'Smalltalk Express Test Meter'!
'Terrence Ma'!
'Modified from On To Smalltalk'!

ViewManager subclass: #GuiViewManager
  instanceVariableNames: ''
  classVariableNames: ''
  poolDictionaries:
    'ColorConstants WBConstants'
!

!GuiViewManager methods!
decrementMeter: theButton
  | meter |
  meter := self paneNamed: 'the meter'.
  meter setValue: meter getValue - 1;
           event: #display
! !

!GuiViewManager methods!
incrementMeter: theButton
  | meter |
  meter := self paneNamed: 'the meter'.
  meter setValue: meter getValue + 1;
           event: #display
! !

!GuiViewManager methods!
initializeMeter: theMeter
  theMeter setMin: 0;
           setMax: 10;
           setValue: 5;
           setTitle: 'Test Meter';
           event: #display
! !

!GuiViewManager methods!
callDrawMeter: theMeter
  theMeter drawMeter
! !

!GuiViewManager methods!
createViews

     "WARNING!  This method was automatically generated by
      WindowBuilder.  Code you add here which does not conform
      to the WindowBuilder API will probably be lost the next time
      you save your layout definition."

     | v |

    self addView: (
        v := self topPaneClass new
            owner: self;
            labelWithoutPrefix:  'Test Meter';
            noSmalltalkMenuBar;
            viewName: 'mainView';
            framingBlock: ( FramingParameters new iDUE: 677 @ 416; xC; yC; cRDU: (9 @ 408 rightBottom: 667 @ 46));
            pStyle: #(sysmenu sizable titlebar minimize maximize);
            addSubpane: (
                Button new
                    owner: self;
                    framingBlock: ( FramingParameters new iDUE: 210 @ 56; lDU: 64 r: #left; rDU: 274 r: #left; tDU: 40 r: #top; bDU: 96 r: #top);
                    startGroup;
                    when: #clicked perform: #decrementMeter:;
                    contents: 'Decrement';
                    yourself
            );
            addSubpane: (
                Button new
                    owner: self;
                    framingBlock: ( FramingParameters new iDUE: 210 @ 56; lDU: 384 r: #left; rDU: 594 r: #left; tDU: 40 r: #top; bDU: 96 r: #top);
                    startGroup;
                    when: #clicked perform: #incrementMeter:;
                    contents: 'Increment';
                    yourself
            );
            addSubpane: (
                MeterGraphPane new
                    owner: self;
                    framingBlock: ( FramingParameters new iDUE: 530 @ 192; lDU: 64 r: #left; rDU: 594 r: #left; tDU: 120 r: #top; bDU: 312 r: #top);
                    paneName: 'the meter';
                    noScrollBars;
                    startGroup;
                    when: #getContents perform: #initializeMeter:;
                    when: #display perform: #callDrawMeter:;
                    yourself
            );
        yourself
    ).
! !

GraphPane subclass: #MeterGraphPane
  instanceVariableNames: 'min max value title'
  classVariableNames: ''
  poolDictionaries: 'ColorConstants'
!

!MeterGraphPane methods!
setMin: aNumber
  min := aNumber
! !

!MeterGraphPane methods!
setMax: aNumber
  max := aNumber
! !

!MeterGraphPane methods!
setValue: aNumber
  value := aNumber
! !

!MeterGraphPane methods!
getValue
  ^ value
! !

!MeterGraphPane methods!
setTitle: aString
  title := aString
! !

!MeterGraphPane methods!
drawMeter
  | thePen meterWidth meterHeight xLft yBot xPointer yPointer
    ptrHeight ptrHalfWidth oldBackColor dialArray 
    range step tics tickPlace tickHeight|
  self erase.
  thePen := self pen.
  meterHeight := 30.  meterWidth := self width * 3 // 4.
  ptrHeight := 10.  ptrHalfWidth := 5.
  xLft := self width - meterWidth // 2.  yBot := self height * 3 // 8.
  "Draw frame for meter"
  thePen drawRectangle: ((xLft - ptrHalfWidth) @ yBot 
                extent: (meterWidth + (ptrHalfWidth * 2)) 
                         @ meterHeight).
  "Draw tick marks.  Adaped from code provided by Richard Lyon.
   Works well for all min and max values"
  range := max - min.
  range = 0 
    ifTrue:
      [self error: 'Cannot put tics in an interval of width zero'].
  range < 0
    ifTrue: [step := -1.  range := range negated]
    ifFalse: [step := 1].
  [range <= 15] whileTrue: [range := range*10. step := step/10].
  [range > 150] whileTrue: [range := range/10. step := step*10].
  range <= 30
    ifTrue: [tics := #(1 5 10)]
    ifFalse:
      [(range <= 60)
         ifTrue: [tics := #(2 10 20)]
         ifFalse: [tics := #(5 10 50)] ].
  step := step * (tics at: 1).
  (((min // (step negated)) negated) to: (max // step)) 
    do: [:k | (k \\ ((tics at: 3) / (tics at: 1)) = 0)
                ifTrue: [tickHeight := meterHeight * 3 // 4]
                ifFalse: 
                  [(k \\ ((tics at: 2) / (tics at: 1)) = 0)
                     ifTrue: [tickHeight := meterHeight // 2]
                     ifFalse: [tickHeight := meterHeight * 3 // 8]].
              tickPlace := xLft
                           + (k * meterWidth * step // max) 
                           - (min * meterWidth // range).
              thePen lineFrom: (tickPlace @ yBot)
                           to: (tickPlace @ (yBot + tickHeight))].
  "Write title"
  title notNil
    ifTrue:
      [thePen 
         centerText: title
         at: ((self width) // 2) 
              @ (yBot + meterHeight + (2 * thePen font height))].
  "Write scale minimum, middle, and maximum"
  min notNil & max notNil
    ifTrue: [thePen centerText: min printString
               at: xLft @ yBot.
             thePen centerText: (max - min // 2 + min) printString
               at: (xLft + (meterWidth // 2)) @ yBot.
             thePen centerText: max printString
               at: (xLft + meterWidth) @ yBot].
  "Draw pointer, if values set"
  min notNil & max notNil & value notNil
    ifTrue:
      [xPointer := (value - min) * meterWidth // (max - min) + xLft.
       yPointer := yBot + meterHeight - 1.
       oldBackColor := thePen backColor.
       thePen backColor: ClrBlack.
       dialArray := Array with: ((xPointer + ptrHalfWidth) @ yPointer)
                          with: (xPointer @ (yPointer - ptrHeight))
                          with: ((xPointer - ptrHalfWidth) @ yPointer).
       thePen polygonFilled: dialArray.
       thePen backColor: oldBackColor]
! !