GUICanvasWML

Canvas

A canvas is a blank drawing area on which the user can draw several shapes. The drawing is done by adding WML structures to the canvas.

Pre commit

This section contains the pre commit functions. These functions will be executed before the drawn canvas is applied on top of the normal background. There should only be one pre commit section and its order regarding the other shapes doesn't matter. The function has effect on the entire canvas, it's not possible to affect only a small part of the canvas.

The section can have one of the following subsections.

Blur

Blurs the background before applying the canvas. This doesn't make sense if the widget isn't semi-transparent.

Keys:

key	type	default	description
depth	unsigned	0	The depth to blur.

Line

Definition of a line. When drawing a line it doesn't get blended on the surface but replaces the pixels instead. A blitting flag might be added later if needed.

Keys:

key	type	default	description
x1	f_unsigned	0	The x coordinate of the startpoint.
y1	f_unsigned	0	The y coordinate of the startpoint.
x2	f_unsigned	0	The x coordinate of the endpoint.
y2	f_unsigned	0	The y coordinate of the endpoint.
color	color	""	The color of the line.
thickness	unsigned	0	The thickness of the line if 0 nothing is drawn.
debug	string	""	Debug message to show upon creation this message is not stored.

Global Variables:.

Variable	type	description
width	unsigned	The width of the canvas.
height	unsigned	The height of the canvas.
text	tstring	The text to render on the widget.
text_maximum_width	unsigned	The maximum width available for the text on the widget.
text_maximum_height	unsigned	The maximum height available for the text on the widget.
text_wrap_mode	int	When the text doesn't fit in the available width there are several ways to fix that. This sets which method is used and possible values are the same as here, that is, 0 (No elllipsization), 1 (ellipsize start of text), 2 (ellipsize end of text), 3 (ellipsize at the middle). More details (slightly technical) are found at the Pango docs here.
text_alignment	h_align	The way the text is aligned inside the canvas.

The size variables are copied to the window and will be determined at runtime. This is needed since the main window can be resized and the dialog needs to resize accordingly. The following variables are available:

Variable	type	description
screen_width	unsigned	The usable width of the Wesnoth main window.
screen_height	unsigned	The usable height of the Wesnoth main window.
gamemapx_offset	unsigned	The distance between left edge of the screen and the game map.
gamemap_width	unsigned	The usable width of the Wesnoth gamemap, if no gamemap shown it's the same value as screen_width.
gamemap_height	unsigned	The usable height of the Wesnoth gamemap, if no gamemap shown it's the same value as screen_height.
mouse_x	unsigned	The x coordinate of the mouse pointer.
mouse_y	unsigned	The y coordinate of the mouse pointer.
window_width	unsigned	The window width. This value has two meanings during the layout phase. This only applies if automatic placement is not enabled. - When set to 0 it should return the wanted maximum width. If no maximum is wanted it should be set to the '"(screen_width)"'. - When not equal to 0 its value is the best width for the window. When the size should remain unchanged it should be set to '"(window_width)"'.
window_height	unsigned	The window height. This value has two meanings during the layout phase. This only applies if automatic placement is not enabled. - When set to 0 it should return the wanted maximum height. If no maximum is wanted it should be set to the '"(screen_height)"'. - When not equal to 0 its value is the best height for the window. When the size should remain unchanged it should be set to '"(window_height)"'.

Note when drawing the valid coordinates are:
0 -> width - 1
0 -> height -1

Drawing outside this area will result in unpredictable results including crashing. (That should be fixed, when encountered.)

Bounded Shape

Common attributes of rectangles, round rectangles and text:

key	type	default	description
x	f_unsigned	0	The x coordinate of the top left corner.
y	f_unsigned	0	The y coordinate of the top left corner.
w	f_unsigned	0	The width of the rectangle.
h	f_unsigned	0	The height of the rectangle.

Rectangle

Definition of a rectangle. When drawing a rectangle it doesn't get blended on the surface but replaces the pixels instead. A blitting flag might be added later if needed.

