The Trunk: Multilingual-tpr.170.mcz

tim Rowledge uploaded a new version of Multilingual to project The Trunk:
http://source.squeak.org/trunk/Multilingual-tpr.170.mcz

==================== Summary ====================

Name: Multilingual-tpr.170
Author: tpr
Time: 23 September 2013, 12:44:13.669 pm
UUID: 497191bf-6012-4d54-916f-7717184d313a
Ancestors: Multilingual-nice.169

A first step in improvingthe characterscanner tree(s);
mostly split out kerning and non-kerning scanning. Also add some guide comments for later parts of the work, so some methods are only changed in comment.

=============== Diff against Multilingual-nice.169 ===============

Item was changed:
  ----- Method: EncodedCharSet class>>scanSelector (in category 'accessing - displaying') -----
  scanSelector
+ "This appears to be redundant - possibly once used as a default and now usurped by LanguageEnvironmet class>scanSelector ?"
  ^ #scanMultiCharactersFrom:to:in:rightX:stopConditions:kern:!

Item was changed:
  ----- Method: LanguageEnvironment class>>scanSelector (in category 'language methods') -----
  scanSelector
+ "return a message to send  to scan multi-byte characters - default when EncodedCharSet has no entry at the required encoding"
-
  ^ #scanMultiCharactersFrom:to:in:rightX:stopConditions:kern:
  !

Item was changed:
  ----- Method: MultiCharacterScanner>>addCharToPresentation: (in category 'multilingual scanning') -----
  addCharToPresentation: char
+ "appears to be unused"
  lastWidth := self widthOf: char inFont: font.
  destX := destX + lastWidth.!

Item was changed:
  ----- Method: MultiCharacterScanner>>basicScanCharactersFrom:to:in:rightX:stopConditions:kern: (in category 'scanning') -----
+ basicScanCharactersFrom: startIndex to: stopIndex in: sourceString rightX: rightX stopConditions: stops kern: kernDelta
+ "In ancient days this would have called primitive 103 to scan a string with StrikeFont, but time moves on. See historicalScanCharactersFrom:to:in:rightX:stopConditions:kern: if you're curious. This code handles the newer shape of CharacterScanner but does *no* pair kerning.
+ There is a pretty deep assumption of simple ASCII strings and characters - beware"
+ | ascii nextDestX char |
- basicScanCharactersFrom: startIndex to: stopIndex in: sourceString rightX: rightX stopConditions: stops kern: kernDelta
- "Primitive. This is the inner loop of text display--but see
- scanCharactersFrom: to:rightX: which would get the string,
- stopConditions and displaying from the instance. March through source
- String from startIndex to stopIndex. If any character is flagged with a
- non-nil entry in stops, then return the corresponding value. Determine
- width of each character from xTable, indexed by map.
- If dextX would exceed rightX, then return stops at: 258.
- Advance destX by the width of the character. If stopIndex has been
- reached, then return stops at: 257. Optional.
- See Object documentation whatIsAPrimitive."
- | ascii nextDestX char floatDestX widthAndKernedWidth nextChar atEndOfRun |
- <primitive: 103>
  lastIndex := startIndex.
- floatDestX := destX.
- widthAndKernedWidth := Array new: 2.
- atEndOfRun := false.
  [lastIndex <= stopIndex]
+ whileTrue: [
+ "get the character value"
+ char := sourceString at: lastIndex.
- whileTrue:
- [char := (sourceString at: lastIndex).
  ascii := char asciiValue + 1.
+ "if there is an entry in 'stops' for this value, return it"
+ (stops at: ascii)
+ ifNotNil: [^ stops at: ascii].
+ "bump nextDestX by the width of the current character"
+ nextDestX := destX + (font widthOf: char).
+ "if the next x is past the right edge, return crossedX"
+ nextDestX > rightX
+ ifTrue: [^ stops crossedX].
+ "update destX and incorporate thr kernDelta"
+ destX := nextDestX + kernDelta.
- (stops at: ascii) == nil ifFalse: [^stops at: ascii].
- "Note: The following is querying the font about the width
- since the primitive may have failed due to a non-trivial
- mapping of characters to glyphs or a non-existing xTable."
- nextChar := (lastIndex + 1 <= stopIndex)
- ifTrue:[sourceString at: lastIndex + 1]
- ifFalse:[
- atEndOfRun := true.
- "if there is a next char in sourceString, then get the kern
- and store it in pendingKernX"
- lastIndex + 1 <= sourceString size
- ifTrue:[sourceString at: lastIndex + 1]
- ifFalse:[ nil]].
- font
- widthAndKernedWidthOfLeft: char
- right: nextChar
- into: widthAndKernedWidth.
- nextDestX := floatDestX + (widthAndKernedWidth at: 1).
- nextDestX > rightX ifTrue: [^stops crossedX].
- floatDestX := floatDestX + kernDelta + (widthAndKernedWidth at: 2).
- atEndOfRun
- ifTrue:[
- pendingKernX := (widthAndKernedWidth at: 2) - (widthAndKernedWidth at: 1).
- floatDestX := floatDestX - pendingKernX].
- destX := floatDestX.
  lastIndex := lastIndex + 1].
  lastIndex := stopIndex.
+ ^ stops endOfRun!
- ^stops endOfRun!

