An Evas object is the most basic visual entity used in Evas. Everything, be it a single line or a complex list of widgets, is an Evas object.
Primitive objects are the base upon which to build a complex interface: rectangles, lines, polygons, images, textblocks and texts.
There is only one function to deal with rectangle objects (see Rectangle Object Functions API). However, the rectangle is manipulated using the generic evas object functions.
The evas rectangle serves a number of key functions when working on Evas programs.
A common requirement of Evas programs is to have a solid color background, which can be accomplished with the following code.
Evas_Object *bg = evas_object_rectangle_add(evas_canvas); //Here we set the rectangles red, green, blue and opacity levels evas_object_color_set(bg, 255, 255, 255, 255); // opaque white background evas_object_resize(bg, WIDTH, HEIGHT); // covers full canvas evas_object_show(bg);
When debugging visual issues with evas programs, the rectangle is a useful tool. The rectangle's simplicity means that it is easier to pinpoint issues with it than with more complex objects. A common technique to use when writing an evas program and not getting the desired visual result is to replace an object for a solid color rectangle and seeing how it interacts with the other elements. This often allows us to notice clipping, parenting or positioning issues. Once the issues are identified and corrected, the rectangle can be replaced for the original object, and in all likelihood any remaining issues are specific to that object's type.
Clipping serves two main functions:
An Evas text object shows a basic single-line single-style text (see Text Object Functions API).
Evas_Object *text = evas_object_text_add(evas_canvas); evas_object_text_text_set(text, "some text"); evas_object_color_set(text, 127, 0, 0, 127); evas_object_show(text);
To set the text, use
evas_object_text_text_set(text, some_text). You can
set the current text with
To set the font, use
evas_object_text_font_set(text, font, size):
text: The text object
font: The font name you want to use
size: The font size you want to use. To query the current font, use
evas_object_text_font_set(text, font, size).
To set the text style, use
evas_object_text_style_set(text, style). The
following styles are supported:
EVAS_TEXT_STYLE_PLAIN: Plain, standard text
EVAS_TEXT_STYLE_SHADOW: Text with shadow underneath
EVAS_TEXT_STYLE_OUTLINE: Text with an outline
EVAS_TEXT_STYLE_SOFT_OUTLINE: Text with a soft outline
EVAS_TEXT_STYLE_GLOW: Text with a glow effect
EVAS_TEXT_STYLE_OUTLINE_SHADOW: Text with both outline and shadow effects
EVAS_TEXT_STYLE_FAR_SHADOW: Text with (far) shadow underneath
EVAS_TEXT_STYLE_OUTLINE_SOFT_SHADOW: Text with outline and soft shadow effects combined
EVAS_TEXT_STYLE_SOFT_SHADOW: Text with (soft) shadow underneath
EVAS_TEXT_STYLE_FAR_SOFT_SHADOW: Text with (far soft) shadow underneath
EVAS_TEXT_STYLE_SHADOW_DIRECTION_BOTTOM_RIGHT: Shadow growing to bottom right
EVAS_TEXT_STYLE_SHADOW_DIRECTION_BOTTOM: Shadow growing to the bottom
EVAS_TEXT_STYLE_SHADOW_DIRECTION_BOTTOM_LEFT: Shadow growing to bottom left
EVAS_TEXT_STYLE_SHADOW_DIRECTION_LEFT: Shadow growing to the left
EVAS_TEXT_STYLE_SHADOW_DIRECTION_TOP_LEFT: Shadow growing to top left
EVAS_TEXT_STYLE_SHADOW_DIRECTION_TOP: Shadow growing to the top
EVAS_TEXT_STYLE_SHADOW_DIRECTION_TOP_RIGHT: Shadow growing to top right
EVAS_TEXT_STYLE_SHADOW_DIRECTION_RIGHT: Shadow growing to the right. To query the current style, use
If the text does not fit, make an ellipsis on it by using
evas_object_text_ellipsis_set(text, ellipsis). The (float) value
specifies, which part of the text is shown.
0.0: The beginning is shown and the end trimmed.
1.0: The beginning is trimmed and the end shown.
-1.0: Ellipsis is disabled. To query the current ellipsis value, use
When the text style is set to glow, set the glow color using
evas_object_text_glow_color_set(text, r, g, b, a), where
a are respectively the red, green, blue, and alpha values. The
effect is placed at a short distance from the text but not touching it. For
glows set right at the text, use
g, b, a). To query the current color, use
evas_object_text_glow_color_get(text, r, g, b, a), respectively
evas_object_text_glow2_color_get(text, r, g, b, a).