Keys:

key	type	default	description
x	f_unsigned	0	The x coordinate of the top left corner.
y	f_unsigned	0	The y coordinate of the top left corner.
w	f_unsigned	0	The width of the rectangle.
h	f_unsigned	0	The height of the rectangle.
border_thickness	unsigned	0	The thickness of the border if the thickness is zero it's not drawn.
border_color	color	""	The color of the border if empty it's not drawn.
fill_color	color	""	The color of the interior if omitted it's not drawn.
debug	string	""	Debug message to show upon creation this message is not stored.

Variables: See Line.

Rounded Rectangle

Definition of a rounded rectangle shape.

When drawing a rounded rectangle it doesn't get blended on the surface but replaces the pixels instead. A blitting flag might be added later if needed.

key	type	default	description
corner_radius	f_unsigned	0	The radius of the rectangle's corners.
border_thickness	unsigned	0	The thickness of the border; if the thickness is zero it's not drawn.
border_color	color	""	The color of the border; if empty it's not drawn.
fill_color	color	""	The color of the interior; if omitted it's not drawn.
debug	string	""	Debug message to show upon creation; this message is not stored.

Circle

Definition of a circle. When drawing a circle it doesn't get blended on the surface but replaces the pixels instead. A blitting flag might be added later if needed.

Keys:

key	type	default	description
x	f_unsigned	0	The x coordinate of the center.
y	f_unsigned	0	The y coordinate of the center.
radius	f_unsigned	0	The radius of the circle if 0 nothing is drawn.
color	color	""	The color of the circle.
debug	string	""	Debug message to show upon creation this message is not stored.

Variables: See Line.

Drawing outside the area will result in unpredictable results including crashing. (That should be fixed, when encountered.)

Image

Definition of an image.

Keys:

key	type	default	description
x	f_unsigned	0	The x coordinate of the top left corner.
y	f_unsigned	0	The y coordinate of the top left corner.
w	f_unsigned	0	The width of the image, if not zero the image will be scaled to the desired width.
h	f_unsigned	0	The height of the image, if not zero the image will be scaled to the desired height.
resize_mode	resize_mode	scale	Determines how an image is scaled to fit the wanted size.
vertical_mirror	f_bool	false	Mirror the image over the vertical axis.
name	f_string	""	The name of the image.
debug	string	""	Debug message to show upon creation this message is not stored.

Local Variables:

Variable	type	description
image_width	unsigned	The width of the image, either the requested width or the natural width of the image. This value can be used to set the x (or y) value of the image. (This means x and y are evaluated after the width and height.)
image_height	unsigned	The height of the image, either the requested height or the natural height of the image. This value can be used to set the y (or x) value of the image. (This means x and y are evaluated after the width and height.)
image_original_width	unsigned	The width of the image as stored on disk, can be used to set x or w (also y and h can be set).
image_original_height	unsigned	The height of the image as stored on disk, can be used to set y or h (also x and y can be set).

Also the general global variables are available, see Line.

Text

Definition of text.

Keys:

key	type	default	description
x	f_unsigned	0	The x coordinate of the top left corner.
y	f_unsigned	0	The y coordinate of the top left corner.
w	f_unsigned	0	The width of the text's bounding rectangle.
h	f_unsigned	0	The height of the text's bounding rectangle.
font_family	font_family	"sans"	The font family used for the text.
font_size	unsigned	mandatory	The size of the text font.
font_style	font_style	""	The style of the text.
text_alignment	f_h_align	"left"	The alignment of the text.
color	color	""	The color of the text.
text	f_tstring	""	The text to draw (translatable).
text_markup	f_bool	false	Can the text have mark-up?
text_link_aware	f_bool	false	Is the text link aware?
text_link_color	f_string	"#ffff00"	The color of links in the text
maximum_width	f_int	-1	The maximum width the text is allowed to be.
maximum_height	f_int	-1	The maximum height the text is allowed to be.
actions	string	""	WFL code that will be executed when this shape is drawn. In particular, set_var can be used here to store any variables mentioned in the variables section for global use inside the canvas.
debug	string	""	Debug message to show upon creation this message is not stored.

NOTE alignment could only be done with the formulas, but now with the text_alignment flag as well, older widgets might still use the formulas and not all widgets may expose the text alignment yet and when exposed not use it yet.

Local Variables:

Variable	type	description
text_width	unsigned	The width of the rendered text.
text_height	unsigned	The height of the rendered text.

Also the general global variables are available, see Line.