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# Package Gtk.Tree`_`View`_`Column

General organization of the tree_view widgets:

______________Tree_View___________________________________ | _________________________ ________________________| | |_____Tree_View_Column1__| |___Tree_View_Column2 __|| | | | | || | | ----------- ---------|| | || | | |Renderer1| |render2 || | || | | | | | || | || | | | | | || | || | | | | | || | || | | |---------| |--------|| | || | |________________________| |_______________________|| |_________________________________________________________|

A tree view can contain multiple physical columns on the screen. These columns can have a button at the top, typically to force an ordering of the tree). They can also be reorganized interactively by the user.

Each physical column can display several information, like buttons, strings, ... Each of this display comes from a cell_renderer, that displays some data it reads from the model associated with the tree_view.

The renderers are then divided into lines, which are typically pointed to by iterators (Gtk_Tree_Iter).

- Gtk.Tree_View_Column Widget Hierarchy
- Gtk.Tree_View_Column Signals
- Gtk.Tree_View_Column Types
- Gtk.Tree_View_Column Subprograms

## Widget Hierarchy

    GObject                       (see section Package Glib.Object)
    Gtk_Object                    (see section Package Gtk.Object)
       \___ Gtk_Tree_View_Column  (see section Package Gtk.Tree_View_Column)

## Signals

- "clicked" procedure Handler (Widget : access Gtk_Tree_View_Column_Record'Class);

## Types

    type Cell_Data_Func is access procedure

    type Data_Type is
        (<>);

    type Gtk_Tree_View_Column_Sizing is
        (Tree_View_Column_Grow_Only,
         Tree_View_Column_Autosize,
         Tree_View_Column_Fixed);

## Subprograms

    procedure Convert;

    procedure Gtk_New
      (Widget             : out    Gtk_Tree_View_Column);

| Create a new Gtk_Tree_View_Column.

    function Get_Type              return Glib.GType;

| Return the internal value associated with this widget.

### Visual representation of the data

All the cells in a column have a similar graphical representation. This
could be either a simple text, an editable text, a toggle button, ... This visual representation is independent from the actual data to represent. For instance, the same data from the model could be used for two different columns, once for a text and once for a button.

The visual representation is specified through a "renderer". See the various Gtk.Cell_Renderer* packages for more information on the available renderers.

Note that the same renderer can be used for multiple columns, even though its properties can be different each time. This means that for instance you can instantiate only one Gtk_Cell_Renderer_Text, and use it for all the columns that need to display text.

    procedure Pack_Start
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Cell               : access Gtk.Cell_Renderer.Gtk_Cell_Renderer_Record'Class;
       Expand             :        Boolean);

| Add a renderer to the Tree_Column. Multiple renderers can be put in a specific column, and each of them can be associated with different data from the model. This provides a very powerful way to display different data in the same column.

    procedure Pack_End
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Cell               : access Gtk.Cell_Renderer.Gtk_Cell_Renderer_Record'Class;
       Expand             :        Boolean);

| Same as the above. See the description of Pack_Start and Pack_End in Gtk.Box for the precise difference between the two

    procedure Clear
      (Tree_Column        : access Gtk_Tree_View_Column_Record);

| Remove all the renderers set in the column. The column will always be empty until you put some new renderers.

    function Get_Cell_Renderers
      (Tree_Column        : access Gtk_Tree_View_Column_Record)
       return Gtk.Cell_Renderer.Cell_Renderer_List.Glist;

| Return the list of cell renderers set in the column

### Specifying the data to display

The data to display in a column is always read from the model associated
with the tree. In some cases (like if you are using the Gtk_Tree_Store model), this means that is has to be physically stored in a data structure. However, if you define your own models, you could also compute it on the fly.

For instance, if you have a database that contains some distance and time information, and you want to display the speed in a tree view: if you are using a Gtk_Tree_Store model, you have to create a third column in the model to store the string, and have a renderer point to that third column.

However, if you are using your own model, it is conceivable that the speed is computed on the fly from the distance and time.

The subprograms below use two or three parameters to precisely identify the part of the tree they impact: the column, the renderer in the column, and in some cases the specific line.

