Yes, you should change the tickPrintBlock because it probably incorrectly use (aFloat roundTo: 0.1) printString.

There is no guaranty that this return the nearest Float to the aimed decimal fraction.
Since this is not the nearest Float, you have additional digits displayed.

The print block should use a selector like printShowingDecimalPlaces: (Squeak) or something equivalent in Pharo (can't remember if the selectors are 100% compatible).

For completeness, do test these expressions:
(0 to: 10) collect: [:i | (i/10) asFloat].

versus
(0 to: 10) collect: [:i | i*0.1].
versus
(0 to: 10) collect: [:i | (i/10) roundTo: 0.1].

Only the first one is correct. Trying to roundTo: 0.1 spoils thing because 0.1 is not exactly 1/10 and thus introduce small errors...

2013/12/24 St�phane Ducasse <stephane.ducasse@inria.fr>

Hi (nicolas :))

I was fixing the sound package and the EnvelopeEditorMorph shows a strange glitch

EnvelopeEditorMorph openOn: (FMSound brass1) copy title: 'brass1'

See ^^^^^^^^^^^^^^^^ below

I have the impression that this related to float printString. Any idea how to fix it?





buildLabels
        | scale x1 y1 y2 captionMorph loopStart offset |
        majorTickLength * minorTickLength < 0
                ifTrue: [ minorTickLength := 0 - minorTickLength ].
        self removeAllMorphs.
        caption ifNotNil:
                [ captionMorph := StringMorph contents: caption.
                offset := captionAbove
                        ifTrue: [majorTickLength abs + captionMorph height + 7]
                        ifFalse: [2].
                captionMorph
                        align: captionMorph bounds bottomCenter
                        with: self bounds bottomCenter - (0 @ offset).
                self addMorph: captionMorph].
        tickPrintBlock ifNotNil:
                        ["Calculate the offset for the labels, depending on whether or not
                          1) there's a caption
                        below, 2) the labels are above or below the ticks, and 3) the
                        ticks go up or down"
                        offset := labelsAbove
                                        ifTrue: [majorTickLength abs + minorTickLength abs + 2]
                                        ifFalse: [2].
                        caption
                                ifNotNil: [captionAbove ifFalse: [offset := offset + captionMorph height + 2]].
                        scale := (self innerBounds width - 1) / (stop - start) asFloat.
                        x1 := self innerBounds left.
                        y1 := self innerBounds bottom.
                        y2 := y1 - offset.
                        "Start loop on multiple of majorTick"
                        loopStart := (start / majorTick) ceiling * majorTick.
                        loopStart to: stop
                                by: majorTick
                                do:
                                        [ :v | | x tickMorph |
                                        x := x1 + (scale * (v - start)).
                                        tickMorph := StringMorph contents: (tickPrintBlock value: v).
                                                                                                 ^^^^^^^^^^^^^^^^ printString?

                                        tickMorph align: tickMorph bounds bottomCenter with: x @ y2.
                                        tickMorph left < self left
                                                ifTrue: [ tickMorph position: self left @ tickMorph top ].
                                        tickMorph right > self right
                                                ifTrue: [ tickMorph position: (self right - tickMorph width) @ tickMorph top].
                                        self addMorph: tickMorph ]]