Phenology — Phenology Image Generator

4.7 Phenology Image Generator

Seasons Theme

It was necessary to alter the operation of the WeeWX Image Generator to draw the horizontal development-stages lines for crop and pest Growing Degree-Day charts (above), but the Phenology extension does not stop at modification. Instead it indulges in a rewrite of the WeeWX Image Generator. The shading techniques used to produce the horizontal development-stages lines require semi-transparent images, so the Phenology Image Generator comes equipped to handle image composition with backgrounds.

Further, the Phenology Image Generator uses a theme structure to specify image options that control appearance.

The Phenology Image Generator "Seasons" theme mimics the charts produced by the WeeWX Seasons skin. By default the Phenology extension produces a (mostly) complete, consistent, and coherent set of charts that duplicate the WeeWX charts regardless of the chosen theme.

4.7.1 Themes

A portfolio of pre-defined themes is included in the [[Themes]] stanza of $SKIN_ROOT/Phenology/phenology.conf. The active theme is the one called [[[Current]]]:

[Extras]
  [[Themes]]
    [[[Seasons]]]
      themes =
    [[[Current]]]
      themes = Seasons

Themes may refer to one another in a cascade. Thus the Current theme refers to the Seasons theme. Note that the Seasons theme is an empty theme. All its image options are defaults.

Image options (if any) are specified as scalars in a theme stanza.

The "themes" scalar may be specified in any given theme. It is a comma-separated list of other theme names. The image options used by the other themes are brought into the given theme — theme by theme from right to left — before image options used by the given theme (if any) are applied.

Here are examples of pre-defined themes.

These are all whimsical. If you're aiming for legibility and ease of comprehension (And who doesn't?), you should stick to the Seasons theme; nevertheless, you are invited to expend hours of tinkering, devising your own, as I have.

4.7.1.1 Blackboard

Blackboard Theme

Blackboard is a reverse-video theme.

[Extras]
  [[Themes]]
    [[[Night]]]
      image_background_color = "Black"
      image_border_color = None
    [[[Mist]]]
      chart_background_color = "#ffffff37"
      chart_border_color = None
    [[[Text Gray]]]
      unit_label_font_color = "#787878"
      bottom_label_font_color = "#787878"
      axis_label_font_color = "#787878"
    [[[Shade]]]
      daynight_day_color = "#00000000"
      daynight_night_color = "#00001030"
      daynight_edge_color = None
    [[[Blackboard]]]
      report_body_style = "background-color: Black; color: Gray;"
      chart_gridline_color = "DimGray"
      themes = Night, Mist, Shade, Text Gray
    [[[Current]]]
      themes = Blackboard

4.7.1.2 Yellowboard

Yellowboard Theme

Yellowboard is a reverse-video theme, too, but with brighter axis labels. The differences between themes can be profound or subtle.

4.7.1.3 Greenboard

Greenboard Theme

Both Greenboard and Yellowboard hark back to the days when educators used yellow chalk because they thought it resulted in less eye fatigue than white.

4.7.1.4 Henry the Navigator

Henry the Navigator Theme

Henry the Navigator gives your Web pages a Renaissance feel.

4.7.1.5 The Woods

The Woods Theme

Bound off into wild backgrounds.

4.7.1.6 Sperry 1100

Sperry 1100 Theme

I was once smitten by the beauty of the front panel on the Sperry-Univac 1100-Series computers where console operators used to dial in their jump keys. It was an under-appreciated piece of industrial art whose color scheme inspired this theme.

4.7.1.7 Friden Flexowriter

Friden Flexowriter Theme

Before interior designers turned to the blues, oranges, and mauves of the Space Age, there came the Jet Age and, before that, the Turboprop Age. The Friden Calculator Company manufactured a line of what can only be described as word-processing machines with paper-tape memory. These Flexowriters were used to streamline form-filling and data-capture. They enlivened the battle-ship gray interiors of military and industrial offices with their earthy hues.

4.7.1.8 Spring

Spring Theme

Experience Springtime in the Rockies. This theme combines noon-day and dusk images from a webcam in Grand Teton National Park in Wyoming.

This theme half-way works for day images, but don't expect too much from it for week images.