A renderer is always associated with a column in the model (even if that is a virtual column not associated with physical data). This is done through the Add_Attribute subprogram. This will read the data from the model. The type of the data read depends on the type of the column in the model. The type of data that Add_Attribute excepts to find in the column is documented in the packages for each of the renderer.

    procedure Add_Attribute
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Cell_Renderer      : access Gtk.Cell_Renderer.Gtk_Cell_Renderer_Record'Class;
       Attribute          :        String;
       Column             :        Gint);

Add an attribute mapping to the list in Tree_Column.
The Column is the column of the model to get a value from, and the Attribute is the parameter on Cell_Renderer to be set from the value. So for example if column 2 of the model contains strings, you could have the "text" attribute of a Gtk_Cell_Renderer_Text get its values from column 2.

For a list of properties available for each Cell_Renderer, please refer to the corresponding package specifications.

See also the function Set_Cell_Data_Func for another way to query the data to display in the tree.

    procedure Set_Cell_Data_Func
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Cell               : access Gtk.Cell_Renderer.Gtk_Cell_Renderer_Record'Class;
       Func               :        Cell_Data_Func);

| Set the function to use for the column. This function is used instead of the standard attributes mapping for setting the column value, and should set the value of Tree_Column's cell renderer as appropriate. Func may be null to remove an older one. It should be used when values from the model should be computed from application-specific data structures rather than stored in the model.

    procedure Set_Cell_Data_Func
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Cell               : access Gtk.Cell_Renderer.Gtk_Cell_Renderer_Record'Class;
       Func               :        Cell_Data_Func;
       Data               :        Data_Type);

    procedure Clear_Attributes
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Cell_Renderer      : access Gtk.Cell_Renderer.Gtk_Cell_Renderer_Record'Class);

| Clear all existing attributes previously set with Gtk.Tree_View_Column.Set_Attributes.

### Options for manipulating the columns

    procedure Set_Spacing
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Spacing            :        Gint);

| Set the spacing field of Tree_Column. The spacing field is the number of pixels to place between cell renderers packed into it.

    function Get_Spacing
      (Tree_Column        : access Gtk_Tree_View_Column_Record)
       return Gint;

| Return the spacing of Tree_Column.

    procedure Set_Visible
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Visible            :        Boolean);

| Set the visibility of Tree_Column.

    function Get_Visible
      (Tree_Column        : access Gtk_Tree_View_Column_Record)
       return Boolean;

| Return True if Tree_Column is visible.

    procedure Set_Resizable
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Resizable          :        Boolean);

| Set whether the Tree_Column is resizable.

    function Get_Resizable
      (Tree_Column        : access Gtk_Tree_View_Column_Record)
       return Boolean;

| Return whether Tree_Column is resizable.

    procedure Set_Sizing
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       The_Type           :        Gtk_Tree_View_Column_Sizing);

| Set the growth behavior of Tree_Column to The_Type.

    function Get_Sizing
      (Tree_Column        : access Gtk_Tree_View_Column_Record)
       return Gtk_Tree_View_Column_Sizing;

| Return the current type of Tree_Column.

    function Get_Width
      (Tree_Column        : access Gtk_Tree_View_Column_Record)
       return Gint;

| Return the current size of the Tree_Column in pixels.

    function Get_Fixed_Width
      (Tree_Column        : access Gtk_Tree_View_Column_Record)
       return Gint;

| Get the fixed width of the column. This value may not be the actual width of the column on the screen, just what is requested.

    procedure Set_Fixed_Width
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Fixed_Width        :        Gint);

| Set the size of the column in pixels. This is meaningful only if the sizing type is Gtk_Tree_View_Column_Fixed. In this case, the value is discarded as the size of the column is based on the calculated width of the column. The width is clamped to the min/max width for the column.

    procedure Set_Min_Width
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Min_Width          :        Gint);

| Set the minimum width of the Tree_Column. If Min_Width is -1, then the minimum width is unset.

    function Get_Min_Width
      (Tree_Column        : access Gtk_Tree_View_Column_Record)
       return Gint;

| Return the minimum width in pixels of the Tree_Column, or -1 if no minimum width is set.

    procedure Set_Max_Width
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Max_Width          :        Gint);

| Set the maximum width of the Tree_Column. If Max_Width is -1, then the maximum width is unset. Note, the column can actually be wider than max width if it's the last column in a view. In this case, the column expands to fill the view.

    function Get_Max_Width
      (Tree_Column        : access Gtk_Tree_View_Column_Record)
       return Gint;

| Return the maximum width in pixels of the Tree_Column, or -1 if no maximum width is set.

    procedure Clicked
      (Tree_Column        : access Gtk_Tree_View_Column_Record);

| Emit the "clicked" signal on the column. This function will only work if the user could have conceivably clicked on the button.

