Name

HSpacing, VSpacing, HStretch, VStretch — Fixed size empty space for layout

Synopsis

HSpacing (void); 
 
VSpacing (void); 
 
HStretch (void); 
 
VStretch (void); 
 

Optional Arguments

integer|float size

Description

HSpacing and VSpacing are layout helpers to add empty space between widgets.

VStretch and HStretch act as "rubber bands" in layouts that take excess space. They have a size of zero if there is no excess space.

The size given is measured in units roughly equivalent to the size of a character in the respective UI. Fractional numbers can be used here, but text based UIs may choose to round the number as appropriate - even if this means simply ignoring a spacing when its size becomes zero.

If size is omitted, it defaults to 1. HSpacing() will create a horizontal spacing with default width and zero height. VSpacing() will create a vertical spacing with default height and zero width. HStretch() will create a horizontal stretch with zero width and height. VStretch() will create a vertical stretch with zero width and height.

A HStretch or VStretch with a size specification will take at least the specified amount of space, but it will take more (in that dimension) if there is excess space in the layout.

Usage

 	`HSpacing( 0.3 ) or `HStretch() or `HStretch( 0.7 )
 

Examples

          {
    // Build dialog with one input field field, 4 Beatles buttons and an OK button.
    UI::OpenDialog(
	       `VBox( 
		     `VSpacing(),
		     `HBox(
			   `Label("Name:"),
			   `InputField(`id(`name), "")
			   ),
		     `VSpacing(0.2),
		     `HBox(
			   `PushButton(`id(`john),	"&John"	),	`HSpacing(0.5),
			   `PushButton(`id(`paul),	"&Paul"	),	`HSpacing(3),
			   `PushButton(`id(`george),	"&George"),	`HSpacing(0.5),
			   `PushButton(`id(`ringo),	"&Ringo"	)
			   ),
		     `VSpacing(0.5),
		     `PushButton(`id(`ok), "&OK")
		     )
	       );

    // Wait for user input.
    any button = nil;

    // Input loop that only the OK button will leave.
    // The 4 Beatles buttons will just propose a name.
    repeat
    {
        button = UI::UserInput();

	if      ( button == `john )	UI::ChangeWidget(`id(`name), `Value, "John Lennon");
	else if ( button == `paul )	UI::ChangeWidget(`id(`name), `Value, "Paul McCartney");
	else if ( button == `george )	UI::ChangeWidget(`id(`name), `Value, "George Harrison");
	else if ( button == `ringo )	UI::ChangeWidget(`id(`name), `Value, "Ringo Starr" );
	
    } until ( button == `ok );

    UI::CloseDialog();
}

        
          {
    // Layout example:
    //
    // Build a dialog with three equal sized buttons,
    // this time with some spacing in between.
    //
    // The equal `HWeight()s will make the buttons even sized.
    // When resized larger, all buttons will retain their size.
    // Excess space will go to the HSpacing() widgets between the
    // buttons, i.e. there will be empty space between the buttons.
    //
    // Notice the importance of `opt(`hstretch) for the `HSpacing()s
    // here: This is what makes the HSpacing()s grow. Otherwise, they
    // would retain a constant size, and the buttons would grow.
    
    UI::OpenDialog(
	       `HBox(
		     `HWeight(1, `PushButton( `opt(`default), "&OK" ) ),
		     `HSpacing(`opt(`hstretch), 3),
		     `HWeight(1, `PushButton( "&Cancel everything" ) ),
		     `HSpacing(`opt(`hstretch), 3),
		     `HWeight(1, `PushButton( "&Help"   ) )
		     )
	       );

    UI::UserInput();
    UI::CloseDialog();
}


          
          {
    // Layout example:
    //
    // Build a dialog with three equal sized buttons.
    //
    // The equal `HWeight()s will make the buttons equal sized.
    // When resized larger, all buttons will retain their size.
    // Excess space will go to the HStretch() widgets between the
    // buttons, i.e. there will be empty space between the buttons.
    
