foresight_backend

foresight_backend, abstract output device.

Two coordinate spaces. Page primitives take pixel coordinates (origin top-left, y downward). The data_* primitives, valid between begin_plot_area and end_plot_area, take unit-square coordinates of the plot area (origin bottom-left, y upward, [0, 1] spanning the axis ranges) and are clipped to it. Keeping data in unit coordinates lets an interactive device zoom and pan by changing a single view transform.

A panel is bracketed by begin_axes/end_axes, which hand the device the panel geometry and axis ranges, and its redrawable decorations (grid, ticks) by named begin_group/end_group: an interactive device regenerates them after a zoom, a static one just writes them.

Source: src/lib/foresight_backend.F90

Dependencies

Contents

• axes_view
• backend_object
• arrow_head

Variables

Name	Type	Attributes	Description
HEAD_LENGTH	real(kind=R8P)	parameter	Arrowhead barb length [px], gnuplot svg default.
HEAD_ANGLE	real(kind=R8P)	parameter	Arrowhead barb angle off the shaft [deg], gnuplot default.

Derived Types

axes_view

Geometry and axis ranges of a plot panel.

Components

Name	Type	Attributes	Description
area	real(kind=R8P)		Plot area: left, right, top, bottom [px].
x	real(kind=R8P)		x axis values at the axis start and end.
y	real(kind=R8P)		y axis values at the axis start and end.
xlog	logical		Log x axis.
ylog	logical		Log y axis.
grid	logical		Grid shown.
font_size	real(kind=R8P)		Font size [px].
xtics	character(len=:)	allocatable	x tick positions for the viewer (tics_object%attribute), empty for auto.
ytics	character(len=:)	allocatable	y tick positions for the viewer, empty for auto.
xformat	character(len=:)	allocatable	x tick label format, empty for the default.
yformat	character(len=:)	allocatable	y tick label format, empty for the default.
mirror	logical		Ticks mirrored on the opposite border: x, y, y2.
y2_active	logical		Second y axis drawn; the y2* components are meaningful only then.
y2	real(kind=R8P)		y2 axis values at the axis start and end.
y2log	logical		Log y2 axis.
y2tics	character(len=:)	allocatable	y2 tick positions for the viewer, empty for auto.
y2format	character(len=:)	allocatable	y2 tick label format, empty for the default.

backend_object

Abstract output device.

Inheritance

Attributes: abstract

Components

Name	Type	Attributes	Description
theme	type(theme_object)		Output theme: colors the layout's ones are mapped to (foresight_theme).

Type-Bound Procedures

Name	Attributes	Description
begin_page	pass(self)	Open the output page.
end_page	pass(self)	Close the output page.
begin_axes	pass(self)	Open a plot panel.
end_axes	pass(self)	Close the plot panel.
begin_group	pass(self)	Open a named group.
end_group	pass(self)	Close the group.
rect	pass(self)	Rectangle [px].
polyline	pass(self)	Polyline [px].
dots	pass(self)	Round dots or markers [px].
polygon	pass(self)	Filled polygon [px].
image	pass(self)	Raster image [px].
text	pass(self)	Text [px].
begin_plot_area	pass(self)	Open the clipped plot area.
end_plot_area	pass(self)	Close the plot area.
data_polyline	pass(self)	Polyline [unit square].
data_dots	pass(self)	Dots or markers [unit square].
data_bars	pass(self)	Error bars [unit square].
data_polygon	pass(self)	Filled polygon [unit square].
data_image	pass(self)	Raster image [unit square].
text_width	pass(self)	Text width [px].
readout	pass(self)	Seven-segment readout [px].
readout_extent	pass(self)	Readout size [px].
data_arrows	pass(self)	Arrows [unit square].
data_label	pass(self)	Text at a point [unit square].

Subroutines

arrow_head

The barbs of an arrowhead at tip pointing away from tail [px, any orientation]: HEAD_LENGTH px long, HEAD_ANGLE degrees off the shaft, as gnuplot's default head; barbs(:, 1) and barbs(:, 2). A zero length shaft points right.

Attributes: pure

subroutine arrow_head(tail, tip, barbs)

Arguments

Name	Type	Intent	Attributes	Description
tail	real(kind=R8P)	in		Tail [px].
tip	real(kind=R8P)	in		Tip [px].
barbs	real(kind=R8P)	out		Barb ends [px].