If your text style is set to display a shadow, use
evas_object_text_shadow_color_set(text, r, g, b, a), where
a are respectively the red, green, blue, and alpha values. To
query the current color, use
evas_object_text_shadow_color_get(text, r, g,
If your text style is set to display an outline, use
evas_object_text_outline_color_set(text, r, g, b, a), where
a are respectively the red, green, blue, and alpha values. To
query the current color, use
evas_object_text_outline_color_get(text, r, g,
See Textblock section.
See Image section.
A smart object is a special Evas object that provides custom functions to handle automatically clipping, hiding, moving, resizing color setting and more on child elements, for the smart object's user. They could be, for example, a group of objects that move together, or implementations of whole complex UI widgets, providing some intelligence and extension to simple Evas objects.
A container is a Smart object that holds children Evas objects in a specific fashion.
A table is a smart object that packs children using a tabular layout (see Table Smart Object API).
table = evas_object_table_add(evas); evas_object_table_homogeneous_set(table, EVAS_OBJECT_TABLE_HOMOGENEOUS_NONE); evas_object_table_padding_set(table, 0, 0); evas_object_resize(table, WIDTH, HEIGHT); evas_object_show(table); rect = evas_object_rectangle_add(evas); evas_object_color_set(rect, 255, 0, 0, 255); evas_object_size_hint_min_set(rect, 100, 50); evas_object_show(rect); evas_object_table_pack(table, rect, 1, 1, 2, 1); rect = evas_object_rectangle_add(d.evas); evas_object_color_set(rect, 0, 255, 0, 255); evas_object_size_hint_min_set(rect, 50, 100); evas_object_show(rect); evas_object_table_pack(table, rect, 1, 2, 1, 2); rect = evas_object_rectangle_add(d.evas); evas_object_color_set(rect, 0, 0, 255, 255); evas_object_size_hint_min_set(rect, 50, 50); evas_object_show(rect); evas_object_table_pack(table, rect, 2, 2, 1, 1); rect = evas_object_rectangle_add(d.evas); evas_object_color_set(rect, 255, 255, 0, 255); evas_object_size_hint_min_set(rect, 50, 50); evas_object_show(rect); evas_object_table_pack(table, rect, 2, 3, 1, 1);
In this example, we add a non-homogeneous table to the canvas with its padding set to 0.
We then add four different colored rectangles with different properties.
To create a table, use
To set the table layout (the cells), use
evas_object_table_homogeneous_set(table, homogeneous). The following
values can be homogeneous:
EVAS_OBJECT_TABLE_HOMOGENEOUS_NONE: This default value has columns and rows calculated based on hints of individual cells. This is flexible, but much heavier on computations.
EVAS_OBJECT_TABLE_HOMOGENEOUS_TABLE: The table size is divided equally among children, filling the whole table area. If the children have a minimum size that is larger than this (including padding), then the table overflows and is aligned respecting the alignment hint, possibly overlapping sibling cells.
EVAS_OBJECT_TABLE_HOMOGENEOUS_ITEM: The greatest minimum cell size is used: if no element is set to expand, the contents of the table are the minimum size and the bounding box of all the children is aligned relatively to the table object using
evas_object_table_align_get(). If the table area is too small to hold this minimum bounding box, then the objects keep their size and the bounding box overflows the box area, still respecting the alignment. To set the current mode, use
The table's content alignment is set using
evas_object_table_align_set(table, horizontal, vertical), where
vertical are floating values. To see them, use
evas_object_table_align_get(table, horizontal, vertical).
To set the padding, use
vertical). To see the current value, use
evas_object_table_padding_get(table, horizontal, vertical).
To see the current column and row count, use
evas_object_table_col_row_size_get(table, columns, rows).
A grid is a smart object that packs its children as with a regular grid layout (see Grid Smart Object API)
Grids are added to the canvas with
To change a grid's virtual resolution, use
width, height), to see it, use
To add an object, use
evas_object_grid_pack(grid, child, x, y, w, h),
xis the virtual X coordinate of the child
yis the virtual y coordinate of the child
wis the virtual width of the child
his the virtual height of the child
A box is a simple container that sets its children objects linearly (see Box Smart Object API).
To add a box to your canvas, use
To add a child to the box, use
evas_object_box_append(box, child): The child is appended.
evas_object_box_insert_after(box, child, reference): The child is added after
evas_object_box_insert_before(box, child, reference): The child is added before
evas_object_box_insert_at(box, child, pos): The child is added at the specified position.
To set the alignment, use
horizontal: 0.0 means aligned to the left, 1.0 means to the right;
vertical: 0.0 means aligned to the top, 1.0 means to the bottom.
Evas has predefined box layouts available: