.. _showlabels:

*****************
Setting a label
*****************

.. only:: html

.. contents::
:local:

Labels are textual information you can display on vector features or maps.
They add details you could not necessarily represent using symbols.
Two types of text-related items are available in QGIS:

* :guilabel:`Text Format`: defines the appearance of the text, including
:ref:`font, size, colors <labels_text>`, :ref:`shadow <labels_shadow>`,
:ref:`background <labels_background>`, :ref:`buffer <labels_buffer>`, ...

They can be used to render texts over the map (layout/map title,
decorations, scale bar, ...), usually through the :ref:`font <font_selector>`
widget.

To create a :guilabel:`Text Format` item:

#. Open the |styleManager| :guilabel:`Style Manager` dialog
#. Activate the :guilabel:`Text format` tab

.. _figure_textformats:

.. figure:: img/stylemanager_textformat.png
:align: center

Text formats in Style Manager dialog

#. Press the |signPlus| :sup:`Add item` button. The :guilabel:`Text Format`
dialog opens for :ref:`configuration <text_format>`.
As usual, these properties are :ref:`data-definable <data_defined>`.

* :guilabel:`Label Settings`: extend the text format settings with properties
related to the location or the interaction with other texts or features
(:ref:`callouts <labels_callouts>`, :ref:`placement <labels_placement>`,
:ref:`overlay, scale visibility <labels_rendering>`, mask ...).

They are used to configure smart labelling for vector layers through the
|labeling| :guilabel:`Labels` tab of the vector :guilabel:`Layer Properties`
dialog or :guilabel:`Layer Styling` panel or using the |labeling| :sup:`Layer
Labeling Options` button of the :ref:`Label toolbar <label_toolbar>`.

To create a :guilabel:`Label Settings` item:

#. Open the |styleManager| :guilabel:`Style Manager` dialog
#. Activate the :guilabel:`Label Settings` tab

.. _figure_label_settings:

.. figure:: img/stylemanager_labelsettings.png
:align: center

Label Settings in Style Manager dialog

#. Press the |signPlus| :sup:`Add item` menu and select the entry corresponding
to the geometry type of the features you want to label.

The :guilabel:`Label Settings` dialog opens with the following properties.
As usual, these properties are :ref:`data-definable <data_defined>`.

.. _text_format:

Formatting the label text
=========================

Most of the following properties are common to :guilabel:`Text Format`
and :guilabel:`Label Settings` items.

.. _labels_text:

Text tab
--------

.. _figure_label_text:

.. figure:: img/label_text.png
:align: center

Labels settings - Text tab

In the |text| :guilabel:`Text` tab, you can set:

* the :guilabel:`Font`, from the ones available on your machine
* the :guilabel:`Style`: along with the common styles of the font, you can set
whether the text should be underlined or striked through
* the :guilabel:`Size` in any :ref:`supported unit <unit_selector>`
* the :guilabel:`Color`
* and the :guilabel:`Opacity`.

At the bottom of the tab, a widget shows a filterable list of compatible items
stored in your :ref:`style manager database <vector_style_manager>`.
This allows you to easily configure the current text format or label setting
based on an existing one, and also save a new item to the style database:
Press the :guilabel:`Save format...` or :guilabel:`Save settings...` button
and provide a name and tag(s).

.. note:: When configuring a :guilabel:`Label Settings` item, text format items
are also available in this widget. Select one to quickly overwrite the current
:ref:`textual properties <text_format>` of the label.
Likewise, you can create/overwrite a text format from there.

.. _labels_formatting:

Formatting tab
--------------

.. _figure_label_formatting:

.. figure:: img/label_formatting.png
:align: center

Label settings - Formatting tab

In the |labelformatting| :guilabel:`Formatting` tab, you can:

* Use the :guilabel:`Type case` option to change the capitalization style of
the text. You have the possibility to render the text as:

* :guilabel:`No change`
* :guilabel:`All uppercase`
* :guilabel:`All lowercase`
* :guilabel:`Title case`: modifies the first letter of each word into capital,
and turns the other letters into lower case if the original text is using
a single type case. In case of mixed type cases in the text, the other
letters are left untouched.
* :guilabel:`Force first letter to capital`: modifies the first letter of each
word into capital and leaves the other letters in the text untouched.

