Difference between revisions of "Conditional Visibility"
From GeoGebra Manual
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| − | <noinclude>{{Manual Page|version=5.0}}</noinclude> | + | <noinclude>{{Manual Page|version=5.0}}</noinclude>{{objects|advanced}} |
| − | {{objects|advanced}} | + | Apart from just showing or hiding certain objects you can also have their visibility status depend on a certain condition. For example, you would like an object to appear on screen if you check a checkbox positioned in the [[File:Menu view graphics.svg|link=|16px]] [[Graphics View]] or if a [[Slider Tool|slider]] is changed to a certain value. |
| − | Apart from just showing or hiding certain objects you can also have their visibility status depend on a certain condition. For example, you would like an object to appear on screen if you check a checkbox positioned in the [[File:Menu view graphics.svg|link=|16px]] [[Graphics View]] or if a | ||
==Conditionally Show or Hide Existing Objects== | ==Conditionally Show or Hide Existing Objects== | ||
| Line 7: | Line 6: | ||
You can use the [[File:Mode showcheckbox.svg|link=|24px]] [[Check Box Tool]] in order to create a checkbox that controls the visibility of one or more existing objects on screen. | You can use the [[File:Mode showcheckbox.svg|link=|24px]] [[Check Box Tool]] in order to create a checkbox that controls the visibility of one or more existing objects on screen. | ||
| − | Alternatively, you could also create a [[Boolean values|Boolean variable]] (e.g. <code>b = true</code>) using the [[Input Bar]] and make it visible as a checkbox in the [[Graphics View | + | Alternatively, you could also create a [[Boolean values|Boolean variable]] (e.g. <code>b = true</code>) using the [[Input Bar]] and make it visible as a checkbox in the [[File:Menu view graphics.svg|link=|16px]] ''Graphics View'' by changing its visibility status (e.g. use [[File:Mode showhideobject.svg|link=|24px]] [[Show / Hide Object Tool]] or the [[Context Menu]]). A checkbox therefore is a visible ''Boolean variable''. |
| + | In order to use this Boolean variable as a condition for the visibility of certain objects, you need to follow the steps described below. | ||
==Changing the Visibility of Newly Created Objects== | ==Changing the Visibility of Newly Created Objects== | ||
| − | In the [[Properties Dialog]], you can enter a condition for the visibility of an object on tab Advanced. | + | In the [[File:Menu-options.svg|link=|16px]] [[Properties Dialog]], you can enter a condition for the visibility of an object on tab ''Advanced''. |
| − | {{note|You can select the logic operators (e.g. ≠, ≥, ˄, ‖) from the | + | {{note|You can select the logic operators (e.g. ≠, ≥, ˄, ‖) from list to the right of the input field in order to create your conditional statements.}} |
{{example| | {{example| | ||
| − | * If a is a slider, then the conditional statement a < 2 means that the corresponding object is only shown in the Graphics View if the slider value is less than 2. | + | * If a is a slider, then the conditional statement a < 2 means that the corresponding object is only shown in the [[File:Menu view graphics.svg|link=|16px]] ''Graphics View'' if the slider value is less than 2. |
* If b is a Boolean variable, you can use b as a conditional statement. The corresponding object is shown whenever the value of b is true and is hidden when the value of b is false. | * If b is a Boolean variable, you can use b as a conditional statement. The corresponding object is shown whenever the value of b is true and is hidden when the value of b is false. | ||
* If g and h are two lines and you would like a text to be shown whenever these lines are parallel, then you could use g ‖ h as a conditional statement for the text.}} | * If g and h are two lines and you would like a text to be shown whenever these lines are parallel, then you could use g ‖ h as a conditional statement for the text.}} | ||
{{Note|1=See also [[SetVisibleInView Command|SetVisibleInView]] command.}} | {{Note|1=See also [[SetVisibleInView Command|SetVisibleInView]] command.}} | ||
Revision as of 13:52, 9 October 2015
Apart from just showing or hiding certain objects you can also have their visibility status depend on a certain condition. For example, you would like an object to appear on screen if you check a checkbox positioned in the 
Graphics View or if a slider is changed to a certain value.
Conditionally Show or Hide Existing Objects
You can use the 
Check Box Tool in order to create a checkbox that controls the visibility of one or more existing objects on screen.
Alternatively, you could also create a Boolean variable (e.g. b = true) using the Input Bar and make it visible as a checkbox in the Graphics View by changing its visibility status (e.g. use 
Show / Hide Object Tool or the Context Menu). A checkbox therefore is a visible Boolean variable.
In order to use this Boolean variable as a condition for the visibility of certain objects, you need to follow the steps described below.
Changing the Visibility of Newly Created Objects
In the 
Properties Dialog, you can enter a condition for the visibility of an object on tab Advanced.
Note: You can select the logic operators (e.g. ≠, ≥, ˄, ‖) from list to the right of the input field in order to create your conditional statements.
Example:
- If a is a slider, then the conditional statement a < 2 means that the corresponding object is only shown in the Graphics View if the slider value is less than 2.
- If b is a Boolean variable, you can use b as a conditional statement. The corresponding object is shown whenever the value of b is true and is hidden when the value of b is false.
- If g and h are two lines and you would like a text to be shown whenever these lines are parallel, then you could use g ‖ h as a conditional statement for the text.
Note: See also SetVisibleInView command.