Be aware that the Phenology Image Generator uses advanced composition techniques. These techniques are much more expensive in terms of computer cycles consumed than those used by the WeeWX Image Generator. Depending on the size of the background images supplied, you should expect to see the time required to produce all the charts grow by an order of magnitude or more. If you are determined to save machine cycles, you must find other smaller images than those provided by the Phenology extension.

4.7.2 Color Names

Opaque Curve Fill

Colors are specified in Phenology/skin.conf according to their X11 names that are commonly used in HTML. They may also be given as #RRGGBBAA strings, where RR, GG, and BB are the red, green, and blue components in hexadecimal, respectively, and AA is the optional alpha transparency. The 0xBBGGRR notation used in WeeWX skins continues to work, too.

Colors without an alpha channel are opaque. Suppose "fill_curve" is true. Then the default fill colors obscure one another.

[Extras]
  [[Themes]]
    [[[Current]]]
      themes = Seasons
      fill_curve = True

Transparent Curve Fill

But, if "chart_fill_colors" are defined to be transparent, then they will show through one another.

[Extras]
  [[Themes]]
    [[[Current]]]
      themes = Seasons
      fill_curve = True        
      chart_fill_colors = "#72b2c48f", "#c472728f", ...

4.7.3 Image Options

Here is a list of image options that the Phenology Image Generator recognizes. The defaults are the ones imposed by the Phenology/skin.conf, not the python script.