* Under :guilabel:`Spacing`, change the space between words and between
individual letters.
* |checkbox| :guilabel:`Enable kerning` of the text font
* Set the :guilabel:`Text orientation` which can be :guilabel:`Horizontal`
or :guilabel:`Vertical`. It can also be :guilabel:`Rotation-based` when
setting a label (e.g., to properly label line features in :ref:`parallel
<labels_line_placement>` placement mode).
* Use the :guilabel:`Blend mode` option to determine how your labels will mix
with the map features below them (more details at :ref:`blend-modes`).
* The |unchecked| :guilabel:`Apply label text substitutes` option allows you
to specify a list of texts to substitute to texts in feature labels (e.g.,
abbreviating street types). Replacement texts are used when displaying
labels on the map. Users can also export and import lists of
substitutes to make reuse and sharing easier.
* Configure :guilabel:`Multiple lines`:

* Set a character that will force a line break in the text with the
:guilabel:`Wrap on character` option
* Set an ideal line size for auto-wrapping using the :guilabel:`Wrap lines to`
option. The size can represent either the :guilabel:`Maximum line length`
or the :guilabel:`Minimum line length`.
* Decide the :guilabel:`Line Height`
* Format the :guilabel:`Alignment`: typical values available are
:guilabel:`Left`, :guilabel:`Right`, :guilabel:`Justify` and :guilabel:`Center`.

When setting point labels properties, the text alignment can also be
:guilabel:`Follow label placement`. In that case, the alignment will depend
on the final placement of the label relative to the point. E.g., if the
label is placed to the left of the point, then the label will be right
aligned, while if it is placed to the right, it will be left aligned.

.. note:: The :guilabel:`Multiple lines` formatting is not yet supported by curve based
:ref:`label placement <labels_placement>`. The options will then be deactivated.

* For line labels you can include :guilabel:`Line direction symbol`
to help determine the line directions, with symbols to use to indicate the
:guilabel:`Left` or :guilabel:`Right`. They work particularly well when
used with the *curved* or *Parallel* placement options from the
:guilabel:`Placement` tab. There are options to set the symbols position, and
to |unchecked| :guilabel:`Reverse direction`.
* Use the |unchecked| :guilabel:`Formatted numbers` option to format numeric
texts. You can set the number of :guilabel:`Decimal places`. By default, ``3``
decimal places will be used. Use the |checkbox| :guilabel:`Show plus sign` if
you want to show the plus sign for positive numbers.

.. _labels_buffer:

Buffer tab
----------

.. _figure_label_buffer:

.. figure:: img/label_buffer.png
:align: center

Label settings - Buffer tab

To create a buffer around the label, activate the |checkbox| :guilabel:`Draw
text buffer` checkbox in the |labelbuffer| :guilabel:`Buffer` tab. Then you can:

* Set the buffer's :guilabel:`Size` in any :ref:`supported unit <unit_selector>`
* Select the buffer's :guilabel:`Color`
* |checkbox| :guilabel:`Color buffer's fill`: The buffer expands from the
label's outline, so, if the option is activated, the label's interior is
filled. This may be relevant when using partially transparent labels or with
non-normal blending modes, which will allow seeing behind the label's text.
Unchecking the option (while using totally transparent labels) will allow you
to create outlined text labels.
* Define the buffer's :guilabel:`Opacity`
* Apply a :guilabel:`Pen join style`: it can be :guilabel:`Round`,
:guilabel:`Miter` or :guilabel:`Bevel`
* Use the :guilabel:`Blend mode` option to determine how your label's buffer
will mix with the map components below them (more details at
:ref:`blend-modes`).
* Check |unchecked| :guilabel:`Draw effects` to add advanced |paintEffects|
:ref:`paint effects <draw_effects>` for improving text readability,
eg through outer glows and blurs.