    UI::OpenDialog(
	       `HBox(
		     `HWeight(1, `PushButton( `opt(`default), "&OK" ) ),
		     `HStretch(),
		     `HWeight(1, `PushButton( "&Cancel everything" ) ),
		     `HStretch(),
		     `HWeight(1, `PushButton( "&Help"   ) )
		     )
	       );

    UI::UserInput();
    UI::CloseDialog();
}


          
          {
    // Layout example:
    //
    // Build a dialog with three equal sized buttons.
    //
    // The equal `HWeight()s will make the buttons equal sized.
    // When resized larger, all buttons will retain their size.
    // Excess space will go to the HStretch() widgets between the
    // buttons, i.e. there will be empty space between the buttons.
    
    UI::OpenDialog(
	       `HBox(
		     `HWeight(1, `PushButton( `opt(`default), "&OK" ) ),
		     `HStretch(),
		     `HWeight(1, `PushButton( "&Cancel everything" ) ),
		     `HStretch(),
		     `HWeight(1, `PushButton( "&Help"   ) )
		     )
	       );

    UI::UserInput();
    UI::CloseDialog();
}


          
          // Table example: Exchange complete table content
{
    list foodItems =
	[
	 `item(`id(3), "Spaghetti",	  8),
	 `item(`id(4), "Steak Sandwich",  12),
	 `item(`id(1), "Chili",           6),
	 `item(`id(2), "Salami Baguette", nil)
	];

    list carItems =
	[
	 `item(`id(0), "Mercedes",	60000),
	 `item(`id(1), "Audi",		50000),
	 `item(`id(2), "VW",		40000),
	 `item(`id(3), "BMW",		60000),
	 `item(`id(3), "Porsche",	80000)
	];

    list itemLists = [ foodItems, carItems ];

    integer listNo = 0;

    UI::OpenDialog(
		   `VBox(
			 `Heading("Prices"),
			 `MinSize( 30, 10, `Table(`id(`table), `header("Name", "Price"), foodItems ) ),
			 `Right(
				`HBox(
				      `PushButton(`id(`next), "Change &Table Contents"),
				      `PushButton(`id(`cancel), "&Close")
				      )
				)
			 )
		   );

    while (UI::UserInput() != `cancel)
    {
	// Change table contents

	listNo = 1 - listNo;
	UI::ChangeWidget(`table, `Items, itemLists[ listNo ]:nil );

	// Double check: Retrieve contents and dump to log
	y2milestone( "New table content:\n%1", UI::QueryWidget(`table, `Items ) );
    }

    UI::CloseDialog();
}


          
          // Table example: Exchange complete table content
{
    list foodItems =
	[
	 `item(`id(3), "Spaghetti",	  8),
	 `item(`id(4), "Steak Sandwich",  12),
	 `item(`id(1), "Chili",           6),
	 `item(`id(2), "Salami Baguette", nil)
	];

    list carItems =
	[
	 `item(`id(0), "Mercedes",	60000),
	 `item(`id(1), "Audi",		50000),
	 `item(`id(2), "VW",		40000),
	 `item(`id(3), "BMW",		60000),
	 `item(`id(3), "Porsche",	80000)
	];

    list itemLists = [ foodItems, carItems ];

    integer listNo = 0;

    UI::OpenDialog(
		   `VBox(
			 `Heading("Prices"),
			 `MinSize( 30, 10, `Table(`id(`table), `header("Name", "Price"), foodItems ) ),
			 `Right(
				`HBox(
				      `PushButton(`id(`next), "Change &Table Contents"),
				      `PushButton(`id(`cancel), "&Close")
				      )
				)
			 )
		   );

    while (UI::UserInput() != `cancel)
    {
	// Change table contents

	listNo = 1 - listNo;
	UI::ChangeWidget(`table, `Items, itemLists[ listNo ]:nil );

	// Double check: Retrieve contents and dump to log
	y2milestone( "New table content:\n%1", UI::QueryWidget(`table, `Items ) );
    }

    UI::CloseDialog();
}