Item was added:
+ ----- Method: MultiCharacterScanner>>basicScanKernableCharactersFrom:to:in:rightX:stopConditions:kern: (in category 'scanning') -----
+ basicScanKernableCharactersFrom: startIndex to: stopIndex in: sourceString rightX: rightX stopConditions: stops kern: kernDelta
+ "In ancient days this would have called primitive 103 to scan a string with StrikeFont, but time moves on. See historicalScanCharactersFrom:to:in:rightX:stopConditions:kern: if you're curious. This code handles the newer shape of CharacterScanner and provides some support for fonts that have pair-kerning; this may be removable with some better factoring.
+ There is a pretty deep assumption of simple ASCII strings and characters - beware"
+ | ascii nextDestX char floatDestX widthAndKernedWidth nextCharOrNil atEndOfRun |
+ lastIndex := startIndex.
+ floatDestX := destX.
+ widthAndKernedWidth := Array new: 2.
+ atEndOfRun := false.
+ [lastIndex <= stopIndex]
+ whileTrue: [
+ "get the character value"
+ char := sourceString at: lastIndex.
+ ascii := char asciiValue + 1.
+ "if there is an entry in 'stops' for this value, return it"
+ (stops at: ascii)
+ ifNotNil: [^ stops at: ascii].
+ "get the next character..."
+ nextCharOrNil := lastIndex + 1 <= stopIndex
+ ifTrue: [sourceString at: lastIndex + 1]
+ ifFalse: ["if we're at or past the stopIndex, see if there is anything in the full string"
+ atEndOfRun := true.
+ lastIndex + 1 <= sourceString size
+ ifTrue: [sourceString at: lastIndex + 1]].
+ "get the font's kerning info for the pair of current character and next character"
+ "for almost all fonts in common use this is a waste of time since they don't support pair kerning and both values are #widthOf: char"
+ font
+ widthAndKernedWidthOfLeft: char
+ right: nextCharOrNil
+ into: widthAndKernedWidth.
+ "bump nextDestX by the width of the current character"
+ nextDestX := floatDestX
+ + (widthAndKernedWidth at: 1).
+ "if the next x is past the right edge, return crossedX"
+ nextDestX > rightX
+ ifTrue: [^ stops crossedX].
+ "bump floatDestX by the *kerned* width of the current
+ character, which is where the *next* char will go"
+ floatDestX := floatDestX + kernDelta
+ + (widthAndKernedWidth at: 2).
+ "if we are at the end of this run we keep track of the
+ character-kern-delta for possible later use and then rather
+ insanely remove that character-kern-delta from floatDestX,
+ making it equivalent to (old floatDestX) + kernDelta +
+ width-of-character - no idea why"
+ atEndOfRun
+ ifTrue: [pendingKernX := (widthAndKernedWidth at: 2)
+ - (widthAndKernedWidth at: 1).
+ floatDestX := floatDestX - pendingKernX].
+ "save the next x for next time around the loop"
+ destX := floatDestX.
+ lastIndex := lastIndex + 1].
+ lastIndex := stopIndex.
+ ^ stops endOfRun!