.. _labels_background:

Background tab
--------------

The |labelbackground| :guilabel:`Background` tab allows you to configure a
shape that stays below each label. To add a background, activate
the |unchecked| :guilabel:`Draw Background` checkbox and select
the :guilabel:`Shape` type. It can be:

* a regular shape such as :guilabel:`Rectangle`, :guilabel:`Square`,
:guilabel:`Circle` or :guilabel:`Ellipse`
* an :guilabel:`SVG` symbol from a file, a URL or embedded in the project
or style database (:ref:`more details <svg_paths>`)
* or a :guilabel:`Marker Symbol` you can create or select from the
:ref:`symbol library <vector_marker_symbols>`.

.. _figure_label_background:

.. figure:: img/label_background.png
:align: center

Label settings - Background tab

Depending on the selected shape, you need to configure some of the following
properties:

* The :guilabel:`Size type` of the frame, which can be:

* :guilabel:`Fixed`: using the same size for all the labels, regardless the
size of the text
* or a :guilabel:`Buffer` over the text's bounding box
* The :guilabel:`Size` of the frame in X and Y directions, using any
:ref:`supported units <unit_selector>`
* A :guilabel:`Rotation` of the background, between :guilabel:`Sync with label`,
:guilabel:`Offset of label` and :guilabel:`Fixed`. The last two require
an angle in degrees.
* An :guilabel:`Offset X,Y` to shift the background item in the X and/or Y directions
* A :guilabel:`Radius X,Y` to round the corners of the background shape (applies
to rectangle and square shapes only)
* An :guilabel:`Opacity` of the background
* A :guilabel:`Blend mode` to mix the background with the other items in the
rendering (see :ref:`blend-modes`).
* The :guilabel:`Fill color`, :guilabel:`Stroke color` and
:guilabel:`Stroke width` for shape types other than the marker symbol.
Use the :guilabel:`Load symbol parameters` to revert changes on an SVG symbol
to its default settings.
* A :guilabel:`Pen join style`: it can be :guilabel:`Round`, :guilabel:`Miter`
or :guilabel:`Bevel` (applies to rectangle and square shapes only)
* |unchecked| :guilabel:`Draw effects` to add advanced |paintEffects|
:ref:`paint effects <draw_effects>` for improving text readability,
eg through outer glows and blurs.

.. _labels_shadow:

Shadow tab
----------

.. _figure_label_shadow:

.. figure:: img/label_shadow.png
:align: center

Label settings - Shadow tab

To add a shadow to the text, enable the |labelshadow| :guilabel:`Shadow`
tab and activate the |checkbox| :guilabel:`Draw drop shadow`. Then you can:

* Indicate the item used to generate the shadow with :guilabel:`Draw under`.
It can be the :guilabel:`Lowest label component` or a particular
component such as the :guilabel:`Text` itself, the :guilabel:`Buffer` or
the :guilabel:`Background`.
* Set the shadow's :guilabel:`Offset` from the item being shadowded, ie:

* The angle: clockwise, it depends on the underlying item orientation
* The distance of offset from the item being shadowded
* The units of the offset

If you tick the |checkbox| :guilabel:`Use global shadow` checkbox,
then the zero point of the angle is always oriented to the north and
doesn't depend on the orientation of the label's item.

* Influence the appearance of the shadow with the :guilabel:`Blur
radius`. The higher the number, the softer the shadows, in the units of
your choice.

.. comment FIXME: at the moment there is an error in this setting

|checkbox| :guilabel:`Blur only alpha pixels`:
It is supposed to show only those
pixels that have a partial alpha component beyond the base opaque pixels of
the component being blurred. For example, if you set the shadow of some
text to be gray and turn on that option, it should still show a duplication
of the text, colored as per the shadow color option, but with any blurred
shadow that extends beyond its text. With the option off, in this example,
it will blur all pixels of the duplicated text.
This is useful for creating a shadow that increases legibility at smaller
output sizes, e.g. like duplicating text and offsetting it a bit in
illustration programs, while still showing a bit of shadow at larger sizes.
Apparently, there is an error with re-painting the opaque pixels back over
top of the shadow (depending upon the shadow's color), when that setting is
used.