Name	Type	Default	Description
data_type	ID	None	Normally the stanza name specifies the variable to be plotted and is unique within each chart. This is not true when the same variable is plotted twice on the same chart with different "aggregate_type"s. "Data_type" overrides the stanza name, and, then, stanza name can be anything unique for each curve on the same chart.
label	Text	None	If given, this is used in place of the data_type in the chart title.
image_width	Pixels	500	This is the width of a chart.
image_height	Pixels	180	This is the height of a chart.
image_background_color	Color	White	This is the color of of the background around the chart.
image_background_pattern	Image	None	This is the background image, which is drawn over the "image_background_color."
image_border	Pixels	2	This is the thickness of the image border.
image_border_color	Color	None	This is the color of the image border.
chart_background_color	Color	White	This is the color of of the background inside the chart axes.
chart_background_pattern	Image	None	This is the background image, which is drawn over the "chart_background_color."
chart_border	Pixels	2	This is the thickness of the chart border.
chart_border_color	Color	None	This is the color of the chart border.
chart_gridline_color	Color	#d0d0d0	This is the color of the gridlines.
anti_alias	Integer	1	This magnification factor is applied to the chart dimensions. You can easily double the size of the chart by specifying an "anti_alias" of 2.
top_label_font_path	Font	font/OpenSans-Bold.ttf	This is the font used to display the titles of the curves on the chart.
top_label_font_size	Points	14	This is the size of the text in the top label.
unit_label_font_path	Font	font/OpenSans-Bold.ttf	This is the font used to display the y-axis label.
unit_label_font_size	Points	12	This is the size of the text in the y-axis label.
unit_label_font_color	Color	#787878	This is the color of the y-axis label.
axis_label_font_path	Font	font/OpenSans-Regular.ttf	This is the font used to display the tic labels.
axis_label_font_size	Points	10	This is the size of the text in the tic labels.
axis_label_font_color	Color	#787878	This is the color of the tic labels.
bottom_label_font_path	Font	font/OpenSans-Regular.ttf	This is the font used to display the date text at the bottom of each chart.
bottom_label_font_size	Points	12	This is size of text in the bottom label.
bottom_label_font_color	Color	"#787878	This is color of the text in the bottom label.
bottom_label_offset	Pixels	3	This is the vertical offset of the bottom label down away from the axis labels.
bottom_label_format	strftime	%x %X	This is the date format used to print the generation date at the bottom of each chart.
rose_mask	Image	icons/North_Pointer.png	This is the compass rose used on wind vector charts.
rose_color	Color	#fc402077	This is the the semi-transparent color of the compass rose on wind vector charts.
vector_rotate	Deg	90	This is the angle of North on the wind vector charts.
horizon_label_font_path	Font	font/OpenSans-Bold.ttf	This is the font used to label the development horizons.
horizon_label_font_size	Points	12	This is the size of the text on development horizons.
horizon_label_font_color	Color	DarkRed	This is the color of the text on development horizons.
horizon_label_padding	Pixels	1	This is the vertical offset of the development horizon label from the horizon line.
horizon_shading	Pixels	15	This is the vertical width of the shading gradient under the development horizon.
horizon_shading_color	Color	#ffbbbb77	This is the color of the shading gradient under the development horizon.
horizon_edge_color	Color	Red	This is the color of the development horizon line.
color	Color	None	This is the color used to draw a curve line on a chart.
chart_line_colors	Color	Tuple	These are the colors used to draw curves. These colors are also used to color-code the name of each curve in the chart title. "Color" applies to all curves. "Chart_line_colors" has multiple values for the separate curves. "Color" takes precedence.
fill_color	Color	None	This is the color used to fill bar charts and optionally line charts.
chart_fill_colors	Color	Tuple	These are the colors used to fill curves and bar plots. "Fill_color" applies to all curves. "Chart_fill_colors" has multiple values for the separate curves. "Fill_color" takes precedence.
chart_fill_pattern	Image	None	This is an image, which is drawn over the "fill_color."
marker_size	Pixels	8	This is the size of plot markers.
marker_type	Ordinal	None	This is the shape of the marker used at each data point along a curve. It may be "cross," "x," "circle," "box," or "None."
width	Pixels	1	This is the thickness of a curve on the chart. If it is greater than one, the curve line is dilated with a 3x3 kernel.
chart_line_width	Pixels	1, 1, 1	This is the thickness in pixels of curves on the chart. "Width" applies to all curves. "Chart_line_width" has multiple values for the separate curves. "Width" takes precedence.
line_gap_fraction	Ratio	0.03	Larger gaps between data points in proportion to the nominal length of the x-axis are not plotted.
show_daynight	Boolean	True	This determines whether day/night phases are illustrated in the chart.
daynight_day_color	Color	#fdfaff	This is color of the day phase of a chart with "show_daynight" before the "daynight_day_pattern" is applied.
daynight_night_color	Color	#dfdfe2	This is color of the night phase of a chart with "show_daynight" before the "daynight_night_pattern" is applied.
daynight_edge_color	Color	#e0d8d8	This is the color of a vertical line drawn on the day/night boundary.
daynight_day_pattern	Image	None	This is the background pattern for the day phase of a chart with "show_daynight." It is drawn over the "daynight_day_color."
daynight_night_pattern	Image	None	This is the background pattern for the night phase of a chart with "show_daynight." It is drawn over the "daynight_night_color."
plot_type	Ordinal	line	The Image Generator produces three kinds of plots (charts): "line," "bar," and "vector."
line_type	Ordinal	solid	Normally the Image Generator tries to plot chart curves as "solid" lines. The wind-direction charts are exceptions. They have line_type of "None."
fill_curve	Boolean	False	Normally the Image Generator does not fill the area below a curve, whereas plot_type "bar" charts are always filled.
aggregate_type	Ordinal	None	This tells how to aggregate readings for longer time scales. It may be "avg," "sum," or "max."
aggregate_interval	Seconds	None	This determines the period over which readings are aggregated for longer time scales.
time_length	Seconds	86400 (24 hrs)	This is the nominal width of the x-axis of a chart.
report_body_style	Style	None	All of the Cheetah templates that the Phenology extension provides attach the value of this option to the HTML <body> so that the style of the Web pages and the colors of the charts that appear on them can be coordinated.
x_interval	Seconds	None	This is the time spacing between tics on the x-axis.
x_label_format	strftime	None	This is the date format used to label the x-axis tics.
x_label_spacing	Integer	2	This tells how many unlabeled tics are skipped between labeled ones along the x-axis. If x_label_spacing is 2, every other tic is skipped.
yscale	Tuple	None, None, None	This is three numbers: The low limit of the y-axis, the high limit, and the interval between tics.
y_nticks	Integer	10	This is the user-recommended number of ticks along the y-axis.
y_label_side	Ordinal	Left	This determines whether the y_axis is labeled on the left side, right side, or both sides of the chart.
y_label	Text	None	This is the units label for the y-axis.
y_label_format	printf	None	This is the format of the numbers used to label the y-axis tics.
y_label_spacing	Integer	2	This tells how many unlabeled tics are skipped between labeled ones along the y-axis. If y_label_spacing is 2, every other tic is skipped.