Item was changed:
  ----- Method: MultiCharacterScanner>>combinableChar:for: (in category 'scanner methods') -----
  combinableChar: char for: prevEntity
+ "appears to be unused"
-
  !

Item was changed:
  ----- Method: MultiCharacterScanner>>removeLastCharFromPresentation (in category 'multilingual scanning') -----
  removeLastCharFromPresentation
+ "appears to be unused"
  destX := destX - lastWidth.
  !

Item was changed:
  ----- Method: MultiCharacterScanner>>scanCharactersFrom:to:in:rightX:stopConditions:kern: (in category 'scanning') -----
+ scanCharactersFrom: startIndex to: stopIndex in: sourceString rightX: rightX stopConditions: stops kern: kernDelta
- scanCharactersFrom: startIndex to: stopIndex in: sourceString rightX: rightX stopConditions: stops kern: kernDelta
-
  | startEncoding selector |
+ sourceString isByteString
+ ifTrue: [font isPairKerningCapable
+ ifTrue: [^ self
+ basicScanKernableCharactersFrom: startIndex
+ to: (stopIndex min: sourceString size)
+ in: sourceString
+ rightX: rightX
+ stopConditions: stops
+ kern: kernDelta]
+ ifFalse: [^ self
+ basicScanCharactersFrom: startIndex
+ to: (stopIndex min: sourceString size)
+ in: sourceString
+ rightX: rightX
+ stopConditions: stops
+ kern: kernDelta]].
+ sourceString isWideString
+ ifTrue: [startIndex > stopIndex
+ ifTrue: [lastIndex := stopIndex.
+ ^ stops endOfRun].
+ startEncoding := (sourceString at: startIndex) leadingChar.
+ selector := EncodedCharSet scanSelectorAt: startEncoding.
+ ^ self
+ perform: selector
+ withArguments: (Array
+ with: startIndex
+ with: stopIndex
+ with: sourceString
+ with: rightX
+ with: stops
+ with: kernDelta)].
+ ^ stops endOfRun!
- (sourceString isByteString) ifTrue: [^ self basicScanCharactersFrom: startIndex to: stopIndex in: sourceString rightX: rightX stopConditions: stops kern: kernDelta.].
-
- (sourceString isWideString) ifTrue: [
- startIndex > stopIndex ifTrue: [lastIndex := stopIndex. ^ stops endOfRun].
- startEncoding :=  (sourceString at: startIndex) leadingChar.
- selector := EncodedCharSet scanSelectorAt: startEncoding.
- ^ self perform: selector withArguments: (Array with: startIndex with: stopIndex with: sourceString with: rightX with: stops with: kernDelta).
- ].
-
- ^ stops endOfRun
- !

Item was changed:
  ----- Method: MultiCharacterScanner>>scanMultiCharactersCombiningFrom:to:in:rightX:stopConditions:kern: (in category 'scanner methods') -----
  scanMultiCharactersCombiningFrom: startIndex to: stopIndex in: sourceString rightX: rightX stopConditions: stops kern: kernDelta
+ "appears to be unused"
-
  | charCode encoding f startEncoding combining combined combiningIndex c |
  lastIndex := startIndex.
  lastIndex > stopIndex ifTrue: [lastIndex := stopIndex. ^ stops endOfRun].
  startEncoding := (sourceString at: startIndex) leadingChar.
  font ifNil: [font := (TextConstants at: #DefaultMultiStyle) fontArray at: 1].
  ((font isMemberOf: StrikeFontSet) or: [font isKindOf: TTCFontSet]) ifTrue: [
  f := [font fontArray at: startEncoding + 1]
  on: Exception do: [:ex | nil].
  f ifNil: [ f := font fontArray at: 1].
  ].
 