* Define the shadow's :guilabel:`Opacity`
* Rescale the shadow's size using the :guilabel:`Scale`
factor
* Choose the shadow's :guilabel:`Color`
* Use the :guilabel:`Blend mode` option to determine how your label's shadow
will mix with the map components below them (more details at
:ref:`blend-modes`).

Configuring interaction with labels
===================================

Other than the text formatting settings exposed above, you can also set how labels
interact with each others or with the features.

.. _labels_mask:

Mask tab
--------

The |labelmask| :guilabel:`Mask` tab allows you to define a mask area around
the labels. This feature is very useful when you have overlapping symbols and
labels with similar colors, and you want to make the labels visible.

.. _figure_label_mask:

.. figure:: img/label_mask.png
:align: center

Labels settings - Mask tab

To create masking effects on labels:

#. Activate the |checkbox| :guilabel:`Enable mask` checkbox in the |labelmask| tab.
#. Then you can set:

* the mask's :guilabel:`Size` in the :ref:`supported units <unit_selector>`
* the :guilabel:`Opacity` of the mask area around the label
* a :guilabel:`Pen Join Style`
* :ref:`paint effects <draw_effects>` through the |checkbox|
:guilabel:`Draw effects` checkbox.

#. Select this mask shape as a mask source in the overlapping layer properties
|labelmask| :guilabel:`Mask` tab (see :ref:`vector_mask_menu`).

.. _labels_callouts:

Callouts tab
------------

A common practice when placing labels on a crowded map is to use **callouts** -
labels which are placed outside (or displaced from) their associated feature
are identified with a dynamic line connecting the label and the feature.
If one of the two endings (either the label or the feature) is moved,
the shape of the connector is recomputed.

.. _figure_label_callouts:

.. figure:: img/label_callouts.png
:align: center

Labels with various callouts settings

To add a callout to a label, enable the |labelcallout| :guilabel:`Callouts`
tab and activate the |checkbox| :guilabel:`Draw callouts`. Then you can:

#. Select the :guilabel:`Style` of connector, one of:

* :guilabel:`Simple lines`: a straight line, the shortest path
* :guilabel:`Manhattan style`: a 90Â° broken line

#. Select the :guilabel:`Line style` with full capabilities of a :ref:`line
symbol <vector_line_symbols>` including layer effects, and data-defined
settings
#. Set the :guilabel:`Minimum length` of callout lines
#. Set the :guilabel:`Offset from feature` option: controls the distance
from the feature (or its anchor point if a polygon) where callout lines end.
Eg, this avoids drawing lines right up against the edges of the features.
#. Set the :guilabel:`Offset from label area` option: controls the distance
from the label anchor point (where the callout line ends).
This avoids drawing lines right up against the text.
#. |checkbox| :guilabel:`Draw lines to all feature parts` from the feature's
label
#. Set the :guilabel:`Anchor point` for the (polygon) feature (the end
point of the connector line). Available options:

* :guilabel:`Pole of inaccessibility`
* :guilabel:`Point on exterior`
* :guilabel:`Point on surface`
* :guilabel:`Centroid`
#. Set the :guilabel:`Label anchor point`: controls where the connector
line should join to the label text. Available options:

* :guilabel:`Closest point`
* :guilabel:`Centroid`
* Fixed position at the edge (:guilabel:`Top left`, :guilabel:`Top center`,
:guilabel:`Top right`, :guilabel:`Left middle`, :guilabel:`Right middle`,
:guilabel:`Bottom left`, :guilabel:`Bottom center` and :guilabel:`Bottom right`).

.. _labels_placement:

Placement tab
-------------

Choose the |labelplacement| :guilabel:`Placement` tab for configuring label placement
and labeling priority. Note that the placement options differ according to the
type of vector layer, namely point, line or polygon, and are affected by
the global :ref:`PAL setting <automated_placement>`.

.. _labels_point_placement:

Placement for point layers
..........................

