DESCRIPTION
The
kplot_alloc function allocates a plotting context for later use by
kplot_attach_data(3),
kplot_draw(3), and so on. It must be freed with
kplot_free(3). The only argument,
cfg, is copied: all allocated members (e.g.,
clrs and Cairo pattern) are re-allocated or referenced, as the case may be, so the caller can free all memory in the meantime. The options provided via the
cfg object are as follows:
-
extrema
-
A bit-field allowing arbitrary assignment of xy-ranges: EXTREMA_XMIN, EXTREMA_XMAX, EXTREMA_YMIN, and/or EXTREMA_YMAX. This fixates the ranges unconditionally (i.e., no auto-scaling will occur and points or lines drawn outside will be clipped).
-
extrema_xmin
-
If EXTREMA_XMIN is set, this value will be used instead of a value computed from the data.
-
extrema_xmax
-
See extrema_xmin.
-
extrema_ymin
-
See extrema_xmin.
-
extrema_ymax
-
See extrema_xmin.
-
margin
-
Bitfield of which margins to draw: MARGIN_LEFT, MARGIN_RIGHT, MARGIN_TOP, MARGIN_BOTTOM, or MARGIN_ALL.
-
marginsz
-
The width of the margin in user-space Cairo coordinates. These are clamped to be non-negative. The margin is the space between the image boundary and the longest (or tallest) label edge, or if no label is specified on any face, the plot area.
-
ticlabel
-
Bitfield of which labels to draw: TICLABEL_LEFT, TICLABEL_RIGHT, TICLABEL_TOP, or TICLABEL_BOTTOM.
-
ticlabelfont
-
All font characteristics of the tic labels.
-
xticlabelpad
-
Space between horizontal (x-axis) tic labels and the plot area. Specifically, between the edge of the longest label along any face and the plot area.
-
yticlabelpad
-
See xticlabelpad.
-
xticlabelrot
-
Rotation of horizontal (x-axis) labels (in radians) clamped to 90 degrees. Rotation is clockwise. Note that if this is nonzero, the tic label is aligned under the tic-mark at the top-left part of the field, instead of the middle as is the usual case.
-
xticlabelfmt
-
This function may be user-defined for formatting the horizontal x-axis label as a UTF-8 string limited to 128 bytes (including nil terminator). It accepts three arguments: the value to format, the string buffer in which to format, and the size of the buffer. The default is to use snprintf(3) with the
%g format string.
-
yticlabelfmt
-
See xticlabelfmt.
-
border
-
Bitfield of which borders to draw: BORDER_LEFT, BORDER_RIGHT, BORDER_TOP, BORDER_BOTTOM, or BORDER_ALL.
-
borderline
-
The configuration of the border line. See kplot_attach_data(3) for an explanation of the line structure.
-
clrs
-
Array of colour configurations for the colour palette. If no colours are specified, which is the default, a default palette will be installed. See kplot_attach_data(3) for a description of the colour structure.
-
clrsz
-
The number of colours in clrs. Colour indices index into the clrs array modulo this value.
-
xtics
-
The number of tics (and thus labels) to draw along the horizontal x-axis. The border condition (one tic) is drawn in the centre.
-
ytics
-
See xtics.
-
tic
-
Bitfield of which tics to draw: TIC_LEFT_IN, TIC_RIGHT_IN, TIC_TOP_IN, TIC_BOTTOM_IN, TIC_LEFT_OUT, TIC_RIGHT_OUT, TIC_TOP_OUT, or TIC_BOTTOM_OUT.
-
ticline
-
The configuration of the tic line. See kplot_attach_data(3) for an explanation of the line structure.
-
xaxislabel
-
The label for the x-axis, shown below the bottom x-axis tic labels (if specified).
-
x2axislabel
-
The label for the second x-axis, shown above the top x-axis tic labels (if specified).
-
yaxislabel
-
See xaxislabel.
-
y2axislabel
-
See xaxislabel.
-
xaxislabelrot
-
The clockwise rotation of the x-axis label. Note that this will turn around its centre, so no matter the rotation, it will be correctly buffered on both sides.
-
yaxislabelrot
-
See xaxislabelrot.
-
xaxislabelpad
-
The padding between the top of the x-axis label and the bottom of the x-axis tics (if specified).
-
yaxislabelpad
-
See xaxislabelpad.
-
axislabelfont
-
All font characteristics for the xaxislabel and yaxislabel.
-
grid
-
Bitfield of which grid lines to draw: GRID_X, GRID_Y, or GRID_ALL.
-
gridline
-
The configuration of grid lines.
If
NULL is passed as a configuration, reasonable defaults are used.