    procedure Set_Title
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Title              :        UTF8_String);

| Set the title of the Tree_Column. If a custom widget has been set, then this value is ignored.

    function Get_Title
      (Tree_Column        : access Gtk_Tree_View_Column_Record)
       return UTF8_String;

| Return the title of the Tree_Column.

    procedure Set_Clickable
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Clickable          :        Boolean);

| Set the header to be active if Active is True. When the header is active, then it can take keyboard focus, and can be clicked.

    function Get_Clickable
      (Tree_Column        : access Gtk_Tree_View_Column_Record)
       return Boolean;

| Return True if the user can click on the header for the column.

    procedure Set_Widget
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Widget             : access Gtk.Widget.Gtk_Widget_Record'Class);

    function Get_Widget
      (Tree_Column        : access Gtk_Tree_View_Column_Record)
       return Gtk.Widget.Gtk_Widget;

| Return the Gtk_Widget in the button in the column header. If a custom widget has not been set, then this will be a Gtk_Alignment with a Gtk_Label in it.

    procedure Set_Alignment
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Xalign             :        Gfloat);

| Set the alignment of the title or custom widget inside the column header The alignment determines its location inside the button 0.0 for left, 0.5 for center, 1.0 for right.

    function Get_Alignment
      (Tree_Column        : access Gtk_Tree_View_Column_Record)
       return Gfloat;

| Return the current x alignment of Tree_Column. This value can range between 0.0 and 1.0.

    procedure Set_Reorderable
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Reorderable        :        Boolean);

    function Get_Reorderable
      (Tree_Column        : access Gtk_Tree_View_Column_Record)
       return Boolean;

    procedure Set_Sort_Column_Id
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Sort_Column_Id     :        Gint);

| Set the logical sort_column_id that this column sorts on when this column is selected for sorting. Doing so makes the column header clickable.

    function Get_Sort_Column_Id
      (Tree_Column        : access Gtk_Tree_View_Column_Record)
       return Gint;

| Get the logical sort_column_id that the model sorts on when this column is selected for sorting. See Gtk.Tree_View_Column.Set_Sort_Column_Id. Return value: the current sort_column_id for this column, or -1 if this column can't be used for sorting.

    procedure Set_Sort_Indicator
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Setting            :        Boolean);

| Call this function with a Setting of True to display an arrow in the header button indicating the column is sorted. Call Set_Sort_Order to change the direction of the arrow.

    function Get_Sort_Indicator
      (Tree_Column        : access Gtk_Tree_View_Column_Record)
       return Boolean;

| Get the value set by Set_Sort_Indicator.

    procedure Set_Sort_Order
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Order              :        Gtk_Sort_Type);

Change the appearance of the sort indicator.
This does *not* actually sort the model. Use Gtk.Tree_View_Column.Set_Sort_Column_Id if you want automatic sorting support. This function is primarily for custom sorting behavior, and should be used in conjunction with Gtk.Tree_Sortable.Set_Sort_Column to do that. For custom models, the mechanism will vary. The sort indicator changes direction to indicate normal sort or reverse sort. Note that you must have the sort indicator enabled to see anything when calling this function; see Set_Sort_Indicator.

    function Get_Sort_Order
      (Tree_Column        : access Gtk_Tree_View_Column_Record)
       return Gtk_Sort_Type;

| Get the value set by Set_Sort_Order.

    procedure Cell_Set_Cell_Data
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Tree_Model         : access Gtk.Tree_Model.Gtk_Tree_Model_Record'Class;
       Iter               :        Gtk.Tree_Model.Gtk_Tree_Iter;
       Is_Expander        :        Boolean;
       Is_Expanded        :        Boolean);

| Set the cell renderer based on the Tree_Model and Tree_Node. That is, for every attribute mapping in Tree_Column, it will get a value from the set column on the Tree_Node, and use that value to set the attribute on the cell renderer. This is used primarily by the Gtk_Tree_View.

    procedure Cell_Get_Size
      (Tree_Column        : access Gtk_Tree_View_Column_Record;
       Cell_Area          :        Gdk.Rectangle.Gdk_Rectangle;
       X_Offset           : out    Gint;
       Y_Offset           : out    Gint;
       Width              : out    Gint;
       Height             : out    Gint);

| Obtain the width and height needed to render the column. This is used primarily by the Gtk_Tree_View.

    function Cell_Is_Visible
      (Tree_Column        : access Gtk_Tree_View_Column_Record)
       return Boolean;

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