Point labels placement modes available are:

.. _cartographic:

* :guilabel:`Cartographic`: point labels are generated with a
better visual relationship with the point feature, following ideal
cartographic placement rules. Labels can be placed:

* at a set :guilabel:`Distance` in :ref:`supported units <unit_selector>`,
either from the point feature itself or from the bounds of the symbol
used to represent the feature (set in :guilabel:`Distance offset from`).
The latter option is especially useful when the symbol size isn't fixed,
e.g. if it's set by a data defined size or when using different symbols
in a :ref:`categorized <categorized_renderer>` renderer.
* following a :guilabel:`Position priority` that can be customized or set for
an individual feature using a data defined list of prioritised positions.
This also allows only certain placements to be used, so e.g.
for coastal features you can prevent labels being placed over the land.

By default, cartographic mode placements are prioritised in the following
order (respecting the `guidelines from Krygier and Wood (2011)
<https://www.researchgate.net/publication/44463780_Making_maps_a_visual_guide_to_map_design_for_GIS_John_Krygier_Denis_Wood>`_
and other cartographic textbooks):

#. top right
#. top left
#. bottom right
#. bottom left
#. middle right
#. middle left
#. top, slightly right
#. bottom, slightly left.

* :guilabel:`Around Point`: labels are placed in a circle around the feature.
equal radius (set in :guilabel:`Distance`) circle around the feature.
The placement priority is clockwise from the "top right". The position can
be constrained using the data-defined :guilabel:`Quadrant` option.

* :guilabel:`Offset from Point`: labels are placed at an :guilabel:`Offset X,Y`
distance from the point feature, in various units, or preferably over the
feature. You can use a data-defined :guilabel:`Quadrant` to constrain the
placement and can assign a :guilabel:`Rotation` to the label.

.. _labels_line_placement:

Placement for line layers
.........................

Label modes for line layers include:

* :guilabel:`Parallel`: draws the label parallel to a generalised line
representing the feature, with preference for placement over straighter
portions of the line. You can define:

* :guilabel:`Allowed positions`: :guilabel:`Above line`, :guilabel:`On line`,
:guilabel:`Below line` and :guilabel:`Line orientation dependent position`
(placing the label at the left or the right of the line). It's possible to
select several options at once. In that case, QGIS will look for the optimal
label position.
* :guilabel:`Distance` between the label and the line
* :guilabel:`Curved`: draws the label following the curvature of the line
feature. In addition to the parameters available with the :guilabel:`Parallel`
mode, you can set the :guilabel:`Maximum angle between curved characters`,
either inside or outside.
* :guilabel:`Horizontal`: draws labels horizontally along the length of the
line feature.

.. _figure_labels_placement_line:

.. figure:: img/line_label_placement.png
:align: center

Label placement examples for lines

Next to placement modes, you can set:

* :guilabel:`Repeating Labels` :guilabel:`Distance` to display multiple
times the label over the length of the feature. The distance can be in
``Millimeters``, ``Points``, ``Pixels``, ``Meters at scale``, ``Map Units``
and ``Inches``.
* A :guilabel:`Label Overrun` :guilabel:`Distance` (not available for
horizontal mode): specifies the maximal allowable distance a label may run
past the end (or start) of line features. Increasing this value can allow
for labels to be shown for shorter line features.
* :guilabel:`Label Anchoring`: controls the placement of the labels along the
line feature they refer to. Click on :guilabel:`Settings ...` to choose:

* the position along the line (as a ratio) which labels will be
placed close to. It can be data-defined and possible values are:

* :guilabel:`Placement Behavior`: use :guilabel:`Preferred Placement Hint`
to treat the label anchor only as a hint for the label placement.
By choosing :guilabel:`Strict`, labels are placed exactly on the label
anchor.

Placement for polygon layers
............................