  spaceWidth := font widthOf: Space.
  combining := nil.
  [lastIndex <= stopIndex] whileTrue: [
  charCode := (sourceString at: lastIndex) charCode.
  c := (sourceString at: lastIndex).
  combining ifNil: [
  combining := CombinedChar new.
  combining add: c.
  combiningIndex := lastIndex.
  lastIndex := lastIndex + 1.
  ] ifNotNil: [
  (combining add: c) ifFalse: [
  self addCharToPresentation: (combined := combining combined).
  combining := CombinedChar new.
  combining add: c.
  charCode := combined charCode.
  encoding := combined leadingChar.
  encoding ~= startEncoding ifTrue: [lastIndex := lastIndex - 1.
  (encoding = 0 and: [charCode < 256 and:[(stops at: charCode + 1) notNil]]) ifTrue: [
  ^ stops at: charCode + 1
  ] ifFalse: [
  ^ stops endOfRun
  ].
  ].
  (encoding = 0 and: [charCode < 256 and:[(stops at: charCode + 1) notNil]]) ifTrue: [
  combining ifNotNil: [
  self addCharToPresentation: (combining combined).
  ].
  ^ stops at: charCode + 1
  ].
  (self isBreakableAt: lastIndex in: sourceString in: Latin1Environment) ifTrue: [
  self registerBreakableIndex.
  ].
  destX > rightX ifTrue: [
  destX ~= firstDestX ifTrue: [
  lastIndex := combiningIndex.
  self removeLastCharFromPresentation.
  ^ stops crossedX]].
  combiningIndex := lastIndex.
  lastIndex := lastIndex + 1.
  ] ifTrue: [
  lastIndex := lastIndex + 1.
  numOfComposition := numOfComposition + 1.
  ].
  ].
  ].
  lastIndex := stopIndex.
  combining ifNotNil: [
  combined := combining combined.
  self addCharToPresentation: combined.
  ].
  ^ stops endOfRun!

Item was changed:
  ----- Method: MultiCompositionScanner>>addCharToPresentation: (in category 'multilingual scanning') -----
  addCharToPresentation: char
+ "appears to be unused, see also scanMultiCharactersCombiningFrom:to:in:rightX:stopConditions:kern:"
-
  presentation nextPut: char.
  super addCharToPresentation: char!

Item was changed:
  ----- Method: MultiCompositionScanner>>removeLastCharFromPresentation (in category 'multilingual scanning') -----
  removeLastCharFromPresentation
+ "appears to be unused"
 
  presentation ifNotNil: [
  presentation position: presentation position - 1.
  ].
  super removeLastCharFromPresentation!

Item was changed:
  ----- Method: StrikeFontSet>>displayString:on:from:to:at:kern:baselineY: (in category 'displaying') -----
  displayString: aString on: aBitBlt from: startIndex to: stopIndex at: aPoint kern: kernDelta baselineY: baselineY
+ "Draw the given string (handles a Text as well) from startIndex to stopIndex at aPoint on the (already prepared) BitBlt."
- "Draw the given string from startIndex to stopIndex
- at aPoint on the (already prepared) BitBlt."
 
  "Assume this is a wide string"
  | isMulti |
  isMulti := true.
 
+ "Look for an excuse to use the fast primitive. This is a terrible way to do this but at least it now avoids use of *three* isKindOf: in one method"
+   (aString isByteString)
- "Look for an excuse to use the fast primitive"
-   (aString isKindOf: ByteString)
  ifTrue:[ isMulti := false]
+ ifFalse:[ (aString isText)
+ ifTrue:[ (aString string isByteString)
- ifFalse:[ (aString isKindOf: Text)
- ifTrue:[ (aString string isKindOf: ByteString)
  ifTrue:[ isMulti := false ]
  ]].
 
  isMulti ifTrue:[^ self displayMultiString: aString on: aBitBlt from: startIndex to: stopIndex at: aPoint kern: kernDelta baselineY: baselineY].
 
  ^ aBitBlt displayString: aString
  from: startIndex
  to: stopIndex
  at: aPoint
  strikeFont: self
  kern: kernDelta!

Item was changed:
  ----- Method: Unicode class>>scanSelector (in category 'accessing - displaying') -----
  scanSelector
+ "return a message to send  to scan multi-byte characters - Unicode is one of the encodings supported by EncodedCharSet"
 
  "^ #scanMultiCharactersCombiningFrom:to:in:rightX:stopConditions:kern:."
  ^ #scanMultiCharactersFrom:to:in:rightX:stopConditions:kern:.
  !