USING: arrays colors fonts help.markup help.syntax
ui.gadgets.scrollers ;
IN: ui.gadgets.line-support

HELP: line-gadget
{ $class-description "Base class for gadgets that implements display of sequences of text."
  $nl
  "Line gadgets have the following slots:"
  { $table
    {
        { $slot "font" }
        { "a " { $link font } "." }
    }
    {
        { $slot "selection-color" }
        { "a " { $link color } "." }
    }
    {
        { $slot "min-rows" }
        { "The preferred minimum number of visible rows when the gadget is contained in a viewport." }
    }
    {
        { $slot "max-rows" }
        { "The preferred maximum number of visible rows when the gadget is cotnained in a viewport." }
    }
    {
        { $slot "min-cols" }
        { "The preferred minimum number of visible columns when the gadget is contained in a viewport." }
    }
    {
        { $slot "max-cols" }
        { "The preferred maximum number of visible columns when the gadget is contained in a viewport." }
    }
  }
} ;

HELP: pref-viewport-dim*
{ $values { "gadget" line-gadget } { "dim" array } }
{ $description "Calculates the preferred viewport dimenstions of the line gadget." }
{ $see-also pref-viewport-dim } ;

ARTICLE: "ui.gadgets.line-support" "Gadget line support"
"The " { $vocab-link "ui.gadgets.line-support" } " vocabulary provides common code shared by gadgets which display a sequence of lines of text. Currently, the two gadgets that use it are " { $link "ui.gadgets.editors" } " and " { $link "ui.gadgets.tables" } "."
$nl
"The class of line gadgets:"
{ $subsections
    line-gadget
    line-gadget?
}
"Line gadgets are backed by a model which must be a sequence. The number of lines in the gadget is the length of the sequence."
$nl
"Line gadgets cannot be created and used directly, instead a subclass must be defined:"
{ $subsections new-line-gadget }
"Subclasses must implement a generic word:"
{ $subsections draw-line }
"Two optional generic words may be implemented; if they are not implemented in the subclass, a default implementation based on font metrics will be used:"
{ $subsections
    line-height
    line-leading
}
"Validating line numbers:"
{ $subsections validate-line }
"Working with visible lines:"
{ $subsections
    visible-lines
    first-visible-line
    last-visible-line
}
"Converting y co-ordinates to line numbers, and vice versa:"
{ $subsections
    line>y
    y>line
} ;

ABOUT: "ui.gadgets.line-support"