You can choose one of the following modes for placing labels of polygons:

.. _figure_labels_placement_polygon:

.. figure:: img/polygon_label_placement.png
:align: center

Label placement examples for polygons

* :guilabel:`Offset from Centroid`: labels are placed over the feature centroid
or at a fixed :guilabel:`Offset X,Y` distance (in :ref:`supported units
<unit_selector>`) from the centroid.
The reference centroid can be determined based on the
part of the polygon rendered in the map canvas (:guilabel:`visible polygon`)
or the :guilabel:`whole polygon`, no matter if you can see it. You can also:

* force the centroid point to lay inside their polygon
* place the label within a specific quadrant
* assign a rotation
* :guilabel:`Allow placing labels outside of polygons` when it is not
possible to place them inside the polygon. Thanks to data-defined properties,
this makes possible to either allow outside labels, prevent outside labels,
or force outside labels on a feature-by-feature basis.

* :guilabel:`Around Centroid`: places the label within a preset distance around
the centroid, with a preference for the placement directly over the centroid.
Again, you can define whether the centroid is the one of the
:guilabel:`visible polygon` or the :guilabel:`whole polygon`, and whether
to force the centroid point inside the polygon.

* :guilabel:`Horizontal`: places at the best position a horizontal label inside
the polygon. The preferred placement is further from the edges of the polygon.
It's possible to :guilabel:`Allow placing labels outside of polygons`.

* :guilabel:`Free (Angled)`: places at the best position a rotated label
inside the polygon. The rotation respects the polygon's orientation and
the preferred placement is further from the edges of the polygon.
It's possible to :guilabel:`Allow placing labels outside of polygons`.

* :guilabel:`Using Perimeter`: draws the label parallel to a generalised line
representing the polygon boundary, with preference for straighter portions
of the perimeter. You can define:

* :guilabel:`Allowed positions`: :guilabel:`Above line`, :guilabel:`On line`,
:guilabel:`Below line` and :guilabel:`Line orientation dependent position`
(placing the label at the left or the right of the polygon's boundary).
It's possible to select several options at once. In that case, QGIS will
look for the optimal label position.
* :guilabel:`Distance` between the label and the polygon's outline
* the :guilabel:`Repeating Labels` :guilabel:`Distance` to display multiple
times the label over the length of the perimeter.

* :guilabel:`Using Perimeter (Curved)`: draws the label following the curvature
of the polygon's boundary. In addition to the parameters available with the
:guilabel:`Using Perimeter` mode, you can set the
:guilabel:`Maximum angle between curved characters polygon`, either inside
or outside.

* :guilabel:`Outside Polygons`: always places labels outside the polygons,
at a set :guilabel:`Distance`

Common placement settings
.........................

Some label placement settings are available for all layer geometry types:

Data Defined
^^^^^^^^^^^^

The :guilabel:`Data Defined` group provides direct control on labels
placement, on a feature-by-feature basis. It relies on their attributes
or an expression to set:

* the :guilabel:`X` and :guilabel:`Y` coordinate
* the text alignment over the custom position set above:

* :guilabel:`Horizontal`: it can be **Left**, **Center** or **Right**
* the text :guilabel:`Vertical`: it can be **Bottom**, **Base**, **Half**,
**Cap** or **Top**
* the text :guilabel:`Rotation`. Check the :guilabel:`Preserve data rotation
values` entry if you want to keep the rotation value in the associated field
and apply it to the label, whether the label is pinned or not. If unchecked,
unpinning the label rotation is reset and its value cleared from the attribute
table.

.. note:: Data-defined rotation with polygon features is currently supported
only with the :guilabel:`Around centroid` placement mode.

.. note:: Expressions can not be used in combination with the labels map tools
(ie the :guilabel:`Rotate label` and :guilabel:`Move label` tools)
to :ref:`data-define <data_defined>` labels placement.
The widget will be reset to the corresponding :ref:`auxiliary storage field
<vector_auxiliary_storage>`.

.. _`labels_priority`:

Priority
^^^^^^^^

In the :guilabel:`Priority` section you can define the placement priority rank
of each label, ie if there are different diagrams or labels candidates for the
same location, the item with the higher priority will be displayed and the
others could be left out.

The priority rank is also used to evaluate whether a label could be omitted
due to a greater weighted :ref:`obstacle feature <labels_obstacles>`.

