Please tim, := assignments would be much appreciated :)


2013/9/23 <commits at source.squeak.org>

> tim Rowledge uploaded a new version of Graphics to project The Trunk:
> http://source.squeak.org/trunk/Graphics-tpr.226.mcz
>
> ==================== Summary ====================
>
> Name: Graphics-tpr.226
> Author: tpr
> Time: 23 September 2013, 12:42:11.34 pm
> UUID: 842c37b1-aab4-41a7-b8ff-1411a96c4590
> Ancestors: Graphics-tpr.225
>
> 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 Graphics-tpr.225 ===============
>
> Item was added:
> + ----- Method: AbstractFont>>isPairKerningCapable (in category 'testing')
> -----
> + isPairKerningCapable
> + "a hopefully temporary test method; better factoring of
> scan/measure/display should remove the need for it.
> + Only FreeType fonts would currently add this to return true"
> +       ^false!
>
> Item was removed:
> - ----- Method: AbstractFont>>widthAndKernedWidthOfLeft:right:into: (in
> category 'kerning') -----
> - widthAndKernedWidthOfLeft: leftCharacter right: rightCharacterOrNil
> into: aTwoElementArray
> -       "Set the first element of aTwoElementArray to the width of
> leftCharacter and
> -       the second element to the width of left character when kerned with
> -       rightCharacterOrNil. Answer aTwoElementArray"
> -       | w k |
> -       w := self widthOf: leftCharacter.
> -       rightCharacterOrNil isNil
> -               ifTrue:[
> -                       aTwoElementArray
> -                               at: 1 put: w;
> -                               at: 2 put: w]
> -               ifFalse:[
> -                       k := self kerningLeft: leftCharacter right:
> rightCharacterOrNil.
> -                       aTwoElementArray
> -                               at: 1 put: w;
> -                               at: 2 put: w+k].
> -       ^aTwoElementArray
> -       !
>
> Item was changed:
>   ----- Method:
> CharacterScanner>>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:
> CharacterScanner>>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 added:
> + ----- Method:
> CharacterScanner>>historicalScanCharactersFrom:to:in:rightX:stopConditions:kern:
> (in category 'scanning') -----
> + historicalScanCharactersFrom: 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.
> +       Historical note: this primitive has been unusable since about
> Squeak 2.8 when the shape of the CharracterScanner class changed. It is
> left here as a reminder that the actual primitive still needs supporting in
> the VM to keep old images such as Scratch1.4 alive - tpr"
> +       | ascii nextDestX char |
> +       <primitive: 103>
> +       lastIndex _ startIndex.
> +       [lastIndex <= stopIndex]
> +               whileTrue:
> +                       [char _ (sourceString at: lastIndex).
> +                       ascii _ char asciiValue + 1.
> +                       (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."
> +                       nextDestX _ destX + (font widthOf: char).
> +                       nextDestX > rightX ifTrue: [^stops at: CrossedX].
> +                       destX _ nextDestX + kernDelta.
> +                       lastIndex _ lastIndex + 1].
> +       lastIndex _ stopIndex.
> +       ^stops at: EndOfRun
> + !
>
> Item was changed:
>   ----- Method: CharacterScanner>>isBreakableAtIndex: (in category
> 'scanner methods') -----
>   isBreakableAtIndex: index
> + "appears t obe unused - cf MultiCharacterScanner>isBreakableAt:in:in"
> -
>         ^ (EncodedCharSet at: ((text at: index) leadingChar + 1))
> isBreakableAt: index in: text.
>   !
>
> Item was changed:
>   ----- Method:
> CharacterScanner>>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 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
> - !
>
> Item was removed:
> - ----- Method:
> CharacterScanner>>scanMultiCharactersCombiningFrom:to:in:rightX:stopConditions:kern:
> (in category 'scanner methods') -----
> - scanMultiCharactersCombiningFrom: startIndex to: stopIndex in:
> sourceString rightX: rightX stopConditions: stops kern: kernDelta
> -       "Implement a workaround for unicode composing.
> -       a MultiCharacterScanner should better be used to handle
> combination."
> -
> -       ^self scanMultiCharactersFrom: startIndex to: stopIndex in:
> sourceString rightX: rightX stopConditions: stops kern: kernDelta!
>
>
>
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