eXept Software AG Logo

Smalltalk/X Webserver

Documentation of class 'Slider':

Home

Documentation
www.exept.de
Everywhere
for:
[back]

Class: Slider


Inheritance:

   Object
   |
   +--GraphicsMedium
      |
      +--DisplaySurface
         |
         +--SimpleView
            |
            +--View
               |
               +--Scroller
                  |
                  +--Slider
                     |
                     +--FractionalWidgetView
                     |
                     +--HorizontalSlider

Package:
stx:libwidg2
Category:
Views-Interactors
Version:
rev: 1.44 date: 2021/03/14 14:30:32
user: cg
file: Slider.st directory: libwidg2
module: stx stc-classLibrary: libwidg2

Description:


this class implements sliders - which are simply scrollers
with a constant thumbHeight. For details on actionBlocks and
MVC operation, see the documentation in Scroller.

copyright

COPYRIGHT (c) 1992 by Claus Gittinger All Rights Reserved This software is furnished under a license and may be used only in accordance with the terms of that license and with the inclusion of the above copyright notice. This software may not be provided or otherwise made available to, or used by, any other person. No title to or ownership of the software is hereby transferred.

Instance protocol:

Compatibility-VW
o  beHorizontal
ST-80 compatibility: make the slider a horizontalSlider

o  beVertical
ST-80 compatibility: make the slider a verticalSlider

accessing
o  sliderHeight: numPixels

o  thumbHeight
redefined since a slider has no height - just origin

event handling
o  buttonPress: butt x: x y: y
(comment from inherited method)
button was pressed - if above thumb, page up; if below thumb, page down;
otherwise start scrolling.
If either shift is pressed, or the 'scrollerMiddleButtonJump' styleSheet
value is true and its the middle button, do a jump to the clicked position.

o  keyPress: key x: x y: y
Modified (format): / 16-11-2016 / 23:13:56 / cg

forced scroll
o  pageDown
fallback to scroll-stepping (same as kbd-right/down)

o  pageUp
fallback to scroll-stepping (same as kbd-right/down)

initialization
o  initStyle
initialize style specifics

o  initialize
(comment from inherited method)
initialize - setup instvars from defaults

private
o  absFromPercent: percent
given a percentage, compute number of pixels

o  computeThumbFrame
redefined, since the thumb-height stays constant

o  percentFromAbs: absValue
given a number of pixels, compute percentage


Examples:


a slider with action block (ST/X style):
    |top s|

    top := StandardSystemView new extent:200@200.
    s := Slider in:top.
    s origin:(0.0@0.0) corner:(15@1.0).
    s scrollAction:[:percent | Transcript show:'moved to: '; showCR:percent asFloat].
    top open
same, horizontal:
    |top s|

    top := StandardSystemView new extent:200@200.
    s := HorizontalSlider in:top.
    s origin:(0.0@0.0) corner:(1.0@15).
    s scrollAction:[:percent | Transcript show:'moved to: '; showCR:percent asFloat].
    top open
with a range other than the default:
    |top s|

    top := StandardSystemView new extent:200@200.
    s := Slider in:top.
    s origin:(0.0@0.0) corner:(20@1.0).
    s scrollAction:[:percent | Transcript show:'moved to: '; showCR:percent asFloat].
    s start:-50 stop:50.
    top open
using a model (ST-80 style): (see the changing value in the inspector)
    |top s m|

    m := 0 asValue.
    m inspect.
    top := StandardSystemView new extent:200@200.
    s := Slider in:top.
    s origin:(0.0@0.0) corner:(20@1.0).
    s model:m.
    top open
reacting to changes from the model: (look at and/or change value using 'self value:' in the inspector).
    |top s m|

    m := 0 asValue.
    m inspect. 
    top := StandardSystemView new extent:200@200.
    s := Slider in:top.
    s origin:(0.0@0.0) corner:(20@1.0).
    s model:m.
    top open
using a different changeSelector:
    |top s1 s2 m|

    m := Plug new.
    m respondTo:#value1: with:[:v | Transcript show:'scroller 1 moved to: '; showCR:v].
    m respondTo:#value2: with:[:v | Transcript show:'scroller 2 moved to: '; showCR:v].

    top := StandardSystemView new extent:200@200.
    s1 := Slider in:top.
    s1 origin:(0.0@0.0) corner:(20@1.0).
    s1 thumbHeight:10.  'percent'.     
    s1 model:m; change:#value1:.

    s2 := Slider in:top.
    s2 origin:(30@0.0) corner:(50@1.0).
    s2 thumbHeight:10.  'percent'.     
    s2 model:m; change:#value2:.
    top open
another example:
    |top redVal greenVal blueVal 
     colorVal upd s1 s2 s3 l|

    redVal := 0 asValue.
    greenVal := 0 asValue.
    blueVal := 0 asValue.

    upd := [colorVal value:(Color red:redVal value
                                  green:greenVal value
                                  blue:blueVal value)].

    colorVal := (Color red:0 green:0 blue:0) asValue.
    colorVal onChangeSend:#value to:[l backgroundColor:colorVal value].

    redVal onChangeSend:#value to:upd.
    greenVal onChangeSend:#value to:upd.
    blueVal onChangeSend:#value to:upd.

    top := StandardSystemView new extent:200@200.
    top label:'Color mixer'.

    s1 := Slider in:top.
    s1 origin:(0.0@0.0) corner:(20@1.0).
    s1 thumbHeight:10.  'percent'.     
    s1 model:redVal.

    s2 := Slider in:top.
    s2 origin:(30@0.0) corner:(50@1.0).
    s2 thumbHeight:10.  'percent'.     
    s2 model:greenVal.

    s3 := Slider in:top.
    s3 origin:(60@0.0) corner:(80@1.0).
    s3 thumbHeight:10.  'percent'.     
    s3 model:blueVal.

    l := Label in:top.
    l origin:90@0.0 corner:1.0@1.0.
    l backgroundColor:Color black.

    top open
the same setup, using action blocks:
    |top red green blue
     colorVal upd s1 s2 s3 labelModel l|

    red := green := blue := 0.

    top := StandardSystemView new extent:200@200.
    top label:'Color mixer'.

    s1 := Slider in:top.
    s1 origin:(0.0@0.0) corner:(20@1.0).
    s1 thumbHeight:10.  'percent'.     
    s1 action:[:percent | red := percent.
                          l backgroundColor:(Color red:red green:green blue:blue)].

    s2 := Slider in:top.
    s2 origin:(30@0.0) corner:(50@1.0).
    s2 thumbHeight:10.  'percent'.     
    s2 action:[:percent | green := percent.
                          l backgroundColor:(Color red:red green:green blue:blue)].

    s3 := Slider in:top.
    s3 origin:(60@0.0) corner:(80@1.0).
    s3 thumbHeight:10.  'percent'.     
    s3 action:[:percent | blue := percent.
                          l backgroundColor:(Color red:red green:green blue:blue)].

    l := Label in:top.
    l origin:90@0.0 corner:1.0@1.0.
    l backgroundColor:Color black.

    top open


ST/X 7.7.0.0; WebServer 1.702 at 20f6060372b9.unknown:8081; Sun, 16 Jun 2024 02:24:06 GMT