.. _`labels_obstacles`:

Obstacles
^^^^^^^^^

In some contexts (eg, high density labels, overlapping features...), the
labels placement can result in labels being placed over unrelated features.

An obstacle is a feature over which QGIS avoids placing other features' labels
or diagrams. This can be controlled from the :guilabel:`Obstacles` section:

#. Activate the |checkbox| :guilabel:`Features act as obstacles`
option to decide that features of the layer should act as obstacles for
any label and diagram (including items from other features in the same layer).

Instead of the whole layer, you can select a subset of features to use as
obstacles, using the |dataDefined| :sup:`data-defined override` control next
to the option.

#. Use the :guilabel:`Settings` button to tweak the obstacle's weighting.

* For every potential obstacle feature you can assign an :guilabel:`Obstacle
weight`: any :ref:`label <labels_priority>` or :ref:`diagram <diagram_placement>`
whose placement priority rank is greater than this value can be placed
over. Labels or diagrams with lower rank will be omitted if no other
placement is possible.

This weighting can also be data-defined, so that within the same layer,
certain features are more likely to be covered than others.
* For polygon layers, you can choose the kind of obstacle the feature is:

* **over the feature's interior**: avoids placing labels over the interior
of the polygon (prefers placing labels totally outside or just slightly
inside the polygon)
* or **over the feature's boundary**: avoids placing labels over the
boundary of the polygon (prefers placing labels outside or completely
inside the polygon). This can be useful for layers where the features
cover the whole area (administrative units, categorical coverages, ...).
In this case, it is impossible to avoid
placing labels within these features, and it looks much better when
placing them over the boundaries between features is avoided.

.. _labels_rendering:

Rendering tab
-------------

In the |render| :guilabel:`Rendering` tab, you can tune when the labels can
be rendered and their interaction with other labels and features.

Label options
.............

Under :guilabel:`Label options`:

* You find the :ref:`scale-based <label_scaledepend>`
and the :guilabel:`Pixel size-based` visibility settings.

* The :guilabel:`Label z-index` determines the order in which labels are rendered,
as well in relation with other feature labels in the layer (using data-defined
override expression), as with labels from other layers. Labels with a higher
z-index are rendered on top of labels (from any layer) with lower z-index.

Additionally, the logic has been tweaked so that if two labels have
matching z-indexes, then:

* if they are from the same layer, the smaller label will be drawn above the
larger label
* if they are from different layers, the labels will be drawn in the same order
as their layers themselves (ie respecting the order set in the map legend).

.. note:: This setting doesn't make labels to be drawn below the
features from other layers, it just controls the order in which
labels are drawn on top of all the layers' features.

* While rendering labels and in order to display readable labels,
QGIS automatically evaluates the position of the labels and can hide some of them
in case of collision. You can however choose to |checkbox| :guilabel:`Show all
labels for this layer (including colliding labels)` in order to manually fix
their placement (see :ref:`label_toolbar`).
* With data-defined expressions in :guilabel:`Show label` and :guilabel:`Always Show`
you can fine tune which labels should be rendered.
* Allow to :guilabel:`Show upside-down labels`: alternatives are **Never**,
**when rotation defined** or **always**.

Feature options
...............

Under :guilabel:`Feature options`:

* You can choose to :guilabel:`Label every part of a multi-part features`
and :guilabel:`Limit number of features to be labeled to`.
* Both line and polygon layers offer the option to set a minimum size for
the features to be labeled, using :guilabel:`Suppress labeling of features
smaller than`.
* For polygon features, you can also filter the labels to show according to
whether they completely fit within their feature or not.
* For line features, you can choose to :guilabel:`Merge connected lines
to avoid duplicate labels`, rendering a quite airy map in conjunction with
the :guilabel:`Distance` or :guilabel:`Repeat` options in the :ref:`Placement
<labels_line_placement>` tab.

.. Substitutions definitions - AVOID EDITING PAST THIS LINE
This will be automatically updated by the find_set_subst.py script.
If you need to create a new substitution manually,
please add it also to the substitutions.txt file in the
source folder.