth max: each minWidth)].
  newSR
].

Graphics addSlot: #Rack valued: Layout derive.

"Racks hold many elements in a row of the same element thickness. It will
regularize the elements' thicknesses when composing them as best it can."

Graphics addSlot: #HRack valued: Rack derive.

hr@(HRack traits) composeSpace
[| newSR unitSR |
  newSR: hr emptySpaceRequirement clone.
  unitSR: EmptySpaceRequirement.
  hr childrensSpaceRequirements do: [| :each |
    newSR preferredHeight: (height max: each preferredHeight).
    unitSR preferredWidth: (width max: each preferredWidth).
    newSR maxHeight: (newSR maxHeight max: each maxHeight).
    unitSR maxWidth: (newSR maxWidth max: each maxWidth).
    newSR minHeight: (newSR minHeight max: each minHeight).
    unitSR minWidth: (newSR minWidth max: each minWidth)].
  newSR: newSR + unitSR * hr children size.
  newSR
].

Graphics addSlot: #VRack valued: Rack derive.

vr@(VRack traits) composeSpace
[| newSR unitSR |
  newSR: vr emptySpaceRequirement clone.
  unitSR: EmptySpaceRequirement.
  vr childrensSpaceRequirements do: [| :each |
    unitSR preferredHeight: (height max: each preferredHeight).
    newSR preferredWidth: (width max: each preferredWidth).
    unitSR maxHeight: (newSR maxHeight max: each maxHeight).
    newSR maxWidth: (newSR maxWidth max: each maxWidth).
    unitSR minHeight: (newSR minHeight max: each minHeight).
    newSR minWidth: (newSR minWidth max: each minWidth)].
  newSR: newSR + unitSR * vr children size.
  newSR
].

Graphics addSlot: #Stack valued: Layout derive.
"Lays out elements one on top of the next, with an alignment."

Graphics addSlot: #Table valued: Layout derive.
"Lays out a 2-dimensional spread of rows and columns of elements."
Table addSlot: numRows valued: 0.
Table addSlot: numColumns valued: 0.
Table addSlot: rowHeights.
Table addSlot: rowWidths.

Graphics addSlot: #Grid valued: Layout derive.
"Same as a Table, but each cell is of the same size."

Graphics addSlot: #Spacing valued: Layout derive.
"Lays out exactly one child with a spacing border."

Graphics addSlot: #Border valued: Layout derive.
"Same as a Spacing, but with a drawn border."

Graphics addSlot: #Restraint valued: Layout derive.
"Prevents the size constraints of the child from propagating beyond
this element."
rm@(Restraint traits) noteSpaceRequirementsChangedFor: ch@(Morph traits)
"Do nothing."
[].

Graphics addSlot: #BulletinBoard valued: Layout derive.
"Same as Squeak's PasteUpMorph, it preserves location and size of contents."